2018-12-20 14:55:19 +01:00
<!DOCTYPE HTML>
2020-03-03 15:08:09 +01:00
< html lang = "en" class = "sidebar-visible no-js light" >
2018-12-20 14:55:19 +01:00
< head >
<!-- Book generated using mdBook -->
< meta charset = "UTF-8" >
< title > chainerror< / title >
2020-03-03 15:08:09 +01:00
< meta name = "robots" content = "noindex" / >
2020-09-01 22:00:17 +02:00
<!-- Custom HTML head -->
2018-12-21 13:55:46 +01:00
< meta name = "description" content = "A tutorial for the chainerror rust crate." >
2018-12-20 14:55:19 +01:00
< meta name = "viewport" content = "width=device-width, initial-scale=1" >
< meta name = "theme-color" content = "#ffffff" / >
2020-09-01 22:00:17 +02:00
< link rel = "icon" href = "favicon.svg" >
2018-12-20 14:55:19 +01:00
< link rel = "shortcut icon" href = "favicon.png" >
< link rel = "stylesheet" href = "css/variables.css" >
< link rel = "stylesheet" href = "css/general.css" >
< link rel = "stylesheet" href = "css/chrome.css" >
< link rel = "stylesheet" href = "css/print.css" media = "print" >
<!-- Fonts -->
< link rel = "stylesheet" href = "FontAwesome/css/font-awesome.css" >
2020-09-01 22:00:17 +02:00
< link rel = "stylesheet" href = "fonts/fonts.css" >
2018-12-20 14:55:19 +01:00
<!-- Highlight.js Stylesheets -->
< link rel = "stylesheet" href = "highlight.css" >
< link rel = "stylesheet" href = "tomorrow-night.css" >
< link rel = "stylesheet" href = "ayu-highlight.css" >
<!-- Custom theme stylesheets -->
< / head >
2020-03-03 15:08:09 +01:00
< body >
2023-07-28 17:17:23 +02:00
< div id = "body-container" >
2018-12-20 14:55:19 +01:00
<!-- Provide site root to javascript -->
2023-07-28 17:17:23 +02:00
< script >
2018-12-20 14:55:19 +01:00
var path_to_root = "";
2020-09-01 22:00:17 +02:00
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light";
2018-12-20 14:55:19 +01:00
< / script >
<!-- Work around some values being stored in localStorage wrapped in quotes -->
2023-07-28 17:17:23 +02:00
< script >
2018-12-20 14:55:19 +01:00
try {
var theme = localStorage.getItem('mdbook-theme');
var sidebar = localStorage.getItem('mdbook-sidebar');
if (theme.startsWith('"') & & theme.endsWith('"')) {
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
}
if (sidebar.startsWith('"') & & sidebar.endsWith('"')) {
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
}
} catch (e) { }
< / script >
<!-- Set the theme before any content is loaded, prevents flash -->
2023-07-28 17:17:23 +02:00
< script >
2018-12-20 14:55:19 +01:00
var theme;
2020-03-03 15:08:09 +01:00
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
2018-12-20 14:55:19 +01:00
if (theme === null || theme === undefined) { theme = default_theme; }
2020-03-03 15:08:09 +01:00
var html = document.querySelector('html');
html.classList.remove('no-js')
html.classList.remove('light')
html.classList.add(theme);
html.classList.add('js');
2018-12-20 14:55:19 +01:00
< / script >
<!-- Hide / unhide sidebar before it is displayed -->
2023-07-28 17:17:23 +02:00
< script >
2018-12-20 14:55:19 +01:00
var html = document.querySelector('html');
2023-07-28 17:17:23 +02:00
var sidebar = null;
2018-12-20 14:55:19 +01:00
if (document.body.clientWidth >= 1080) {
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
sidebar = sidebar || 'visible';
2023-07-28 17:17:23 +02:00
} else {
sidebar = 'hidden';
2018-12-20 14:55:19 +01:00
}
html.classList.remove('sidebar-visible');
html.classList.add("sidebar-" + sidebar);
< / script >
< nav id = "sidebar" class = "sidebar" aria-label = "Table of contents" >
2020-09-01 22:00:17 +02:00
< div class = "sidebar-scrollbox" >
< ol class = "chapter" > < li class = "chapter-item expanded affix " > < a href = "index.html" > chainerror< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial1.html" > < strong aria-hidden = "true" > 1.< / strong > Simple String Errors< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial2.html" > < strong aria-hidden = "true" > 2.< / strong > Simple Chained String Errors< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial3.html" > < strong aria-hidden = "true" > 3.< / strong > Mapping Errors< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial4.html" > < strong aria-hidden = "true" > 4.< / strong > More Information< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial5.html" > < strong aria-hidden = "true" > 5.< / strong > The source() of Errors< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial6.html" > < strong aria-hidden = "true" > 6.< / strong > Downcast the Errors< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial7.html" > < strong aria-hidden = "true" > 7.< / strong > The root cause of all Errors< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial8.html" > < strong aria-hidden = "true" > 8.< / strong > Finding an Error cause< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial9.html" > < strong aria-hidden = "true" > 9.< / strong > Selective Error Handling< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial10.html" > < strong aria-hidden = "true" > 10.< / strong > ErrorKind to the rescue< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial11.html" > < strong aria-hidden = "true" > 11.< / strong > Debug for the ErrorKind< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial12.html" > < strong aria-hidden = "true" > 12.< / strong > Deref for the ErrorKind< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial13.html" > < strong aria-hidden = "true" > 13.< / strong > Writing a library< / a > < / li > < li class = "chapter-item expanded " > < a href = "tutorial14.html" > < strong aria-hidden = "true" > 14.< / strong > Going back to std< / a > < / li > < li class = "chapter-item expanded affix " > < a href = "end.html" > The End< / a > < / li > < / ol >
2020-03-03 15:08:09 +01:00
< / div >
< div id = "sidebar-resize-handle" class = "sidebar-resize-handle" > < / div >
2018-12-20 14:55:19 +01:00
< / nav >
2023-07-28 17:17:23 +02:00
<!-- Track and set sidebar scroll position -->
< script >
var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox');
sidebarScrollbox.addEventListener('click', function(e) {
if (e.target.tagName === 'A') {
sessionStorage.setItem('sidebar-scroll', sidebarScrollbox.scrollTop);
}
}, { passive: true });
var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll');
sessionStorage.removeItem('sidebar-scroll');
if (sidebarScrollTop) {
// preserve sidebar scroll position when navigating via links within sidebar
sidebarScrollbox.scrollTop = sidebarScrollTop;
} else {
// scroll sidebar to current active section when navigating via "next/previous chapter" buttons
var activeSection = document.querySelector('#sidebar .active');
if (activeSection) {
activeSection.scrollIntoView({ block: 'center' });
}
}
< / script >
2018-12-20 14:55:19 +01:00
< div id = "page-wrapper" class = "page-wrapper" >
< div class = "page" >
2023-07-28 17:17:23 +02:00
< div id = "menu-bar-hover-placeholder" > < / div >
< div id = "menu-bar" class = "menu-bar sticky" >
2020-09-01 22:00:17 +02:00
< div class = "left-buttons" >
< button id = "sidebar-toggle" class = "icon-button" type = "button" title = "Toggle Table of Contents" aria-label = "Toggle Table of Contents" aria-controls = "sidebar" >
< i class = "fa fa-bars" > < / i >
< / button >
< button id = "theme-toggle" class = "icon-button" type = "button" title = "Change theme" aria-label = "Change theme" aria-haspopup = "true" aria-expanded = "false" aria-controls = "theme-list" >
< i class = "fa fa-paint-brush" > < / i >
< / button >
< ul id = "theme-list" class = "theme-popup" aria-label = "Themes" role = "menu" >
2023-07-28 17:17:23 +02:00
< li role = "none" > < button role = "menuitem" class = "theme" id = "light" > Light< / button > < / li >
2020-09-01 22:00:17 +02:00
< li role = "none" > < button role = "menuitem" class = "theme" id = "rust" > Rust< / button > < / li >
< li role = "none" > < button role = "menuitem" class = "theme" id = "coal" > Coal< / button > < / li >
< li role = "none" > < button role = "menuitem" class = "theme" id = "navy" > Navy< / button > < / li >
< li role = "none" > < button role = "menuitem" class = "theme" id = "ayu" > Ayu< / button > < / li >
