From 5a15b81b2f24dd3fd36d95e41433a23b46903fd3 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Mon, 24 Sep 2018 20:11:24 -0600
Subject: [PATCH] Include patched source
---
.gitignore | 2 +-
.../buffered.rs | 1325 ++++++++++
.../cursor.rs | 712 +++++
.../error.rs | 563 ++++
.../impls.rs | 341 +++
.../mod.rs | 2310 +++++++++++++++++
.../prelude.rs | 25 +
.../util.rs | 250 ++
8 files changed, 5527 insertions(+), 1 deletion(-)
create mode 100644 src/b81da278623d9dcda1776008612bd42e1922e9c3/buffered.rs
create mode 100644 src/b81da278623d9dcda1776008612bd42e1922e9c3/cursor.rs
create mode 100644 src/b81da278623d9dcda1776008612bd42e1922e9c3/error.rs
create mode 100644 src/b81da278623d9dcda1776008612bd42e1922e9c3/impls.rs
create mode 100644 src/b81da278623d9dcda1776008612bd42e1922e9c3/mod.rs
create mode 100644 src/b81da278623d9dcda1776008612bd42e1922e9c3/prelude.rs
create mode 100644 src/b81da278623d9dcda1776008612bd42e1922e9c3/util.rs
diff --git a/.gitignore b/.gitignore
index 4f357b4..b550e82 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
target
Cargo.lock
-src/????????????????????????????????????????
+#src/????????????????????????????????????????
diff --git a/src/b81da278623d9dcda1776008612bd42e1922e9c3/buffered.rs b/src/b81da278623d9dcda1776008612bd42e1922e9c3/buffered.rs
new file mode 100644
index 0000000..3994fc9
--- /dev/null
+++ b/src/b81da278623d9dcda1776008612bd42e1922e9c3/buffered.rs
@@ -0,0 +1,1325 @@
+// Copyright 2013 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.
+
+//! Buffering wrappers for I/O traits
+
+use core::prelude::v1::*;
+use io::prelude::*;
+
+use core::cmp;
+use core::fmt;
+use io::{self, Initializer, DEFAULT_BUF_SIZE, Error, ErrorKind, SeekFrom};
+use io::memchr;
+
+/// The `BufReader` struct adds buffering to any reader.
+///
+/// It can be excessively inefficient to work directly with a [`Read`] instance.
+/// For example, every call to [`read`][`TcpStream::read`] on [`TcpStream`]
+/// results in a system call. A `BufReader` performs large, infrequent reads on
+/// the underlying [`Read`] and maintains an in-memory buffer of the results.
+///
+/// `BufReader` can improve the speed of programs that make *small* and
+/// *repeated* read calls to the same file or network socket. It does not
+/// help when reading very large amounts at once, or reading just one or a few
+/// times. It also provides no advantage when reading from a source that is
+/// already in memory, like a `Vec<u8>`.
+///
+/// [`Read`]: ../../std/io/trait.Read.html
+/// [`TcpStream::read`]: ../../std/net/struct.TcpStream.html#method.read
+/// [`TcpStream`]: ../../std/net/struct.TcpStream.html
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufReader;
+/// use std::fs::File;
+///
+/// fn main() -> std::io::Result<()> {
+/// let f = File::open("log.txt")?;
+/// let mut reader = BufReader::new(f);
+///
+/// let mut line = String::new();
+/// let len = reader.read_line(&mut line)?;
+/// println!("First line is {} bytes long", len);
+/// Ok(())
+/// }
+/// ```
+pub struct BufReader<R> {
+ inner: R,
+ buf: Box<[u8]>,
+ pos: usize,
+ cap: usize,
+}
+
+impl<R: Read> BufReader<R> {
+ /// Creates a new `BufReader` with a default buffer capacity.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufReader;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let f = File::open("log.txt")?;
+ /// let reader = BufReader::new(f);
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn new(inner: R) -> BufReader<R> {
+ BufReader::with_capacity(DEFAULT_BUF_SIZE, inner)
+ }
+
+ /// Creates a new `BufReader` with the specified buffer capacity.
+ ///
+ /// # Examples
+ ///
+ /// Creating a buffer with ten bytes of capacity:
+ ///
+ /// ```no_run
+ /// use std::io::BufReader;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let f = File::open("log.txt")?;
+ /// let reader = BufReader::with_capacity(10, f);
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
+ unsafe {
+ let mut buffer = Vec::with_capacity(cap);
+ buffer.set_len(cap);
+ inner.initializer().initialize(&mut buffer);
+ BufReader {
+ inner,
+ buf: buffer.into_boxed_slice(),
+ pos: 0,
+ cap: 0,
+ }
+ }
+ }
+
+ /// Gets a reference to the underlying reader.
+ ///
+ /// It is inadvisable to directly read from the underlying reader.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufReader;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let f1 = File::open("log.txt")?;
+ /// let reader = BufReader::new(f1);
+ ///
+ /// let f2 = reader.get_ref();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_ref(&self) -> &R { &self.inner }
+
+ /// Gets a mutable reference to the underlying reader.
+ ///
+ /// It is inadvisable to directly read from the underlying reader.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufReader;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let f1 = File::open("log.txt")?;
+ /// let mut reader = BufReader::new(f1);
+ ///
+ /// let f2 = reader.get_mut();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
+
+ /// Returns `true` if there are no bytes in the internal buffer.
+ ///
+ /// # Examples
+ //
+ /// ```no_run
+ /// # #![feature(bufreader_is_empty)]
+ /// use std::io::BufReader;
+ /// use std::io::BufRead;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let f1 = File::open("log.txt")?;
+ /// let mut reader = BufReader::new(f1);
+ /// assert!(reader.is_empty());
+ ///
+ /// if reader.fill_buf()?.len() > 0 {
+ /// assert!(!reader.is_empty());
+ /// }
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn is_empty(&self) -> bool {
+ self.buffer().is_empty()
+ }
+
+ /// Returns a reference to the internally buffered data.
+ ///
+ /// Unlike `fill_buf`, this will not attempt to fill the buffer if it is empty.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// # #![feature(bufreader_buffer)]
+ /// use std::io::{BufReader, BufRead};
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let f = File::open("log.txt")?;
+ /// let mut reader = BufReader::new(f);
+ /// assert!(reader.buffer().is_empty());
+ ///
+ /// if reader.fill_buf()?.len() > 0 {
+ /// assert!(!reader.buffer().is_empty());
+ /// }
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn buffer(&self) -> &[u8] {
+ &self.buf[self.pos..self.cap]
+ }
+
+ /// Unwraps this `BufReader`, returning the underlying reader.
+ ///
+ /// Note that any leftover data in the internal buffer is lost.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufReader;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let f1 = File::open("log.txt")?;
+ /// let reader = BufReader::new(f1);
+ ///
+ /// let f2 = reader.into_inner();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn into_inner(self) -> R { self.inner }
+}
+
+impl<R: Seek> BufReader<R> {
+ /// Seeks relative to the current position. If the new position lies within the buffer,
+ /// the buffer will not be flushed, allowing for more efficient seeks.
+ /// This method does not return the location of the underlying reader, so the caller
+ /// must track this information themselves if it is required.
+ pub fn seek_relative(&mut self, offset: i64) -> io::Result<()> {
+ let pos = self.pos as u64;
+ if offset < 0 {
+ if let Some(new_pos) = pos.checked_sub((-offset) as u64) {
+ self.pos = new_pos as usize;
+ return Ok(())
+ }
+ } else {
+ if let Some(new_pos) = pos.checked_add(offset as u64) {
+ if new_pos <= self.cap as u64 {
+ self.pos = new_pos as usize;
+ return Ok(())
+ }
+ }
+ }
+ self.seek(SeekFrom::Current(offset)).map(|_|())
+ }
+}
+
+impl<R: Read> Read for BufReader<R> {
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ // If we don't have any buffered data and we're doing a massive read
+ // (larger than our internal buffer), bypass our internal buffer
+ // entirely.
+ if self.pos == self.cap && buf.len() >= self.buf.len() {
+ return self.inner.read(buf);
+ }
+ let nread = {
+ let mut rem = self.fill_buf()?;
+ rem.read(buf)?
+ };
+ self.consume(nread);
+ Ok(nread)
+ }
+
+ // we can't skip unconditionally because of the large buffer case in read.
+ unsafe fn initializer(&self) -> Initializer {
+ self.inner.initializer()
+ }
+}
+
+impl<R: Read> BufRead for BufReader<R> {
+ fn fill_buf(&mut self) -> io::Result<&[u8]> {
+ // If we've reached the end of our internal buffer then we need to fetch
+ // some more data from the underlying reader.
+ // Branch using `>=` instead of the more correct `==`
+ // to tell the compiler that the pos..cap slice is always valid.
+ if self.pos >= self.cap {
+ debug_assert!(self.pos == self.cap);
+ self.cap = self.inner.read(&mut self.buf)?;
+ self.pos = 0;
+ }
+ Ok(&self.buf[self.pos..self.cap])
+ }
+
+ fn consume(&mut self, amt: usize) {
+ self.pos = cmp::min(self.pos + amt, self.cap);
+ }
+}
+
+impl<R> fmt::Debug for BufReader<R> where R: fmt::Debug {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ fmt.debug_struct("BufReader")
+ .field("reader", &self.inner)
+ .field("buffer", &format_args!("{}/{}", self.cap - self.pos, self.buf.len()))
+ .finish()
+ }
+}
+
+impl<R: Seek> Seek for BufReader<R> {
+ /// Seek to an offset, in bytes, in the underlying reader.
+ ///
+ /// The position used for seeking with `SeekFrom::Current(_)` is the
+ /// position the underlying reader would be at if the `BufReader` had no
+ /// internal buffer.
+ ///
+ /// Seeking always discards the internal buffer, even if the seek position
+ /// would otherwise fall within it. This guarantees that calling
+ /// `.into_inner()` immediately after a seek yields the underlying reader
+ /// at the same position.
