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1460 lines
83 KiB
HTML
1460 lines
83 KiB
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<ol class="chapter"><li class="expanded affix "><a href="index.html">chainerror</a></li><li class="expanded "><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Simple String Errors</a></li><li class="expanded "><a href="tutorial2.html" class="active"><strong aria-hidden="true">2.</strong> Simple Chained String Errors</a></li><li class="expanded "><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Mapping Errors</a></li><li class="expanded "><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Saving coding chars</a></li><li class="expanded "><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> The source() of Errors</a></li><li class="expanded "><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Downcast the Errors</a></li><li class="expanded "><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> The root cause of all Errors</a></li><li class="expanded "><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Finding an Error cause</a></li><li class="expanded "><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Selective Error Handling</a></li><li class="expanded "><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> ErrorKind to the rescue</a></li><li class="expanded "><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Debug for the ErrorKind</a></li><li class="expanded "><a href="tutorial12.html"><strong aria-hidden="true">12.</strong> Deref for the ErrorKind</a></li><li class="expanded "><a href="tutorial13.html"><strong aria-hidden="true">13.</strong> Writing a library</a></li><li class="expanded "><a href="tutorial14.html"><strong aria-hidden="true">14.</strong> Going back to std</a></li><li class="expanded affix "><a href="end.html">The End</a></li></ol>
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<main>
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<h1><a class="header" href="#simple-chained-string-errors" id="simple-chained-string-errors">Simple Chained String Errors</a></h1>
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<p>With relatively small changes and the help of the <code>cherr!</code> macro of the <code>chainerror</code> crate
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the <code>String</code> errors are now chained together.</p>
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<p>Press the play button in the upper right corner and see the nice debug output.</p>
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<pre><pre class="playpen"><code class="language-rust">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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fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
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Err(io::Error::from(io::ErrorKind::NotFound))?;
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Ok(())
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}
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fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
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if let Err(e) = do_some_io() {
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Err(cherr!(e, "func2 error"))?;
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}
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Ok(())
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}
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fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
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if let Err(e) = func2() {
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Err(cherr!(e, "func1 error"))?;
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}
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Ok(())
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}
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fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
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func1()
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}
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<span class="boring">#[allow(dead_code)]
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</span><span class="boring">mod chainerror {
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</span><span class="boring">//! `chainerror` provides an error backtrace without doing a real backtrace, so even after you `strip` your
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</span><span class="boring">//! binaries, you still have the error backtrace.
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</span><span class="boring">//!
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</span><span class="boring">//! `chainerror` has no dependencies!
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</span><span class="boring">//!
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</span><span class="boring">//! `chainerror` uses `.source()` of `std::error::Error` along with `line()!` and `file()!` to provide a nice debug error backtrace.
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</span><span class="boring">//! It encapsulates all types, which have `Display + Debug` and can store the error cause internally.
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</span><span class="boring">//!
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</span><span class="boring">//! Along with the `ChainError<T>` struct, `chainerror` comes with some useful helper macros to save a lot of typing.
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</span><span class="boring">//!
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</span><span class="boring">//! ## Features
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</span><span class="boring">//!
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</span><span class="boring">//! `no-fileline`
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</span><span class="boring">//! : completely turn off storing filename and line
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</span><span class="boring">//!
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</span><span class="boring">//! `display-cause`
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</span><span class="boring">//! : turn on printing a backtrace of the errors in `Display`
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</span><span class="boring">//!
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</span><span class="boring">//! `no-debug-cause`
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</span><span class="boring">//! : turn off printing a backtrace of the errors in `Debug`
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</span><span class="boring">//!
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</span><span class="boring">//!
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</span><span class="boring">//! # Tutorial
|
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</span><span class="boring">//!
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</span><span class="boring">//! Read the [Tutorial](https://haraldh.github.io/chainerror/tutorial1.html)
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</span><span class="boring">//!
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</span><span class="boring">//! # Examples
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</span><span class="boring">//!
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</span><span class="boring">//! ```rust
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</span><span class="boring">//! use chainerror::*;
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</span><span class="boring">//! use std::error::Error;
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</span><span class="boring">//! use std::io;
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</span><span class="boring">//! use std::result::Result;
|
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</span><span class="boring">//!
|
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</span><span class="boring">//! fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">//! Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring">//! Ok(())
|
|
</span><span class="boring">//! }
|
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</span><span class="boring">//!
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|
</span><span class="boring">//! fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">//! let filename = "foo.txt";
|
|
</span><span class="boring">//! do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
|
</span><span class="boring">//! Ok(())
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">//! func2().map_err(mstrerr!("func1 error"))?;
|
|
</span><span class="boring">//! Ok(())
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! fn main() {
|
|
</span><span class="boring">//! if let Err(e) = func1() {
|
|
</span><span class="boring">//! #[cfg(not(windows))]
|
|
</span><span class="boring">//! assert_eq!(
|
|
</span><span class="boring">//! format!("\n{:?}\n", e), r#"
|
|
</span><span class="boring">//! src/lib.rs:20: func1 error
|
|
</span><span class="boring">//! Caused by:
|
|
</span><span class="boring">//! src/lib.rs:15: Error reading 'foo.txt'
|
|
</span><span class="boring">//! Caused by:
|
|
</span><span class="boring">//! Kind(NotFound)
|
|
</span><span class="boring">//! "#
|
|
</span><span class="boring">//! );
|
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</span><span class="boring">//! }
|
|
</span><span class="boring">//! # else {
|
|
</span><span class="boring">//! # unreachable!();
|
|
</span><span class="boring">//! # }
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! ```
|
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</span><span class="boring">//!
|
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</span><span class="boring">//!
