359 lines
12 KiB
Rust
359 lines
12 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use boxed::Box;
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use convert::Into;
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use error;
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use fmt;
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use marker::{Send, Sync};
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use option::Option::{self, Some, None};
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use result;
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use sys;
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/// A specialized [`Result`][result] type for I/O operations.
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///
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/// [result]: ../result/enum.Result.html
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///
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/// This type is broadly used across `std::io` for any operation which may
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/// produce an error.
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///
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/// This typedef is generally used to avoid writing out `io::Error` directly and
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/// is otherwise a direct mapping to `Result`.
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///
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/// While usual Rust style is to import types directly, aliases of `Result`
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/// often are not, to make it easier to distinguish between them. `Result` is
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/// generally assumed to be `std::result::Result`, and so users of this alias
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/// will generally use `io::Result` instead of shadowing the prelude's import
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/// of `std::result::Result`.
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///
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/// # Examples
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///
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/// A convenience function that bubbles an `io::Result` to its caller:
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///
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/// ```
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/// use std::io;
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///
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/// fn get_string() -> io::Result<String> {
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/// let mut buffer = String::new();
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///
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/// try!(io::stdin().read_line(&mut buffer));
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///
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/// Ok(buffer)
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/// }
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub type Result<T> = result::Result<T, Error>;
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/// The error type for I/O operations of the `Read`, `Write`, `Seek`, and
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/// associated traits.
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///
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/// Errors mostly originate from the underlying OS, but custom instances of
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/// `Error` can be created with crafted error messages and a particular value of
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/// `ErrorKind`.
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#[derive(Debug)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Error {
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repr: Repr,
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}
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enum Repr {
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Os(i32),
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Custom(Box<Custom>),
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}
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#[derive(Debug)]
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struct Custom {
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kind: ErrorKind,
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error: Box<error::Error+Send+Sync>,
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}
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/// A list specifying general categories of I/O error.
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///
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/// This list is intended to grow over time and it is not recommended to
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/// exhaustively match against it.
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#[derive(Copy, PartialEq, Eq, Clone, Debug)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub enum ErrorKind {
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/// An entity was not found, often a file.
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#[stable(feature = "rust1", since = "1.0.0")]
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NotFound,
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/// The operation lacked the necessary privileges to complete.
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#[stable(feature = "rust1", since = "1.0.0")]
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PermissionDenied,
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/// The connection was refused by the remote server.
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#[stable(feature = "rust1", since = "1.0.0")]
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ConnectionRefused,
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/// The connection was reset by the remote server.
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#[stable(feature = "rust1", since = "1.0.0")]
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ConnectionReset,
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/// The connection was aborted (terminated) by the remote server.
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#[stable(feature = "rust1", since = "1.0.0")]
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ConnectionAborted,
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/// The network operation failed because it was not connected yet.
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#[stable(feature = "rust1", since = "1.0.0")]
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NotConnected,
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/// A socket address could not be bound because the address is already in
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/// use elsewhere.
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#[stable(feature = "rust1", since = "1.0.0")]
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AddrInUse,
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/// A nonexistent interface was requested or the requested address was not
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/// local.
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#[stable(feature = "rust1", since = "1.0.0")]
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AddrNotAvailable,
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/// The operation failed because a pipe was closed.
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#[stable(feature = "rust1", since = "1.0.0")]
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BrokenPipe,
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/// An entity already exists, often a file.
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#[stable(feature = "rust1", since = "1.0.0")]
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AlreadyExists,
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/// The operation needs to block to complete, but the blocking operation was
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/// requested to not occur.
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#[stable(feature = "rust1", since = "1.0.0")]
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WouldBlock,
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/// A parameter was incorrect.
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#[stable(feature = "rust1", since = "1.0.0")]
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InvalidInput,
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/// Data not valid for the operation were encountered.
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///
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/// Unlike `InvalidInput`, this typically means that the operation
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/// parameters were valid, however the error was caused by malformed
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/// input data.
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#[stable(feature = "io_invalid_data", since = "1.2.0")]
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InvalidData,
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/// The I/O operation's timeout expired, causing it to be canceled.
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#[stable(feature = "rust1", since = "1.0.0")]
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TimedOut,
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/// An error returned when an operation could not be completed because a
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/// call to `write` returned `Ok(0)`.
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///
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/// This typically means that an operation could only succeed if it wrote a
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/// particular number of bytes but only a smaller number of bytes could be
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/// written.
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#[stable(feature = "rust1", since = "1.0.0")]
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WriteZero,
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/// This operation was interrupted.
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///
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/// Interrupted operations can typically be retried.
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#[stable(feature = "rust1", since = "1.0.0")]
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Interrupted,
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/// Any I/O error not part of this list.
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#[stable(feature = "rust1", since = "1.0.0")]
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Other,
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/// Any I/O error not part of this list.
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#[unstable(feature = "io_error_internals",
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reason = "better expressed through extensible enums that this \
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enum cannot be exhaustively matched against")]
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#[doc(hidden)]
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__Nonexhaustive,
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}
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impl Error {
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/// Creates a new I/O error from a known kind of error as well as an
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/// arbitrary error payload.
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///
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/// This function is used to generically create I/O errors which do not
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/// originate from the OS itself. The `error` argument is an arbitrary
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/// payload which will be contained in this `Error`.
