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<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html" class="active">The End</a></li></ol>
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<p>That's it for now…</p>
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129
index.html
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<!-- Book generated using mdBook -->
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<meta charset="UTF-8">
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<title>Chapter 1 - chainerror</title>
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<title>chainerror - chainerror</title>
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<nav id="sidebar" class="sidebar" aria-label="Table of contents">
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<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
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<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
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@ -140,37 +140,116 @@
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<div id="content" class="content">
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<div id="content" class="content">
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<main>
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<main>
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<a class="header" href="#simple-string-errors" id="simple-string-errors"><h1>Simple String Errors</h1></a>
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<a class="header" href="#chainerror" id="chainerror"><h1>chainerror</h1></a>
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<p>The most simplest of doing error handling in rust is by returning <code>String</code> as a <code>Box<Error></code>.</p>
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<p><code>chainerror</code> provides an error backtrace like <code>failure</code> without doing a real backtrace, so even after you <code>strip</code> your
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<p>As you can see by running the example (the "Play" button in upper right of the code block), this only
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binaries, you still have the error backtrace.</p>
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prints out the last <code>Error</code>.</p>
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<p><code>chainerror</code> has no dependencies!</p>
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<p>If the rust <code>main</code> function returns an Err(), this Err() will be displayed with <code>std::fmt::Debug</code>.</p>
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<p><code>chainerror</code> uses <code>.source()</code> of <code>std::error::Error</code> along with <code>line()!</code> and <code>file()!</code> to provide a nice debug error backtrace.
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<pre><pre class="playpen"><code class="language-rust">use std::error::Error;
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It encapsulates all types, which have <code>Display + Debug</code> and can store the error cause internally.</p>
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<p>Along with the <code>ChainError<T></code> struct, <code>chainerror</code> comes with some useful helper macros to save a lot of typing.</p>
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<p>Debug information is worth it!</p>
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<p>Now continue reading the
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<a href="https://haraldh.github.io/chainerror/tutorial1.html">Tutorial</a></p>
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<a class="header" href="#example" id="example"><h2>Example:</h2></a>
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<p>Output:</p>
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<pre><code>$ cargo run -q --example example
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Main Error Report: func1 error calling func2
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Error reported by Func2Error: func2 error: calling func3
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The root cause was: std::io::Error: Kind(
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NotFound
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)
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Debug Error:
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examples/example.rs:45: func1 error calling func2
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Caused by:
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examples/example.rs:20: Func2Error(func2 error: calling func3)
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Caused by:
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examples/example.rs:13: Error reading 'foo.txt'
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Caused by:
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Kind(NotFound)
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</code></pre>
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<pre><code class="language-rust ignore">use chainerror::*;
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use std::error::Error;
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use std::io;
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use std::result::Result;
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use std::result::Result;
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fn do_some_io() -> Result<(), Box<Error>> {
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fn do_some_io() -> Result<(), Box<Error>> {
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Err("do_some_io error")?;
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Err(io::Error::from(io::ErrorKind::NotFound))?;
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Ok(())
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Ok(())
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}
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}
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fn func2() -> Result<(), Box<Error>> {
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fn func3() -> Result<(), Box<Error>> {
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if let Err(_) = do_some_io() {
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let filename = "foo.txt";
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Err("func2 error")?;
|
do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
Ok(())
|
||||||
|
}
|
||||||
|
|
||||||
|
derive_str_cherr!(Func2Error);
|
||||||
|
|
||||||
|
fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
Ok(())
|
||||||
|
}
|
||||||
|
|
||||||
|
enum Func1Error {
|
||||||
|
Func2,
|
||||||
|
IO(String),
|
||||||
|
}
|
||||||
|
|
||||||
|
impl ::std::fmt::Display for Func1Error {
|
||||||
|
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
match self {
|
||||||
|
Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
}
|
}
|
||||||
Ok(())
|
|
||||||
}
|
|
||||||
|
|
||||||
fn func1() -> Result<(), Box<Error>> {
|
|
||||||
if let Err(_) = func2() {
|
|
||||||
Err("func1 error")?;
|
|
||||||
}
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
impl ::std::fmt::Debug for Func1Error {
|
||||||
|
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
write!(f, "{}", self)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
let filename = String::from("bar.txt");
|
||||||
|
do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
fn main() -> Result<(), Box<Error>> {
|
fn main() {
|
||||||
func1()
|
if let Err(e) = func1() {
|
||||||
|
match e.kind() {
|
||||||
|
Func1Error::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