|
|
</span><span class="boring">//! ```rust
|
|
</span><span class="boring">//! use chainerror::*;
|
|
</span><span class="boring">//! use std::error::Error;
|
|
</span><span class="boring">//! use std::io;
|
|
</span><span class="boring">//! use std::result::Result;
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">//! Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring">//! Ok(())
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! fn func3() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">//! let filename = "foo.txt";
|
|
</span><span class="boring">//! do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
|
</span><span class="boring">//! Ok(())
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! derive_str_cherr!(Func2Error);
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! fn func2() -> ChainResult<(), Func2Error> {
|
|
</span><span class="boring">//! func3().map_err(mstrerr!(Func2Error, "func2 error: calling func3"))?;
|
|
</span><span class="boring">//! Ok(())
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! enum Func1Error {
|
|
</span><span class="boring">//! Func2,
|
|
</span><span class="boring">//! IO(String),
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! impl ::std::fmt::Display for Func1Error {
|
|
</span><span class="boring">//! fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
|
</span><span class="boring">//! match self {
|
|
</span><span class="boring">//! Func1Error::Func2 => write!(f, "func1 error calling func2"),
|
|
</span><span class="boring">//! Func1Error::IO(filename) => write!(f, "Error reading '{}'", filename),
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! impl ::std::fmt::Debug for Func1Error {
|
|
</span><span class="boring">//! fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
|
</span><span class="boring">//! write!(f, "{}", self)
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! fn func1() -> ChainResult<(), Func1Error> {
|
|
</span><span class="boring">//! func2().map_err(|e| cherr!(e, Func1Error::Func2))?;
|
|
</span><span class="boring">//! let filename = String::from("bar.txt");
|
|
</span><span class="boring">//! do_some_io().map_err(|e| cherr!(e, Func1Error::IO(filename)))?;
|
|
</span><span class="boring">//! Ok(())
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! fn main() {
|
|
</span><span class="boring">//! if let Err(e) = func1() {
|
|
</span><span class="boring">//! assert!(
|
|
</span><span class="boring">//! match e.kind() {
|
|
</span><span class="boring">//! Func1Error::Func2 => {
|
|
</span><span class="boring">//! eprintln!("Main Error Report: func1 error calling func2");
|
|
</span><span class="boring">//! true
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! Func1Error::IO(filename) => {
|
|
</span><span class="boring">//! eprintln!("Main Error Report: func1 error reading '{}'", filename);
|
|
</span><span class="boring">//! false
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! );
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! assert!(e.find_chain_cause::<Func2Error>().is_some());
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! if let Some(e) = e.find_chain_cause::<Func2Error>() {
|
|
</span><span class="boring">//! eprintln!("\nError reported by Func2Error: {}", e)
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! assert!(e.root_cause().is_some());
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! if let Some(e) = e.root_cause() {
|
|
</span><span class="boring">//! let io_error = e.downcast_ref::<io::Error>().unwrap();
|
|
</span><span class="boring">//! eprintln!("\nThe root cause was: std::io::Error: {:#?}", io_error);
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//!
|
|
</span><span class="boring">//! #[cfg(not(windows))]
|
|
</span><span class="boring">//! assert_eq!(
|
|
</span><span class="boring">//! format!("\n{:?}\n", e), r#"
|
|
</span><span class="boring">//! src/lib.rs:47: func1 error calling func2
|
|
</span><span class="boring">//! Caused by:
|
|
</span><span class="boring">//! src/lib.rs:22: Func2Error(func2 error: calling func3)
|
|
</span><span class="boring">//! Caused by:
|
|
</span><span class="boring">//! src/lib.rs:15: Error reading 'foo.txt'
|
|
</span><span class="boring">//! Caused by:
|
|
</span><span class="boring">//! Kind(NotFound)
|
|
</span><span class="boring">//! "#
|
|
</span><span class="boring">//! );
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! # else {
|
|
</span><span class="boring">//! # unreachable!();
|
|
</span><span class="boring">//! # }
|
|
</span><span class="boring">//! }
|
|
</span><span class="boring">//! ```
|
|
</span><span class="boring">
|
|
</span><span class="boring">#![deny(
|
|
</span><span class="boring"> warnings,
|
|
</span><span class="boring"> absolute_paths_not_starting_with_crate,
|
|
</span><span class="boring"> deprecated_in_future,
|
|
</span><span class="boring"> keyword_idents,
|
|
</span><span class="boring"> macro_use_extern_crate,
|
|
</span><span class="boring"> missing_debug_implementations,
|
|
</span><span class="boring"> trivial_numeric_casts,
|
|
</span><span class="boring"> unused_extern_crates,
|
|
</span><span class="boring"> unused_import_braces,
|
|
</span><span class="boring"> unused_qualifications,
|
|
</span><span class="boring"> unused_results,
|
|
</span><span class="boring"> unused_labels,
|
|
</span><span class="boring"> unused_lifetimes,
|
|
</span><span class="boring"> unstable_features,
|
|
</span><span class="boring"> unreachable_pub,
|
|
</span><span class="boring"> future_incompatible,
|
|
</span><span class="boring"> missing_copy_implementations,
|
|
</span><span class="boring"> missing_doc_code_examples,
|
|
</span><span class="boring"> rust_2018_idioms,
|
|
</span><span class="boring"> rust_2018_compatibility
|
|
</span><span class="boring">)]
|
|
</span><span class="boring">
|
|
</span><span class="boring">use std::any::TypeId;
|
|
</span><span class="boring">use std::error::Error;
|
|
</span><span class="boring">use std::fmt::{Debug, Display, Formatter, Result};
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// chains an inner error kind `T` with a causing error
|
|
</span><span class="boring">pub struct ChainError<T> {
|
|
</span><span class="boring"> #[cfg(not(feature = "no-fileline"))]
|
|
</span><span class="boring"> occurrence: Option<&'static str>,
|
|
</span><span class="boring"> kind: T,
|
|
</span><span class="boring"> error_cause: Option<Box<dyn Error + 'static + Send + Sync>>,
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// convenience type alias
|
|
</span><span class="boring">pub type ChainResult<O, E> = std::result::Result<O, ChainError<E>>;
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T: 'static + Display + Debug> ChainError<T> {
|
|
</span><span class="boring"> #[cfg(not(feature = "no-fileline"))]
|
|
</span><span class="boring"> /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> pub fn new(
|
|
</span><span class="boring"> kind: T,
|
|
</span><span class="boring"> error_cause: Option<Box<dyn Error + 'static + Send + Sync>>,
|
|
</span><span class="boring"> occurrence: Option<&'static str>,
|
|
</span><span class="boring"> ) -> Self {
|
|
</span><span class="boring"> Self {
|
|
</span><span class="boring"> occurrence,
|
|
</span><span class="boring"> kind,
|
|
</span><span class="boring"> error_cause,
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[cfg(feature = "no-fileline")]
|
|
</span><span class="boring"> /// Use the `cherr!()` or `mstrerr!()` macro instead of calling this directly