< / ul >
< button id = "search-toggle" class = "icon-button" type = "button" title = "Search. (Shortkey: s)" aria-label = "Toggle Searchbar" aria-expanded = "false" aria-keyshortcuts = "S" aria-controls = "searchbar" >
< i class = "fa fa-search" > < / i >
< / button >
< / div >
< h1 class = "menu-title" > chainerror< / h1 >
< div class = "right-buttons" >
< a href = "print.html" title = "Print this book" aria-label = "Print this book" >
< i id = "print-button" class = "fa fa-print" > < / i >
< / a >
2023-07-28 17:17:23 +02:00
2018-12-20 14:55:19 +01:00
< / div >
< / div >
< div id = "search-wrapper" class = "hidden" >
< form id = "searchbar-outer" class = "searchbar-outer" >
2023-07-28 17:17:23 +02:00
< input type = "search" id = "searchbar" name = "searchbar" placeholder = "Search this book ..." aria-controls = "searchresults-outer" aria-describedby = "searchresults-header" >
2018-12-20 14:55:19 +01:00
< / form >
< div id = "searchresults-outer" class = "searchresults-outer hidden" >
< div id = "searchresults-header" class = "searchresults-header" > < / div >
< ul id = "searchresults" >
< / ul >
< / div >
< / div >
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
2023-07-28 17:17:23 +02:00
< script >
2018-12-20 14:55:19 +01:00
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
});
< / script >
< div id = "content" class = "content" >
< main >
2020-09-01 22:00:17 +02:00
< p > < a href = "https://crates.io/crates/chainerror" > < img src = "https://img.shields.io/crates/v/chainerror.svg" alt = "Crate" / > < / a >
< a href = "https://docs.rs/chainerror/" > < img src = "https://img.shields.io/badge/api-rustdoc-blue.svg" alt = "Rust Documentation" / > < / a >
2023-07-28 17:17:23 +02:00
< a href = "https://codecov.io/gh/haraldh/chainerror" > < img src = "https://codecov.io/gh/haraldh/chainerror/branch/master/graph/badge.svg?token=HGLJFGA11B" alt = "Coverage Status" / > < / a >
2020-09-01 22:00:17 +02:00
< img src = "https://img.shields.io/badge/maintenance-activly--developed-brightgreen.svg" alt = "Maintenance" / > < / p >
2023-07-28 17:17:23 +02:00
< h1 id = "chainerror" > < a class = "header" href = "#chainerror" > chainerror< / a > < / h1 >
2020-09-01 22:00:17 +02:00
< p > < code > chainerror< / code > provides an error backtrace without doing a real backtrace, so even after you < code > strip< / code > your
2018-12-21 13:55:46 +01:00
binaries, you still have the error backtrace.< / p >
2020-09-01 23:09:36 +02:00
< p > Having nested function returning errors, the output doesn't tell where the error originates from.< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > use std::path::PathBuf;
2020-09-01 22:00:17 +02:00
2020-09-01 23:09:36 +02:00
type BoxedError = Box< dyn std::error::Error + Send + Sync> ;
fn read_config_file(path: PathBuf) -> Result< (), BoxedError> {
// do stuff, return other errors
let _buf = std::fs::read_to_string(& path)?;
// do stuff, return other errors
2020-09-01 22:00:17 +02:00
Ok(())
}
2018-12-21 13:55:46 +01:00
2020-09-01 23:09:36 +02:00
fn process_config_file() -> Result< (), BoxedError> {
// do stuff, return other errors
let _buf = read_config_file(" foo.txt" .into())?;
// do stuff, return other errors
2020-09-01 22:00:17 +02:00
Ok(())
}
2018-12-21 13:55:46 +01:00
2020-09-01 23:09:36 +02:00
fn main() {
if let Err(e) = process_config_file() {
eprintln!(" Error:\n{:?}" , e);
}
2023-07-28 17:17:23 +02:00
}< / code > < / pre > < / pre >
2020-09-01 23:09:36 +02:00
< p > This gives the output:< / p >
< pre > < code class = "language-console" > Error:
Os { code: 2, kind: NotFound, message: " No such file or directory" }
< / code > < / pre >
< p > and you have no idea where it comes from.< / p >
< p > With < code > chainerror< / code > , you can supply a context and get a nice error backtrace:< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2020-09-01 23:09:36 +02:00
use std::path::PathBuf;
2018-12-21 13:55:46 +01:00
2020-09-01 23:09:36 +02:00
type BoxedError = Box< dyn std::error::Error + Send + Sync> ;
fn read_config_file(path: PathBuf) -> Result< (), BoxedError> {
// do stuff, return other errors
let _buf = std::fs::read_to_string(& path).context(format!(" Reading file: {:?}" , & path))?;
// do stuff, return other errors
2018-12-21 13:55:46 +01:00
Ok(())
}
2020-09-01 23:09:36 +02:00
fn process_config_file() -> Result< (), BoxedError> {
// do stuff, return other errors
let _buf = read_config_file(" foo.txt" .into()).context(" read the config file" )?;
// do stuff, return other errors
2018-12-21 13:55:46 +01:00
Ok(())
}
2020-09-01 23:09:36 +02:00
fn main() {
if let Err(e) = process_config_file() {
eprintln!(" Error:\n{:?}" , e);
2018-12-21 13:55:46 +01:00
}
2023-07-28 17:17:23 +02:00
}< / code > < / pre > < / pre >
2020-09-01 23:09:36 +02:00
< p > with the output:< / p >
< pre > < code class = "language-console" > Error:
examples/simple.rs:14:51: read the config file
2020-09-01 22:00:17 +02:00
Caused by:
2020-09-01 23:09:36 +02:00
examples/simple.rs:7:47: Reading file: " foo.txt"
2020-09-01 22:00:17 +02:00
Caused by:
2020-09-01 23:09:36 +02:00
Os { code: 2, kind: NotFound, message: " No such file or directory" }
< / code > < / pre >
< p > < code > chainerror< / code > uses < code > .source()< / code > of < code > std::error::Error< / code > along with < code > #[track_caller]< / code > and < code > Location< / code > to provide a nice debug error backtrace.
It encapsulates all types, which have < code > Display + Debug< / code > and can store the error cause internally.< / p >
2023-07-28 17:17:23 +02:00
< p > Along with the < code > Error< T> < / code > struct, < code > chainerror< / code > comes with some useful helper macros to save a lot of typing.< / p >
2020-09-01 23:09:36 +02:00
< p > < code > chainerror< / code > has no dependencies!< / p >
< p > Debug information is worth it!< / p >
2023-07-28 17:17:23 +02:00
< h2 id = "multiple-output-formats" > < a class = "header" href = "#multiple-output-formats" > Multiple Output Formats< / a > < / h2 >
< p > < code > chainerror< / code > supports multiple output formats, which can be selected with the different format specifiers:< / p >
< ul >
< li > < code > {}< / code > : Display< / li >
< / ul >
< pre > < code class = "language-console" > func1 error calling func2
< / code > < / pre >
< ul >
< li > < code > {:#}< / code > : Alternative Display< / li >
< / ul >
< pre > < code class = "language-console" > func1 error calling func2
Caused by:
func2 error: calling func3
Caused by:
(passed error)
Caused by:
Error reading 'foo.txt'
Caused by:
entity not found
< / code > < / pre >
< ul >
< li > < code > {:?}< / code > : Debug< / li >
< / ul >
< pre > < code class = "language-console" > examples/example.rs:50:13: func1 error calling func2
Caused by:
examples/example.rs:25:13: Func2Error(func2 error: calling func3)
Caused by:
examples/example.rs:18:13: (passed error)
Caused by:
examples/example.rs:13:18: Error reading 'foo.txt'
Caused by:
Kind(NotFound)
< / code > < / pre >
< ul >
< li > < code > {:#?}< / code > : Alternative Debug< / li >
< / ul >
< pre > < code class = "language-console" > Error< example::Func1Error> {
occurrence: Some(
" examples/example.rs:50:13" ,
),
kind: func1 error calling func2,
source: Some(
Error< example::Func2Error> {
occurrence: Some(
" examples/example.rs:25:13" ,
),
kind: Func2Error(func2 error: calling func3),
source: Some(
Error< chainerror::AnnotatedError> {
occurrence: Some(
" examples/example.rs:18:13" ,
),
kind: (passed error),
source: Some(
Error< alloc::string::String> {
occurrence: Some(
" examples/example.rs:13:18" ,
),
kind: " Error reading 'foo.txt'" ,
source: Some(
Kind(
NotFound,
),
),
},
),
},
),
},
),
}
< / code > < / pre >
< h2 id = "tutorial" > < a class = "header" href = "#tutorial" > Tutorial< / a > < / h2 >
2020-09-01 23:09:36 +02:00
< p > Read the < a href = "https://haraldh.github.io/chainerror/tutorial1.html" > Tutorial< / a > < / p >
2023-07-28 17:17:23 +02:00
< h2 id = "license" > < a class = "header" href = "#license" > License< / a > < / h2 >
2020-09-01 22:00:17 +02:00
< p > Licensed under either of< / p >
< ul >
2023-07-28 17:17:23 +02:00