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///
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/// # Examples
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///
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/// ```
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/// use std::io::{Error, ErrorKind};
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///
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/// // errors can be created from strings
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/// let custom_error = Error::new(ErrorKind::Other, "oh no!");
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///
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/// // errors can also be created from other errors
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/// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new<E>(kind: ErrorKind, error: E) -> Error
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where E: Into<Box<error::Error+Send+Sync>>
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{
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Error {
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repr: Repr::Custom(Box::new(Custom {
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kind: kind,
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error: error.into(),
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}))
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}
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}
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/// Returns an error representing the last OS error which occurred.
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///
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/// This function reads the value of `errno` for the target platform (e.g.
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/// `GetLastError` on Windows) and will return a corresponding instance of
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/// `Error` for the error code.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn last_os_error() -> Error {
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Error::from_raw_os_error(sys::os::errno() as i32)
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}
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/// Creates a new instance of an `Error` from a particular OS error code.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn from_raw_os_error(code: i32) -> Error {
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Error { repr: Repr::Os(code) }
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}
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/// Returns the OS error that this error represents (if any).
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///
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/// If this `Error` was constructed via `last_os_error` or
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/// `from_raw_os_error`, then this function will return `Some`, otherwise
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/// it will return `None`.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn raw_os_error(&self) -> Option<i32> {
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match self.repr {
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Repr::Os(i) => Some(i),
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Repr::Custom(..) => None,
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}
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}
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/// Returns a reference to the inner error wrapped by this error (if any).
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///
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/// If this `Error` was constructed via `new` then this function will
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/// return `Some`, otherwise it will return `None`.
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#[unstable(feature = "io_error_inner",
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reason = "recently added and requires UFCS to downcast")]
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pub fn get_ref(&self) -> Option<&(error::Error+Send+Sync+'static)> {
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match self.repr {
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Repr::Os(..) => None,
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Repr::Custom(ref c) => Some(&*c.error),
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}
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}
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/// Returns a mutable reference to the inner error wrapped by this error
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/// (if any).
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///
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/// If this `Error` was constructed via `new` then this function will
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/// return `Some`, otherwise it will return `None`.
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#[unstable(feature = "io_error_inner",
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reason = "recently added and requires UFCS to downcast")]
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pub fn get_mut(&mut self) -> Option<&mut (error::Error+Send+Sync+'static)> {
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match self.repr {
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Repr::Os(..) => None,
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Repr::Custom(ref mut c) => Some(&mut *c.error),
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}
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}
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/// Consumes the `Error`, returning its inner error (if any).
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///
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/// If this `Error` was constructed via `new` then this function will
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/// return `Some`, otherwise it will return `None`.
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#[unstable(feature = "io_error_inner",
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reason = "recently added and requires UFCS to downcast")]
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pub fn into_inner(self) -> Option<Box<error::Error+Send+Sync>> {
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match self.repr {
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Repr::Os(..) => None,
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Repr::Custom(c) => Some(c.error)
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}
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}
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/// Returns the corresponding `ErrorKind` for this error.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn kind(&self) -> ErrorKind {
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match self.repr {
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Repr::Os(code) => sys::decode_error_kind(code),
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Repr::Custom(ref c) => c.kind,
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}
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}
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}
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impl fmt::Debug for Repr {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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match self {
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&Repr::Os(ref code) =>
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fmt.debug_struct("Os").field("code", code)
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.field("message", &sys::os::error_string(*code)).finish(),
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&Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
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}
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl fmt::Display for Error {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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match self.repr {
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Repr::Os(code) => {
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let detail = sys::os::error_string(code);
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write!(fmt, "{} (os error {})", detail, code)
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}
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Repr::Custom(ref c) => c.error.fmt(fmt),
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}
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl error::Error for Error {
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fn description(&self) -> &str {
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match self.repr {
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Repr::Os(..) => "os error",
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Repr::Custom(ref c) => c.error.description(),
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}
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}
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fn cause(&self) -> Option<&error::Error> {
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match self.repr {
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Repr::Os(..) => None,
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Repr::Custom(ref c) => c.error.cause(),
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}
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}
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}
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fn _assert_error_is_sync_send() {
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fn _is_sync_send<T: Sync+Send>() {}
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_is_sync_send::<Error>();
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}
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#[cfg(test)]
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mod test {
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use prelude::v1::*;
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use super::{Error, ErrorKind};
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use error;
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use error::Error as error_Error;
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use fmt;
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use sys::os::error_string;
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#[test]
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fn test_debug_error() {
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let code = 6;
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let msg = error_string(code);
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let err = Error { repr: super::Repr::Os(code) };
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let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
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assert_eq!(format!("{:?}", err), expected);
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}
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#[test]
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fn test_downcasting() {
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#[derive(Debug)]
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struct TestError;
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impl fmt::Display for TestError {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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Ok(())
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}
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}
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impl error::Error for TestError {
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fn description(&self) -> &str {
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"asdf"
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}
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}
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// we have to call all of these UFCS style right now since method
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// resolution won't implicitly drop the Send+Sync bounds
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let mut err = Error::new(ErrorKind::Other, TestError);
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assert!(error::Error::is::<TestError>(err.get_ref().unwrap()));
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assert_eq!("asdf", err.get_ref().unwrap().description());
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assert!(error::Error::is::<TestError>(err.get_mut().unwrap()));
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let extracted = err.into_inner().unwrap();
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error::Error::downcast::<TestError>(extracted).unwrap();
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}
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}
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