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> pub fn new(
|
|
</span><span class="boring"> kind: T,
|
|
</span><span class="boring"> error_cause: Option<Box<dyn Error + 'static + Send + Sync>>,
|
|
</span><span class="boring"> _occurrence: Option<&'static str>,
|
|
</span><span class="boring"> ) -> Self {
|
|
</span><span class="boring"> Self { kind, error_cause }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> /// return the root cause of the error chain, if any exists
|
|
</span><span class="boring"> pub fn root_cause(&self) -> Option<&(dyn Error + 'static)> {
|
|
</span><span class="boring"> self.iter().last()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> /// Find the first error cause of type U, if any exists
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// # Examples
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// ```rust
|
|
</span><span class="boring"> /// use chainerror::*;
|
|
</span><span class="boring"> /// use std::error::Error;
|
|
</span><span class="boring"> /// use std::io;
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring"> /// Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring"> /// Ok(())
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// derive_str_cherr!(Func2Error);
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring"> /// let filename = "foo.txt";
|
|
</span><span class="boring"> /// do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
|
</span><span class="boring"> /// Ok(())
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// derive_str_cherr!(Func1Error);
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring"> /// func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
|
</span><span class="boring"> /// Ok(())
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn main() {
|
|
</span><span class="boring"> /// if let Err(e) = func1() {
|
|
</span><span class="boring"> /// if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// assert!(f1err.find_cause::<io::Error>().is_some());
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> /// # else {
|
|
</span><span class="boring"> /// # panic!();
|
|
</span><span class="boring"> /// # }
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> /// # else {
|
|
</span><span class="boring"> /// # unreachable!();
|
|
</span><span class="boring"> /// # }
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> /// ```
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> pub fn find_cause<U: Error + 'static>(&self) -> Option<&U> {
|
|
</span><span class="boring"> self.iter().filter_map(Error::downcast_ref::<U>).next()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> /// Find the first error cause of type `ChainError<U>`, if any exists
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// Same as `find_cause`, but hides the `ChainError<U>` implementation internals
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// # Examples
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// ```rust
|
|
</span><span class="boring"> /// # use chainerror::*;
|
|
</span><span class="boring"> /// # derive_str_cherr!(FooError);
|
|
</span><span class="boring"> /// # let err = ChainError::new(String::new(), None, None);
|
|
</span><span class="boring"> /// // Instead of writing
|
|
</span><span class="boring"> /// err.find_cause::<ChainError<FooError>>();
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// // leave out the ChainError<FooError> implementation detail
|
|
</span><span class="boring"> /// err.find_chain_cause::<FooError>();
|
|
</span><span class="boring"> /// ```
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> pub fn find_chain_cause<U: Error + 'static>(&self) -> Option<&ChainError<U>> {
|
|
</span><span class="boring"> self.iter()
|
|
</span><span class="boring"> .filter_map(Error::downcast_ref::<ChainError<U>>)
|
|
</span><span class="boring"> .next()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> /// Find the first error cause of type `ChainError<U>` or `U`, if any exists and return `U`
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// Same as `find_cause` and `find_chain_cause`, but hides the `ChainError<U>` implementation internals
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// # Examples
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// ```rust
|
|
</span><span class="boring"> /// # use chainerror::*;
|
|
</span><span class="boring"> /// # derive_str_cherr!(FooErrorKind);
|
|
</span><span class="boring"> /// # let err = ChainError::new(String::new(), None, None);
|
|
</span><span class="boring"> /// // Instead of writing
|
|
</span><span class="boring"> /// err.find_cause::<ChainError<FooErrorKind>>();
|
|
</span><span class="boring"> /// // and/or
|
|
</span><span class="boring"> /// err.find_chain_cause::<FooErrorKind>();
|
|
</span><span class="boring"> /// // and/or
|
|
</span><span class="boring"> /// err.find_cause::<FooErrorKind>();
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// // leave out the ChainError<FooErrorKind> implementation detail
|
|
</span><span class="boring"> /// err.find_kind_or_cause::<FooErrorKind>();
|
|
</span><span class="boring"> /// ```
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> pub fn find_kind_or_cause<U: Error + 'static>(&self) -> Option<&U> {
|
|
</span><span class="boring"> self.iter()
|
|
</span><span class="boring"> .filter_map(|e| {
|
|
</span><span class="boring"> e.downcast_ref::<ChainError<U>>()
|
|
</span><span class="boring"> .map(|e| e.kind())
|
|
</span><span class="boring"> .or_else(|| e.downcast_ref::<U>())
|
|
</span><span class="boring"> })
|
|
</span><span class="boring"> .next()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> /// Return a reference to T of `ChainError<T>`
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// # Examples
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// ```rust
|
|
</span><span class="boring"> /// use chainerror::*;
|
|
</span><span class="boring"> /// use std::error::Error;
|
|
</span><span class="boring"> /// use std::io;
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring"> /// Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring"> /// Ok(())
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// derive_str_cherr!(Func2Error);
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring"> /// let filename = "foo.txt";
|
|
</span><span class="boring"> /// do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
|
</span><span class="boring"> /// Ok(())
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// #[derive(Debug)]
|
|
</span><span class="boring"> /// enum Func1ErrorKind {
|
|
</span><span class="boring"> /// Func2,
|
|
</span><span class="boring"> /// IO(String),
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// /// impl ::std::fmt::Display for Func1ErrorKind {…}
|
|
</span><span class="boring"> /// # impl ::std::fmt::Display for Func1ErrorKind {
|
|
</span><span class="boring"> /// # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
|
</span><span class="boring"> /// # match self {
|
|
</span><span class="boring"> /// # Func1ErrorKind::Func2 => write!(f, "func1 error calling func2"),
|
|
</span><span class="boring"> /// # Func1ErrorKind::IO(filename) => write!(f, "Error reading '{}'", filename),
|
|
</span><span class="boring"> /// # }
|
|
</span><span class="boring"> /// # }
|
|
</span><span class="boring"> /// # }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn func1() -> ChainResult<(), Func1ErrorKind> {
|
|
</span><span class="boring"> /// func2().map_err(|e| cherr!(e, Func1ErrorKind::Func2))?;
|