< li > Apache License, Version 2.0, (< a href = "LICENSE-APACHE" > LICENSE-APACHE< / a > or < a href = "https://www.apache.org/licenses/LICENSE-2.0" > https://www.apache.org/licenses/LICENSE-2.0< / a > )< / li >
< li > MIT license (< a href = "LICENSE-MIT" > LICENSE-MIT< / a > or < a href = "https://opensource.org/licenses/MIT" > https://opensource.org/licenses/MIT< / a > )< / li >
2020-09-01 22:00:17 +02:00
< / ul >
< p > at your option.< / p >
2023-07-28 17:17:23 +02:00
< h3 id = "contribution" > < a class = "header" href = "#contribution" > Contribution< / a > < / h3 >
2020-09-01 22:00:17 +02:00
< p > Unless you explicitly state otherwise, any contribution intentionally
submitted for inclusion in the work by you, as defined in the Apache-2.0
license, shall be dual licensed as above, without any additional terms or
conditions.< / p >
2023-07-28 17:17:23 +02:00
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "simple-string-errors" > < a class = "header" href = "#simple-string-errors" > Simple String Errors< / a > < / h1 >
2018-12-21 13:55:46 +01:00
< p > An easy way of doing error handling in rust is by returning < code > String< / code > as a < code > Box< std::error::Error> < / code > .< / p >
< p > If the rust < code > main< / code > function returns an < code > Err()< / code > , this < code > Err()< / code > will be displayed with < code > std::fmt::Debug< / code > .< / p >
2020-03-03 15:08:09 +01:00
< p > As you can see by running the example (by pressing the " Play" button in upper right of the code block),
this only
2018-12-20 16:37:43 +01:00
prints out the last < code > Error< / code > .< / p >
2020-09-01 22:00:17 +02:00
< pre > < code > Error: " func1 error"
2018-12-21 13:55:46 +01:00
< / code > < / pre >
< p > The next chapters of this tutorial show how < code > chainerror< / code > adds more information
and improves inspecting the sources of an error.< / p >
2020-03-03 15:08:09 +01:00
< p > You can also run the tutorial examples in the checked out
2018-12-21 13:55:46 +01:00
< a href = "https://github.com/haraldh/chainerror" > chainerror git repo< / a > .< / p >
2020-03-03 15:16:51 +01:00
< pre > < code class = "language-console" > $ cargo run -q --example tutorial1
2018-12-21 13:55:46 +01:00
< / code > < / pre >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > #![allow(clippy::single_match)]
#![allow(clippy::redundant_pattern_matching)]
use std::error::Error;
2018-12-21 13:55:46 +01:00
use std::io;
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-21 13:55:46 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(_) = do_some_io() {
Err(" func2 error" )?;
}
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(_) = func2() {
Err(" func1 error" )?;
}
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
func1()
2023-07-28 17:17:23 +02:00
}< / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "simple-chained-string-errors" > < a class = "header" href = "#simple-chained-string-errors" > Simple Chained String Errors< / a > < / h1 >
2020-09-01 22:00:17 +02:00
< p > With relatively small changes and the help of the < code > context()< / code > method of the < code > chainerror< / code > crate
the < code > & str< / code > errors are now chained together.< / p >
2018-12-20 15:12:59 +01:00
< p > Press the play button in the upper right corner and see the nice debug output.< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2018-12-21 13:55:46 +01:00
2018-12-20 14:55:19 +01:00
use std::error::Error;
2018-12-21 13:55:46 +01:00
use std::io;
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-21 13:55:46 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = do_some_io() {
2020-09-01 22:00:17 +02:00
Err(e).context(" func2 error" )?;
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func2() {
2020-09-01 22:00:17 +02:00
Err(e).context(" func1 error" )?;
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
func1()
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// use std::io;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< h3 id = "what-did-we-do-here" > < a class = "header" href = "#what-did-we-do-here" > What did we do here?< / a > < / h3 >
< pre > < code class = "language-rust ignore" > Err(e).context(" func2 error" )?;
2018-12-20 16:02:24 +01:00
}
2023-07-28 17:17:23 +02:00
Ok(())< / code > < / pre >
2020-09-01 22:00:17 +02:00
< p > The function < code > context(newerror)< / code > stores < code > olderror< / code > as the source/cause of < code > newerror< / code >
along with the < code > Location< / code > of the < code > context()< / code > call and returns < code > Err(newerror)< / code > .< / p >
< p > < code > ?< / code > then returns the inner error applying < code > .into()< / code > , so that we
2020-03-03 15:08:09 +01:00
again have a < code > Err(Box< Error + Send + Sync> )< / code > as a result.< / p >
2023-07-28 17:17:23 +02:00
< p > The < code > Debug< / code > implementation of < code > chainerror::Error< T> < / code > (which is returned by < code > context()< / code > )
2018-12-20 16:02:24 +01:00
prints the < code > Debug< / code > of < code > T< / code > prefixed with the stored filename and line number.< / p >
2023-07-28 17:17:23 +02:00
< p > < code > chainerror::Error< T> < / code > in our case is < code > chainerror::Error< & str> < / code > .< / p >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "mapping-errors" > < a class = "header" href = "#mapping-errors" > Mapping Errors< / a > < / h1 >
2020-09-01 22:00:17 +02:00
< p > Now let's get more rust idiomatic by using < code > .context()< / code > directly on the previous < code > Result< / code > .< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2018-12-21 13:55:46 +01:00
2018-12-20 14:55:19 +01:00
use std::error::Error;
2018-12-21 13:55:46 +01:00
use std::io;
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-21 13:55:46 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2020-09-01 22:00:17 +02:00
do_some_io().context(" func2 error" )?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2020-09-01 22:00:17 +02:00
func2().context(" func1 error" )?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
eprintln!(" {:?}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
2018-12-20 16:02:24 +01:00
< p > If you compare the output to the previous example, you will see,
that:< / p >
2023-07-28 17:17:23 +02:00
< pre > < code > Error: examples/tutorial2.rs:20:16: func1 error
2018-12-20 16:02:24 +01:00
< / code > < / pre >
< p > changed to just:< / p >
2023-07-28 17:17:23 +02:00
< pre > < code > examples/tutorial3.rs:17:13: func1 error
2018-12-20 16:02:24 +01:00
< / code > < / pre >
< p > This is, because we caught the error of < code > func1()< / code > in < code > main()< / code > and print it out ourselves.< / p >
< p > We can now control, whether to output in < code > Debug< / code > or < code > Display< / code > mode.
Maybe depending on < code > --debug< / code > as a CLI argument.< / p >
2023-07-28 17:17:23 +02:00
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "more-information" > < a class = "header" href = "#more-information" > More information< / a > < / h1 >
2020-09-01 22:00:17 +02:00
< p > To give more context to the error, you want to use < code > format!< / code >
to extend the information in the context string.< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2018-12-20 14:55:19 +01:00
use std::error::Error;
2018-12-21 13:55:46 +01:00
use std::io;
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-21 13:55:46 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 16:02:24 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(format!(" Error reading '{}'" , filename))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2020-09-01 22:00:17 +02:00
func2().context(" func1 error" )?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
eprintln!(" {:?}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "the-source-of-errors" > < a class = "header" href = "#the-source-of-errors" > The source() of Errors< / a > < / h1 >
2018-12-20 16:02:24 +01:00
< p > Sometimes you want to inspect the < code > source()< / code > of an < code > Error< / code > .