|
||||||
|
Func1Error::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)
|
||||||
|
}
|
||||||
|
|
||||||
|
if let Some(e) = e.root_cause() {
|
||||||
|
let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
}
|
||||||
|
|
||||||
|
eprintln!("\nDebug Error:\n{:?}", e);
|
||||||
|
}
|
||||||
}
|
}
|
||||||
</code></pre></pre>
|
|
||||||
|
</code></pre>
|
||||||
|
<a class="header" href="#features" id="features"><h2>Features</h2></a>
|
||||||
|
<p><code>no-fileline</code>
|
||||||
|
: completely turn off storing filename and line</p>
|
||||||
|
<p><code>display-cause</code>
|
||||||
|
: turn on printing a backtrace of the errors in <code>Display</code></p>
|
||||||
|
<p><code>no-debug-cause</code>
|
||||||
|
: turn off printing a backtrace of the errors in <code>Debug</code></p>
|
||||||
|
|
||||||
</main>
|
</main>
|
||||||
|
|
||||||
|
|
@ -198,12 +277,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
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<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
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|
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|
|
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|
|
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|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
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|
|
|
||||||
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|
|
@ -1 +0,0 @@
|
||||||
ace.define("ace/theme/dawn",["require","exports","module","ace/lib/dom"],function(e,t,n){t.isDark=!1,t.cssClass="ace-dawn",t.cssText=".ace-dawn .ace_gutter {background: #ebebeb;color: #333}.ace-dawn .ace_print-margin {width: 1px;background: #e8e8e8}.ace-dawn {background-color: #F9F9F9;color: #080808}.ace-dawn .ace_cursor {color: #000000}.ace-dawn .ace_marker-layer .ace_selection {background: rgba(39, 95, 255, 0.30)}.ace-dawn.ace_multiselect .ace_selection.ace_start {box-shadow: 0 0 3px 0px #F9F9F9;}.ace-dawn .ace_marker-layer .ace_step {background: rgb(255, 255, 0)}.ace-dawn .ace_marker-layer .ace_bracket {margin: -1px 0 0 -1px;border: 1px solid rgba(75, 75, 126, 0.50)}.ace-dawn .ace_marker-layer .ace_active-line {background: rgba(36, 99, 180, 0.12)}.ace-dawn .ace_gutter-active-line {background-color : #dcdcdc}.ace-dawn .ace_marker-layer .ace_selected-word {border: 1px solid rgba(39, 95, 255, 0.30)}.ace-dawn .ace_invisible {color: rgba(75, 75, 126, 0.50)}.ace-dawn .ace_keyword,.ace-dawn .ace_meta {color: #794938}.ace-dawn .ace_constant,.ace-dawn .ace_constant.ace_character,.ace-dawn .ace_constant.ace_character.ace_escape,.ace-dawn .ace_constant.ace_other {color: #811F24}.ace-dawn .ace_invalid.ace_illegal {text-decoration: underline;font-style: italic;color: #F8F8F8;background-color: #B52A1D}.ace-dawn .ace_invalid.ace_deprecated {text-decoration: underline;font-style: italic;color: #B52A1D}.ace-dawn .ace_support {color: #691C97}.ace-dawn .ace_support.ace_constant {color: #B4371F}.ace-dawn .ace_fold {background-color: #794938;border-color: #080808}.ace-dawn .ace_list,.ace-dawn .ace_markup.ace_list,.ace-dawn .ace_support.ace_function {color: #693A17}.ace-dawn .ace_storage {font-style: italic;color: #A71D5D}.ace-dawn .ace_string {color: #0B6125}.ace-dawn .ace_string.ace_regexp {color: #CF5628}.ace-dawn .ace_comment {font-style: italic;color: #5A525F}.ace-dawn .ace_heading,.ace-dawn .ace_markup.ace_heading {color: #19356D}.ace-dawn .ace_variable {color: #234A97}.ace-dawn .ace_indent-guide {background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAACCAYAAACZgbYnAAAAEklEQVQImWNgYGBgYLh/5+x/AAizA4hxNNsZAAAAAElFTkSuQmCC) right repeat-y}";var r=e("../lib/dom");r.importCssString(t.cssText,t.cssClass)})
|
|
||||||
|
|
@ -1 +0,0 @@
|
||||||
ace.define("ace/theme/tomorrow_night",["require","exports","module","ace/lib/dom"],function(e,t,n){t.isDark=!0,t.cssClass="ace-tomorrow-night",t.cssText=".ace-tomorrow-night .ace_gutter {background: #25282c;color: #C5C8C6}.ace-tomorrow-night .ace_print-margin {width: 1px;background: #25282c}.ace-tomorrow-night {background-color: #1D1F21;color: #C5C8C6}.ace-tomorrow-night .ace_cursor {color: #AEAFAD}.ace-tomorrow-night .ace_marker-layer .ace_selection {background: #373B41}.ace-tomorrow-night.ace_multiselect .ace_selection.ace_start {box-shadow: 0 0 3px 0px #1D1F21;}.ace-tomorrow-night .ace_marker-layer .ace_step {background: rgb(102, 82, 0)}.ace-tomorrow-night .ace_marker-layer .ace_bracket {margin: -1px 0 0 -1px;border: 1px solid #4B4E55}.ace-tomorrow-night .ace_marker-layer .ace_active-line {background: #282A2E}.ace-tomorrow-night .ace_gutter-active-line {background-color: #282A2E}.ace-tomorrow-night .ace_marker-layer .ace_selected-word {border: 1px solid #373B41}.ace-tomorrow-night .ace_invisible {color: #4B4E55}.ace-tomorrow-night .ace_keyword,.ace-tomorrow-night .ace_meta,.ace-tomorrow-night .ace_storage,.ace-tomorrow-night .ace_storage.ace_type,.ace-tomorrow-night .ace_support.ace_type {color: #B294BB}.ace-tomorrow-night .ace_keyword.ace_operator {color: #8ABEB7}.ace-tomorrow-night .ace_constant.ace_character,.ace-tomorrow-night .ace_constant.ace_language,.ace-tomorrow-night .ace_constant.ace_numeric,.ace-tomorrow-night .ace_keyword.ace_other.ace_unit,.ace-tomorrow-night .ace_support.ace_constant,.ace-tomorrow-night .ace_variable.ace_parameter {color: #DE935F}.ace-tomorrow-night .ace_constant.ace_other {color: #CED1CF}.ace-tomorrow-night .ace_invalid {color: #CED2CF;background-color: #DF5F5F}.ace-tomorrow-night .ace_invalid.ace_deprecated {color: #CED2CF;background-color: #B798BF}.ace-tomorrow-night .ace_fold {background-color: #81A2BE;border-color: #C5C8C6}.ace-tomorrow-night .ace_entity.ace_name.ace_function,.ace-tomorrow-night .ace_support.ace_function,.ace-tomorrow-night .ace_variable {color: #81A2BE}.ace-tomorrow-night .ace_support.ace_class,.ace-tomorrow-night .ace_support.ace_type {color: #F0C674}.ace-tomorrow-night .ace_heading,.ace-tomorrow-night .ace_markup.ace_heading,.ace-tomorrow-night .ace_string {color: #B5BD68}.ace-tomorrow-night .ace_entity.ace_name.ace_tag,.ace-tomorrow-night .ace_entity.ace_other.ace_attribute-name,.ace-tomorrow-night .ace_meta.ace_tag,.ace-tomorrow-night .ace_string.ace_regexp,.ace-tomorrow-night .ace_variable {color: #CC6666}.ace-tomorrow-night .ace_comment {color: #969896}.ace-tomorrow-night .ace_indent-guide {background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAACCAYAAACZgbYnAAAAEklEQVQImWNgYGBgYHB3d/8PAAOIAdULw8qMAAAAAElFTkSuQmCC) right repeat-y}";var r=e("../lib/dom");r.importCssString(t.cssText,t.cssClass)})
|
|
||||||
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 1 - chainerror</title>
|
<title>Simple String Errors - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html" class="active"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html" class="active"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -141,15 +141,25 @@
|
||||||
<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#simple-string-errors" id="simple-string-errors"><h1>Simple String Errors</h1></a>
|
<a class="header" href="#simple-string-errors" id="simple-string-errors"><h1>Simple String Errors</h1></a>
|
||||||
<p>The most simplest of doing error handling in rust is by returning <code>String</code> as a <code>Box<Error></code>.</p>
|
<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>As you can see by running the example (the "Play" button in upper right of the code block), this only
|
<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>
|
||||||
|
<p>As you can see by running the example (by pressing the "Play" button in upper right of the code block),
|
||||||
|
this only
|
||||||
prints out the last <code>Error</code>.</p>
|
prints out the last <code>Error</code>.</p>
|
||||||