|
</span><span class="boring"> /// do_some_io().map_err(|e| cherr!(e, Func1ErrorKind::IO("bar.txt".into())))?;
|
|
</span><span class="boring"> /// Ok(())
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// fn main() {
|
|
</span><span class="boring"> /// if let Err(e) = func1() {
|
|
</span><span class="boring"> /// match e.kind() {
|
|
</span><span class="boring"> /// Func1ErrorKind::Func2 => {}
|
|
</span><span class="boring"> /// Func1ErrorKind::IO(filename) => panic!(),
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> /// # else {
|
|
</span><span class="boring"> /// # unreachable!();
|
|
</span><span class="boring"> /// # }
|
|
</span><span class="boring"> /// }
|
|
</span><span class="boring"> /// ```
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> pub fn kind(&self) -> &T {
|
|
</span><span class="boring"> &self.kind
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> /// Returns an Iterator over all error causes/sources
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> /// # Example
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> ///
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> pub fn iter(&self) -> impl Iterator<Item = &(dyn Error + 'static)> {
|
|
</span><span class="boring"> ErrorIter {
|
|
</span><span class="boring"> current: Some(self),
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">struct ErrorIter<'a> {
|
|
</span><span class="boring"> current: Option<&'a (dyn Error + 'static)>,
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<'a> Iterator for ErrorIter<'a> {
|
|
</span><span class="boring"> type Item = &'a (dyn Error + 'static);
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn next(&mut self) -> Option<Self::Item> {
|
|
</span><span class="boring"> let current = self.current;
|
|
</span><span class="boring"> self.current = self.current.and_then(Error::source);
|
|
</span><span class="boring"> current
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T: 'static + Display + Debug> std::ops::Deref for ChainError<T> {
|
|
</span><span class="boring"> type Target = T;
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn deref(&self) -> &Self::Target {
|
|
</span><span class="boring"> &self.kind
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// Convenience trait to hide the `ChainError<T>` implementation internals
|
|
</span><span class="boring">pub trait ChainErrorDown {
|
|
</span><span class="boring"> /// Test if of type `ChainError<T>`
|
|
</span><span class="boring"> fn is_chain<T: 'static + Display + Debug>(&self) -> bool;
|
|
</span><span class="boring"> /// Downcast to a reference of `ChainError<T>`
|
|
</span><span class="boring"> fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>>;
|
|
</span><span class="boring"> /// Downcast to a mutable reference of `ChainError<T>`
|
|
</span><span class="boring"> fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>>;
|
|
</span><span class="boring"> /// Downcast to T of `ChainError<T>`
|
|
</span><span class="boring"> fn downcast_inner_ref<T: 'static + Error>(&self) -> Option<&T>;
|
|
</span><span class="boring"> /// Downcast to T mutable reference of `ChainError<T>`
|
|
</span><span class="boring"> fn downcast_inner_mut<T: 'static + Error>(&mut self) -> Option<&mut T>;
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<U: 'static + Display + Debug> ChainErrorDown for ChainError<U> {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
|
</span><span class="boring"> TypeId::of::<T>() == TypeId::of::<U>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>> {
|
|
</span><span class="boring"> if self.is_chain::<T>() {
|
|
</span><span class="boring"> #[allow(clippy::cast_ptr_alignment)]
|
|
</span><span class="boring"> unsafe {
|
|
</span><span class="boring"> #[allow(trivial_casts)]
|
|
</span><span class="boring"> Some(&*(self as *const dyn Error as *const &ChainError<T>))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> } else {
|
|
</span><span class="boring"> None
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>> {
|
|
</span><span class="boring"> if self.is_chain::<T>() {
|
|
</span><span class="boring"> #[allow(clippy::cast_ptr_alignment)]
|
|
</span><span class="boring"> unsafe {
|
|
</span><span class="boring"> #[allow(trivial_casts)]
|
|
</span><span class="boring"> Some(&mut *(self as *mut dyn Error as *mut &mut ChainError<T>))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> } else {
|
|
</span><span class="boring"> None
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_ref<T: 'static + Error>(&self) -> Option<&T> {
|
|
</span><span class="boring"> if self.is_chain::<T>() {
|
|
</span><span class="boring"> #[allow(clippy::cast_ptr_alignment)]
|
|
</span><span class="boring"> unsafe {
|
|
</span><span class="boring"> #[allow(trivial_casts)]
|
|
</span><span class="boring"> Some(&(*(self as *const dyn Error as *const &ChainError<T>)).kind)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> } else {
|
|
</span><span class="boring"> None
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_mut<T: 'static + Error>(&mut self) -> Option<&mut T> {
|
|
</span><span class="boring"> if self.is_chain::<T>() {
|
|
</span><span class="boring"> #[allow(clippy::cast_ptr_alignment)]
|
|
</span><span class="boring"> unsafe {
|
|
</span><span class="boring"> #[allow(trivial_casts)]
|
|
</span><span class="boring"> Some(&mut (*(self as *mut dyn Error as *mut &mut ChainError<T>)).kind)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> } else {
|
|
</span><span class="boring"> None
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl ChainErrorDown for dyn Error + 'static {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
|
</span><span class="boring"> self.is::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>> {
|
|
</span><span class="boring"> self.downcast_ref::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>> {
|
|
</span><span class="boring"> self.downcast_mut::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_ref<T: 'static + Error>(&self) -> Option<&T> {
|
|
</span><span class="boring"> self.downcast_ref::<T>()
|
|
</span><span class="boring"> .or_else(|| self.downcast_ref::<ChainError<T>>().map(|e| e.kind()))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_mut<T: 'static + Error>(&mut self) -> Option<&mut T> {
|
|
</span><span class="boring"> if self.is::<T>() {
|
|
</span><span class="boring"> return self.downcast_mut::<T>();
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> self.downcast_mut::<ChainError<T>>()
|
|
</span><span class="boring"> .and_then(|e| e.downcast_inner_mut::<T>())
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl ChainErrorDown for dyn Error + 'static + Send {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
|
</span><span class="boring"> self.is::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>> {
|
|
</span><span class="boring"> self.downcast_ref::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>> {
|
|
</span><span class="boring"> self.downcast_mut::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_ref<T: 'static + Error>(&self) -> Option<&T> {
|
|
</span><span class="boring"> self.downcast_ref::<T>()
|
|
</span><span class="boring"> .or_else(|| self.downcast_ref::<ChainError<T>>().map(|e| e.kind()))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_mut<T: 'static + Error>(&mut self) -> Option<&mut T> {
|
|
</span><span class="boring"> if self.is::<T>() {
|
|
</span><span class="boring"> return self.downcast_mut::<T>();
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> self.downcast_mut::<ChainError<T>>()