< code > chainerror< / code > implements < code > std::error::Error::source()< / code > , so you can get the cause of an error.< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2018-12-20 14:55:19 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(format!(" Error reading '{}'" , filename))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func2() {
if let Some(s) = e.source() {
eprintln!(" func2 failed because of '{}'" , s);
2020-09-01 22:00:17 +02:00
Err(e).context(" func1 error" )?;
2018-12-20 14:55:19 +01:00
}
}
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
eprintln!(" {}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
2020-03-03 15:08:09 +01:00
< p > Note, that because we changed the output of the error in < code > main()< / code > from
2018-12-21 13:55:46 +01:00
< code > Debug< / code > to < code > Display< / code > , we don't see the error backtrace with filename and line number.< / p >
2023-07-28 17:17:23 +02:00
< p > To use the < code > Display< / code > backtrace, you have to use the alternative display format output < code > {:#}< / code > .< / p >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "downcast-the-errors" > < a class = "header" href = "#downcast-the-errors" > Downcast the Errors< / a > < / h1 >
2020-03-03 15:08:09 +01:00
< p > < code > std::error::Error< / code > comes with some helper methods to get to the original object of the
2018-12-21 13:55:46 +01:00
< code > & (dyn Error + 'static)< / code > returned by < code > .source()< / code > .< / p >
< pre > < code class = "language-rust ignore" > pub fn downcast_ref< T: Error + 'static> (& self) -> Option< & T>
2023-07-28 17:17:23 +02:00
pub fn downcast_mut< T: Error + 'static> (& mut self) -> Option< & mut T> < / code > < / pre >
2018-12-21 13:55:46 +01:00
< p > This is how it looks like, when using those:< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > #![allow(clippy::single_match)]
#![allow(clippy::redundant_pattern_matching)]
use chainerror::Context as _;
2018-12-20 14:55:19 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(format!(" Error reading '{}'" , filename))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2020-09-01 22:00:17 +02:00
func2().context(" func1 error" )?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
eprintln!(" Error: {}" , e);
2020-03-03 15:16:51 +01:00
let mut s: & (dyn Error) = e.as_ref();
2018-12-20 14:55:19 +01:00
while let Some(c) = s.source() {
if let Some(ioerror) = c.downcast_ref::< io::Error> () {
eprintln!(" caused by: std::io::Error: {}" , ioerror);
match ioerror.kind() {
io::ErrorKind::NotFound => eprintln!(" of kind: std::io::ErrorKind::NotFound" ),
_ => {}
}
} else {
eprintln!(" caused by: {}" , c);
}
s = c;
}
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "the-root-cause-of-all-errors" > < a class = "header" href = "#the-root-cause-of-all-errors" > The root cause of all Errors< / a > < / h1 >
2018-12-21 13:55:46 +01:00
< p > < code > chainerror< / code > also has some helper methods:< / p >
< pre > < code class = "language-rust ignore" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool
2023-07-28 17:17:23 +02:00
fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & chainerror::Error< T> >
fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut chainerror::Error< T> >
2018-12-21 13:55:46 +01:00
fn root_cause(& self) -> Option< & (dyn Error + 'static)>
fn find_cause< U: Error + 'static> (& self) -> Option< & U>
2023-07-28 17:17:23 +02:00
fn find_chain_cause< U: Error + 'static> (& self) -> Option< & chainerror::Error< U> >
fn kind< 'a> (& 'a self) -> & 'a T< / code > < / pre >
< p > Using < code > downcast_chain_ref::< String> ()< / code > gives a < code > chainerror::Error< String> < / code > , which can be used
2020-03-03 15:08:09 +01:00
to call < code > .find_cause::< io::Error> ()< / code > . < / p >
2018-12-21 13:55:46 +01:00
< pre > < code class = "language-rust ignore" > if let Some(s) = e.downcast_chain_ref::< String> () {
2023-07-28 17:17:23 +02:00
if let Some(ioerror) = s.find_cause::< io::Error> () {< / code > < / pre >
2018-12-21 13:55:46 +01:00
< p > or to use < code > .root_cause()< / code > , which of course can be of any type implementing < code > std::error::Error< / code > .< / p >
2023-07-28 17:17:23 +02:00
< pre > < code class = "language-rust ignore" > if let Some(e) = s.root_cause() {< / code > < / pre >
< pre > < pre class = "playground" > < code class = "language-rust" > #![allow(clippy::single_match)]
#![allow(clippy::redundant_pattern_matching)]
use chainerror::{Context as _, ErrorDown as _};
2018-12-20 14:55:19 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(format!(" Error reading '{}'" , filename))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
func2().context(" func1 error" )?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
eprintln!(" Error: {}" , e);
if let Some(s) = e.downcast_chain_ref::< String> () {
if let Some(ioerror) = s.find_cause::< io::Error> () {
eprintln!(" caused by: std::io::Error: {}" , ioerror);
match ioerror.kind() {
io::ErrorKind::NotFound => eprintln!(" of kind: std::io::ErrorKind::NotFound" ),
_ => {}
}
}
if let Some(e) = s.root_cause() {
let ioerror = e.downcast_ref::< io::Error> ().unwrap();
eprintln!(" The root cause was: std::io::Error: {:#?}" , ioerror);
}
}
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "finding-an-error-cause" > < a class = "header" href = "#finding-an-error-cause" > Finding an Error cause< / a > < / h1 >
< p > To distinguish the errors occurring in various places, we can define named string errors with the
2018-12-21 13:55:46 +01:00
" new type" pattern.< / p >
2023-07-28 17:17:23 +02:00
< pre > < code class = "language-rust ignore" > chainerror::str_context!(Func2Error);
chainerror::str_context!(Func1Error);< / code > < / pre >
< p > Instead of < code > chainerror::Error< String> < / code > we now have < code > struct Func1Error(String)< / code > and < code > chainerror::Error< Func1Error> < / code > .< / p >
2018-12-21 13:55:46 +01:00
< p > In the < code > main< / code > function you can see, how we can match the different errors.< / p >
< p > Also see:< / p >
2023-07-28 17:17:23 +02:00
< pre > < code class = "language-rust ignore" > if let Some(f2err) = f1err.find_chain_cause::< Func2Error> () {< / code > < / pre >
2018-12-21 13:55:46 +01:00
< p > as a shortcut to< / p >
2023-07-28 17:17:23 +02:00
< pre > < code class = "language-rust ignore" > if let Some(f2err) = f1err.find_cause::< chainerror::Error< Func2Error> > () {< / code > < / pre >
< p > hiding the < code > chainerror::Error< T> < / code > implementation detail.< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::{Context as _, ErrorDown as _};
2018-12-20 14:55:19 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func2Error);
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func1Error);
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
func2().context(Func1Error::new(" func1 error" ))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
eprintln!(" Func1Error: {}" , f1err);
2023-07-28 17:17:23 +02:00
if let Some(f2err) = f1err.find_cause::< chainerror::Error< Func2Error> > () {
2018-12-20 14:55:19 +01:00
eprintln!(" Func2Error: {}" , f2err);
}
if let Some(f2err) = f1err.find_chain_cause::< Func2Error> () {
eprintln!(" Debug Func2Error:\n{:?}" , f2err);
}
}
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "selective-error-handling" > < a class = "header" href = "#selective-error-handling" > Selective Error Handling< / a > < / h1 >
2018-12-21 13:55:46 +01:00
< p > What about functions returning different Error types?< / p >
< p > In this example < code > func1()< / code > can return either < code > Func1ErrorFunc2< / code > or < code > Func1ErrorIO< / code > .< / p >
< p > We might want to < code > match< / code > on < code > func1()< / code > with something like:< / p >
2020-03-03 15:08:09 +01:00
< pre > < code class = "language-rust ignore" > fn main() -> Result< (), Box< Error + Send + Sync> > {
2018-12-21 13:55:46 +01:00
match func1() {
Err(e) if let Some(s) = e.downcast_chain_ref::< Func1ErrorIO> () =>
eprintln!(" Func1ErrorIO:\n{:?}" , s),
Err(e) if let Some(s) = e.downcast_chain_ref::< Func1ErrorFunc2> () =>
eprintln!(" Func1ErrorFunc2:\n{:?}" , s),
Ok(_) => {},
}
Ok(())
2023-07-28 17:17:23 +02:00
}< / code > < / pre >
2018-12-21 13:55:46 +01:00
< p > but this is not valid rust code, so we end up doing it the hard way.