<p>If the rust <code>main</code> function returns an Err(), this Err() will be displayed with <code>std::fmt::Debug</code>.</p>
|
<pre><code>Error: StringError("func1 error")
|
||||||
|
</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>
|
||||||
|
<p>You can also run the tutorial examples in the checked out
|
||||||
|
<a href="https://github.com/haraldh/chainerror">chainerror git repo</a>.</p>
|
||||||
|
<pre><code>$ cargo run -q --example tutorial1
|
||||||
|
</code></pre>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use std::error::Error;
|
<pre><pre class="playpen"><code class="language-rust">use std::error::Error;
|
||||||
|
use std::io;
|
||||||
use std::result::Result;
|
use std::result::Result;
|
||||||
|
|
||||||
fn do_some_io() -> Result<(), Box<Error>> {
|
fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
Err("do_some_io error")?;
|
Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
@ -170,6 +180,7 @@ fn func1() -> Result<(), Box<Error>> {
|
||||||
fn main() -> Result<(), Box<Error>> {
|
fn main() -> Result<(), Box<Error>> {
|
||||||
func1()
|
func1()
|
||||||
}
|
}
|
||||||
|
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
</main>
|
</main>
|
||||||
|
|
@ -177,6 +188,10 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
<nav class="nav-wrapper" aria-label="Page navigation">
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|
@ -206,12 +225,6 @@ fn main() -> Result<(), Box<Error>> {
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|
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580
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|
@ -3,9 +3,9 @@
|
||||||
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|
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<title>Chapter 10 - chainerror</title>
|
<title>ErrorKind to the rescue - chainerror</title>
|
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|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html" class="active"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html" class="active"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -141,7 +141,16 @@
|
||||||
<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#errorkind-to-the-rescue" id="errorkind-to-the-rescue"><h1>ErrorKind to the rescue</h1></a>
|
<a class="header" href="#errorkind-to-the-rescue" id="errorkind-to-the-rescue"><h1>ErrorKind to the rescue</h1></a>
|
||||||
<p>[TBD]</p>
|
<p>To cope with different kind of errors, we introduce the kind of an error <code>Func1ErrorKind</code> with an enum.</p>
|
||||||
|
<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>
|
||||||
|
<p>Not using <code>String</code> errors anymore, the <code>cherr!()</code> macro seen in the beginning of
|
||||||
|
the tutorial has to be used again.</p>
|
||||||
|
<p>Only returning <code>Func1ErrorKind</code> in <code>func1()</code> now let us get rid of <code>Result<(), Box<Error>></code> and we can
|
||||||
|
use <code>ChainResult<(), Func1ErrorKind></code>.</p>
|
||||||
|
<p>In <code>main</code> we can now directly use the methods of <code>ChainError<T></code> without downcasting the error first.</p>
|
||||||
|
<p>Also a nice <code>match</code> on <code>ChainError<T>.kind()</code> is now possible, which returns <code>&T</code>, meaning
|
||||||
|
<code>&Func1ErrorKind</code> here.</p>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
use std::io;
|
use std::io;
|
||||||
|
|
@ -161,38 +170,38 @@ fn func2() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
|
|
||||||
#[derive(Debug)]
|
#[derive(Debug)]
|
||||||
enum Func1Error {
|
enum Func1ErrorKind {
|
||||||
Func2,
|
Func2,
|
||||||
IO(String),
|
IO(String),
|
||||||
}
|
}
|
||||||
|
|
||||||
impl ::std::fmt::Display for Func1Error {
|
impl ::std::fmt::Display for Func1ErrorKind {
|
||||||
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
match self {
|
match self {
|
||||||
Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
Func1ErrorKind::Func2 => write!(f, "func1 error calling func2"),
|
||||||
Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
Func1ErrorKind::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
fn func1() -> ChainResult<(), Func1Error> {
|
fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
let filename = String::from("bar.txt");
|
let filename = String::from("bar.txt");
|
||||||
do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO(filename)))?;
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
fn main() -> Result<(), Box<Error>> {
|
fn main() -> Result<(), Box<Error>> {
|
||||||
if let Err(e) = func1() {
|
if let Err(e) = func1() {
|
||||||
match e.kind() {
|
match e.kind() {
|
||||||
Func1Error::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
|
Func1ErrorKind::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
|
||||||
Func1Error::IO(filename) => {
|
Func1ErrorKind::IO(filename) => {
|
||||||
eprintln!("Main Error Report: func1 error reading '{}'", filename)
|
eprintln!("Main Error Report: func1 error reading '{}'", filename)
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
eprintln!("Error reported by Func2Error: {}", e)
|
eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
}
|
}
|
||||||
|
|
||||||
eprintln!("\nDebug Error:\n{:?}", e);
|
eprintln!("\nDebug Error:\n{:?}", e);
|
||||||
|
|
@ -201,10 +210,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -212,10 +378,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -229,6 +397,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -237,6 +406,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -245,6 +415,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -259,6 +477,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -273,19 +506,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -404,7 +702,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -417,6 +719,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -427,6 +816,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -440,6 +915,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -457,26 +975,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
|
|
@ -522,12 +1020,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
592
tutorial11.html
592
tutorial11.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 11 - chainerror</title>
|
<title>Debug for the ErrorKind - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html" class="active"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html" class="active"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -141,7 +141,18 @@
|
||||||
<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#debug-for-the-errorkind" id="debug-for-the-errorkind"><h1>Debug for the ErrorKind</h1></a>
|
<a class="header" href="#debug-for-the-errorkind" id="debug-for-the-errorkind"><h1>Debug for the ErrorKind</h1></a>
|
||||||
<p>[TBD]</p>
|
<p>One small improvement at the end of the tutorial is to fix the debug output of
|
||||||
|
<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>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
use std::io;
|
use std::io;
|
||||||
|
|
@ -160,44 +171,44 @@ fn func2() -> Result<(), Box<Error>> {
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
enum Func1Error {
|
enum Func1ErrorKind {
|
||||||
Func2,
|
Func2,
|
||||||
IO(String),
|
IO(String),
|
||||||
}
|
}
|
||||||
|
|
||||||
impl ::std::fmt::Display for Func1Error {
|
impl ::std::fmt::Display for Func1ErrorKind {
|
||||||
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
match self {
|
match self {
|
||||||
Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
Func1ErrorKind::Func2 => write!(f, "func1 error calling func2"),
|
||||||
Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
Func1ErrorKind::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
impl ::std::fmt::Debug for Func1Error {
|
impl ::std::fmt::Debug for Func1ErrorKind {
|
||||||