|
|
</span><span class="boring"> .and_then(|e| e.downcast_inner_mut::<T>())
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl ChainErrorDown for dyn Error + 'static + Send + Sync {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn is_chain<T: 'static + Display + Debug>(&self) -> bool {
|
|
</span><span class="boring"> self.is::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_ref<T: 'static + Display + Debug>(&self) -> Option<&ChainError<T>> {
|
|
</span><span class="boring"> self.downcast_ref::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_chain_mut<T: 'static + Display + Debug>(&mut self) -> Option<&mut ChainError<T>> {
|
|
</span><span class="boring"> self.downcast_mut::<ChainError<T>>()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_ref<T: 'static + Error>(&self) -> Option<&T> {
|
|
</span><span class="boring"> self.downcast_ref::<T>()
|
|
</span><span class="boring"> .or_else(|| self.downcast_ref::<ChainError<T>>().map(|e| e.kind()))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn downcast_inner_mut<T: 'static + Error>(&mut self) -> Option<&mut T> {
|
|
</span><span class="boring"> if self.is::<T>() {
|
|
</span><span class="boring"> return self.downcast_mut::<T>();
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> self.downcast_mut::<ChainError<T>>()
|
|
</span><span class="boring"> .and_then(|e| e.downcast_inner_mut::<T>())
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T: 'static + Display + Debug> Error for ChainError<T> {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn source(&self) -> Option<&(dyn Error + 'static)> {
|
|
</span><span class="boring"> self.error_cause
|
|
</span><span class="boring"> .as_ref()
|
|
</span><span class="boring"> .map(|e| e.as_ref() as &(dyn Error + 'static))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T: 'static + Display + Debug> Error for &ChainError<T> {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn source(&self) -> Option<&(dyn Error + 'static)> {
|
|
</span><span class="boring"> self.error_cause
|
|
</span><span class="boring"> .as_ref()
|
|
</span><span class="boring"> .map(|e| e.as_ref() as &(dyn Error + 'static))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T: 'static + Display + Debug> Error for &mut ChainError<T> {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn source(&self) -> Option<&(dyn Error + 'static)> {
|
|
</span><span class="boring"> self.error_cause
|
|
</span><span class="boring"> .as_ref()
|
|
</span><span class="boring"> .map(|e| e.as_ref() as &(dyn Error + 'static))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T: 'static + Display + Debug> Display for ChainError<T> {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn fmt(&self, f: &mut Formatter<'_>) -> Result {
|
|
</span><span class="boring"> write!(f, "{}", self.kind)?;
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[cfg(feature = "display-cause")]
|
|
</span><span class="boring"> {
|
|
</span><span class="boring"> if let Some(e) = self.source() {
|
|
</span><span class="boring"> writeln!(f, "\nCaused by:")?;
|
|
</span><span class="boring"> Display::fmt(&e, f)?;
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> Ok(())
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T: 'static + Display + Debug> Debug for ChainError<T> {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn fmt(&self, f: &mut Formatter<'_>) -> Result {
|
|
</span><span class="boring"> #[cfg(not(feature = "no-fileline"))]
|
|
</span><span class="boring"> {
|
|
</span><span class="boring"> if let Some(ref o) = self.occurrence {
|
|
</span><span class="boring"> Display::fmt(o, f)?;
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> if self.is_chain::<String>() {
|
|
</span><span class="boring"> Display::fmt(&self.kind, f)?;
|
|
</span><span class="boring"> } else {
|
|
</span><span class="boring"> Debug::fmt(&self.kind, f)?;
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> #[cfg(not(feature = "no-debug-cause"))]
|
|
</span><span class="boring"> {
|
|
</span><span class="boring"> if let Some(e) = self.source() {
|
|
</span><span class="boring"> writeln!(f, "\nCaused by:")?;
|
|
</span><span class="boring"> Debug::fmt(&e, f)?;
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> Ok(())
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// `ChainErrorFrom<T>` is similar to `From<T>`
|
|
</span><span class="boring">pub trait ChainErrorFrom<T>: Sized {
|
|
</span><span class="boring"> /// similar to From<T>::from()
|
|
</span><span class="boring"> fn chain_error_from(from: T, line_filename: Option<&'static str>) -> ChainError<Self>;
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// `IntoChainError<T>` is similar to `Into<T>`
|
|
</span><span class="boring">pub trait IntoChainError<T>: Sized {
|
|
</span><span class="boring"> /// similar to Into<T>::into()
|
|
</span><span class="boring"> fn into_chain_error(self, line_filename: Option<&'static str>) -> ChainError<T>;
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T, U> IntoChainError<U> for T
|
|
</span><span class="boring">where
|
|
</span><span class="boring"> U: ChainErrorFrom<T>,
|
|
</span><span class="boring">{
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn into_chain_error(self, line_filename: Option<&'static str>) -> ChainError<U> {
|
|
</span><span class="boring"> U::chain_error_from(self, line_filename)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">impl<T, U> ChainErrorFrom<T> for U
|
|
</span><span class="boring">where
|
|
</span><span class="boring"> T: Into<U>,
|
|
</span><span class="boring"> U: 'static + Display + Debug,
|
|
</span><span class="boring">{
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn chain_error_from(t: T, line_filename: Option<&'static str>) -> ChainError<Self> {
|
|
</span><span class="boring"> let e: U = t.into();
|
|
</span><span class="boring"> ChainError::new(e, None, line_filename)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/*
|
|
</span><span class="boring">impl<T, U> ChainErrorFrom<T> for U
|
|
</span><span class="boring"> where
|
|
</span><span class="boring"> T: 'static + Error + Into<Box<T>> + Clone,
|
|
</span><span class="boring"> U: 'static + Display + Debug + From<T>,
|
|
</span><span class="boring">{
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn chain_error_from(t: T, line_filename: Option<&'static str>) -> ChainError<Self> {
|
|
</span><span class="boring"> ChainError::new(U::from(t.clone()), Some(Box::from(t)), line_filename)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">}
|
|
</span><span class="boring">*/
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// map into `ChainError<T>` with `T::from(err)`
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// adds `line!()` and `file!()` information
|
|
</span><span class="boring">#[macro_export]
|
|
</span><span class="boring">macro_rules! minto_cherr {
|
|
</span><span class="boring"> ( $k:ident ) => (
|
|
</span><span class="boring"> |e| $crate::cherr!(e, $k::from(&e))
|
|
</span><span class="boring"> );
|
|
</span><span class="boring"> ( $enum:ident $(:: $enum_path:ident)* ) => (
|
|
</span><span class="boring"> |e| $crate::cherr!(e, $enum $(:: $enum_path)*::from(&e))
|
|
</span><span class="boring"> );
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// Creates a new `ChainError<T>`
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// # Examples
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// Create a new ChainError<FooError>, where `FooError` must implement `Display` and `Debug`.