+ ///
+ /// To seek without discarding the internal buffer, use [`seek_relative`].
+ ///
+ /// See `std::io::Seek` for more details.
+ ///
+ /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+ /// where `n` minus the internal buffer length overflows an `i64`, two
+ /// seeks will be performed instead of one. If the second seek returns
+ /// `Err`, the underlying reader will be left at the same position it would
+ /// have if you called `seek` with `SeekFrom::Current(0)`.
+ ///
+ /// [`seek_relative`]: #method.seek_relative
+ fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+ let result: u64;
+ if let SeekFrom::Current(n) = pos {
+ let remainder = (self.cap - self.pos) as i64;
+ // it should be safe to assume that remainder fits within an i64 as the alternative
+ // means we managed to allocate 8 exbibytes and that's absurd.
+ // But it's not out of the realm of possibility for some weird underlying reader to
+ // support seeking by i64::min_value() so we need to handle underflow when subtracting
+ // remainder.
+ if let Some(offset) = n.checked_sub(remainder) {
+ result = self.inner.seek(SeekFrom::Current(offset))?;
+ } else {
+ // seek backwards by our remainder, and then by the offset
+ self.inner.seek(SeekFrom::Current(-remainder))?;
+ self.pos = self.cap; // empty the buffer
+ result = self.inner.seek(SeekFrom::Current(n))?;
+ }
+ } else {
+ // Seeking with Start/End doesn't care about our buffer length.
+ result = self.inner.seek(pos)?;
+ }
+ self.pos = self.cap; // empty the buffer
+ Ok(result)
+ }
+}
+
+/// Wraps a writer and buffers its output.
+///
+/// It can be excessively inefficient to work directly with something that
+/// implements [`Write`]. For example, every call to
+/// [`write`][`Tcpstream::write`] on [`TcpStream`] results in a system call. A
+/// `BufWriter` keeps an in-memory buffer of data and writes it to an underlying
+/// writer in large, infrequent batches.
+///
+/// `BufWriter` can improve the speed of programs that make *small* and
+/// *repeated* write calls to the same file or network socket. It does not
+/// help when writing very large amounts at once, or writing just one or a few
+/// times. It also provides no advantage when writing to a destination that is
+/// in memory, like a `Vec<u8>`.
+///
+/// When the `BufWriter` is dropped, the contents of its buffer will be written
+/// out. However, any errors that happen in the process of flushing the buffer
+/// when the writer is dropped will be ignored. Code that wishes to handle such
+/// errors must manually call [`flush`] before the writer is dropped.
+///
+/// # Examples
+///
+/// Let's write the numbers one through ten to a [`TcpStream`]:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::net::TcpStream;
+///
+/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+///
+/// for i in 0..10 {
+/// stream.write(&[i+1]).unwrap();
+/// }
+/// ```
+///
+/// Because we're not buffering, we write each one in turn, incurring the
+/// overhead of a system call per byte written. We can fix this with a
+/// `BufWriter`:
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::BufWriter;
+/// use std::net::TcpStream;
+///
+/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+///
+/// for i in 0..10 {
+/// stream.write(&[i+1]).unwrap();
+/// }
+/// ```
+///
+/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped
+/// together by the buffer, and will all be written out in one system call when
+/// the `stream` is dropped.
+///
+/// [`Write`]: ../../std/io/trait.Write.html
+/// [`Tcpstream::write`]: ../../std/net/struct.TcpStream.html#method.write
+/// [`TcpStream`]: ../../std/net/struct.TcpStream.html
+/// [`flush`]: #method.flush
+pub struct BufWriter<W: Write> {
+ inner: Option<W>,
+ buf: Vec<u8>,
+ // #30888: If the inner writer panics in a call to write, we don't want to
+ // write the buffered data a second time in BufWriter's destructor. This
+ // flag tells the Drop impl if it should skip the flush.
+ panicked: bool,
+}
+
+/// An error returned by `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)]
+pub struct IntoInnerError<W>(W, Error);
+
+impl<W: Write> BufWriter<W> {
+ /// Creates a new `BufWriter` with a default buffer capacity.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufWriter;
+ /// use std::net::TcpStream;
+ ///
+ /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+ /// ```
+ pub fn new(inner: W) -> BufWriter<W> {
+ BufWriter::with_capacity(DEFAULT_BUF_SIZE, inner)
+ }
+
+ /// Creates a new `BufWriter` with the specified buffer capacity.
+ ///
+ /// # Examples
+ ///
+ /// Creating a buffer with a buffer of a hundred bytes.
+ ///
+ /// ```no_run
+ /// use std::io::BufWriter;
+ /// use std::net::TcpStream;
+ ///
+ /// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();
+ /// let mut buffer = BufWriter::with_capacity(100, stream);
+ /// ```
+ pub fn with_capacity(cap: usize, inner: W) -> BufWriter<W> {
+ BufWriter {
+ inner: Some(inner),
+ buf: Vec::with_capacity(cap),
+ panicked: false,
+ }
+ }
+
+ fn flush_buf(&mut self) -> io::Result<()> {
+ let mut written = 0;
+ let len = self.buf.len();
+ let mut ret = Ok(());
+ while written < len {
+ self.panicked = true;
+ let r = self.inner.as_mut().unwrap().write(&self.buf[written..]);
+ self.panicked = false;
+
+ match r {
+ Ok(0) => {
+ ret = Err(Error::new(ErrorKind::WriteZero,
+ "failed to write the buffered data"));
+ break;
+ }
+ Ok(n) => written += n,
+ Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+ Err(e) => { ret = Err(e); break }
+
+ }
+ }
+ if written > 0 {
+ self.buf.drain(..written);
+ }
+ ret
+ }
+
+ /// Gets a reference to the underlying writer.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufWriter;
+ /// use std::net::TcpStream;
+ ///
+ /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+ ///
+ /// // we can use reference just like buffer
+ /// let reference = buffer.get_ref();
+ /// ```
+ pub fn get_ref(&self) -> &W { self.inner.as_ref().unwrap() }
+
+ /// Gets a mutable reference to the underlying writer.
+ ///
+ /// It is inadvisable to directly write to the underlying writer.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufWriter;
+ /// use std::net::TcpStream;
+ ///
+ /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+ ///
+ /// // we can use reference just like buffer
+ /// let reference = buffer.get_mut();
+ /// ```
+ pub fn get_mut(&mut self) -> &mut W { self.inner.as_mut().unwrap() }
+
+ /// Unwraps this `BufWriter`, returning the underlying writer.
+ ///
+ /// The buffer is written out before returning the writer.
+ ///
+ /// # Errors
+ ///
+ /// An `Err` will be returned if an error occurs while flushing the buffer.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::BufWriter;
+ /// use std::net::TcpStream;
+ ///
+ /// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
+ ///
+ /// // unwrap the TcpStream and flush the buffer
+ /// let stream = buffer.into_inner().unwrap();
+ /// ```
+ pub fn into_inner(mut self) -> Result<W, IntoInnerError<BufWriter<W>>> {
+ match self.flush_buf() {
+ Err(e) => Err(IntoInnerError(self, e)),
+ Ok(()) => Ok(self.inner.take().unwrap())
+ }
+ }
+}
+
+impl<W: Write> Write for BufWriter<W> {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ if self.buf.len() + buf.len() > self.buf.capacity() {
+ self.flush_buf()?;
+ }
+ if buf.len() >= self.buf.capacity() {
+ self.panicked = true;
+ let r = self.inner.as_mut().unwrap().write(buf);
+ self.panicked = false;
+ r
+ } else {
+ Write::write(&mut self.buf, buf)
+ }
+ }
+ fn flush(&mut self) -> io::Result<()> {
+ self.flush_buf().and_then(|()| self.get_mut().flush())
+ }
+}
+
+impl<W: Write> fmt::Debug for BufWriter<W> where W: fmt::Debug {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ fmt.debug_struct("BufWriter")
+ .field("writer", &self.inner.as_ref().unwrap())
+ .field("buffer", &format_args!("{}/{}", self.buf.len(), self.buf.capacity()))
+ .finish()
+ }
+}
+
+impl<W: Write + Seek> Seek for BufWriter<W> {
+ /// Seek to the offset, in bytes, in the underlying writer.
+ ///
+ /// Seeking always writes out the internal buffer before seeking.
+ fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+ self.flush_buf().and_then(|_| self.get_mut().seek(pos))
+ }
+}
+
+impl<W: Write> Drop for BufWriter<W> {
+ fn drop(&mut self) {
+ if self.inner.is_some() && !self.panicked {
+ // dtors should not panic, so we ignore a failed flush
+ let _r = self.flush_buf();
+ }
+ }
+}
+
+impl<W> IntoInnerError<W> {
+ /// Returns the error which caused the call to `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.");
+ /// }
+ /// };
+ /// ```
+ 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()
+ /// }
+ /// };
+ /// ```
+ pub fn into_inner(self) -> W { self.0 }
+}
+
+impl<W> From<IntoInnerError<W>> for Error {
+ fn from(iie: IntoInnerError<W>) -> Error { iie.1 }
+}
+
+impl<W> fmt::Display for IntoInnerError<W> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ self.error().fmt(f)
+ }
+}
+
+/// Wraps a writer and buffers output to it, flushing whenever a newline
+/// (`0x0a`, `'\n'`) is detected.
+///
+/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// But it only does this batched write when it goes out of scope, or when the
+/// internal buffer is full. Sometimes, you'd prefer to write each line as it's
+/// completed, rather than the entire buffer at once. Enter `LineWriter`. It
+/// does exactly that.
+///
+/// Like [`BufWriter`], a `LineWriter`’s buffer will also be flushed when the
+/// `LineWriter` goes out of scope or when its internal buffer is full.
+///
+/// [bufwriter]: struct.BufWriter.html
+///
+/// If there's still a partial line in the buffer when the `LineWriter` is
+/// dropped, it will flush those contents.