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
write!(f, "{}", self)
|
write!(f, "{}", self)
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
fn func1() -> ChainResult<(), Func1Error> {
|
fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
let filename = String::from("bar.txt");
|
let filename = String::from("bar.txt");
|
||||||
do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO(filename)))?;
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
fn main() -> Result<(), Box<Error>> {
|
fn main() -> Result<(), Box<Error>> {
|
||||||
if let Err(e) = func1() {
|
if let Err(e) = func1() {
|
||||||
match e.kind() {
|
match e.kind() {
|
||||||
Func1Error::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
|
Func1ErrorKind::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
|
||||||
Func1Error::IO(filename) => {
|
Func1ErrorKind::IO(filename) => {
|
||||||
eprintln!("Main Error Report: func1 error reading '{}'", filename)
|
eprintln!("Main Error Report: func1 error reading '{}'", filename)
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
eprintln!("Error reported by Func2Error: {}", e)
|
eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
}
|
}
|
||||||
|
|
||||||
eprintln!("\nDebug Error:\n{:?}", e);
|
eprintln!("\nDebug Error:\n{:?}", e);
|
||||||
|
|
@ -206,10 +217,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -217,10 +385,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -234,6 +404,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -242,6 +413,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -250,6 +422,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -264,6 +484,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -278,19 +513,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -409,7 +709,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -422,6 +726,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -432,6 +823,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -445,6 +922,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -462,26 +982,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
|
|
@ -496,6 +996,10 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
<a rel="next" href="end.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||||||
|
<i class="fa fa-angle-right"></i>
|
||||||
|
</a>
|
||||||
|
|
||||||
|
|
||||||
<div style="clear: both"></div>
|
<div style="clear: both"></div>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
@ -510,6 +1014,10 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
<a href="end.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||||||
|
<i class="fa fa-angle-right"></i>
|
||||||
|
</a>
|
||||||
|
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
</div>
|
</div>
|
||||||
|
|
@ -519,12 +1027,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
565
tutorial2.html
565
tutorial2.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 2 - chainerror</title>
|
<title>Simple Chained String Errors - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html" class="active"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html" class="active"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -141,14 +141,17 @@
|
||||||
<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#simple-chained-string-errors" id="simple-chained-string-errors"><h1>Simple Chained String Errors</h1></a>
|
<a class="header" href="#simple-chained-string-errors" id="simple-chained-string-errors"><h1>Simple Chained String Errors</h1></a>
|
||||||
<p>Now with the help of the <code>chainerror</code> crate, we can have a nicer output.</p>
|
<p>With relatively small changes and the help of the <code>cherr!</code> macro of the <code>chainerror</code> crate
|
||||||
|
the <code>String</code> errors are now chained together.</p>
|
||||||
<p>Press the play button in the upper right corner and see the nice debug output.</p>
|
<p>Press the play button in the upper right corner and see the nice debug output.</p>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
|
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
|
use std::io;
|
||||||
use std::result::Result;
|
use std::result::Result;
|
||||||
|
|
||||||
fn do_some_io() -> Result<(), Box<Error>> {
|
fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
Err("do_some_io error")?;
|
Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
@ -171,10 +174,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -182,10 +342,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -199,6 +361,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -207,6 +370,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -215,6 +379,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -229,6 +441,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -243,19 +470,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -374,7 +666,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -387,6 +683,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -397,6 +780,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -410,6 +879,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -427,26 +939,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
<a class="header" href="#what-did-we-do-here" id="what-did-we-do-here"><h3>What did we do here?</h3></a>
|
<a class="header" href="#what-did-we-do-here" id="what-did-we-do-here"><h3>What did we do here?</h3></a>
|
||||||
|
|
@ -454,13 +946,14 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
Err(cherr!(e, "func2 error"))?;
|
Err(cherr!(e, "func2 error"))?;
|
||||||
}
|
}
|
||||||
</code></pre>
|
</code></pre>
|
||||||
<p>The macro <code>cherr!(cause, newerror)</code> stores <code>cause</code> as the source/cause of <code>newerror</code> and returns
|
<p>The macro <code>cherr!(olderror, newerror)</code> stores <code>olderror</code> as the source/cause of <code>newerror</code>
|
||||||
<code>newerror</code>, along with the filename (<code>file!()</code>) and line number (<code>line!()</code>).</p>
|
along with the filename (<code>file!()</code>) and line number (<code>line!()</code>)
|
||||||
<p><code>Err(e)?</code> then returns the error <code>e</code> applying <code>e.into()</code>, so that we
|
and returns <code>newerror</code>.</p>
|
||||||
|
<p><code>Err()?</code> then returns the inner error applying <code>.into()</code>, so that we
|
||||||
again have a <code>Err(Box<Error>)</code> as a result.</p>
|
again have a <code>Err(Box<Error>)</code> as a result.</p>
|
||||||
<p>The <code>Debug</code> implementation of <code>ChainError<T></code> (which is returned by <code>cherr!()</code>)
|
<p>The <code>Debug</code> implementation of <code>ChainError<T></code> (which is returned by <code>cherr!()</code>)
|
||||||
prints the <code>Debug</code> of <code>T</code> prefixed with the stored filename and line number.</p>
|
prints the <code>Debug</code> of <code>T</code> prefixed with the stored filename and line number.</p>
|
||||||
<p><code>ChainError<T></code> is in our case <code>ChainError<String></code>.</p>
|
<p><code>ChainError<T></code> in our case is <code>ChainError<String></code>.</p>
|
||||||
|
|
||||||
</main>
|
</main>
|
||||||
|
|
||||||
|
|
@ -504,12 +997,6 @@ prints the <code>Debug</code> of <code>T</code> prefixed with the stored filenam
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
553
tutorial3.html
553
tutorial3.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 3 - chainerror</title>
|
<title>Mapping Errors - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html" class="active"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html" class="active"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -143,11 +143,13 @@
|
||||||
<a class="header" href="#mapping-errors" id="mapping-errors"><h1>Mapping Errors</h1></a>
|
<a class="header" href="#mapping-errors" id="mapping-errors"><h1>Mapping Errors</h1></a>