|
|
</span><span class="boring">/// ```rust
|
|
</span><span class="boring">/// # use chainerror::*;
|
|
</span><span class="boring">/// # #[derive(Debug)]
|
|
</span><span class="boring">/// enum FooError {
|
|
</span><span class="boring">/// Bar,
|
|
</span><span class="boring">/// Baz(&'static str),
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// # impl ::std::fmt::Display for FooError {
|
|
</span><span class="boring">/// # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
|
</span><span class="boring">/// # match self {
|
|
</span><span class="boring">/// # FooError::Bar => write!(f, "Bar Error"),
|
|
</span><span class="boring">/// # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// // impl ::std::fmt::Display for FooError
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn do_some_stuff() -> bool {
|
|
</span><span class="boring">/// false
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func() -> ChainResult<(), FooError> {
|
|
</span><span class="boring">/// if ! do_some_stuff() {
|
|
</span><span class="boring">/// Err(cherr!(FooError::Baz("Error")))?;
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// # pub fn main() {
|
|
</span><span class="boring">/// # match func().unwrap_err().kind() {
|
|
</span><span class="boring">/// # FooError::Baz(s) if s == &"Error" => {}
|
|
</span><span class="boring">/// # _ => panic!(),
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// ```
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// Additionally an error cause can be added.
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// ```rust
|
|
</span><span class="boring">/// # use chainerror::*;
|
|
</span><span class="boring">/// # use std::io;
|
|
</span><span class="boring">/// # use std::error::Error;
|
|
</span><span class="boring">/// # #[derive(Debug)]
|
|
</span><span class="boring">/// # enum FooError {
|
|
</span><span class="boring">/// # Bar,
|
|
</span><span class="boring">/// # Baz(&'static str),
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # impl ::std::fmt::Display for FooError {
|
|
</span><span class="boring">/// # fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
|
</span><span class="boring">/// # match self {
|
|
</span><span class="boring">/// # FooError::Bar => write!(f, "Bar Error"),
|
|
</span><span class="boring">/// # FooError::Baz(s) => write!(f, "Baz Error: '{}'", s),
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// fn do_some_stuff() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func() -> ChainResult<(), FooError> {
|
|
</span><span class="boring">/// do_some_stuff().map_err(
|
|
</span><span class="boring">/// |e| cherr!(e, FooError::Baz("Error"))
|
|
</span><span class="boring">/// )?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// # pub fn main() {
|
|
</span><span class="boring">/// # match func().unwrap_err().kind() {
|
|
</span><span class="boring">/// # FooError::Baz(s) if s == &"Error" => {}
|
|
</span><span class="boring">/// # _ => panic!(),
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// ```
|
|
</span><span class="boring">#[macro_export]
|
|
</span><span class="boring">macro_rules! cherr {
|
|
</span><span class="boring"> ( $k:expr ) => ({
|
|
</span><span class="boring"> $crate::ChainError::new($k, None, Some(concat!(file!(), ":", line!(), ": ")))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( None, $k:expr ) => ({
|
|
</span><span class="boring"> $crate::ChainError::new($k, None, Some(concat!(file!(), ":", line!(), ": ")))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( None, $fmt:expr, $($arg:tt)+ ) => ({
|
|
</span><span class="boring"> $crate::cherr!(None, format!($fmt, $($arg)+ ))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( None, $fmt:expr, $($arg:tt)+ ) => ({
|
|
</span><span class="boring"> $crate::cherr!(None, format!($fmt, $($arg)+ ))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( $e:path, $k:expr ) => ({
|
|
</span><span class="boring"> $crate::ChainError::new($k, Some(Box::from($e)), Some(concat!(file!(), ":", line!(), ": ")))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( $e:path, $fmt:expr, $($arg:tt)+ ) => ({
|
|
</span><span class="boring"> $crate::cherr!($e, format!($fmt, $($arg)+ ))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// Convenience macro for `|e| cherr!(e, format!(…))`
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// # Examples
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// ```rust
|
|
</span><span class="boring">/// # use crate::chainerror::*;
|
|
</span><span class="boring">/// # use std::error::Error;
|
|
</span><span class="boring">/// # use std::io;
|
|
</span><span class="boring">/// # use std::result::Result;
|
|
</span><span class="boring">/// # fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring">/// # Ok(())
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// let filename = "foo.txt";
|
|
</span><span class="boring">/// do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// func2().map_err(mstrerr!("func1 error"))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// # fn main() {
|
|
</span><span class="boring">/// # if let Err(e) = func1() {
|
|
</span><span class="boring">/// # #[cfg(not(windows))]
|
|
</span><span class="boring">/// # assert_eq!(
|
|
</span><span class="boring">/// # format!("\n{:?}\n", e), r#"
|
|
</span><span class="boring">/// # src/lib.rs:18: func1 error
|
|
</span><span class="boring">/// # Caused by:
|
|
</span><span class="boring">/// # src/lib.rs:13: Error reading 'foo.txt'
|
|
</span><span class="boring">/// # Caused by:
|
|
</span><span class="boring">/// # Kind(NotFound)
|
|
</span><span class="boring">/// # "#
|
|
</span><span class="boring">/// # );
|
|
</span><span class="boring">/// # } else {
|
|
</span><span class="boring">/// # unreachable!();
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// ```
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// `mstrerr!()` can also be used to map a new `ChainError<T>`, where T was defined with
|
|
</span><span class="boring">/// `derive_str_cherr!(T)`
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// ```rust
|
|
</span><span class="boring">/// # use crate::chainerror::*;
|
|
</span><span class="boring">/// # use std::error::Error;
|
|
</span><span class="boring">/// # use std::io;
|
|
</span><span class="boring">/// # use std::result::Result;
|
|
</span><span class="boring">/// # fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring">/// # Ok(())
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// derive_str_cherr!(Func2Error);
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// let filename = "foo.txt";
|
|
</span><span class="boring">/// do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// derive_str_cherr!(Func1Error);
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// # fn main() {
|
|
</span><span class="boring">/// # if let Err(e) = func1() {
|
|
</span><span class="boring">/// # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
|
</span><span class="boring">/// # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
|
</span><span class="boring">/// # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
|