+///
+/// # Examples
+///
+/// We can use `LineWriter` to write one line at a time, significantly
+/// reducing the number of actual writes to the file.
+///
+/// ```no_run
+/// use std::fs::File;
+/// use std::io::prelude::*;
+/// use std::io::LineWriter;
+///
+/// fn main() -> std::io::Result<()> {
+/// let road_not_taken = b"I shall be telling this with a sigh
+/// Somewhere ages and ages hence:
+/// Two roads diverged in a wood, and I -
+/// I took the one less traveled by,
+/// And that has made all the difference.";
+///
+/// let file = File::create("poem.txt")?;
+/// let mut file = LineWriter::new(file);
+///
+/// for &byte in road_not_taken.iter() {
+/// file.write(&[byte]).unwrap();
+/// }
+///
+/// // let's check we did the right thing.
+/// let mut file = File::open("poem.txt")?;
+/// let mut contents = String::new();
+///
+/// file.read_to_string(&mut contents)?;
+///
+/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+/// Ok(())
+/// }
+/// ```
+pub struct LineWriter<W: Write> {
+ inner: BufWriter<W>,
+ need_flush: bool,
+}
+
+impl<W: Write> LineWriter<W> {
+ /// Creates a new `LineWriter`.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::fs::File;
+ /// use std::io::LineWriter;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let file = File::create("poem.txt")?;
+ /// let file = LineWriter::new(file);
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn new(inner: W) -> LineWriter<W> {
+ // Lines typically aren't that long, don't use a giant buffer
+ LineWriter::with_capacity(1024, inner)
+ }
+
+ /// Creates a new `LineWriter` with a specified capacity for the internal
+ /// buffer.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::fs::File;
+ /// use std::io::LineWriter;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let file = File::create("poem.txt")?;
+ /// let file = LineWriter::with_capacity(100, file);
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
+ LineWriter {
+ inner: BufWriter::with_capacity(cap, inner),
+ need_flush: false,
+ }
+ }
+
+ /// Gets a reference to the underlying writer.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::fs::File;
+ /// use std::io::LineWriter;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let file = File::create("poem.txt")?;
+ /// let file = LineWriter::new(file);
+ ///
+ /// let reference = file.get_ref();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_ref(&self) -> &W { self.inner.get_ref() }
+
+ /// Gets a mutable reference to the underlying writer.
+ ///
+ /// Caution must be taken when calling methods on the mutable reference
+ /// returned as extra writes could corrupt the output stream.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::fs::File;
+ /// use std::io::LineWriter;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let file = File::create("poem.txt")?;
+ /// let mut file = LineWriter::new(file);
+ ///
+ /// // we can use reference just like file
+ /// let reference = file.get_mut();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
+
+ /// Unwraps this `LineWriter`, returning the underlying writer.
+ ///
+ /// The internal buffer is written out before returning the writer.
+ ///
+ // # Errors
+ ///
+ /// An `Err` will be returned if an error occurs while flushing the buffer.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::fs::File;
+ /// use std::io::LineWriter;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let file = File::create("poem.txt")?;
+ ///
+ /// let writer: LineWriter<File> = LineWriter::new(file);
+ ///
+ /// let file: File = writer.into_inner()?;
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
+ self.inner.into_inner().map_err(|IntoInnerError(buf, e)| {
+ IntoInnerError(LineWriter {
+ inner: buf,
+ need_flush: false,
+ }, e)
+ })
+ }
+}
+
+impl<W: Write> Write for LineWriter<W> {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ if self.need_flush {
+ self.flush()?;
+ }
+
+ // Find the last newline character in the buffer provided. If found then
+ // we're going to write all the data up to that point and then flush,
+ // otherewise we just write the whole block to the underlying writer.
+ let i = match memchr::memrchr(b'\n', buf) {
+ Some(i) => i,
+ None => return self.inner.write(buf),
+ };
+
+
+ // Ok, we're going to write a partial amount of the data given first
+ // followed by flushing the newline. After we've successfully written
+ // some data then we *must* report that we wrote that data, so future
+ // errors are ignored. We set our internal `need_flush` flag, though, in
+ // case flushing fails and we need to try it first next time.
+ let n = self.inner.write(&buf[..i + 1])?;
+ self.need_flush = true;
+ if self.flush().is_err() || n != i + 1 {
+ return Ok(n)
+ }
+
+ // At this point we successfully wrote `i + 1` bytes and flushed it out,
+ // meaning that the entire line is now flushed out on the screen. While
+ // we can attempt to finish writing the rest of the data provided.
+ // Remember though that we ignore errors here as we've successfully
+ // written data, so we need to report that.
+ match self.inner.write(&buf[i + 1..]) {
+ Ok(i) => Ok(n + i),
+ Err(_) => Ok(n),
+ }
+ }
+
+ fn flush(&mut self) -> io::Result<()> {
+ self.inner.flush()?;
+ self.need_flush = false;
+ Ok(())
+ }
+}
+
+impl<W: Write> fmt::Debug for LineWriter<W> where W: fmt::Debug {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ fmt.debug_struct("LineWriter")
+ .field("writer", &self.inner.inner)
+ .field("buffer",
+ &format_args!("{}/{}", self.inner.buf.len(), self.inner.buf.capacity()))
+ .finish()
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use io::prelude::*;
+ use io::{self, BufReader, BufWriter, LineWriter, SeekFrom};
+ use sync::atomic::{AtomicUsize, Ordering};
+ use thread;
+ use test;
+
+ /// A dummy reader intended at testing short-reads propagation.
+ pub struct ShortReader {
+ lengths: Vec<usize>,
+ }
+
+ impl Read for ShortReader {
+ fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+ if self.lengths.is_empty() {
+ Ok(0)
+ } else {
+ Ok(self.lengths.remove(0))
+ }
+ }
+ }
+
+ #[test]
+ fn test_buffered_reader() {
+ let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+ let mut reader = BufReader::with_capacity(2, inner);
+
+ let mut buf = [0, 0, 0];
+ let nread = reader.read(&mut buf);
+ assert_eq!(nread.unwrap(), 3);
+ let b: &[_] = &[5, 6, 7];
+ assert_eq!(buf, b);
+
+ let mut buf = [0, 0];
+ let nread = reader.read(&mut buf);
+ assert_eq!(nread.unwrap(), 2);
+ let b: &[_] = &[0, 1];
+ assert_eq!(buf, b);
+
+ let mut buf = [0];
+ let nread = reader.read(&mut buf);
+ assert_eq!(nread.unwrap(), 1);
+ let b: &[_] = &[2];
+ assert_eq!(buf, b);
+
+ let mut buf = [0, 0, 0];
+ let nread = reader.read(&mut buf);
+ assert_eq!(nread.unwrap(), 1);
+ let b: &[_] = &[3, 0, 0];
+ assert_eq!(buf, b);
+
+ let nread = reader.read(&mut buf);
+ assert_eq!(nread.unwrap(), 1);
+ let b: &[_] = &[4, 0, 0];
+ assert_eq!(buf, b);
+
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ }
+
+ #[test]
+ fn test_buffered_reader_seek() {
+ let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+ let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+ assert_eq!(reader.seek(SeekFrom::Start(3)).ok(), Some(3));
+ assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+ assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(3));
+ assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+ assert_eq!(reader.seek(SeekFrom::Current(1)).ok(), Some(4));
+ assert_eq!(reader.fill_buf().ok(), Some(&[1, 2][..]));
+ reader.consume(1);
+ assert_eq!(reader.seek(SeekFrom::Current(-2)).ok(), Some(3));
+ }
+
+ #[test]
+ fn test_buffered_reader_seek_relative() {
+ let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
+ let mut reader = BufReader::with_capacity(2, io::Cursor::new(inner));
+
+ assert!(reader.seek_relative(3).is_ok());
+ assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+ assert!(reader.seek_relative(0).is_ok());
+ assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+ assert!(reader.seek_relative(1).is_ok());
+ assert_eq!(reader.fill_buf().ok(), Some(&[1][..]));
+ assert!(reader.seek_relative(-1).is_ok());
+ assert_eq!(reader.fill_buf().ok(), Some(&[0, 1][..]));
+ assert!(reader.seek_relative(2).is_ok());
+ assert_eq!(reader.fill_buf().ok(), Some(&[2, 3][..]));
+ }
+
+ #[test]
+ fn test_buffered_reader_seek_underflow() {
+ // gimmick reader that yields its position modulo 256 for each byte
+ struct PositionReader {
+ pos: u64
+ }
+ impl Read for PositionReader {
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ let len = buf.len();
+ for x in buf {
+ *x = self.pos as u8;
+ self.pos = self.pos.wrapping_add(1);
+ }
+ Ok(len)
+ }
+ }
+ impl Seek for PositionReader {
+ fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+ match pos {
+ SeekFrom::Start(n) => {
+ self.pos = n;
+ }
+ SeekFrom::Current(n) => {
+ self.pos = self.pos.wrapping_add(n as u64);
+ }
+ SeekFrom::End(n) => {
+ self.pos = u64::max_value().wrapping_add(n as u64);
+ }
+ }
+ Ok(self.pos)
+ }
+ }
+
+ let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
+ assert_eq!(reader.fill_buf().ok(), Some(&[0, 1, 2, 3, 4][..]));
+ assert_eq!(reader.seek(SeekFrom::End(-5)).ok(), Some(u64::max_value()-5));
+ assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+ // the following seek will require two underlying seeks
+ let expected = 9223372036854775802;
+ assert_eq!(reader.seek(SeekFrom::Current(i64::min_value())).ok(), Some(expected));
+ assert_eq!(reader.fill_buf().ok().map(|s| s.len()), Some(5));
+ // seeking to 0 should empty the buffer.