|
||||||
<p>Now let's get more rust idiomatic by using <code>.map_err()</code>.</p>
|
<p>Now let's get more rust idiomatic by using <code>.map_err()</code>.</p>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
|
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
|
use std::io;
|
||||||
use std::result::Result;
|
use std::result::Result;
|
||||||
|
|
||||||
fn do_some_io() -> Result<(), Box<Error>> {
|
fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
Err("do_some_io error")?;
|
Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
@ -169,10 +171,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -180,10 +339,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -197,6 +358,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -205,6 +367,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -213,6 +376,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -227,6 +438,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -241,19 +467,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -372,7 +663,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -385,6 +680,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -395,6 +777,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -408,6 +876,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -425,26 +936,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
<p>If you compare the output to the previous example, you will see,
|
<p>If you compare the output to the previous example, you will see,
|
||||||
|
|
@ -500,12 +991,6 @@ Maybe depending on <code>--debug</code> as a CLI argument.</p>
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
552
tutorial4.html
552
tutorial4.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 4 - chainerror</title>
|
<title>Saving coding chars - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html" class="active"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html" class="active"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -148,10 +148,11 @@ more debug strings.</p>
|
||||||
<p><code>mstrerror!()</code> even understands <code>format!()</code> syntax like <code>println!()</code>.</p>
|
<p><code>mstrerror!()</code> even understands <code>format!()</code> syntax like <code>println!()</code>.</p>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
|
use std::io;
|
||||||
use std::result::Result;
|
use std::result::Result;
|
||||||
|
|
||||||
fn do_some_io() -> Result<(), Box<Error>> {
|
fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
Err("do_some_io error")?;
|
Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
Ok(())
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
@ -174,10 +175,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -185,10 +343,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -202,6 +362,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -210,6 +371,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -218,6 +380,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -232,6 +442,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -246,19 +471,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -377,7 +667,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -390,6 +684,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -400,6 +781,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -413,6 +880,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -430,26 +940,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
|
|
@ -495,12 +985,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
553
tutorial5.html
553
tutorial5.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 5 - chainerror</title>
|
<title>The source() of Errors - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html" class="active"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html" class="active"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -177,10 +177,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -188,10 +345,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -205,6 +364,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -213,6 +373,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -221,6 +382,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -235,6 +444,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -249,19 +473,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -380,7 +669,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -393,6 +686,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -403,6 +783,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -416,6 +882,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -433,30 +942,10 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
<p>Note, that we changed the output of the error in <code>main()</code> from <code>Debug</code> to <code>Display</code>, so we don't see
|
<p>Note, that because we changed the output of the error in <code>main()</code> from
|
||||||
the error backtrace with filename and line number.</p>
|
<code>Debug</code> to <code>Display</code>, we don't see the error backtrace with filename and line number.</p>
|
||||||
<p>To enable the <code>Display</code> backtrace, you have to enable the feature <code>display-cause</code> for <code>chainerror</code>.</p>
|
<p>To enable the <code>Display</code> backtrace, you have to enable the feature <code>display-cause</code> for <code>chainerror</code>.</p>
|
||||||
|
|
||||||
</main>
|
</main>
|
||||||
|
|
@ -501,12 +990,6 @@ the error backtrace with filename and line number.</p>
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
556
tutorial6.html
556
tutorial6.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 6 - chainerror</title>
|
<title>Downcast the Errors - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html" class="active"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html" class="active"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -141,7 +141,12 @@
|
||||||
<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#downcast-the-errors" id="downcast-the-errors"><h1>Downcast the Errors</h1></a>
|
<a class="header" href="#downcast-the-errors" id="downcast-the-errors"><h1>Downcast the Errors</h1></a>
|
||||||
<p>[TBD]</p>
|
<p><code>std::error::Error</code> comes with some helper methods to get to the original object of the
|
||||||
|
<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>
|
||||||
|
pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T>
|
||||||
|
</code></pre>
|
||||||
|
<p>This is how it looks like, when using those:</p>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
use std::io;
|
use std::io;
|
||||||
|
|
@ -184,10 +189,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -195,10 +357,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -212,6 +376,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -220,6 +385,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -228,6 +394,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -242,6 +456,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -256,19 +485,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -387,7 +681,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -400,6 +698,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -410,6 +795,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -423,6 +894,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -440,26 +954,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
|
|
@ -505,12 +999,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
567
tutorial7.html
567
tutorial7.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 7 - chainerror</title>
|
<title>The root cause of all Errors - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html" class="active"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html" class="active"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -141,7 +141,23 @@
|
||||||