In the next chapter, we will see, how to solve this more elegantly.< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::{Context as _, ErrorDown};
2018-12-20 14:55:19 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func2Error);
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func1ErrorFunc2);
chainerror::str_context!(Func1ErrorIO);
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
func2().context(Func1ErrorFunc2::new(" func1 error calling func2" ))?;
2018-12-20 14:55:19 +01:00
let filename = " bar.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(Func1ErrorIO(format!(" Error reading '{}'" , filename)))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
2023-07-28 17:17:23 +02:00
if let Some(s) = e.downcast_ref::< chainerror::Error< Func1ErrorIO> > () {
2018-12-20 14:55:19 +01:00
eprintln!(" Func1ErrorIO:\n{:?}" , s);
}
2018-12-21 13:55:46 +01:00
if let Some(s) = e.downcast_chain_ref::< Func1ErrorFunc2> () {
2018-12-20 14:55:19 +01:00
eprintln!(" Func1ErrorFunc2:\n{:?}" , s);
}
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "errorkind-to-the-rescue" > < a class = "header" href = "#errorkind-to-the-rescue" > ErrorKind to the rescue< / a > < / h1 >
< p > To cope with different kind of errors, we introduce the < code > kind< / code > of an error < code > Func1ErrorKind< / code > with an enum.< / p >
2018-12-21 13:55:46 +01:00
< p > Because we derive < code > Debug< / code > and implement < code > Display< / code > our < code > Func1ErrorKind< / code > enum, this enum can be used as
a < code > std::error::Error< / code > .< / p >
2020-03-03 15:08:09 +01:00
< p > Only returning < code > Func1ErrorKind< / code > in < code > func1()< / code > now let us get rid of < code > Result< (), Box< Error + Send + Sync> > < / code > and we can
2018-12-21 13:55:46 +01:00
use < code > ChainResult< (), Func1ErrorKind> < / code > .< / p >
2023-07-28 17:17:23 +02:00
< p > In < code > main< / code > we can now directly use the methods of < code > chainerror::Error< T> < / code > without downcasting the error first.< / p >
< p > Also, a nice < code > match< / code > on < code > chainerror::Error< T> .kind()< / code > is now possible, which returns < code > & T< / code > , meaning < code > & Func1ErrorKind< / code > here.< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2018-12-20 14:55:19 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func2Error);
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
#[derive(Debug)]
2018-12-21 13:55:46 +01:00
enum Func1ErrorKind {
2018-12-20 14:55:19 +01:00
Func2,
IO(String),
}
2018-12-21 13:55:46 +01:00
impl ::std::fmt::Display for Func1ErrorKind {
2018-12-20 14:55:19 +01:00
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
match self {
2018-12-21 13:55:46 +01:00
Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
2018-12-20 14:55:19 +01:00
}
}
}
2019-02-07 09:02:01 +01:00
impl ::std::error::Error for Func1ErrorKind {}
2018-12-20 14:55:19 +01:00
2023-07-28 17:17:23 +02:00
fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
func2().context(Func1ErrorKind::Func2)?;
2018-12-20 14:55:19 +01:00
let filename = String::from(" bar.txt" );
2020-09-01 22:00:17 +02:00
do_some_io().context(Func1ErrorKind::IO(filename))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
match e.kind() {
2018-12-21 13:55:46 +01:00
Func1ErrorKind::Func2 => eprintln!(" Main Error Report: func1 error calling func2" ),
Func1ErrorKind::IO(filename) => {
2018-12-20 14:55:19 +01:00
eprintln!(" Main Error Report: func1 error reading '{}'" , filename)
}
}
if let Some(e) = e.find_chain_cause::< Func2Error> () {
2018-12-21 13:55:46 +01:00
eprintln!(" \nError reported by Func2Error: {}" , e)
2018-12-20 14:55:19 +01:00
}
eprintln!(" \nDebug Error:\n{:?}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "debug-for-the-errorkind" > < a class = "header" href = "#debug-for-the-errorkind" > Debug for the ErrorKind< / a > < / h1 >
2020-09-01 22:00:17 +02:00
< p > One small improvement is to fix the debug output of
2019-02-07 09:02:01 +01:00
< code > Func1ErrorKind< / code > . As you probably noticed, the output doesn't say much of the enum.< / p >
< pre > < code > Debug Error:
src/main.rs:35: Func2
[…]
< / code > < / pre >
< p > As a lazy shortcut, we implement < code > Debug< / code > by calling < code > Display< / code > and end up with< / p >
< pre > < code > Debug Error:
src/main.rs:40: func1 error calling func2
[…}
< / code > < / pre >
< p > which gives us a lot more detail.< / p >
< p > To create your own Errors, you might find < a href = "https://crates.io" > crates< / a > which create enum < code > Display+Debug< / code > via derive macros.< / p >
2023-07-28 17:17:23 +02:00
< p > Also, noteworthy is < a href = "https://crates.io/crates/custom_error" > custom_error< / a > to define your custom errors,
2019-02-07 09:02:01 +01:00
which can then be used with < code > chainerror< / code > .< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2019-02-07 09:02:01 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2019-02-07 09:02:01 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func2Error);
2019-02-07 09:02:01 +01:00
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2019-02-07 09:02:01 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2019-02-07 09:02:01 +01:00
Ok(())
}
enum Func1ErrorKind {
Func2,
IO(String),
}
impl ::std::fmt::Display for Func1ErrorKind {
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
match self {
Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
}
}
}
impl ::std::fmt::Debug for Func1ErrorKind {
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
write!(f, " {}" , self)
}
}
impl ::std::error::Error for Func1ErrorKind {}
2023-07-28 17:17:23 +02:00
fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
func2().context(Func1ErrorKind::Func2)?;
2019-02-07 09:02:01 +01:00
let filename = String::from(" bar.txt" );
2020-09-01 22:00:17 +02:00
do_some_io().context(Func1ErrorKind::IO(filename))?;
2019-02-07 09:02:01 +01:00
Ok(())
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2019-02-07 09:02:01 +01:00
if let Err(e) = func1() {
match e.kind() {
Func1ErrorKind::Func2 => eprintln!(" Main Error Report: func1 error calling func2" ),
Func1ErrorKind::IO(filename) => {
eprintln!(" Main Error Report: func1 error reading '{}'" , filename)
}
}
if let Some(e) = e.find_chain_cause::< Func2Error> () {
eprintln!(" \nError reported by Func2Error: {}" , e)
}
eprintln!(" \nDebug Error:\n{:?}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2019-02-07 09:02:01 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "deref-for-the-errorkind" > < a class = "header" href = "#deref-for-the-errorkind" > Deref for the ErrorKind< / a > < / h1 >
< p > Because chainerror::Error< T > implements Deref to & T, we can also match on < code > *e< / code > instead of < code > e.kind()< / code >
2019-02-07 09:02:01 +01:00
or call a function with < code > & e< / code > < / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > use chainerror::Context as _;
2018-12-20 14:55:19 +01:00
use std::error::Error;
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func2Error);
2018-12-20 14:55:19 +01:00
2020-03-03 15:16:51 +01:00
fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2018-12-21 13:55:46 +01:00
enum Func1ErrorKind {
2018-12-20 14:55:19 +01:00
Func2,
IO(String),
}
2018-12-21 13:55:46 +01:00
impl ::std::fmt::Display for Func1ErrorKind {
2018-12-20 14:55:19 +01:00
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
match self {
2018-12-21 13:55:46 +01:00
Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
2018-12-20 14:55:19 +01:00
}
}
}
2018-12-21 13:55:46 +01:00
impl ::std::fmt::Debug for Func1ErrorKind {
2018-12-20 14:55:19 +01:00
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
write!(f, " {}" , self)
}
}
2019-02-07 09:02:01 +01:00
impl ::std::error::Error for Func1ErrorKind {}
2023-07-28 17:17:23 +02:00
fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
func2().context(Func1ErrorKind::Func2)?;
2018-12-20 14:55:19 +01:00
let filename = String::from(" bar.txt" );
2020-09-01 22:00:17 +02:00
do_some_io().context(Func1ErrorKind::IO(filename))?;
2018-12-20 14:55:19 +01:00
Ok(())
}
2019-02-07 09:02:01 +01:00
fn handle_func1errorkind(e: & Func1ErrorKind) {
match e {
Func1ErrorKind::Func2 => eprintln!(" Main Error Report: func1 error calling func2" ),
Func1ErrorKind::IO(ref filename) => {
eprintln!(" Main Error Report: func1 error reading '{}'" , filename)
}
}
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn Error + Send + Sync> > {
2018-12-20 14:55:19 +01:00
if let Err(e) = func1() {
2019-02-07 09:02:01 +01:00
match *e {
2018-12-21 13:55:46 +01:00
Func1ErrorKind::Func2 => eprintln!(" Main Error Report: func1 error calling func2" ),
2019-02-07 09:02:01 +01:00
Func1ErrorKind::IO(ref filename) => {
2018-12-20 14:55:19 +01:00
eprintln!(" Main Error Report: func1 error reading '{}'" , filename)
}
}
2019-02-07 09:02:01 +01:00
handle_func1errorkind(& e);
2018-12-20 14:55:19 +01:00
if let Some(e) = e.find_chain_cause::< Func2Error> () {
2018-12-21 13:55:46 +01:00
eprintln!(" \nError reported by Func2Error: {}" , e)
2018-12-20 14:55:19 +01:00
}
eprintln!(" \nDebug Error:\n{:?}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2018-12-20 14:55:19 +01:00
}
Ok(())
}
2020-03-03 15:08:09 +01:00
< span class = "boring" > #[allow(dead_code)]
< / span > < span class = "boring" > mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > }< / span > < / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "writing-a-library" > < a class = "header" href = "#writing-a-library" > Writing a library< / a > < / h1 >
< p > I would advise to only expose an < code > mycrate::ErrorKind< / code > and type alias < code > mycrate::Error< / code > to < code > chainerror::Error< mycrate::ErrorKind> < / code >
2019-03-04 11:46:17 +01:00
so you can tell your library users to use the < code > .kind()< / code > method as < code > std::io::Error< / code > does.< / p >
< p > If you later decide to make your own < code > Error< / code > implementation, your library users don't
have to change much or anything.< / p >
2020-09-01 22:00:17 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > < span class = "boring" > #[allow(dead_code)]
2020-03-03 15:08:09 +01:00
< / span > < span class = "boring" > #[macro_use]
< / span > < span class = "boring" > pub mod chainerror {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #![doc = include_str!(" ../README.md" )]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(clippy::all)]
2020-09-01 23:09:36 +02:00
< / span > < span class = "boring" > #![allow(clippy::needless_doctest_main)]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > #![deny(missing_docs)]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > use std::any::TypeId;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > use std::error::Error as StdError;
< / span > < span class = "boring" > use std::fmt::{Debug, Display, Formatter};
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > use std::panic::Location;
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// chains an inner error kind `T` with a causing error
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// convenience type alias
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub type Result< O, E> = std::result::Result< O, Error< E> > ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Error< T> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Use the `context()` or `map_context()` Result methods instead of calling this directly
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn new(
< / span > < span class = "boring" > kind: T,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > error_cause: Option< Box< dyn StdError + 'static + Send + Sync> > ,
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > occurrence: Option< String> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ) -> Self {
< / span > < span class = "boring" > Self {
< / span > < span class = "boring" > occurrence,
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > error_cause,
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// return the root cause of the error chain, if any exists
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn root_cause(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter().last()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Find the first error cause of type U, if any exists
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
< / span > < span class = "boring" > /// use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error + Send + Sync> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
< / span > < span class = "boring" > /// assert!(f1err.find_cause::< io::Error> ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_cause< U: StdError + 'static> (& self) -> Option< & U> {
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< U> )
< / span > < span class = "boring" > .next()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error), if any exists
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooError);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooError> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooError> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_chain_cause::< FooError> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_chain_cause< U: StdError + 'static> (& self) -> Option< & Error< U> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .filter_map(< dyn StdError> ::downcast_ref::< Error< U> > )
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Find the first error cause of type [`Error< U> `](Error) or `U`, if any exists and return `U`
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Same as `find_cause` and `find_chain_cause`, but hides the [`Error< U> `](Error) implementation internals
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # chainerror::str_context!(FooErrorKind);
< / span > < span class = "boring" > /// # let err = chainerror::Error::new(String::new(), None, None);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // Instead of writing
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// err.find_cause::< chainerror::Error< FooErrorKind> > ();
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_chain_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// // and/or
< / span > < span class = "boring" > /// err.find_cause::< FooErrorKind> ();
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// // leave out the chainerror::Error< FooErrorKind> implementation detail
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// err.find_kind_or_cause::< FooErrorKind> ();
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn find_kind_or_cause< U: StdError + 'static> (& self) -> Option< & U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.iter()
< / span > < span class = "boring" > .filter_map(|e| {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > e.downcast_ref::< Error< U> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .map(|e| e.kind())