+ assert_eq!(reader.seek(SeekFrom::Current(0)).ok(), Some(expected));
+ assert_eq!(reader.get_ref().pos, expected);
+ }
+
+ #[test]
+ fn test_buffered_writer() {
+ let inner = Vec::new();
+ let mut writer = BufWriter::with_capacity(2, inner);
+
+ writer.write(&[0, 1]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1]);
+
+ writer.write(&[2]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1]);
+
+ writer.write(&[3]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1]);
+
+ writer.flush().unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+ writer.write(&[4]).unwrap();
+ writer.write(&[5]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
+
+ writer.write(&[6]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
+
+ writer.write(&[7, 8]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
+
+ writer.write(&[9, 10, 11]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+ writer.flush().unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+ }
+
+ #[test]
+ fn test_buffered_writer_inner_flushes() {
+ let mut w = BufWriter::with_capacity(3, Vec::new());
+ w.write(&[0, 1]).unwrap();
+ assert_eq!(*w.get_ref(), []);
+ let w = w.into_inner().unwrap();
+ assert_eq!(w, [0, 1]);
+ }
+
+ #[test]
+ fn test_buffered_writer_seek() {
+ let mut w = BufWriter::with_capacity(3, io::Cursor::new(Vec::new()));
+ w.write_all(&[0, 1, 2, 3, 4, 5]).unwrap();
+ w.write_all(&[6, 7]).unwrap();
+ assert_eq!(w.seek(SeekFrom::Current(0)).ok(), Some(8));
+ assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
+ assert_eq!(w.seek(SeekFrom::Start(2)).ok(), Some(2));
+ w.write_all(&[8, 9]).unwrap();
+ assert_eq!(&w.into_inner().unwrap().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
+ }
+
+ #[test]
+ fn test_read_until() {
+ let inner: &[u8] = &[0, 1, 2, 1, 0];
+ let mut reader = BufReader::with_capacity(2, inner);
+ let mut v = Vec::new();
+ reader.read_until(0, &mut v).unwrap();
+ assert_eq!(v, [0]);
+ v.truncate(0);
+ reader.read_until(2, &mut v).unwrap();
+ assert_eq!(v, [1, 2]);
+ v.truncate(0);
+ reader.read_until(1, &mut v).unwrap();
+ assert_eq!(v, [1]);
+ v.truncate(0);
+ reader.read_until(8, &mut v).unwrap();
+ assert_eq!(v, [0]);
+ v.truncate(0);
+ reader.read_until(9, &mut v).unwrap();
+ assert_eq!(v, []);
+ }
+
+ #[test]
+ fn test_line_buffer_fail_flush() {
+ // Issue #32085
+ struct FailFlushWriter<'a>(&'a mut Vec<u8>);
+
+ impl<'a> Write for FailFlushWriter<'a> {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ self.0.extend_from_slice(buf);
+ Ok(buf.len())
+ }
+ fn flush(&mut self) -> io::Result<()> {
+ Err(io::Error::new(io::ErrorKind::Other, "flush failed"))
+ }
+ }
+
+ let mut buf = Vec::new();
+ {
+ let mut writer = LineWriter::new(FailFlushWriter(&mut buf));
+ let to_write = b"abc\ndef";
+ if let Ok(written) = writer.write(to_write) {
+ assert!(written < to_write.len(), "didn't flush on new line");
+ // PASS
+ return;
+ }
+ }
+ assert!(buf.is_empty(), "write returned an error but wrote data");
+ }
+
+ #[test]
+ fn test_line_buffer() {
+ let mut writer = LineWriter::new(Vec::new());
+ writer.write(&[0]).unwrap();
+ assert_eq!(*writer.get_ref(), []);
+ writer.write(&[1]).unwrap();
+ assert_eq!(*writer.get_ref(), []);
+ writer.flush().unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1]);
+ writer.write(&[0, b'\n', 1, b'\n', 2]).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n']);
+ writer.flush().unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2]);
+ writer.write(&[3, b'\n']).unwrap();
+ assert_eq!(*writer.get_ref(), [0, 1, 0, b'\n', 1, b'\n', 2, 3, b'\n']);
+ }
+
+ #[test]
+ fn test_read_line() {
+ let in_buf: &[u8] = b"a\nb\nc";
+ let mut reader = BufReader::with_capacity(2, in_buf);
+ let mut s = String::new();
+ reader.read_line(&mut s).unwrap();
+ assert_eq!(s, "a\n");
+ s.truncate(0);
+ reader.read_line(&mut s).unwrap();
+ assert_eq!(s, "b\n");
+ s.truncate(0);
+ reader.read_line(&mut s).unwrap();
+ assert_eq!(s, "c");
+ s.truncate(0);
+ reader.read_line(&mut s).unwrap();
+ assert_eq!(s, "");
+ }
+
+ #[test]
+ fn test_lines() {
+ let in_buf: &[u8] = b"a\nb\nc";
+ let reader = BufReader::with_capacity(2, in_buf);
+ let mut it = reader.lines();
+ assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+ assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+ assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+ assert!(it.next().is_none());
+ }
+
+ #[test]
+ fn test_short_reads() {
+ let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
+ let mut reader = BufReader::new(inner);
+ let mut buf = [0, 0];
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ assert_eq!(reader.read(&mut buf).unwrap(), 1);
+ assert_eq!(reader.read(&mut buf).unwrap(), 2);
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ assert_eq!(reader.read(&mut buf).unwrap(), 1);
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ }
+
+ #[test]
+ #[allow(deprecated)]
+ fn read_char_buffered() {
+ let buf = [195, 159];
+ let reader = BufReader::with_capacity(1, &buf[..]);
+ assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
+ }
+
+ #[test]
+ #[allow(deprecated)]
+ fn test_chars() {
+ let buf = [195, 159, b'a'];
+ let reader = BufReader::with_capacity(1, &buf[..]);
+ let mut it = reader.chars();
+ assert_eq!(it.next().unwrap().unwrap(), 'ß');
+ assert_eq!(it.next().unwrap().unwrap(), 'a');
+ assert!(it.next().is_none());
+ }
+
+ #[test]
+ #[should_panic]
+ fn dont_panic_in_drop_on_panicked_flush() {
+ struct FailFlushWriter;
+
+ impl Write for FailFlushWriter {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+ fn flush(&mut self) -> io::Result<()> {
+ Err(io::Error::last_os_error())
+ }
+ }
+
+ let writer = FailFlushWriter;
+ let _writer = BufWriter::new(writer);
+
+ // If writer panics *again* due to the flush error then the process will
+ // abort.
+ panic!();
+ }
+
+ #[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ fn panic_in_write_doesnt_flush_in_drop() {
+ static WRITES: AtomicUsize = AtomicUsize::new(0);
+
+ struct PanicWriter;
+
+ impl Write for PanicWriter {
+ fn write(&mut self, _: &[u8]) -> io::Result<usize> {
+ WRITES.fetch_add(1, Ordering::SeqCst);
+ panic!();
+ }
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+ }
+
+ thread::spawn(|| {
+ let mut writer = BufWriter::new(PanicWriter);
+ let _ = writer.write(b"hello world");
+ let _ = writer.flush();
+ }).join().unwrap_err();
+
+ assert_eq!(WRITES.load(Ordering::SeqCst), 1);
+ }
+
+ #[bench]
+ fn bench_buffered_reader(b: &mut test::Bencher) {
+ b.iter(|| {
+ BufReader::new(io::empty())
+ });
+ }
+
+ #[bench]
+ fn bench_buffered_writer(b: &mut test::Bencher) {
+ b.iter(|| {
+ BufWriter::new(io::sink())
+ });
+ }
+
+ struct AcceptOneThenFail {
+ written: bool,
+ flushed: bool,
+ }
+
+ impl Write for AcceptOneThenFail {
+ fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+ if !self.written {
+ assert_eq!(data, b"a\nb\n");
+ self.written = true;
+ Ok(data.len())
+ } else {
+ Err(io::Error::new(io::ErrorKind::NotFound, "test"))
+ }
+ }
+
+ fn flush(&mut self) -> io::Result<()> {
+ assert!(self.written);
+ assert!(!self.flushed);
+ self.flushed = true;
+ Err(io::Error::new(io::ErrorKind::Other, "test"))
+ }
+ }
+
+ #[test]
+ fn erroneous_flush_retried() {
+ let a = AcceptOneThenFail {
+ written: false,
+ flushed: false,
+ };
+
+ let mut l = LineWriter::new(a);
+ assert_eq!(l.write(b"a\nb\na").unwrap(), 4);
+ assert!(l.get_ref().written);
+ assert!(l.get_ref().flushed);
+ l.get_mut().flushed = false;
+
+ assert_eq!(l.write(b"a").unwrap_err().kind(), io::ErrorKind::Other)
+ }
+}
diff --git a/src/b81da278623d9dcda1776008612bd42e1922e9c3/cursor.rs b/src/b81da278623d9dcda1776008612bd42e1922e9c3/cursor.rs
new file mode 100644
index 0000000..3f9b7b0
--- /dev/null
+++ b/src/b81da278623d9dcda1776008612bd42e1922e9c3/cursor.rs
@@ -0,0 +1,712 @@
+// Copyright 2015 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.
+
+use io::prelude::*;
+
+use core::cmp;
+use io::{self, Initializer, SeekFrom, Error, ErrorKind};
+
+/// A `Cursor` wraps another type and provides it with a
+/// [`Seek`] implementation.
+///
+/// `Cursor`s are typically used with in-memory buffers to allow them to
+/// implement [`Read`] and/or [`Write`], allowing these buffers to be used
+/// anywhere you might use a reader or writer that does actual I/O.
+///
+/// The standard library implements some I/O traits on various types which
+/// are commonly used as a buffer, like `Cursor<`[`Vec`]`<u8>>` and
+/// `Cursor<`[`&[u8]`][bytes]`>`.