<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#the-root-cause-of-all-errors" id="the-root-cause-of-all-errors"><h1>The root cause of all Errors</h1></a>
|
<a class="header" href="#the-root-cause-of-all-errors" id="the-root-cause-of-all-errors"><h1>The root cause of all Errors</h1></a>
|
||||||
<p>[TBD]</p>
|
<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
|
||||||
|
fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>
|
||||||
|
fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>
|
||||||
|
fn root_cause(&self) -> Option<&(dyn Error + 'static)>
|
||||||
|
fn find_cause<U: Error + 'static>(&self) -> Option<&U>
|
||||||
|
fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>>
|
||||||
|
fn kind<'a>(&'a self) -> &'a T
|
||||||
|
</code></pre>
|
||||||
|
<p>Using <code>downcast_chain_ref::<String>()</code> gives a <code>ChainError<String></code>, which can be used
|
||||||
|
to call <code>.find_cause::<io::Error>()</code>.</p>
|
||||||
|
<pre><code class="language-rust ignore"> if let Some(s) = e.downcast_chain_ref::<String>() {
|
||||||
|
if let Some(ioerror) = s.find_cause::<io::Error>() {
|
||||||
|
</code></pre>
|
||||||
|
<p>or to use <code>.root_cause()</code>, which of course can be of any type implementing <code>std::error::Error</code>.</p>
|
||||||
|
<pre><code class="language-rust ignore"> if let Some(e) = s.root_cause() {
|
||||||
|
</code></pre>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
use std::io;
|
use std::io;
|
||||||
|
|
@ -185,10 +201,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -196,10 +369,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -213,6 +388,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -221,6 +397,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -229,6 +406,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -243,6 +468,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -257,19 +497,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -388,7 +693,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -401,6 +710,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -411,6 +807,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -424,6 +906,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -441,26 +966,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
|
|
@ -506,12 +1011,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
564
tutorial8.html
564
tutorial8.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 8 - chainerror</title>
|
<title>Finding an Error cause - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html" class="active"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html" class="active"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
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|
|
@ -141,7 +141,20 @@
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<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#finding-an-error-cause" id="finding-an-error-cause"><h1>Finding an Error cause</h1></a>
|
<a class="header" href="#finding-an-error-cause" id="finding-an-error-cause"><h1>Finding an Error cause</h1></a>
|
||||||
<p>[TBD]</p>
|
<p>To distinguish the errors occuring in various places, we can define named string errors with the
|
||||||
|
"new type" pattern.</p>
|
||||||
|
<pre><code class="language-rust ignore">derive_str_cherr!(Func2Error);
|
||||||
|
derive_str_cherr!(Func1Error);
|
||||||
|
</code></pre>
|
||||||
|
<p>Instead of <code>ChainError<String></code> we now have <code>struct Func1Error(String)</code> and <code>ChainError<Func1Error></code>.</p>
|
||||||
|
<p>In the <code>main</code> function you can see, how we can match the different errors.</p>
|
||||||
|
<p>Also see:</p>
|
||||||
|
<pre><code class="language-rust ignore"> if let Some(f2err) = f1err.find_chain_cause::<Func2Error>() {
|
||||||
|
</code></pre>
|
||||||
|
<p>as a shortcut to</p>
|
||||||
|
<pre><code class="language-rust ignore"> if let Some(f2err) = f1err.find_cause::<ChainError<Func2Error>>() {
|
||||||
|
</code></pre>
|
||||||
|
<p>hiding the <code>ChainError<T></code> implementation detail.</p>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
use std::io;
|
use std::io;
|
||||||
|
|
@ -185,10 +198,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -196,10 +366,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -213,6 +385,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -221,6 +394,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -229,6 +403,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -243,6 +465,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -257,19 +494,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -388,7 +690,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -401,6 +707,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -411,6 +804,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -424,6 +903,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -441,26 +963,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
|
|
@ -506,12 +1008,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
570
tutorial9.html
570
tutorial9.html
|
|
@ -3,9 +3,9 @@
|
||||||
<head>
|
<head>
|
||||||
<!-- Book generated using mdBook -->
|
<!-- Book generated using mdBook -->
|
||||||
<meta charset="UTF-8">
|
<meta charset="UTF-8">
|
||||||
<title>Chapter 9 - chainerror</title>
|
<title>Selective Error Handling - chainerror</title>
|
||||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||||
<meta name="description" content="">
|
<meta name="description" content="A tutorial for the chainerror rust crate.">
|
||||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||||
<meta name="theme-color" content="#ffffff" />
|
<meta name="theme-color" content="#ffffff" />
|
||||||
|
|
||||||
|
|
@ -75,7 +75,7 @@
|
||||||
</script>
|
</script>
|
||||||
|
|
||||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||||
<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html" class="active"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
|
<ol class="chapter"><li class="affix"><a href="index.html">chainerror</a></li><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li><a href="tutorial9.html" class="active"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="affix"><a href="end.html">The End</a></li></ol>
|
||||||
</nav>
|
</nav>
|
||||||
|
|
||||||
<div id="page-wrapper" class="page-wrapper">
|
<div id="page-wrapper" class="page-wrapper">
|
||||||
|
|
@ -141,7 +141,24 @@
|
||||||
<div id="content" class="content">
|
<div id="content" class="content">
|
||||||
<main>
|
<main>
|
||||||
<a class="header" href="#selective-error-handling" id="selective-error-handling"><h1>Selective Error Handling</h1></a>
|
<a class="header" href="#selective-error-handling" id="selective-error-handling"><h1>Selective Error Handling</h1></a>
|
||||||
<p>[TBD]</p>
|
<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>
|
||||||
|
<pre><code class="language-rust ignore">fn main() -> Result<(), Box<Error>> {
|
||||||
|
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(())
|
||||||
|
}
|
||||||
|
</code></pre>
|
||||||
|
<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>
|
||||||
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
<pre><pre class="playpen"><code class="language-rust">use crate::chainerror::*;
|
||||||
use std::error::Error;
|
use std::error::Error;
|
||||||
use std::io;
|
use std::io;
|
||||||
|
|
@ -176,7 +193,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
eprintln!("Func1ErrorIO:\n{:?}", s);
|
eprintln!("Func1ErrorIO:\n{:?}", s);
|
||||||
}
|
}
|
||||||
|
|
||||||
if let Some(s) = try_cherr_ref!(e, Func1ErrorFunc2) {
|
if let Some(s) = e.downcast_chain_ref::<Func1ErrorFunc2>() {
|
||||||
eprintln!("Func1ErrorFunc2:\n{:?}", s);
|
eprintln!("Func1ErrorFunc2:\n{:?}", s);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