< / span > < span class = "boring" > .or_else(|| e.downcast_ref::< U> ())
< / span > < span class = "boring" > })
< / span > < span class = "boring" > .next()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Return a reference to T of [`Error< T> `](Error)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::error::Error;
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func2() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug)]
< / span > < span class = "boring" > /// enum Func1ErrorKind {
< / span > < span class = "boring" > /// Func2,
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
< / span > < span class = "boring" > /// # impl ::std::fmt::Display for Func1ErrorKind {
< / span > < span class = "boring" > /// # fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > /// # match self {
< / span > < span class = "boring" > /// # Func1ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
< / span > < span class = "boring" > /// # Func1ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func1() -> chainerror::Result< (), Func1ErrorKind> {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// func2().context(Func1ErrorKind::Func2)?;
< / span > < span class = "boring" > /// do_some_io().context(Func1ErrorKind::IO(" bar.txt" .into()))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// if let Err(e) = func1() {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// Func1ErrorKind::Func2 => {}
< / span > < span class = "boring" > /// Func1ErrorKind::IO(filename) => panic!(),
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > pub fn kind(& self) -> & T {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Returns an Iterator over all error causes/sources
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Example
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub fn iter(& self) -> impl Iterator< Item = & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ErrorIter {
< / span > < span class = "boring" > current: Some(self),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience methods for `Result< > ` to turn the error into a decorated [`Error`](Error)
< / span > < span class = "boring" > pub trait Context< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// Decorate the error with a `kind` of type `T` and the source `Location`
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the error just with the source `Location`
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Decorate the `error` with a `kind` of type `T` produced with a `FnOnce(& error)` and the source `Location`
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > ;
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// Convenience type to just decorate the error with the source `Location`
< / span > < span class = "boring" > pub struct AnnotatedError(());
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Display for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl Debug for AnnotatedError {
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
< / span > < span class = "boring" > write!(f, " (passed error)" )
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< O, E: Into< Box< dyn StdError + 'static + Send + Sync> > > Context< O, E>
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > for std::result::Result< O, E>
< / span > < span class = "boring" > {
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn context< T: 'static + Display + Debug> (self, kind: T) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn annotate(self) -> std::result::Result< O, Error< AnnotatedError> > {
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => Err(Error::new(
< / span > < span class = "boring" > AnnotatedError(()),
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > )),
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[track_caller]
< / span > < span class = "boring" > #[inline]
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > fn map_context< T: 'static + Display + Debug, F: FnOnce(& E) -> T> (
< / span > < span class = "boring" > self,
< / span > < span class = "boring" > op: F,
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > ) -> std::result::Result< O, Error< T> > {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > match self {
< / span > < span class = "boring" > Ok(t) => Ok(t),
< / span > < span class = "boring" > Err(error_cause) => {
< / span > < span class = "boring" > let kind = op(& error_cause);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Err(Error::new(
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > kind,
< / span > < span class = "boring" > Some(error_cause.into()),
< / span > < span class = "boring" > Some(Location::caller().to_string()),
< / span > < span class = "boring" > ))
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > /// An iterator over all error causes/sources
< / span > < span class = "boring" > pub struct ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > current: Option< & 'a (dyn StdError + 'static)> ,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl< 'a> Iterator for ErrorIter< 'a> {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > type Item = & 'a (dyn StdError + 'static);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn next(& mut self) -> Option< Self::Item> {
< / span > < span class = "boring" > let current = self.current;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.current = self.current.and_then(StdError::source);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > current
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> std::ops::Deref for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > type Target = T;
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn deref(& self) -> & Self::Target {
< / span > < span class = "boring" > & self.kind
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Convenience trait to hide the [`Error< T> `](Error) implementation internals
< / span > < span class = "boring" > pub trait ErrorDown {
< / span > < span class = "boring" > /// Test if of type `Error< T> `
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool;
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Downcast to a reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > ;
< / span > < span class = "boring" > /// Downcast to a mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > ;
< / span > < span class = "boring" > /// Downcast to T of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> ;
< / span > < span class = "boring" > /// Downcast to T mutable reference of `Error< T> `
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> ;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< U: 'static + Display + Debug> ErrorDown for Error< U> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
< / span > < span class = "boring" > TypeId::of::< T> () == TypeId::of::< U> ()
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(*(self as *const dyn StdError as *const & Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut *(self as *mut dyn StdError as *mut & mut Error< T> ))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& (*(self as *const dyn StdError as *const & Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is_chain::< T> () {
< / span > < span class = "boring" > #[allow(clippy::cast_ptr_alignment)]
< / span > < span class = "boring" > unsafe {
< / span > < span class = "boring" > #[allow(trivial_casts)]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > Some(& mut (*(self as *mut dyn StdError as *mut & mut Error< T> )).kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > None
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl ErrorDown for dyn StdError + 'static + Send + Sync {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
< / span > < span class = "boring" > fn is_chain< T: 'static + Display + Debug> (& self) -> bool {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.is::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_ref< T: 'static + Display + Debug> (& self) -> Option< & Error< T> > {
< / span > < span class = "boring" > self.downcast_ref::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_chain_mut< T: 'static + Display + Debug> (& mut self) -> Option< & mut Error< T> > {
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_ref< T: 'static + StdError> (& self) -> Option< & T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.downcast_ref::< T> ()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .or_else(|| self.downcast_ref::< Error< T> > ().map(|e| e.kind()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn downcast_inner_mut< T: 'static + StdError> (& mut self) -> Option< & mut T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if self.is::< T> () {
< / span > < span class = "boring" > return self.downcast_mut::< T> ();
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > self.downcast_mut::< Error< T> > ()
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > .and_then(|e| e.downcast_inner_mut::< T> ())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> StdError for & mut Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn StdError + 'static)> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > self.error_cause
< / span > < span class = "boring" > .as_ref()
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > .map(|e| e.as_ref() as & (dyn StdError + 'static))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Display for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > write!(f, " {}" , self.kind)?;
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > if f.alternate() {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n {:#}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" >
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > Ok(())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T: 'static + Display + Debug> Debug for Error< T> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn fmt(& self, f: & mut Formatter< '_> ) -> std::fmt::Result {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if f.alternate() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > let mut f = f.debug_struct(& format!(" Error< {}> " , std::any::type_name::< T> ()));
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > let f = f
< / span > < span class = "boring" > .field(" occurrence" , & self.occurrence)
< / span > < span class = "boring" > .field(" kind" , & self.kind)
< / span > < span class = "boring" > .field(" source" , & self.source());
< / span > < span class = "boring" >
< / span > < span class = "boring" > f.finish()
< / span > < span class = "boring" > } else {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > if let Some(ref o) = self.occurrence {
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > write!(f, " {}: " , o)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > if TypeId::of::< String> () == TypeId::of::< T> ()
< / span > < span class = "boring" > || TypeId::of::< & str> () == TypeId::of::< T> ()
< / span > < span class = "boring" > {
< / span > < span class = "boring" > Display::fmt(& self.kind, f)?;
< / span > < span class = "boring" > } else {
< / span > < span class = "boring" > Debug::fmt(& self.kind, f)?;
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > if let Some(e) = self.source() {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > write!(f, " \nCaused by:\n{:?}" , & e)?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > Ok(())
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl< T> From< T> for Error< T>
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > where
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > T: 'static + Display + Debug,
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > #[track_caller]
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > #[inline]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > fn from(e: T) -> Error< T> {
< / span > < span class = "boring" > Error::new(e, None, Some(Location::caller().to_string()))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > /// Convenience macro to create a " new type" T(String) and implement Display + Debug for T
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # use chainerror::Context as _;
< / span > < span class = "boring" > /// # use chainerror::ErrorDown as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # use std::error::Error;
< / span > < span class = "boring" > /// # use std::io;
< / span > < span class = "boring" > /// # use std::result::Result;
< / span > < span class = "boring" > /// # fn do_some_io() -> Result< (), Box< dyn Error + Send + Sync> > {
< / span > < span class = "boring" > /// # Err(io::Error::from(io::ErrorKind::NotFound))?;
< / span > < span class = "boring" > /// # Ok(())
< / span > < span class = "boring" > /// # }
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func2Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// fn func2() -> chainerror::Result< (), Func2Error> {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::str_context!(Func1Error);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn func1() -> Result< (), Box< dyn Error> > {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// func2().context(Func1Error::new(" func1 error" ))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// # if let Err(e) = func1() {
< / span > < span class = "boring" > /// # if let Some(f1err) = e.downcast_chain_ref::< Func1Error> () {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// # assert!(f1err.find_cause::< chainerror::Error< Func2Error> > ().is_some());
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// # assert!(f1err.find_chain_cause::< Func2Error> ().is_some());
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # panic!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// # } else {
< / span > < span class = "boring" > /// # unreachable!();
< / span > < span class = "boring" > /// # }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! str_context {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident) => {
< / span > < span class = "boring" > #[derive(Clone)]
< / span > < span class = "boring" > pub struct $e(pub String);
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn new< S: Into< String> > (s: S) -> Self {
< / span > < span class = "boring" > $e(s.into())
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > impl ::std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}" , self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut ::std::fmt::Formatter) -> ::std::fmt::Result {
< / span > < span class = "boring" > write!(f, " {}({})" , stringify!($e), self.0)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > impl ::std::error::Error for $e {}
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// Derive an Error for an ErrorKind, which wraps a [`Error`](Error) and implements a `kind()` method
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// It basically hides [`Error`](Error) to the outside and only exposes the [`kind()`](Error::kind)
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// method.
