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//! Buffering wrappers for I/O traits
mod bufreader;
mod bufwriter;
mod linewriter;
mod linewritershim;
#[cfg(test)]
mod tests;
use crate::error;
use crate::fmt;
use crate::io::Error;
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::{bufreader::BufReader, bufwriter::BufWriter, linewriter::LineWriter};
use linewritershim::LineWriterShim;
#[stable(feature = "bufwriter_into_parts", since = "1.56.0")]
pub use bufwriter::WriterPanicked;
/// An error returned by [`BufWriter::into_inner`] which combines an error that
/// happened while writing out the buffer, and the buffered writer object
/// which may be used to recover from the condition.
///
/// # Examples
///
/// ```no_run
/// use std::io::BufWriter;
/// use std::net::TcpStream;
///
/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
///
/// // do stuff with the stream
///
/// // we want to get our `TcpStream` back, so let's try:
///
/// let stream = match stream.into_inner() {
/// Ok(s) => s,
/// Err(e) => {
/// // Here, e is an IntoInnerError
/// panic!("An error occurred");
/// }
/// };
/// ```
#[derive(Debug)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct IntoInnerError<W>(W, Error);
impl<W> IntoInnerError<W> {
/// Construct a new IntoInnerError
fn new(writer: W, error: Error) -> Self {
Self(writer, error)
}
/// Helper to construct a new IntoInnerError; intended to help with
/// adapters that wrap other adapters
fn new_wrapped<W2>(self, f: impl FnOnce(W) -> W2) -> IntoInnerError<W2> {
let Self(writer, error) = self;
IntoInnerError::new(f(writer), error)
}
/// Returns the error which caused the call to [`BufWriter::into_inner()`]
/// to fail.
///
/// This error was returned when attempting to write the internal buffer.
///
/// # Examples
///
/// ```no_run
/// use std::io::BufWriter;
/// use std::net::TcpStream;
///
/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
///
/// // do stuff with the stream
///
/// // we want to get our `TcpStream` back, so let's try:
///
/// let stream = match stream.into_inner() {
/// Ok(s) => s,
/// Err(e) => {
/// // Here, e is an IntoInnerError, let's log the inner error.
/// //
/// // We'll just 'log' to stdout for this example.
/// println!("{}", e.error());
///
/// panic!("An unexpected error occurred.");
/// }
/// };
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn error(&self) -> &Error {
&self.1
}
/// Returns the buffered writer instance which generated the error.
///
/// The returned object can be used for error recovery, such as
/// re-inspecting the buffer.
///
/// # Examples
///
/// ```no_run
/// use std::io::BufWriter;
/// use std::net::TcpStream;
///
/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
///
/// // do stuff with the stream
///
/// // we want to get our `TcpStream` back, so let's try:
///
/// let stream = match stream.into_inner() {
/// Ok(s) => s,
/// Err(e) => {
/// // Here, e is an IntoInnerError, let's re-examine the buffer:
/// let buffer = e.into_inner();
///
/// // do stuff to try to recover
///
/// // afterwards, let's just return the stream
/// buffer.into_inner().unwrap()
/// }
/// };
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn into_inner(self) -> W {
self.0
}
/// Consumes the [`IntoInnerError`] and returns the error which caused the call to
/// [`BufWriter::into_inner()`] to fail. Unlike `error`, this can be used to
/// obtain ownership of the underlying error.
///
/// # Example
/// ```
/// use std::io::{BufWriter, ErrorKind, Write};
///
/// let mut not_enough_space = [0u8; 10];
/// let mut stream = BufWriter::new(not_enough_space.as_mut());
/// write!(stream, "this cannot be actually written").unwrap();
/// let into_inner_err = stream.into_inner().expect_err("now we discover it's too small");
/// let err = into_inner_err.into_error();
/// assert_eq!(err.kind(), ErrorKind::WriteZero);
/// ```
#[stable(feature = "io_into_inner_error_parts", since = "1.55.0")]
pub fn into_error(self) -> Error {
self.1
}
/// Consumes the [`IntoInnerError`] and returns the error which caused the call to
/// [`BufWriter::into_inner()`] to fail, and the underlying writer.
///
/// This can be used to simply obtain ownership of the underlying error; it can also be used for
/// advanced error recovery.
///
/// # Example
/// ```
/// use std::io::{BufWriter, ErrorKind, Write};
///
/// let mut not_enough_space = [0u8; 10];
/// let mut stream = BufWriter::new(not_enough_space.as_mut());
/// write!(stream, "this cannot be actually written").unwrap();
/// let into_inner_err = stream.into_inner().expect_err("now we discover it's too small");
/// let (err, recovered_writer) = into_inner_err.into_parts();
/// assert_eq!(err.kind(), ErrorKind::WriteZero);
/// assert_eq!(recovered_writer.buffer(), b"t be actually written");
/// ```
#[stable(feature = "io_into_inner_error_parts", since = "1.55.0")]
pub fn into_parts(self) -> (Error, W) {
(self.1, self.0)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<W> From<IntoInnerError<W>> for Error {
fn from(iie: IntoInnerError<W>) -> Error {
iie.1
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<W: Send + fmt::Debug> error::Error for IntoInnerError<W> {
#[allow(deprecated, deprecated_in_future)]
fn description(&self) -> &str {
error::Error::description(self.error())
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<W> fmt::Display for IntoInnerError<W> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.error().fmt(f)
}
}