@ -184,10 +201,167 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
}
|
}
|
||||||
# #[allow(dead_code)]
|
# #[allow(dead_code)]
|
||||||
# mod chainerror {
|
# mod chainerror {
|
||||||
|
# /*!
|
||||||
|
#
|
||||||
|
# `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
|
||||||
|
# binaries, you still have the error backtrace.
|
||||||
|
#
|
||||||
|
# `chainerror` has no dependencies!
|
||||||
|
#
|
||||||
|
# `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
|
||||||
|
# It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
|
||||||
|
#
|
||||||
|
# Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:20: func1 error
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# use chainerror::*;
|
||||||
|
# use std::error::Error;
|
||||||
|
# use std::io;
|
||||||
|
# use std::result::Result;
|
||||||
|
#
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func3() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# enum Func1Error {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Display for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# match self {
|
||||||
|
# Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
||||||
|
# Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# impl ::std::fmt::Debug for Func1Error {
|
||||||
|
# fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# write!(f, "{}", self)
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1Error> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
||||||
|
# let filename = String::from("bar.txt");
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# assert!(
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1Error::Func2 => {
|
||||||
|
# eprintln!("Main Error Report: func1 error calling func2");
|
||||||
|
# true
|
||||||
|
# }
|
||||||
|
# Func1Error::IO(filename) => {
|
||||||
|
# eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# );
|
||||||
|
#
|
||||||
|
# assert!(e.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
||||||
|
# eprintln!("\nError reported by Func2Error: {}", e)
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
#
|
||||||
|
# assert!(e.root_cause().is_some());
|
||||||
|
#
|
||||||
|
# if let Some(e) = e.root_cause() {
|
||||||
|
# let ioerror = e.downcast_ref::<io::Error>().unwrap();
|
||||||
|
# eprintln!("\nThe root cause was: std::io::Error: {:#?}", ioerror);
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# assert_eq!(
|
||||||
|
# format!("\n{:?}\n", e), r#"
|
||||||
|
# src/lib.rs:47: func1 error calling func2
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:22: Func2Error(func2 error: calling func3)
|
||||||
|
# Caused by:
|
||||||
|
# src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# Caused by:
|
||||||
|
# Kind(NotFound)
|
||||||
|
# "#
|
||||||
|
# );
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# !*/
|
||||||
|
#
|
||||||
|
# use std::any::TypeId;
|
||||||
# use std::error::Error;
|
# use std::error::Error;
|
||||||
# use std::fmt::{Debug, Display, Formatter, Result};
|
# use std::fmt::{Debug, Display, Formatter, Result};
|
||||||
# use std::result::Result as StdResult;
|
|
||||||
#
|
#
|
||||||
|
# /** chains an inner error kind `T` with a causing error
|
||||||
|
# **/
|
||||||
# pub struct ChainError<T> {
|
# pub struct ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
# occurrence: Option<(u32, &'static str)>,
|
# occurrence: Option<(u32, &'static str)>,
|
||||||
|
|
@ -195,10 +369,12 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# pub type ChainResult<O, E> = StdResult<O, ChainError<E>>;
|
# /// convenience type alias
|
||||||
|
# pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
||||||
#
|
#
|
||||||
# impl<T: 'static + Display + Debug> ChainError<T> {
|
# impl<T: 'static + Display + Debug> ChainError<T> {
|
||||||
# #[cfg(not(feature = "no-fileline"))]
|
# #[cfg(not(feature = "no-fileline"))]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -212,6 +388,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(feature = "no-fileline")]
|
# #[cfg(feature = "no-fileline")]
|
||||||
|
# /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
||||||
# pub fn new(
|
# pub fn new(
|
||||||
# kind: T,
|
# kind: T,
|
||||||
# error_cause: Option<Box<dyn Error + 'static>>,
|
# error_cause: Option<Box<dyn Error + 'static>>,
|
||||||
|
|
@ -220,6 +397,7 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Self { kind, error_cause }
|
# Self { kind, error_cause }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /// return the root cause of the error chain, if any exists
|
||||||
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
# pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# while let Some(c) = cause.source() {
|
# while let Some(c) = cause.source() {
|
||||||
|
|
@ -228,6 +406,54 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# Some(cause)
|
# Some(cause)
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type U, if any exists
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_cause::<io::Error>().is_some());
|
||||||
|
#
|
||||||
|
# assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
# pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -242,6 +468,21 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** find the first error cause of type ChainError<U>, if any exists
|
||||||
|
#
|
||||||
|
# Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust,ignore
|
||||||
|
# /// Instead of writing
|
||||||
|
# err.find_cause::<ChainError<FooError>>();
|
||||||
|
#
|
||||||
|
# /// leave out the ChainError<T> implementation detail
|
||||||
|
# err.find_chain_cause::<FooError>();
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
# pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
||||||
# let mut cause = self as &(dyn Error + 'static);
|
# let mut cause = self as &(dyn Error + 'static);
|
||||||
# loop {
|
# loop {
|
||||||
|
|
@ -256,19 +497,84 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** return a reference to T of `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# #[derive(Debug)]
|
||||||
|
# enum Func1ErrorKind {
|
||||||
|
# Func2,
|
||||||
|
# IO(String),
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for Func1ErrorKind {…}
|
||||||
|
# # 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),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# fn func1() -> ChainResult<(), Func1ErrorKind> {
|
||||||
|
# func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
||||||
|
# do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn main() {
|
||||||
|
# if let Err(e) = func1() {
|
||||||
|
# match e.kind() {
|
||||||
|
# Func1ErrorKind::Func2 => {},
|
||||||
|
# Func1ErrorKind::IO(filename) => panic!(),
|
||||||
|
# }
|
||||||
|
# }
|
||||||
|
# # else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# pub fn kind<'a>(&'a self) -> &'a T {
|
# pub fn kind<'a>(&'a self) -> &'a T {
|
||||||
# &self.kind
|
# &self.kind
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience trait to hide the `ChainError<T>` implementation internals
|
||||||
|
# **/
|
||||||
# pub trait ChainErrorDown {
|
# pub trait ChainErrorDown {
|
||||||
|
# /** test if of type `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
||||||
|
# /** downcast to a reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
# fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
||||||
|
# /** downcast to a mutable reference of `ChainError<T>`
|
||||||
|
# **/
|
||||||
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
# fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
# use std::any::TypeId;
|
|
||||||
#
|
|
||||||
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
# impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
||||||
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
# fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
||||||
# TypeId::of::<T>() == TypeId::of::<U>()
|
# TypeId::of::<T>() == TypeId::of::<U>()
|
||||||
|
|
@ -387,7 +693,11 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# if self.is_chain::<String>() {
|
||||||
|
# Display::fmt(&self.kind, f)?;
|
||||||
|
# } else {
|
||||||
# Debug::fmt(&self.kind, f)?;
|
# Debug::fmt(&self.kind, f)?;
|
||||||
|
# }
|
||||||
#
|
#
|
||||||
# #[cfg(not(feature = "no-debug-cause"))]
|
# #[cfg(not(feature = "no-debug-cause"))]
|
||||||
# {
|
# {
|
||||||
|
|
@ -400,6 +710,93 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# }
|
# }
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** creates a new `ChainError<T>`
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# enum FooError {
|
||||||
|
# Bar,
|
||||||
|
# Baz(&'static str),
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
#
|
||||||
|
# // impl ::std::fmt::Display for FooError
|
||||||
|
#
|
||||||
|
# fn do_some_stuff() -> bool {
|
||||||
|
# false
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# if ! do_some_stuff() {
|
||||||
|
# Err(cherr!(FooError::Baz("Error")))?;
|
||||||
|
# }
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# Additionally an error cause can be added.
