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Diffstat (limited to 'src/libstd/error.rs')
| -rw-r--r-- | src/libstd/error.rs | 137 |
1 files changed, 0 insertions, 137 deletions
diff --git a/src/libstd/error.rs b/src/libstd/error.rs deleted file mode 100644 index ff128461978..00000000000 --- a/src/libstd/error.rs +++ /dev/null @@ -1,137 +0,0 @@ -// Copyright 2014 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -//! Traits for working with Errors. -//! -//! # The `Error` trait -//! -//! `Error` is a trait representing the basic expectations for error values, -//! i.e. values of type `E` in `Result<T, E>`. At a minimum, errors must provide -//! a description, but they may optionally provide additional detail and cause -//! chain information: -//! -//! ``` -//! trait Error { -//! fn description(&self) -> &str; -//! -//! fn detail(&self) -> Option<String> { None } -//! fn cause(&self) -> Option<&Error> { None } -//! } -//! ``` -//! -//! The `cause` method is generally used when errors cross "abstraction -//! boundaries", i.e. when a one module must report an error that is "caused" -//! by an error from a lower-level module. This setup makes it possible for the -//! high-level module to provide its own errors that do not commit to any -//! particular implementation, but also reveal some of its implementation for -//! debugging via `cause` chains. -//! -//! # The `FromError` trait -//! -//! `FromError` is a simple trait that expresses conversions between different -//! error types. To provide maximum flexibility, it does not require either of -//! the types to actually implement the `Error` trait, although this will be the -//! common case. -//! -//! The main use of this trait is in the `try!` macro, which uses it to -//! automatically convert a given error to the error specified in a function's -//! return type. -//! -//! For example, -//! -//! ``` -//! use std::error::FromError; -//! use std::io::{File, IoError}; -//! use std::os::{MemoryMap, MapError}; -//! use std::path::Path; -//! -//! enum MyError { -//! Io(IoError), -//! Map(MapError) -//! } -//! -//! impl FromError<IoError> for MyError { -//! fn from_error(err: IoError) -> MyError { -//! MyError::Io(err) -//! } -//! } -//! -//! impl FromError<MapError> for MyError { -//! fn from_error(err: MapError) -> MyError { -//! MyError::Map(err) -//! } -//! } -//! -//! #[allow(unused_variables)] -//! fn open_and_map() -> Result<(), MyError> { -//! let f = try!(File::open(&Path::new("foo.txt"))); -//! let m = try!(MemoryMap::new(0, &[])); -//! // do something interesting here... -//! Ok(()) -//! } -//! ``` - -#![stable] - -use prelude::v1::*; - -use str::Utf8Error; -use string::{FromUtf8Error, FromUtf16Error}; - -/// Base functionality for all errors in Rust. -#[unstable = "the exact API of this trait may change"] -pub trait Error { - /// A short description of the error; usually a static string. - fn description(&self) -> &str; - - /// A detailed description of the error, usually including dynamic information. - fn detail(&self) -> Option<String> { None } - - /// The lower-level cause of this error, if any. - fn cause(&self) -> Option<&Error> { None } -} - -/// A trait for types that can be converted from a given error type `E`. -#[stable] -pub trait FromError<E> { - /// Perform the conversion. - fn from_error(err: E) -> Self; -} - -// Any type is convertable from itself -#[stable] -impl<E> FromError<E> for E { - fn from_error(err: E) -> E { - err - } -} - -#[stable] -impl Error for Utf8Error { - fn description(&self) -> &str { - match *self { - Utf8Error::TooShort => "invalid utf-8: not enough bytes", - Utf8Error::InvalidByte(..) => "invalid utf-8: corrupt contents", - } - } - - fn detail(&self) -> Option<String> { Some(self.to_string()) } -} - -#[stable] -impl Error for FromUtf8Error { - fn description(&self) -> &str { "invalid utf-8" } - fn detail(&self) -> Option<String> { Some(self.to_string()) } -} - -#[stable] -impl Error for FromUtf16Error { - fn description(&self) -> &str { "invalid utf-16" } -} |