</span><span class="boring">/// # } else {
|
|
</span><span class="boring">/// # panic!();
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # } else {
|
|
</span><span class="boring">/// # unreachable!();
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// ```
|
|
</span><span class="boring">#[macro_export]
|
|
</span><span class="boring">macro_rules! mstrerr {
|
|
</span><span class="boring"> ( $t:path, $msg:expr ) => ({
|
|
</span><span class="boring"> |e| $crate::cherr!(e, $t ($msg.to_string()))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( $t:path, $msg:expr, ) => ({
|
|
</span><span class="boring"> |e| $crate::cherr!(e, $t ($msg.to_string()))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( $t:path, $fmt:expr, $($arg:tt)+ ) => ({
|
|
</span><span class="boring"> |e| $crate::cherr!(e, $t (format!($fmt, $($arg)+ )))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ($msg:expr) => ({
|
|
</span><span class="boring"> |e| $crate::cherr!(e, $msg.to_string())
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ($msg:expr, ) => ({
|
|
</span><span class="boring"> |e| $crate::cherr!(e, $msg.to_string())
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ($fmt:expr, $($arg:tt)+) => ({
|
|
</span><span class="boring"> |e| $crate::cherr!(e, format!($fmt, $($arg)+ ))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// Convenience macro for `cherr!(T(format!(…)))` where `T(String)`
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// # Examples
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// ```rust
|
|
</span><span class="boring">/// # use crate::chainerror::*;
|
|
</span><span class="boring">/// # use std::error::Error;
|
|
</span><span class="boring">/// # use std::result::Result;
|
|
</span><span class="boring">/// derive_str_cherr!(Func2Error);
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func2() -> ChainResult<(), Func2Error> {
|
|
</span><span class="boring">/// let filename = "foo.txt";
|
|
</span><span class="boring">/// Err(strerr!(Func2Error, "Error reading '{}'", filename))
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// derive_str_cherr!(Func1Error);
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func1() -> Result<(), Box<dyn Error>> {
|
|
</span><span class="boring">/// func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// # fn main() {
|
|
</span><span class="boring">/// # if let Err(e) = func1() {
|
|
</span><span class="boring">/// # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
|
</span><span class="boring">/// # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
|
</span><span class="boring">/// # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
|
</span><span class="boring">/// # } else {
|
|
</span><span class="boring">/// # panic!();
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # } else {
|
|
</span><span class="boring">/// # unreachable!();
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// ```
|
|
</span><span class="boring">#[macro_export]
|
|
</span><span class="boring">macro_rules! strerr {
|
|
</span><span class="boring"> ( $t:path, $msg:expr ) => ({
|
|
</span><span class="boring"> $crate::cherr!($t ($msg.to_string()))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( $t:path, $msg:expr, ) => ({
|
|
</span><span class="boring"> $crate::cherr!($t ($msg.to_string()))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ( $t:path, $fmt:expr, $($arg:tt)+ ) => ({
|
|
</span><span class="boring"> $crate::cherr!($t (format!($fmt, $($arg)+ )))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ($msg:expr) => ({
|
|
</span><span class="boring"> $crate::cherr!($msg.to_string())
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ($msg:expr, ) => ({
|
|
</span><span class="boring"> $crate::cherr!($msg.to_string())
|
|
</span><span class="boring"> });
|
|
</span><span class="boring"> ($fmt:expr, $($arg:tt)+) => ({
|
|
</span><span class="boring"> $crate::cherr!(format!($fmt, $($arg)+ ))
|
|
</span><span class="boring"> });
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// Convenience macro to create a "new type" T(String) and implement Display + Debug for T
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// # Examples
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// ```rust
|
|
</span><span class="boring">/// # use crate::chainerror::*;
|
|
</span><span class="boring">/// # use std::error::Error;
|
|
</span><span class="boring">/// # use std::io;
|
|
</span><span class="boring">/// # use std::result::Result;
|
|
</span><span class="boring">/// # fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
|
|
</span><span class="boring">/// # Err(io::Error::from(io::ErrorKind::NotFound))?;
|
|
</span><span class="boring">/// # Ok(())
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// derive_str_cherr!(Func2Error);
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func2() -> ChainResult<(), Func2Error> {
|
|
</span><span class="boring">/// let filename = "foo.txt";
|
|
</span><span class="boring">/// do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// derive_str_cherr!(Func1Error);
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn func1() -> Result<(), Box<dyn Error>> {
|
|
</span><span class="boring">/// func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// # fn main() {
|
|
</span><span class="boring">/// # if let Err(e) = func1() {
|
|
</span><span class="boring">/// # if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
|
|
</span><span class="boring">/// # assert!(f1err.find_cause::<ChainError<Func2Error>>().is_some());
|
|
</span><span class="boring">/// # assert!(f1err.find_chain_cause::<Func2Error>().is_some());
|
|
</span><span class="boring">/// # } else {
|
|
</span><span class="boring">/// # panic!();
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # } else {
|
|
</span><span class="boring">/// # unreachable!();
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// # }
|
|
</span><span class="boring">/// ```
|
|
</span><span class="boring">#[macro_export]
|
|
</span><span class="boring">macro_rules! derive_str_cherr {
|
|
</span><span class="boring"> ($e:ident) => {
|
|
</span><span class="boring"> #[derive(Clone)]
|
|
</span><span class="boring"> pub struct $e(pub String);
|
|
</span><span class="boring"> impl ::std::fmt::Display for $e {
|
|
</span><span class="boring"> fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
|
</span><span class="boring"> write!(f, "{}", self.0)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> impl ::std::fmt::Debug for $e {
|
|
</span><span class="boring"> fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
|
|
</span><span class="boring"> write!(f, "{}({})", stringify!($e), self.0)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> impl ::std::error::Error for $e {}
|
|
</span><span class="boring"> };
|
|
</span><span class="boring">}
|
|
</span><span class="boring">
|
|
</span><span class="boring">/// Derive an Error for an ErrorKind, which wraps a `ChainError` and implements a `kind()` method
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// It basically hides `ChainError` to the outside and only exposes the `kind()`
|
|
</span><span class="boring">/// method.