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use chainerror::*;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# #
|
||||||
|
# # #[derive(Debug)]
|
||||||
|
# # enum FooError {
|
||||||
|
# # Bar,
|
||||||
|
# # Baz(&'static str),
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# # impl ::std::fmt::Display for FooError {
|
||||||
|
# # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
||||||
|
# # match self {
|
||||||
|
# # FooError::Bar => write!(f, "Bar Error"),
|
||||||
|
# # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn do_some_stuff() -> Result<(), Box<Error>> {
|
||||||
|
# Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func() -> ChainResult<(), FooError> {
|
||||||
|
# do_some_stuff().map_err(
|
||||||
|
# |e| cherr!(e, FooError::Baz("Error"))
|
||||||
|
# )?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # pub fn main() {
|
||||||
|
# # match func().unwrap_err().kind() {
|
||||||
|
# # FooError::Baz(s) if s == &"Error" => {},
|
||||||
|
# # _ => panic!(),
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! cherr {
|
# macro_rules! cherr {
|
||||||
# ( $k:expr ) => {
|
# ( $k:expr ) => {
|
||||||
|
|
@ -410,6 +807,92 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro for |e| cherr!(e, format!(…))
|
||||||
|
#
|
||||||
|
# # Examples
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!("func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # assert_eq!(
|
||||||
|
# # format!("\n{:?}\n", e), r#"
|
||||||
|
# # src/lib.rs:20: func1 error
|
||||||
|
# # Caused by:
|
||||||
|
# # src/lib.rs:15: Error reading 'foo.txt'
|
||||||
|
# # Caused by:
|
||||||
|
# # Kind(NotFound)
|
||||||
|
# # "#
|
||||||
|
# # );
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
||||||
|
# `derive_str_cherr!(T)`
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> Result<(), Box<Error>> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! mstrerr {
|
# macro_rules! mstrerr {
|
||||||
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
# ( $t:ident, $v:expr $(, $more:expr)* ) => {
|
||||||
|
|
@ -423,6 +906,49 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
#
|
||||||
|
# /** convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
||||||
|
#
|
||||||
|
# ~~~rust
|
||||||
|
# # use crate::chainerror::*;
|
||||||
|
# # use std::error::Error;
|
||||||
|
# # use std::io;
|
||||||
|
# # use std::result::Result;
|
||||||
|
# #
|
||||||
|
# # fn do_some_io() -> Result<(), Box<Error>> {
|
||||||
|
# # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
||||||
|
# # Ok(())
|
||||||
|
# # }
|
||||||
|
# #
|
||||||
|
# derive_str_cherr!(Func2Error);
|
||||||
|
#
|
||||||
|
# fn func2() -> ChainResult<(), Func2Error> {
|
||||||
|
# let filename = "foo.txt";
|
||||||
|
# do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
#
|
||||||
|
# derive_str_cherr!(Func1Error);
|
||||||
|
#
|
||||||
|
# fn func1() -> Result<(), Box<Error>> {
|
||||||
|
# func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
||||||
|
# Ok(())
|
||||||
|
# }
|
||||||
|
# #
|
||||||
|
# # fn main() {
|
||||||
|
# # if let Err(e) = func1() {
|
||||||
|
# # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
||||||
|
# # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
||||||
|
# # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
||||||
|
# # } else {
|
||||||
|
# # panic!();
|
||||||
|
# # }
|
||||||
|
# # } else {
|
||||||
|
# # unreachable!();
|
||||||
|
# # }
|
||||||
|
# # }
|
||||||
|
# ~~~
|
||||||
|
#
|
||||||
|
# **/
|
||||||
# #[macro_export]
|
# #[macro_export]
|
||||||
# macro_rules! derive_str_cherr {
|
# macro_rules! derive_str_cherr {
|
||||||
# ($e:ident) => {
|
# ($e:ident) => {
|
||||||
|
|
@ -440,26 +966,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
# impl ::std::error::Error for $e {}
|
# impl ::std::error::Error for $e {}
|
||||||
# };
|
# };
|
||||||
# }
|
# }
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_ref {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_ref::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
#
|
|
||||||
# #[macro_export]
|
|
||||||
# macro_rules! try_cherr_mut {
|
|
||||||
# ( $e:expr, $t:ident ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# ( $e:expr, $t:path ) => {
|
|
||||||
# $e.downcast_mut::<ChainError<$t>>()
|
|
||||||
# };
|
|
||||||
# }
|
|
||||||
# }
|
# }
|
||||||
</code></pre></pre>
|
</code></pre></pre>
|
||||||
|
|
||||||
|
|
@ -505,12 +1011,6 @@ fn main() -> Result<(), Box<Error>> {
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||||
|
|
|
||||||
Loading…
Reference in a new issue