+///
+/// # Examples
+///
+/// We may want to write bytes to a [`File`] in our production
+/// code, but use an in-memory buffer in our tests. We can do this with
+/// `Cursor`:
+///
+/// [`Seek`]: trait.Seek.html
+/// [`Read`]: ../../std/io/trait.Read.html
+/// [`Write`]: ../../std/io/trait.Write.html
+/// [`Vec`]: ../../std/vec/struct.Vec.html
+/// [bytes]: ../../std/primitive.slice.html
+/// [`File`]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::io::{self, SeekFrom};
+/// use std::fs::File;
+///
+/// // a library function we've written
+/// fn write_ten_bytes_at_end<W: Write + Seek>(writer: &mut W) -> io::Result<()> {
+/// writer.seek(SeekFrom::End(-10))?;
+///
+/// for i in 0..10 {
+/// writer.write(&[i])?;
+/// }
+///
+/// // all went well
+/// Ok(())
+/// }
+///
+/// # fn foo() -> io::Result<()> {
+/// // Here's some code that uses this library function.
+/// //
+/// // We might want to use a BufReader here for efficiency, but let's
+/// // keep this example focused.
+/// let mut file = File::create("foo.txt")?;
+///
+/// write_ten_bytes_at_end(&mut file)?;
+/// # Ok(())
+/// # }
+///
+/// // now let's write a test
+/// #[test]
+/// fn test_writes_bytes() {
+/// // setting up a real File is much slower than an in-memory buffer,
+/// // let's use a cursor instead
+/// use std::io::Cursor;
+/// let mut buff = Cursor::new(vec![0; 15]);
+///
+/// write_ten_bytes_at_end(&mut buff).unwrap();
+///
+/// assert_eq!(&buff.get_ref()[5..15], &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+/// }
+/// ```
+#[derive(Clone, Debug)]
+pub struct Cursor<T> {
+ inner: T,
+ pos: u64,
+}
+
+impl<T> Cursor<T> {
+ /// Creates a new cursor wrapping the provided underlying I/O object.
+ ///
+ /// Cursor initial position is `0` even if underlying object (e.
+ /// g. `Vec`) is not empty. So writing to cursor starts with
+ /// overwriting `Vec` content, not with appending to it.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::Cursor;
+ ///
+ /// let buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ /// ```
+ pub fn new(inner: T) -> Cursor<T> {
+ Cursor { pos: 0, inner: inner }
+ }
+
+ /// Consumes this cursor, returning the underlying value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::Cursor;
+ ///
+ /// let buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ ///
+ /// let vec = buff.into_inner();
+ /// ```
+ pub fn into_inner(self) -> T { self.inner }
+
+ /// Gets a reference to the underlying value in this cursor.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::Cursor;
+ ///
+ /// let buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ ///
+ /// let reference = buff.get_ref();
+ /// ```
+ pub fn get_ref(&self) -> &T { &self.inner }
+
+ /// Gets a mutable reference to the underlying value in this cursor.
+ ///
+ /// Care should be taken to avoid modifying the internal I/O state of the
+ /// underlying value as it may corrupt this cursor's position.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::Cursor;
+ ///
+ /// let mut buff = Cursor::new(Vec::new());
+ /// # fn force_inference(_: &Cursor<Vec<u8>>) {}
+ /// # force_inference(&buff);
+ ///
+ /// let reference = buff.get_mut();
+ /// ```
+ pub fn get_mut(&mut self) -> &mut T { &mut self.inner }
+
+ /// Returns the current position of this cursor.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::Cursor;
+ /// use std::io::prelude::*;
+ /// use std::io::SeekFrom;
+ ///
+ /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+ ///
+ /// assert_eq!(buff.position(), 0);
+ ///
+ /// buff.seek(SeekFrom::Current(2)).unwrap();
+ /// assert_eq!(buff.position(), 2);
+ ///
+ /// buff.seek(SeekFrom::Current(-1)).unwrap();
+ /// assert_eq!(buff.position(), 1);
+ /// ```
+ pub fn position(&self) -> u64 { self.pos }
+
+ /// Sets the position of this cursor.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::Cursor;
+ ///
+ /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
+ ///
+ /// assert_eq!(buff.position(), 0);
+ ///
+ /// buff.set_position(2);
+ /// assert_eq!(buff.position(), 2);
+ ///
+ /// buff.set_position(4);
+ /// assert_eq!(buff.position(), 4);
+ /// ```
+ pub fn set_position(&mut self, pos: u64) { self.pos = pos; }
+}
+
+impl<T> io::Seek for Cursor<T> where T: AsRef<[u8]> {
+ fn seek(&mut self, style: SeekFrom) -> io::Result<u64> {
+ let (base_pos, offset) = match style {
+ SeekFrom::Start(n) => { self.pos = n; return Ok(n); }
+ SeekFrom::End(n) => (self.inner.as_ref().len() as u64, n),
+ SeekFrom::Current(n) => (self.pos, n),
+ };
+ let new_pos = if offset >= 0 {
+ base_pos.checked_add(offset as u64)
+ } else {
+ base_pos.checked_sub((offset.wrapping_neg()) as u64)
+ };
+ match new_pos {
+ Some(n) => {self.pos = n; Ok(self.pos)}
+ None => Err(Error::new(ErrorKind::InvalidInput,
+ "invalid seek to a negative or overflowing position"))
+ }
+ }
+}
+
+impl<T> Read for Cursor<T> where T: AsRef<[u8]> {
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ let n = Read::read(&mut self.get_buf()?, buf)?;
+ self.pos += n as u64;
+ Ok(n)
+ }
+
+ fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+ let n = buf.len();
+ Read::read_exact(&mut self.get_buf()?, buf)?;
+ self.pos += n as u64;
+ Ok(())
+ }
+
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ Initializer::nop()
+ }
+}
+
+impl<T> Cursor<T> where T: AsRef<[u8]> {
+ fn get_buf(&mut self) -> io::Result<&[u8]> {
+ let amt = cmp::min(self.pos, self.inner.as_ref().len() as u64);
+ Ok(&self.inner.as_ref()[(amt as usize)..])
+ }
+}
+
+#[cfg(feature="collections")]
+impl<T> BufRead for Cursor<T> where T: AsRef<[u8]> {
+ fn fill_buf(&mut self) -> io::Result<&[u8]> { self.get_buf() }
+ fn consume(&mut self, amt: usize) { self.pos += amt as u64; }
+}
+
+// Non-resizing write implementation
+fn slice_write(pos_mut: &mut u64, slice: &mut [u8], buf: &[u8]) -> io::Result<usize> {
+ let pos = cmp::min(*pos_mut, slice.len() as u64);
+ let amt = (&mut slice[(pos as usize)..]).write(buf)?;
+ *pos_mut += amt as u64;
+ Ok(amt)
+}
+
+/// Compensate removal of some impls per
+/// https://github.com/rust-lang/rust/pull/49305#issuecomment-376293243
+#[cfg(any(target_pointer_width = "16",
+ target_pointer_width = "32"))]
+fn try_into(n: u64) -> Result<usize, ()> {
+ if n <= (<usize>::max_value() as u64) {
+ Ok(n as usize)
+ } else {
+ Err(())
+ }
+}
+
+#[cfg(any(target_pointer_width = "64"))]
+fn try_into(n: u64) -> Result<usize, ()> {
+ Ok(n as usize)
+}
+
+// Resizing write implementation
+#[cfg(feature="collections")]
+fn vec_write(pos_mut: &mut u64, vec: &mut Vec<u8>, buf: &[u8]) -> io::Result<usize> {
+ let pos: usize = try_into(*pos_mut).map_err(|_| {
+ Error::new(ErrorKind::InvalidInput,
+ "cursor position exceeds maximum possible vector length")
+ })?;
+ // Make sure the internal buffer is as least as big as where we
+ // currently are
+ let len = vec.len();
+ if len < pos {
+ // use `resize` so that the zero filling is as efficient as possible
+ vec.resize(pos, 0);
+ }
+ // Figure out what bytes will be used to overwrite what's currently
+ // there (left), and what will be appended on the end (right)
+ {
+ let space = vec.len() - pos;
+ let (left, right) = buf.split_at(cmp::min(space, buf.len()));
+ vec[pos..pos + left.len()].copy_from_slice(left);
+ vec.extend_from_slice(right);
+ }
+
+ // Bump us forward
+ *pos_mut = (pos + buf.len()) as u64;
+ Ok(buf.len())
+}
+
+impl<'a> Write for Cursor<&'a mut [u8]> {
+ #[inline]
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ slice_write(&mut self.pos, self.inner, buf)
+ }
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(feature="collections")]
+impl<'a> Write for Cursor<&'a mut Vec<u8>> {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ vec_write(&mut self.pos, self.inner, buf)
+ }
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(feature = "collections")]
+impl Write for Cursor<Vec<u8>> {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ vec_write(&mut self.pos, &mut self.inner, buf)
+ }
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(feature = "alloc")]
+impl Write for Cursor<::alloc::boxed::Box<[u8]>> {
+ #[inline]
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ slice_write(&mut self.pos, &mut self.inner, buf)
+ }
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+ use io::prelude::*;
+ use io::{Cursor, SeekFrom};
+
+ #[test]
+ fn test_vec_writer() {
+ let mut writer = Vec::new();
+ assert_eq!(writer.write(&[0]).unwrap(), 1);
+ assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+ assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+ let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+ assert_eq!(writer, b);
+ }
+
+ #[test]
+ fn test_mem_writer() {
+ let mut writer = Cursor::new(Vec::new());
+ assert_eq!(writer.write(&[0]).unwrap(), 1);
+ assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+ assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+ let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+ assert_eq!(&writer.get_ref()[..], b);
+ }
+
+ #[test]
+ fn test_mem_mut_writer() {
+ let mut vec = Vec::new();
+ let mut writer = Cursor::new(&mut vec);
+ assert_eq!(writer.write(&[0]).unwrap(), 1);
+ assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+ assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+ let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+ assert_eq!(&writer.get_ref()[..], b);
+ }
+
+ #[test]
+ fn test_box_slice_writer() {
+ let mut writer = Cursor::new(vec![0u8; 9].into_boxed_slice());
+ assert_eq!(writer.position(), 0);
+ assert_eq!(writer.write(&[0]).unwrap(), 1);
+ assert_eq!(writer.position(), 1);
+ assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+ assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+ assert_eq!(writer.position(), 8);
+ assert_eq!(writer.write(&[]).unwrap(), 0);
+ assert_eq!(writer.position(), 8);
+
+ assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+ assert_eq!(writer.write(&[10]).unwrap(), 0);
+ let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+ assert_eq!(&**writer.get_ref(), b);
+ }
+
+ #[test]
+ fn test_buf_writer() {
+ let mut buf = [0 as u8; 9];
+ {
+ let mut writer = Cursor::new(&mut buf[..]);
+ assert_eq!(writer.position(), 0);
+ assert_eq!(writer.write(&[0]).unwrap(), 1);
+ assert_eq!(writer.position(), 1);
+ assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+ assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+ assert_eq!(writer.position(), 8);
+ assert_eq!(writer.write(&[]).unwrap(), 0);
+ assert_eq!(writer.position(), 8);
+
+ assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+ assert_eq!(writer.write(&[10]).unwrap(), 0);
+ }
+ let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
+ assert_eq!(buf, b);
+ }
+
+ #[test]
+ fn test_buf_writer_seek() {
+ let mut buf = [0 as u8; 8];
+ {
+ let mut writer = Cursor::new(&mut buf[..]);
+ assert_eq!(writer.position(), 0);
+ assert_eq!(writer.write(&[1]).unwrap(), 1);
+ assert_eq!(writer.position(), 1);
+
+ assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
+ assert_eq!(writer.position(), 2);
+ assert_eq!(writer.write(&[2]).unwrap(), 1);
+ assert_eq!(writer.position(), 3);
+
+ assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
+ assert_eq!(writer.position(), 1);
+ assert_eq!(writer.write(&[3]).unwrap(), 1);
+ assert_eq!(writer.position(), 2);
+
+ assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+ assert_eq!(writer.position(), 7);
+ assert_eq!(writer.write(&[4]).unwrap(), 1);
+ assert_eq!(writer.position(), 8);
+
+ }
+ let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
+ assert_eq!(buf, b);
+ }
+
+ #[test]
+ fn test_buf_writer_error() {
+ let mut buf = [0 as u8; 2];
+ let mut writer = Cursor::new(&mut buf[..]);
+ assert_eq!(writer.write(&[0]).unwrap(), 1);
+ assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+ assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
+ }
+
+ #[test]
+ fn test_mem_reader() {
+ let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
+ let mut buf = [];
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ assert_eq!(reader.position(), 0);
+ let mut buf = [0];
+ assert_eq!(reader.read(&mut buf).unwrap(), 1);
+ assert_eq!(reader.position(), 1);
+ let b: &[_] = &[0];
+ assert_eq!(buf, b);
+ let mut buf = [0; 4];
+ assert_eq!(reader.read(&mut buf).unwrap(), 4);
+ assert_eq!(reader.position(), 5);
+ let b: &[_] = &[1, 2, 3, 4];
+ assert_eq!(buf, b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 3);
+ let b: &[_] = &[5, 6, 7];
+ assert_eq!(&buf[..3], b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ }
+
+ #[test]
+ fn test_boxed_slice_reader() {
+ let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7].into_boxed_slice());
+ let mut buf = [];
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ assert_eq!(reader.position(), 0);
+ let mut buf = [0];
+ assert_eq!(reader.read(&mut buf).unwrap(), 1);
+ assert_eq!(reader.position(), 1);
+ let b: &[_] = &[0];
+ assert_eq!(buf, b);
+ let mut buf = [0; 4];
+ assert_eq!(reader.read(&mut buf).unwrap(), 4);
+ assert_eq!(reader.position(), 5);
+ let b: &[_] = &[1, 2, 3, 4];
+ assert_eq!(buf, b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 3);
+ let b: &[_] = &[5, 6, 7];
+ assert_eq!(&buf[..3], b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ }
+
+ #[test]
+ fn read_to_end() {
+ let mut reader = Cursor::new(vec![0, 1, 2, 3, 4, 5, 6, 7]);
+ let mut v = Vec::new();
+ reader.read_to_end(&mut v).unwrap();
+ assert_eq!(v, [0, 1, 2, 3, 4, 5, 6, 7]);
+ }
+
+ #[test]
+ fn test_slice_reader() {
+ let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+ let reader = &mut &in_buf[..];
+ let mut buf = [];
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ let mut buf = [0];
+ assert_eq!(reader.read(&mut buf).unwrap(), 1);
+ assert_eq!(reader.len(), 7);
+ let b: &[_] = &[0];
+ assert_eq!(&buf[..], b);
+ let mut buf = [0; 4];
+ assert_eq!(reader.read(&mut buf).unwrap(), 4);
+ assert_eq!(reader.len(), 3);
+ let b: &[_] = &[1, 2, 3, 4];
+ assert_eq!(&buf[..], b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 3);
+ let b: &[_] = &[5, 6, 7];
+ assert_eq!(&buf[..3], b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ }
+
+ #[test]
+ fn test_read_exact() {
+ let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+ let reader = &mut &in_buf[..];
+ let mut buf = [];
+ assert!(reader.read_exact(&mut buf).is_ok());
+ let mut buf = [8];
+ assert!(reader.read_exact(&mut buf).is_ok());
+ assert_eq!(buf[0], 0);
+ assert_eq!(reader.len(), 7);
+ let mut buf = [0, 0, 0, 0, 0, 0, 0];
+ assert!(reader.read_exact(&mut buf).is_ok());
+ assert_eq!(buf, [1, 2, 3, 4, 5, 6, 7]);
+ assert_eq!(reader.len(), 0);
+ let mut buf = [0];
+ assert!(reader.read_exact(&mut buf).is_err());
+ }
+
+ #[test]
+ fn test_buf_reader() {
+ let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
+ let mut reader = Cursor::new(&in_buf[..]);
+ let mut buf = [];
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ assert_eq!(reader.position(), 0);
+ let mut buf = [0];
+ assert_eq!(reader.read(&mut buf).unwrap(), 1);
+ assert_eq!(reader.position(), 1);
+ let b: &[_] = &[0];
+ assert_eq!(buf, b);
+ let mut buf = [0; 4];
+ assert_eq!(reader.read(&mut buf).unwrap(), 4);
+ assert_eq!(reader.position(), 5);
+ let b: &[_] = &[1, 2, 3, 4];
+ assert_eq!(buf, b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 3);
+ let b: &[_] = &[5, 6, 7];
+ assert_eq!(&buf[..3], b);
+ assert_eq!(reader.read(&mut buf).unwrap(), 0);
+ }
+
+ #[test]
+ #[allow(deprecated)]
+ fn test_read_char() {
+ let b = &b"Vi\xE1\xBB\x87t"[..];
+ let mut c = Cursor::new(b).chars();
+ assert_eq!(c.next().unwrap().unwrap(), 'V');
+ assert_eq!(c.next().unwrap().unwrap(), 'i');
+ assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+ assert_eq!(c.next().unwrap().unwrap(), 't');
+ assert!(c.next().is_none());
+ }
+
+ #[test]
+ #[allow(deprecated)]
+ fn test_read_bad_char() {
+ let b = &b"\x80"[..];
+ let mut c = Cursor::new(b).chars();
+ assert!(c.next().unwrap().is_err());
+ }
+
+ #[test]
+ fn seek_past_end() {
+ let buf = [0xff];
+ let mut r = Cursor::new(&buf[..]);
+ assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+ assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+ let mut r = Cursor::new(vec![10]);
+ assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+ assert_eq!(r.read(&mut [0]).unwrap(), 0);
+
+ let mut buf = [0];
+ let mut r = Cursor::new(&mut buf[..]);
+ assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+ assert_eq!(r.write(&[3]).unwrap(), 0);
+
+ let mut r = Cursor::new(vec![10].into_boxed_slice());
+ assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+ assert_eq!(r.write(&[3]).unwrap(), 0);
+ }
+
+ #[test]
+ fn seek_past_i64() {
+ let buf = [0xff];
+ let mut r = Cursor::new(&buf[..]);
+ assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+ assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+ assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+ assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+ assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+ assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+
+ let mut r = Cursor::new(vec![10]);
+ assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+ assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+ assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+ assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+ assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+ assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+
+ let mut buf = [0];
+ let mut r = Cursor::new(&mut buf[..]);
+ assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+ assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+ assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+ assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+ assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+ assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+
+ let mut r = Cursor::new(vec![10].into_boxed_slice());
+ assert_eq!(r.seek(SeekFrom::Start(6)).unwrap(), 6);
+ assert_eq!(r.seek(SeekFrom::Current(0x7ffffffffffffff0)).unwrap(), 0x7ffffffffffffff6);
+ assert_eq!(r.seek(SeekFrom::Current(0x10)).unwrap(), 0x8000000000000006);
+ assert_eq!(r.seek(SeekFrom::Current(0)).unwrap(), 0x8000000000000006);
+ assert!(r.seek(SeekFrom::Current(0x7ffffffffffffffd)).is_err());
+ assert_eq!(r.seek(SeekFrom::Current(-0x8000000000000000)).unwrap(), 6);
+ }
+
+ #[test]
+ fn seek_before_0() {
+ let buf = [0xff];
+ let mut r = Cursor::new(&buf[..]);
+ assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+ let mut r = Cursor::new(vec![10]);
+ assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+ let mut buf = [0];
+ let mut r = Cursor::new(&mut buf[..]);
+ assert!(r.seek(SeekFrom::End(-2)).is_err());
+
+ let mut r = Cursor::new(vec![10].into_boxed_slice());
+ assert!(r.seek(SeekFrom::End(-2)).is_err());
+ }
+
+ #[test]
+ fn test_seekable_mem_writer() {
+ let mut writer = Cursor::new(Vec::<u8>::new());
+ assert_eq!(writer.position(), 0);
+ assert_eq!(writer.write(&[0]).unwrap(), 1);
+ assert_eq!(writer.position(), 1);
+ assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+ assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
+ assert_eq!(writer.position(), 8);
+ let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
+ assert_eq!(&writer.get_ref()[..], b);
+
+ assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
+ assert_eq!(writer.position(), 0);
+ assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
+ let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
+ assert_eq!(&writer.get_ref()[..], b);
+
+ assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+ assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
+ let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
+ assert_eq!(&writer.get_ref()[..], b);
+
+ assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+ assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
+ let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
+ assert_eq!(&writer.get_ref()[..], b);
+
+ assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+ assert_eq!(writer.write(&[1]).unwrap(), 1);
+ let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
+ assert_eq!(&writer.get_ref()[..], b);
+ }
+
+ #[test]
+ fn vec_seek_past_end() {
+ let mut r = Cursor::new(Vec::new());
+ assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+ assert_eq!(r.write(&[3]).unwrap(), 1);
+ }
+
+ #[test]
+ fn vec_seek_before_0() {
+ let mut r = Cursor::new(Vec::new());
+ assert!(r.seek(SeekFrom::End(-2)).is_err());
+ }
+
+ #[test]
+ #[cfg(target_pointer_width = "32")]
+ fn vec_seek_and_write_past_usize_max() {
+ let mut c = Cursor::new(Vec::new());
+ c.set_position(<usize>::max_value() as u64 + 1);
+ assert!(c.write_all(&[1, 2, 3]).is_err());
+ }
+}
diff --git a/src/b81da278623d9dcda1776008612bd42e1922e9c3/error.rs b/src/b81da278623d9dcda1776008612bd42e1922e9c3/error.rs
new file mode 100644
index 0000000..3acdadf
--- /dev/null
+++ b/src/b81da278623d9dcda1776008612bd42e1922e9c3/error.rs
@@ -0,0 +1,563 @@
+// Copyright 2015 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.