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// Error::kind() returns the ErrorKind
|
|
</span><span class="boring">/// Error::source() returns the parent error
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// # Examples
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// ```rust
|
|
</span><span class="boring">/// use std::io;
|
|
</span><span class="boring">/// use chainerror::*;
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// fn do_some_io(_f: &str) -> std::result::Result<(), io::Error> {
|
|
</span><span class="boring">/// return Err(io::Error::from(io::ErrorKind::NotFound));
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// #[derive(Debug, Clone)]
|
|
</span><span class="boring">/// pub enum ErrorKind {
|
|
</span><span class="boring">/// IO(String),
|
|
</span><span class="boring">/// FatalError(String),
|
|
</span><span class="boring">/// Unknown,
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// derive_err_kind!(Error, ErrorKind);
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// impl std::fmt::Display for ErrorKind {
|
|
</span><span class="boring">/// fn fmt(&self, f: &mut ::std::fmt::Formatter) -> std::fmt::Result {
|
|
</span><span class="boring">/// match self {
|
|
</span><span class="boring">/// ErrorKind::FatalError(e) => write!(f, "fatal error {}", e),
|
|
</span><span class="boring">/// ErrorKind::Unknown => write!(f, "unknown error"),
|
|
</span><span class="boring">/// ErrorKind::IO(filename) => write!(f, "Error reading '{}'", filename),
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// impl ErrorKind {
|
|
</span><span class="boring">/// fn from_io_error(e: &io::Error, f: String) -> Self {
|
|
</span><span class="boring">/// match e.kind() {
|
|
</span><span class="boring">/// io::ErrorKind::BrokenPipe => panic!("Should not happen"),
|
|
</span><span class="boring">/// io::ErrorKind::ConnectionReset => {
|
|
</span><span class="boring">/// ErrorKind::FatalError(format!("While reading `{}`: {}", f, e))
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// _ => ErrorKind::IO(f),
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// impl From<&io::Error> for ErrorKind {
|
|
</span><span class="boring">/// fn from(e: &io::Error) -> Self {
|
|
</span><span class="boring">/// ErrorKind::IO(format!("{}", e))
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// pub fn func1() -> std::result::Result<(), Error> {
|
|
</span><span class="boring">/// let filename = "bar.txt";
|
|
</span><span class="boring">///
|
|
</span><span class="boring">/// do_some_io(filename)
|
|
</span><span class="boring">/// .map_err(|e| cherr!(e, ErrorKind::from_io_error(&e, filename.into())))?;
|
|
</span><span class="boring">/// do_some_io(filename).map_err(|e| cherr!(e, ErrorKind::IO(filename.into())))?;
|
|
</span><span class="boring">/// do_some_io(filename).map_err(|e| cherr!(e, ErrorKind::from(&e)))?;
|
|
</span><span class="boring">/// do_some_io(filename).map_err(minto_cherr!(ErrorKind))?;
|
|
</span><span class="boring">/// Ok(())
|
|
</span><span class="boring">/// }
|
|
</span><span class="boring">/// ```
|
|
</span><span class="boring">#[macro_export]
|
|
</span><span class="boring">macro_rules! derive_err_kind {
|
|
</span><span class="boring"> ($e:ident, $k:ident) => {
|
|
</span><span class="boring"> pub struct $e($crate::ChainError<$k>);
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl $e {
|
|
</span><span class="boring"> pub fn kind(&self) -> &$k {
|
|
</span><span class="boring"> self.0.kind()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl From<$k> for $e {
|
|
</span><span class="boring"> fn from(e: $k) -> Self {
|
|
</span><span class="boring"> $e($crate::ChainError::new(e, None, None))
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl From<ChainError<$k>> for $e {
|
|
</span><span class="boring"> fn from(e: $crate::ChainError<$k>) -> Self {
|
|
</span><span class="boring"> $e(e)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl From<&$e> for $k
|
|
</span><span class="boring"> where
|
|
</span><span class="boring"> $k: Clone,
|
|
</span><span class="boring"> {
|
|
</span><span class="boring"> fn from(e: &$e) -> Self {
|
|
</span><span class="boring"> e.kind().clone()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl $crate::ChainErrorFrom<$e> for $k
|
|
</span><span class="boring"> where
|
|
</span><span class="boring"> $k: Clone,
|
|
</span><span class="boring"> {
|
|
</span><span class="boring"> #[inline]
|
|
</span><span class="boring"> fn chain_error_from(
|
|
</span><span class="boring"> t: $e,
|
|
</span><span class="boring"> line_filename: Option<&'static str>,
|
|
</span><span class="boring"> ) -> $crate::ChainError<$k> {
|
|
</span><span class="boring"> $crate::ChainError::new((*t.kind()).clone(), Some(Box::from(t)), line_filename)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl std::error::Error for $e {
|
|
</span><span class="boring"> fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
|
|
</span><span class="boring"> self.0.source()
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl std::fmt::Display for $e {
|
|
</span><span class="boring"> fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
|
|
</span><span class="boring"> std::fmt::Display::fmt(&self.0, f)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring">
|
|
</span><span class="boring"> impl std::fmt::Debug for $e {
|
|
</span><span class="boring"> fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
|
|
</span><span class="boring"> std::fmt::Debug::fmt(&self.0, f)
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> }
|
|
</span><span class="boring"> };
|
|
</span><span class="boring">}
|
|
</span><span class="boring">}
|
|
</span></code></pre></pre>
|
|
<h3><a class="header" href="#what-did-we-do-here" id="what-did-we-do-here">What did we do here?</a></h3>
|
|
<pre><code class="language-rust ignore"> if let Err(e) = do_some_io() {
|
|
Err(cherr!(e, "func2 error"))?;
|
|
}
|
|
</code></pre>
|
|
<p>The macro <code>cherr!(olderror, newerror)</code> stores <code>olderror</code> as the source/cause of <code>newerror</code>
|
|
along with the filename (<code>file!()</code>) and line number (<code>line!()</code>)
|
|
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 + Send + Sync>)</code> as a result.</p>
|
|
<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>
|
|
<p><code>ChainError<T></code> in our case is <code>ChainError<String></code>.</p>
|
|
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