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// Error::kind() returns the ErrorKind
< / span > < span class = "boring" > /// Error::source() returns the parent error
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// # Examples
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// ```rust
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// use chainerror::Context as _;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// use std::io;
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// fn do_some_io(_f: & str) -> std::result::Result< (), io::Error> {
< / span > < span class = "boring" > /// return Err(io::Error::from(io::ErrorKind::NotFound));
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// #[derive(Debug, Clone)]
< / span > < span class = "boring" > /// pub enum ErrorKind {
< / span > < span class = "boring" > /// IO(String),
< / span > < span class = "boring" > /// FatalError(String),
< / span > < span class = "boring" > /// Unknown,
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > /// chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl std::fmt::Display for ErrorKind {
< / span > < span class = "boring" > /// fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > /// match self {
< / span > < span class = "boring" > /// ErrorKind::FatalError(e) => write!(f, " fatal error {}" , e),
< / span > < span class = "boring" > /// ErrorKind::Unknown => write!(f, " unknown error" ),
< / span > < span class = "boring" > /// ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl ErrorKind {
< / span > < span class = "boring" > /// fn from_io_error(e: & io::Error, f: String) -> Self {
< / span > < span class = "boring" > /// match e.kind() {
< / span > < span class = "boring" > /// io::ErrorKind::BrokenPipe => panic!(" Should not happen" ),
< / span > < span class = "boring" > /// io::ErrorKind::ConnectionReset => {
< / span > < span class = "boring" > /// ErrorKind::FatalError(format!(" While reading `{}`: {}" , f, e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// _ => ErrorKind::IO(f),
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// impl From< & io::Error> for ErrorKind {
< / span > < span class = "boring" > /// fn from(e: & io::Error) -> Self {
< / span > < span class = "boring" > /// ErrorKind::IO(format!(" {}" , e))
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > ///
< / span > < span class = "boring" > /// pub fn func1() -> std::result::Result< (), Error> {
< / span > < span class = "boring" > /// let filename = " bar.txt" ;
< / span > < span class = "boring" > ///
2020-09-01 22:00:17 +02:00
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from_io_error(e, filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::IO(filename.into()))?;
< / span > < span class = "boring" > /// do_some_io(filename).map_context(|e| ErrorKind::from(e))?;
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > /// Ok(())
< / span > < span class = "boring" > /// }
< / span > < span class = "boring" > /// ```
< / span > < span class = "boring" > #[macro_export]
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > macro_rules! err_kind {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > ($e:ident, $k:ident) => {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > pub struct $e($crate::Error< $k> );
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl $e {
< / span > < span class = "boring" > pub fn kind(& self) -> & $k {
< / span > < span class = "boring" > self.0.kind()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< $k> for $e {
< / span > < span class = "boring" > fn from(e: $k) -> Self {
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > $e($crate::Error::new(e, None, None))
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
2023-07-28 17:17:23 +02:00
< / span > < span class = "boring" > impl From< $crate::Error< $k> > for $e {
< / span > < span class = "boring" > fn from(e: $crate::Error< $k> ) -> Self {
2020-03-03 15:16:51 +01:00
< / span > < span class = "boring" > $e(e)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl From< & $e> for $k
< / span > < span class = "boring" > where
< / span > < span class = "boring" > $k: Clone,
< / span > < span class = "boring" > {
< / span > < span class = "boring" > fn from(e: & $e) -> Self {
< / span > < span class = "boring" > e.kind().clone()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::error::Error for $e {
< / span > < span class = "boring" > fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
< / span > < span class = "boring" > self.0.source()
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Display for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Display::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" >
< / span > < span class = "boring" > impl std::fmt::Debug for $e {
< / span > < span class = "boring" > fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
< / span > < span class = "boring" > std::fmt::Debug::fmt(& self.0, f)
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
< / span > < span class = "boring" > };
< / span > < span class = "boring" > }
< / span > < span class = "boring" > }
2020-03-03 15:08:09 +01:00
< / span > pub mod mycrate {
2019-03-04 11:46:17 +01:00
use crate::chainerror::*; // omit the `crate::` part
2023-07-28 17:17:23 +02:00
pub mod mycrate {
use chainerror::Context as _;
2019-03-04 11:46:17 +01:00
use std::io;
2020-03-03 15:16:51 +01:00
fn do_some_io() -> std::result::Result< (), Box< dyn std::error::Error + Send + Sync> > {
2019-03-04 11:46:17 +01:00
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
2023-07-28 17:17:23 +02:00
chainerror::str_context!(Func2Error);
2019-03-04 11:46:17 +01:00
2020-03-03 15:16:51 +01:00
fn func2() -> std::result::Result< (), Box< dyn std::error::Error + Send + Sync> > {
2019-03-04 11:46:17 +01:00
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().context(Func2Error(format!(" Error reading '{}'" , filename)))?;
2019-03-04 11:46:17 +01:00
Ok(())
}
2020-03-03 15:08:09 +01:00
#[derive(Debug, Clone)]
2019-03-04 11:46:17 +01:00
pub enum ErrorKind {
Func2,
IO(String),
}
2023-07-28 17:17:23 +02:00
chainerror::err_kind!(Error, ErrorKind);
2020-03-03 15:08:09 +01:00
2019-03-04 11:46:17 +01:00
pub type Result< T> = std::result::Result< T, Error> ;
2020-03-03 15:08:09 +01:00
impl std::fmt::Display for ErrorKind {
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
2019-03-04 11:46:17 +01:00
match self {
ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
}
}
}
pub fn func1() -> Result< ()> {
2020-09-01 22:00:17 +02:00
func2().context(ErrorKind::Func2)?;
2019-03-04 11:46:17 +01:00
let filename = String::from(" bar.txt" );
2020-09-01 22:00:17 +02:00
do_some_io().context(ErrorKind::IO(filename))?;
2019-03-04 11:46:17 +01:00
Ok(())
}
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn std::error::Error + Send + Sync> > {
2019-03-04 11:46:17 +01:00
use mycrate::func1;
use mycrate::ErrorKind;
use std::error::Error;
use std::io;
if let Err(e) = func1() {
match e.kind() {
ErrorKind::Func2 => eprintln!(" Main Error Report: func1 error calling func2" ),
ErrorKind::IO(ref filename) => {
eprintln!(" Main Error Report: func1 error reading '{}'" , filename)
}
}
eprintln!();
2020-03-03 15:16:51 +01:00
let mut s: & dyn Error = & e;
2019-03-04 11:46:17 +01:00
while let Some(c) = s.source() {