+
+#[cfg(feature="alloc")] use alloc::boxed::Box;
+#[cfg(not(feature="alloc"))] use ::FakeBox as Box;
+use core::convert::Into;
+use core::fmt;
+use core::marker::{Send, Sync};
+use core::option::Option::{self, Some, None};
+use core::result;
+#[cfg(feature="collections")] use collections::string::String;
+#[cfg(not(feature="collections"))] use ::ErrorString as String;
+use core::convert::From;
+
+/// A specialized [`Result`](../result/enum.Result.html) type for I/O
+/// operations.
+///
+/// This type is broadly used across [`std::io`] for any operation which may
+/// produce an error.
+///
+/// This typedef is generally used to avoid writing out [`io::Error`] directly and
+/// is otherwise a direct mapping to [`Result`].
+///
+/// While usual Rust style is to import types directly, aliases of [`Result`]
+/// often are not, to make it easier to distinguish between them. [`Result`] is
+/// generally assumed to be [`std::result::Result`][`Result`], and so users of this alias
+/// will generally use `io::Result` instead of shadowing the prelude's import
+/// of [`std::result::Result`][`Result`].
+///
+/// [`std::io`]: ../io/index.html
+/// [`io::Error`]: ../io/struct.Error.html
+/// [`Result`]: ../result/enum.Result.html
+///
+/// # Examples
+///
+/// A convenience function that bubbles an `io::Result` to its caller:
+///
+/// ```
+/// use std::io;
+///
+/// fn get_string() -> io::Result<String> {
+/// let mut buffer = String::new();
+///
+/// io::stdin().read_line(&mut buffer)?;
+///
+/// Ok(buffer)
+/// }
+/// ```
+pub type Result<T> = result::Result<T, Error>;
+
+/// The error type for I/O operations of the [`Read`], [`Write`], [`Seek`], and
+/// associated traits.
+///
+/// Errors mostly originate from the underlying OS, but custom instances of
+/// `Error` can be created with crafted error messages and a particular value of
+/// [`ErrorKind`].
+///
+/// [`Read`]: ../io/trait.Read.html
+/// [`Write`]: ../io/trait.Write.html
+/// [`Seek`]: ../io/trait.Seek.html
+/// [`ErrorKind`]: enum.ErrorKind.html
+pub struct Error {
+ repr: Repr,
+}
+
+impl fmt::Debug for Error {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Debug::fmt(&self.repr, f)
+ }
+}
+
+enum Repr {
+ Os(i32),
+ Simple(ErrorKind),
+ #[cfg(feature="alloc")]
+ Custom(Box<Custom>),
+ #[cfg(not(feature="alloc"))]
+ Custom(Custom),
+}
+
+#[derive(Debug)]
+struct Custom {
+ kind: ErrorKind,
+ error: String,
+}
+
+/// A list specifying general categories of I/O error.
+///
+/// This list is intended to grow over time and it is not recommended to
+/// exhaustively match against it.
+///
+/// It is used with the [`io::Error`] type.
+///
+/// [`io::Error`]: struct.Error.html
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[allow(deprecated)]
+pub enum ErrorKind {
+ /// An entity was not found, often a file.
+ NotFound,
+ /// The operation lacked the necessary privileges to complete.
+ PermissionDenied,
+ /// The connection was refused by the remote server.
+ ConnectionRefused,
+ /// The connection was reset by the remote server.
+ ConnectionReset,
+ /// The connection was aborted (terminated) by the remote server.
+ ConnectionAborted,
+ /// The network operation failed because it was not connected yet.
+ NotConnected,
+ /// A socket address could not be bound because the address is already in
+ /// use elsewhere.
+ AddrInUse,
+ /// A nonexistent interface was requested or the requested address was not
+ /// local.
+ AddrNotAvailable,
+ /// The operation failed because a pipe was closed.
+ BrokenPipe,
+ /// An entity already exists, often a file.
+ AlreadyExists,
+ /// The operation needs to block to complete, but the blocking operation was
+ /// requested to not occur.
+ WouldBlock,
+ /// A parameter was incorrect.
+ InvalidInput,
+ /// Data not valid for the operation were encountered.
+ ///
+ /// Unlike [`InvalidInput`], this typically means that the operation
+ /// parameters were valid, however the error was caused by malformed
+ /// input data.
+ ///
+ /// For example, a function that reads a file into a string will error with
+ /// `InvalidData` if the file's contents are not valid UTF-8.
+ ///
+ /// [`InvalidInput`]: #variant.InvalidInput
+ InvalidData,
+ /// The I/O operation's timeout expired, causing it to be canceled.
+ TimedOut,
+ /// An error returned when an operation could not be completed because a
+ /// call to [`write`] returned [`Ok(0)`].
+ ///
+ /// This typically means that an operation could only succeed if it wrote a
+ /// particular number of bytes but only a smaller number of bytes could be
+ /// written.
+ ///
+ /// [`write`]: ../../std/io/trait.Write.html#tymethod.write
+ /// [`Ok(0)`]: ../../std/io/type.Result.html
+ WriteZero,
+ /// This operation was interrupted.
+ ///
+ /// Interrupted operations can typically be retried.
+ Interrupted,
+ /// Any I/O error not part of this list.
+ Other,
+
+ /// An error returned when an operation could not be completed because an
+ /// "end of file" was reached prematurely.
+ ///
+ /// This typically means that an operation could only succeed if it read a
+ /// particular number of bytes but only a smaller number of bytes could be
+ /// read.
+ UnexpectedEof,
+
+ /// A marker variant that tells the compiler that users of this enum cannot
+ /// match it exhaustively.
+ #[doc(hidden)]
+ __Nonexhaustive,
+}
+
+impl ErrorKind {
+ fn as_str(&self) -> &'static str {
+ match *self {
+ ErrorKind::NotFound => "entity not found",
+ ErrorKind::PermissionDenied => "permission denied",
+ ErrorKind::ConnectionRefused => "connection refused",
+ ErrorKind::ConnectionReset => "connection reset",
+ ErrorKind::ConnectionAborted => "connection aborted",
+ ErrorKind::NotConnected => "not connected",
+ ErrorKind::AddrInUse => "address in use",
+ ErrorKind::AddrNotAvailable => "address not available",
+ ErrorKind::BrokenPipe => "broken pipe",
+ ErrorKind::AlreadyExists => "entity already exists",
+ ErrorKind::WouldBlock => "operation would block",
+ ErrorKind::InvalidInput => "invalid input parameter",
+ ErrorKind::InvalidData => "invalid data",
+ ErrorKind::TimedOut => "timed out",
+ ErrorKind::WriteZero => "write zero",
+ ErrorKind::Interrupted => "operation interrupted",
+ ErrorKind::Other => "other os error",
+ ErrorKind::UnexpectedEof => "unexpected end of file",
+ ErrorKind::__Nonexhaustive => unreachable!()
+ }
+ }
+}
+
+/// Intended for use for errors not exposed to the user, where allocating onto
+/// the heap (for normal construction via Error::new) is too costly.
+impl From<ErrorKind> for Error {
+ #[inline]
+ fn from(kind: ErrorKind) -> Error {
+ Error {
+ repr: Repr::Simple(kind)
+ }
+ }
+}
+
+impl Error {
+ /// Creates a new I/O error from a known kind of error as well as an
+ /// arbitrary error payload.
+ ///
+ /// This function is used to generically create I/O errors which do not
+ /// originate from the OS itself. The `error` argument is an arbitrary
+ /// payload which will be contained in this `Error`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{Error, ErrorKind};
+ ///
+ /// // errors can be created from strings
+ /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
+ ///
+ /// // errors can also be created from other errors
+ /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
+ /// ```
+ pub fn new<E>(kind: ErrorKind, error: E) -> Error
+ where E: Into<String>
+ {
+ Self::_new(kind, error.into())
+ }
+
+ fn _new(kind: ErrorKind, error: String) -> Error {
+ Error {
+ repr: Repr::Custom(Box::new(Custom {
+ kind,
+ error,
+ }))
+ }
+ }
+
+ /// Creates a new instance of an `Error` from a particular OS error code.
