552 lines
17 KiB
Rust
552 lines
17 KiB
Rust
#[cfg(feature="alloc")] use alloc::boxed::Box;
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#[cfg(not(feature="alloc"))] use ::FakeBox as Box;
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use core::convert::Into;
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use core::fmt;
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use core::marker::{Send, Sync};
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use core::option::Option::{self, Some, None};
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use core::result;
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#[cfg(feature="collections")] use collections::string::String;
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#[cfg(not(feature="collections"))] use ::ErrorString as String;
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use core::convert::From;
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/// A specialized [`Result`](../result/enum.Result.html) type for I/O
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/// operations.
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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`][`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`][`Result`].
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///
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/// [`std::io`]: ../io/index.html
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/// [`io::Error`]: ../io/struct.Error.html
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/// [`Result`]: ../result/enum.Result.html
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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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/// 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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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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///
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/// [`Read`]: ../io/trait.Read.html
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/// [`Write`]: ../io/trait.Write.html
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/// [`Seek`]: ../io/trait.Seek.html
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/// [`ErrorKind`]: enum.ErrorKind.html
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pub struct Error {
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repr: Repr,
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}
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impl fmt::Debug for Error {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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fmt::Debug::fmt(&self.repr, f)
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}
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}
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enum Repr {
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Os(i32),
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Simple(ErrorKind),
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#[cfg(feature="alloc")]
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Custom(Box<Custom>),
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#[cfg(not(feature="alloc"))]
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Custom(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: String,
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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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///
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/// It is used with the [`io::Error`] type.
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///
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/// [`io::Error`]: struct.Error.html
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#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
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#[allow(deprecated)]
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#[non_exhaustive]
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pub enum ErrorKind {
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/// An entity was not found, often a file.
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NotFound,
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/// The operation lacked the necessary privileges to complete.
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PermissionDenied,
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/// The connection was refused by the remote server.
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ConnectionRefused,
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/// The connection was reset by the remote server.
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ConnectionReset,
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/// The connection was aborted (terminated) by the remote server.
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ConnectionAborted,
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/// The network operation failed because it was not connected yet.
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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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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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AddrNotAvailable,
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/// The operation failed because a pipe was closed.
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BrokenPipe,
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/// An entity already exists, often a file.
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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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WouldBlock,
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/// A parameter was incorrect.
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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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///
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/// For example, a function that reads a file into a string will error with
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/// `InvalidData` if the file's contents are not valid UTF-8.
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///
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/// [`InvalidInput`]: #variant.InvalidInput
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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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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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///
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/// [`write`]: ../../std/io/trait.Write.html#tymethod.write
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/// [`Ok(0)`]: ../../std/io/type.Result.html
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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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Interrupted,
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/// Any I/O error not part of this list.
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Other,
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/// An error returned when an operation could not be completed because an
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/// "end of file" was reached prematurely.
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///
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/// This typically means that an operation could only succeed if it read a
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/// particular number of bytes but only a smaller number of bytes could be
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/// read.
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UnexpectedEof,
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}
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impl ErrorKind {
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pub(crate) fn as_str(&self) -> &'static str {
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match *self {
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ErrorKind::NotFound => "entity not found",
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ErrorKind::PermissionDenied => "permission denied",
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ErrorKind::ConnectionRefused => "connection refused",
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ErrorKind::ConnectionReset => "connection reset",
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ErrorKind::ConnectionAborted => "connection aborted",
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ErrorKind::NotConnected => "not connected",
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ErrorKind::AddrInUse => "address in use",
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ErrorKind::AddrNotAvailable => "address not available",
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ErrorKind::BrokenPipe => "broken pipe",
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ErrorKind::AlreadyExists => "entity already exists",
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ErrorKind::WouldBlock => "operation would block",
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ErrorKind::InvalidInput => "invalid input parameter",
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ErrorKind::InvalidData => "invalid data",
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ErrorKind::TimedOut => "timed out",
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ErrorKind::WriteZero => "write zero",
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ErrorKind::Interrupted => "operation interrupted",
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ErrorKind::Other => "other os error",
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ErrorKind::UnexpectedEof => "unexpected end of file",
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}
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}
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}
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/// Intended for use for errors not exposed to the user, where allocating onto
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/// the heap (for normal construction via Error::new) is too costly.
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impl From<ErrorKind> for Error {
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/// Converts an [`ErrorKind`] into an [`Error`].
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///
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/// This conversion allocates a new error with a simple representation of error kind.
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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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/// let not_found = ErrorKind::NotFound;
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/// let error = Error::from(not_found);
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/// assert_eq!("entity not found", format!("{}", error));
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/// ```
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///
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/// [`ErrorKind`]: ../../std/io/enum.ErrorKind.html
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/// [`Error`]: ../../std/io/struct.Error.html
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#[inline]
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fn from(kind: ErrorKind) -> Error {
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Error { repr: Repr::Simple(kind) }
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}
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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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pub fn new<E>(kind: ErrorKind, error: E) -> Error
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where
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E: Into<String>,
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{
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Self::_new(kind, error.into())
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}
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fn _new(kind: ErrorKind, error: String) -> Error {
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Error { repr: Repr::Custom(Box::new(Custom { kind, error })) }
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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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///
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/// # Examples
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///
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/// On Linux:
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///
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/// ```
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/// # if cfg!(target_os = "linux") {
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/// use std::io;
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///
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/// let error = io::Error::from_raw_os_error(22);
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/// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
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/// # }
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/// ```
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///
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/// On Windows:
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///
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/// ```
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/// # if cfg!(windows) {
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/// use std::io;
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///
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/// let error = io::Error::from_raw_os_error(10022);
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/// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
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/// # }
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/// ```
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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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///
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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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/// fn print_os_error(err: &Error) {
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/// if let Some(raw_os_err) = err.raw_os_error() {
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/// println!("raw OS error: {:?}", raw_os_err);
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/// } else {
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/// println!("Not an OS error");
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/// }
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/// }
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///
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/// fn main() {
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/// // Will print "raw OS error: ...".