if let Some(ioerror) = c.downcast_ref::< io::Error> () {
eprintln!(" caused by: std::io::Error: {}" , ioerror);
match ioerror.kind() {
io::ErrorKind::NotFound => eprintln!(" of kind: std::io::ErrorKind::NotFound" ),
_ => {}
}
} else {
eprintln!(" caused by: {}" , c);
}
s = c;
}
eprintln!(" \nDebug Error:\n{:?}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2019-03-04 11:46:17 +01:00
}
Ok(())
2023-07-28 17:17:23 +02:00
}< / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "going-back-to-std" > < a class = "header" href = "#going-back-to-std" > Going back to std< / a > < / h1 >
2020-03-03 15:08:09 +01:00
< p > Not using < code > chainerror< / code > and going full < code > std< / code > would look like this:< / p >
< p > Btw, the code size is bigger than using < code > chainerror< / code > :-)< / p >
2023-07-28 17:17:23 +02:00
< pre > < pre class = "playground" > < code class = "language-rust" > #![allow(clippy::single_match)]
#![allow(clippy::redundant_pattern_matching)]
pub mod mycrate {
2020-03-03 15:08:09 +01:00
use std::error::Error as StdError;
2020-09-01 22:00:17 +02:00
use self::func2mod::{do_some_io, func2};
2020-03-03 15:08:09 +01:00
pub mod func2mod {
use std::error::Error as StdError;
use std::io;
pub enum ErrorKind {
IO(String),
}
impl std::fmt::Display for ErrorKind {
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
match self {
ErrorKind::IO(s) => std::fmt::Display::fmt(s, f),
}
}
}
impl std::fmt::Debug for ErrorKind {
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
match self {
ErrorKind::IO(s) => std::fmt::Display::fmt(s, f),
}
}
}
2020-09-01 22:00:17 +02:00
macro_rules! mcontext {
2020-03-03 15:08:09 +01:00
( $k:expr ) => {{
|e| {
Error(
$k,
Some(Box::from(e)),
Some(concat!(file!(), " :" , line!(), " : " )),
)
}
}};
}
pub struct Error(
ErrorKind,
Option< Box< dyn std::error::Error + 'static> > ,
Option< & 'static str> ,
);
impl Error {
pub fn kind(& self) -> & ErrorKind {
& self.0
}
}
impl From< ErrorKind> for Error {
fn from(e: ErrorKind) -> Self {
Error(e, None, None)
}
}
impl std::error::Error for Error {
fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
self.1.as_ref().map(|e| e.as_ref())
}
}
impl std::fmt::Display for Error {
fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
std::fmt::Display::fmt(& self.0, f)
}
}
impl std::fmt::Debug for Error {
fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
if let Some(ref o) = self.2 {
std::fmt::Display::fmt(o, f)?;
}
std::fmt::Debug::fmt(& self.0, f)?;
if let Some(e) = self.source() {
std::fmt::Display::fmt(" \nCaused by:\n" , f)?;
std::fmt::Debug::fmt(& e, f)?;
}
Ok(())
}
}
pub fn do_some_io() -> std::result::Result< (), Box< dyn std::error::Error> > {
Err(io::Error::from(io::ErrorKind::NotFound))?;
Ok(())
}
pub fn func2() -> std::result::Result< (), Error> {
let filename = " foo.txt" ;
2020-09-01 22:00:17 +02:00
do_some_io().map_err(mcontext!(ErrorKind::IO(format!(
2020-03-03 15:08:09 +01:00
" Error reading '{}'" ,
filename
))))?;
Ok(())
}
}
#[derive(Debug)]
pub enum ErrorKind {
Func2,
IO(String),
}
impl std::fmt::Display for ErrorKind {
fn fmt(& self, f: & mut ::std::fmt::Formatter) -> std::fmt::Result {
match self {
ErrorKind::Func2 => write!(f, " func1 error calling func2" ),
ErrorKind::IO(filename) => write!(f, " Error reading '{}'" , filename),
}
}
}
2020-09-01 22:00:17 +02:00
macro_rules! mcontext {
2020-03-03 15:08:09 +01:00
( $k:expr ) => {{
|e| {
Error(
$k,
Some(Box::from(e)),
Some(concat!(file!(), " :" , line!(), " : " )),
)
}
}};
}
pub struct Error(
ErrorKind,
Option< Box< dyn std::error::Error + 'static> > ,
Option< & 'static str> ,
);
impl Error {
pub fn kind(& self) -> & ErrorKind {
& self.0
}
}
impl From< ErrorKind> for Error {
fn from(e: ErrorKind) -> Self {
Error(e, None, None)
}
}
impl std::error::Error for Error {
fn source(& self) -> Option< & (dyn std::error::Error + 'static)> {
self.1.as_ref().map(|e| e.as_ref())
}
}
impl std::fmt::Display for Error {
fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
std::fmt::Display::fmt(& self.0, f)
}
}
impl std::fmt::Debug for Error {
fn fmt(& self, f: & mut std::fmt::Formatter) -> std::fmt::Result {
if let Some(ref o) = self.2 {
std::fmt::Display::fmt(o, f)?;
}
std::fmt::Debug::fmt(& self.0, f)?;
if let Some(e) = self.source() {
std::fmt::Display::fmt(" \nCaused by:\n" , f)?;
std::fmt::Debug::fmt(& e, f)?;
}
Ok(())
}
}
pub type Result< T> = std::result::Result< T, Error> ;
pub fn func1() -> Result< ()> {
2020-09-01 22:00:17 +02:00
func2().map_err(mcontext!(ErrorKind::Func2))?;
2020-03-03 15:08:09 +01:00
let filename = String::from(" bar.txt" );
2020-09-01 22:00:17 +02:00
do_some_io().map_err(mcontext!(ErrorKind::IO(filename)))?;
2020-03-03 15:08:09 +01:00
Ok(())
}
}
2020-03-03 15:16:51 +01:00
fn main() -> Result< (), Box< dyn std::error::Error + Send + Sync> > {
2020-03-03 15:08:09 +01:00
use mycrate::func1;
use mycrate::ErrorKind;
use std::error::Error;
use std::io;
if let Err(e) = func1() {
match e.kind() {
ErrorKind::Func2 => eprintln!(" Main Error Report: func1 error calling func2" ),
ErrorKind::IO(ref filename) => {
eprintln!(" Main Error Report: func1 error reading '{}'" , filename)
}
}
eprintln!();
2020-03-03 15:16:51 +01:00
let mut s: & dyn Error = & e;
2020-03-03 15:08:09 +01:00
while let Some(c) = s.source() {
if let Some(ioerror) = c.downcast_ref::< io::Error> () {
eprintln!(" caused by: std::io::Error: {}" , ioerror);
match ioerror.kind() {
io::ErrorKind::NotFound => eprintln!(" of kind: std::io::ErrorKind::NotFound" ),
_ => {}
}
} else {
eprintln!(" caused by: {}" , c);
}
s = c;
}
eprintln!(" \nDebug Error:\n{:?}" , e);
2020-09-01 22:00:17 +02:00
std::process::exit(1);
2020-03-03 15:08:09 +01:00
}
Ok(())
2023-07-28 17:17:23 +02:00
}< / code > < / pre > < / pre >
< div style = "break-before: page; page-break-before: always;" > < / div > < h1 id = "the-end" > < a class = "header" href = "#the-end" > The End< / a > < / h1 >
2018-12-21 13:55:46 +01:00
< p > That's it for now…< / p >
< p > Happy error handling!< / p >
2018-12-21 14:07:02 +01:00
< p > To report issues, submit pull request or for the source code, examples and the book source, visit
the < a href = "https://github.com/haraldh/chainerror" > Git Repo< / a > .< / p >
2018-12-20 14:55:19 +01:00
< / main >
< nav class = "nav-wrapper" aria-label = "Page navigation" >
<!-- Mobile navigation buttons -->
< div style = "clear: both" > < / div >
< / nav >
< / div >
< / div >
< nav class = "nav-wide-wrapper" aria-label = "Page navigation" >
< / nav >
< / div >
2020-09-01 22:00:17 +02:00
2023-07-28 17:17:23 +02:00
< script >
2020-09-01 22:00:17 +02:00
window.playground_copyable = true;
2020-03-03 15:08:09 +01:00
< / script >
2018-12-20 14:55:19 +01:00
2023-07-28 17:17:23 +02:00
< script src = "elasticlunr.min.js" > < / script >
< script src = "mark.min.js" > < / script >
< script src = "searcher.js" > < / script >
2018-12-20 14:55:19 +01:00
2023-07-28 17:17:23 +02:00
< script src = "clipboard.min.js" > < / script >
< script src = "highlight.js" > < / script >
< script src = "book.js" > < / script >
2018-12-20 14:55:19 +01:00
<!-- Custom JS scripts -->
2023-07-28 17:17:23 +02:00
< script >
2018-12-20 14:55:19 +01:00
window.addEventListener('load', function() {
window.setTimeout(window.print, 100);
});
< / script >
2023-07-28 17:17:23 +02:00
< / div >
2018-12-20 14:55:19 +01:00
< / body >
< / html >