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/// print_os_error(&Error::last_os_error());
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/// // Will print "Not an OS error".
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/// print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
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/// }
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/// ```
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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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Repr::Simple(..) => 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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///
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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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/// fn print_error(err: &Error) {
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/// if let Some(inner_err) = err.get_ref() {
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/// println!("Inner error: {:?}", inner_err);
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/// } else {
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/// println!("No inner error");
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/// }
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/// }
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///
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/// fn main() {
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/// // Will print "No inner error".
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/// print_error(&Error::last_os_error());
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/// // Will print "Inner error: ...".
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/// print_error(&Error::new(ErrorKind::Other, "oh no!"));
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/// }
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/// ```
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pub fn get_ref(&self) -> Option<&String> {
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match self.repr {
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Repr::Os(..) => None,
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Repr::Simple(..) => 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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///
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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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/// use std::{error, fmt};
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/// use std::fmt::Display;
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///
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/// #[derive(Debug)]
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/// struct MyError {
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/// v: String,
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/// }
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///
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/// impl MyError {
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/// fn new() -> MyError {
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/// MyError {
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/// v: "oh no!".to_string()
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/// }
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/// }
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///
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/// fn change_message(&mut self, new_message: &str) {
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/// self.v = new_message.to_string();
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/// }
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/// }
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///
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/// impl error::Error for MyError {}
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///
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/// impl Display for MyError {
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/// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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/// write!(f, "MyError: {}", &self.v)
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/// }
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/// }
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///
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/// fn change_error(mut err: Error) -> Error {
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/// if let Some(inner_err) = err.get_mut() {
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/// inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
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/// }
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/// err
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/// }
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///
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/// fn print_error(err: &Error) {
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/// if let Some(inner_err) = err.get_ref() {
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/// println!("Inner error: {}", inner_err);
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/// } else {
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/// println!("No inner error");
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/// }
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/// }
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///
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/// fn main() {
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/// // Will print "No inner error".
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/// print_error(&change_error(Error::last_os_error()));
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/// // Will print "Inner error: ...".
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/// print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
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/// }
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/// ```
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pub fn get_mut(&mut self) -> Option<&mut String> {
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match self.repr {
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Repr::Os(..) => None,
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Repr::Simple(..) => 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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///
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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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/// fn print_error(err: Error) {
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/// if let Some(inner_err) = err.into_inner() {
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/// println!("Inner error: {}", inner_err);
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/// } else {
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/// println!("No inner error");
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/// }
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/// }
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///
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/// fn main() {
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/// // Will print "No inner error".
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/// print_error(Error::last_os_error());
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/// // Will print "Inner error: ...".
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/// print_error(Error::new(ErrorKind::Other, "oh no!"));
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/// }
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/// ```
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pub fn into_inner(self) -> Option<String> {
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match self.repr {
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Repr::Os(..) => None,
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Repr::Simple(..) => 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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///
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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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/// fn print_error(err: Error) {
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/// println!("{:?}", err.kind());
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/// }
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///
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/// fn main() {
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/// // Will print "No inner error".
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/// print_error(Error::last_os_error());
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/// // Will print "Inner error: ...".
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/// print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
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/// }
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/// ```
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pub fn kind(&self) -> ErrorKind {
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match self.repr {
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Repr::Os(_code) => ErrorKind::Other,
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Repr::Custom(ref c) => c.kind,
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Repr::Simple(kind) => 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(code) => fmt
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.debug_struct("Os")
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.field("code", &code)
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.finish(),
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Repr::Custom(ref c) => fmt::Debug::fmt(&c, fmt),
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Repr::Simple(kind) => fmt.debug_tuple("Kind").field(&kind).finish(),
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}
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}
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}
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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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write!(fmt, "os error {}", code)
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}
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Repr::Custom(ref c) => c.error.fmt(fmt),
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Repr::Simple(kind) => write!(fmt, "{}", kind.as_str()),
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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 super::{Custom, Error, ErrorKind, Repr};
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use crate::error;
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use crate::fmt;
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use crate::sys::decode_error_kind;
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use crate::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 kind = decode_error_kind(code);
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let err = Error {
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repr: Repr::Custom(box Custom {
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kind: ErrorKind::InvalidInput,
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error: box Error { repr: super::Repr::Os(code) },
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}),
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};
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let expected = format!(
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"Custom {{ \
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kind: InvalidInput, \
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error: Os {{ \
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code: {:?}, \
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kind: {:?}, \
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message: {:?} \
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}} \
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}}",
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code, kind, msg
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);
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assert_eq!(format!("{:?}", err), expected);
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}
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|
|
|
#[test]
|
|
fn test_downcasting() {
|
|
#[derive(Debug)]
|
|
struct TestError;
|
|
|
|
impl fmt::Display for TestError {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.write_str("asdf")
|
|
}
|
|
}
|
|
|
|
impl error::Error for TestError {}
|
|
|
|
// we have to call all of these UFCS style right now since method
|
|
// resolution won't implicitly drop the Send+Sync bounds
|
|
let mut err = Error::new(ErrorKind::Other, TestError);
|
|
assert!(err.get_ref().unwrap().is::<TestError>());
|
|
assert_eq!("asdf", err.get_ref().unwrap().to_string());
|
|
assert!(err.get_mut().unwrap().is::<TestError>());
|
|
let extracted = err.into_inner().unwrap();
|
|
extracted.downcast::<TestError>().unwrap();
|
|
}
|
|
}
|