+ ///
+ /// # Examples
+ ///
+ /// On Linux:
+ ///
+ /// ```
+ /// # if cfg!(target_os = "linux") {
+ /// use std::io;
+ ///
+ /// let error = io::Error::from_raw_os_error(22);
+ /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
+ /// # }
+ /// ```
+ ///
+ /// On Windows:
+ ///
+ /// ```
+ /// # if cfg!(windows) {
+ /// use std::io;
+ ///
+ /// let error = io::Error::from_raw_os_error(10022);
+ /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
+ /// # }
+ /// ```
+ pub fn from_raw_os_error(code: i32) -> Error {
+ Error { repr: Repr::Os(code) }
+ }
+
+ /// Returns the OS error that this error represents (if any).
+ ///
+ /// If this `Error` was constructed via `last_os_error` or
+ /// `from_raw_os_error`, then this function will return `Some`, otherwise
+ /// it will return `None`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{Error, ErrorKind};
+ ///
+ /// fn print_os_error(err: &Error) {
+ /// if let Some(raw_os_err) = err.raw_os_error() {
+ /// println!("raw OS error: {:?}", raw_os_err);
+ /// } else {
+ /// println!("Not an OS error");
+ /// }
+ /// }
+ ///
+ /// fn main() {
+ /// // Will print "raw OS error: ...".
+ /// print_os_error(&Error::last_os_error());
+ /// // Will print "Not an OS error".
+ /// print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
+ /// }
+ /// ```
+ pub fn raw_os_error(&self) -> Option<i32> {
+ match self.repr {
+ Repr::Os(i) => Some(i),
+ Repr::Custom(..) => None,
+ Repr::Simple(..) => None,
+ }
+ }
+
+ /// Returns a reference to the inner error wrapped by this error (if any).
+ ///
+ /// If this `Error` was constructed via `new` then this function will
+ /// return `Some`, otherwise it will return `None`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{Error, ErrorKind};
+ ///
+ /// fn print_error(err: &Error) {
+ /// if let Some(inner_err) = err.get_ref() {
+ /// println!("Inner error: {:?}", inner_err);
+ /// } else {
+ /// println!("No inner error");
+ /// }
+ /// }
+ ///
+ /// fn main() {
+ /// // Will print "No inner error".
+ /// print_error(&Error::last_os_error());
+ /// // Will print "Inner error: ...".
+ /// print_error(&Error::new(ErrorKind::Other, "oh no!"));
+ /// }
+ /// ```
+ pub fn get_ref(&self) -> Option<&String> {
+ match self.repr {
+ Repr::Os(..) => None,
+ Repr::Simple(..) => None,
+ Repr::Custom(ref c) => Some(&c.error),
+ }
+ }
+
+ /// Returns a mutable reference to the inner error wrapped by this error
+ /// (if any).
+ ///
+ /// If this `Error` was constructed via `new` then this function will
+ /// return `Some`, otherwise it will return `None`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{Error, ErrorKind};
+ /// use std::{error, fmt};
+ /// use std::fmt::Display;
+ ///
+ /// #[derive(Debug)]
+ /// struct MyError {
+ /// v: String,
+ /// }
+ ///
+ /// impl MyError {
+ /// fn new() -> MyError {
+ /// MyError {
+ /// v: "oh no!".to_string()
+ /// }
+ /// }
+ ///
+ /// fn change_message(&mut self, new_message: &str) {
+ /// self.v = new_message.to_string();
+ /// }
+ /// }
+ ///
+ /// impl error::Error for MyError {
+ /// fn description(&self) -> &str { &self.v }
+ /// }
+ ///
+ /// impl Display for MyError {
+ /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ /// write!(f, "MyError: {}", &self.v)
+ /// }
+ /// }
+ ///
+ /// fn change_error(mut err: Error) -> Error {
+ /// if let Some(inner_err) = err.get_mut() {
+ /// inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
+ /// }
+ /// err
+ /// }
+ ///
+ /// fn print_error(err: &Error) {
+ /// if let Some(inner_err) = err.get_ref() {
+ /// println!("Inner error: {}", inner_err);
+ /// } else {
+ /// println!("No inner error");
+ /// }
+ /// }
+ ///
+ /// fn main() {
+ /// // Will print "No inner error".
+ /// print_error(&change_error(Error::last_os_error()));
+ /// // Will print "Inner error: ...".
+ /// print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
+ /// }
+ /// ```
+ pub fn get_mut(&mut self) -> Option<&mut String> {
+ match self.repr {
+ Repr::Os(..) => None,
+ Repr::Simple(..) => None,
+ Repr::Custom(ref mut c) => Some(&mut c.error),
+ }
+ }
+
+ /// Consumes the `Error`, returning its inner error (if any).
+ ///
+ /// If this `Error` was constructed via `new` then this function will
+ /// return `Some`, otherwise it will return `None`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{Error, ErrorKind};
+ ///
+ /// fn print_error(err: Error) {
+ /// if let Some(inner_err) = err.into_inner() {
+ /// println!("Inner error: {}", inner_err);
+ /// } else {
+ /// println!("No inner error");
+ /// }
+ /// }
+ ///
+ /// fn main() {
+ /// // Will print "No inner error".
+ /// print_error(Error::last_os_error());
+ /// // Will print "Inner error: ...".
+ /// print_error(Error::new(ErrorKind::Other, "oh no!"));
+ /// }
+ /// ```
+ pub fn into_inner(self) -> Option<String> {
+ match self.repr {
+ Repr::Os(..) => None,
+ Repr::Simple(..) => None,
+ Repr::Custom(c) => Some(c.error)
+ }
+ }
+
+ /// Returns the corresponding `ErrorKind` for this error.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{Error, ErrorKind};
+ ///
+ /// fn print_error(err: Error) {
+ /// println!("{:?}", err.kind());
+ /// }
+ ///
+ /// fn main() {
+ /// // Will print "No inner error".
+ /// print_error(Error::last_os_error());
+ /// // Will print "Inner error: ...".
+ /// print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
+ /// }
+ /// ```
+ pub fn kind(&self) -> ErrorKind {
+ match self.repr {
+ Repr::Os(_code) => ErrorKind::Other,
+ Repr::Custom(ref c) => c.kind,
+ Repr::Simple(kind) => kind,
+ }
+ }
+}
+
+impl fmt::Debug for Repr {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ match *self {
+ Repr::Os(code) =>
+ fmt.debug_struct("Os")
+ .field("code", &code).finish(),
+ Repr::Custom(ref c) => fmt::Debug::fmt(&c, fmt),
+ Repr::Simple(kind) => fmt.debug_tuple("Kind").field(&kind).finish(),
+ }
+ }
+}
+
+impl fmt::Display for Error {
+ fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+ match self.repr {
+ Repr::Os(code) => {
+ write!(fmt, "os error {}", code)
+ }
+ Repr::Custom(ref c) => c.error.fmt(fmt),
+ Repr::Simple(kind) => write!(fmt, "{}", kind.as_str()),
+ }
+ }
+}
+
+fn _assert_error_is_sync_send() {
+ fn _is_sync_send<T: Sync+Send>() {}
+ _is_sync_send::<Error>();
+}
+
+#[cfg(test)]
+mod test {
+ use super::{Error, ErrorKind, Repr, Custom};
+ use error;
+ use fmt;
+ use sys::os::error_string;
+ use sys::decode_error_kind;
+
+ #[test]
+ fn test_debug_error() {
+ let code = 6;
+ let msg = error_string(code);
+ let kind = decode_error_kind(code);
+ let err = Error {
+ repr: Repr::Custom(box Custom {
+ kind: ErrorKind::InvalidInput,
+ error: box Error {
+ repr: super::Repr::Os(code)
+ },
+ })
+ };
+ let expected = format!(
+ "Custom {{ \
+ kind: InvalidInput, \
+ error: Os {{ \
+ code: {:?}, \
+ kind: {:?}, \
+ message: {:?} \
+ }} \
+ }}",
+ code, kind, msg
+ );
+ assert_eq!(format!("{:?}", err), expected);
+ }
+
+ #[test]
+ fn test_downcasting() {
+ #[derive(Debug)]
+ struct TestError;
+
+ impl fmt::Display for TestError {
+ fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+ Ok(())
+ }
+ }
+
+ impl error::Error for TestError {
+ fn description(&self) -> &str {
+ "asdf"
+ }
+ }
+
+ // 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().description());
+ assert!(err.get_mut().unwrap().is::<TestError>());
+ let extracted = err.into_inner().unwrap();
+ extracted.downcast::<TestError>().unwrap();
+ }
+}
diff --git a/src/b81da278623d9dcda1776008612bd42e1922e9c3/impls.rs b/src/b81da278623d9dcda1776008612bd42e1922e9c3/impls.rs
new file mode 100644
index 0000000..452b8b7
--- /dev/null
+++ b/src/b81da278623d9dcda1776008612bd42e1922e9c3/impls.rs
@@ -0,0 +1,341 @@
+// Copyright 2015 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.
+
+#[cfg(feature="alloc")] use alloc::boxed::Box;
+use core::cmp;
+use io::{self, SeekFrom, Read, Initializer, Write, Seek, Error, ErrorKind};
+#[cfg(feature="collections")] use io::BufRead;
+use core::fmt;
+use core::mem;
+#[cfg(feature="collections")] use collections::string::String;
+#[cfg(feature="collections")] use collections::vec::Vec;
+
+// =============================================================================
+// Forwarding implementations
+
+impl<'a, R: Read + ?Sized> Read for &'a mut R {
+ #[inline]
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ (**self).read(buf)
+ }
+
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ (**self).initializer()
+ }
+
+ #[cfg(feature="collections")]
+ #[inline]
+ fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+ (**self).read_to_end(buf)
+ }
+
+ #[cfg(feature="collections")]
+ #[inline]
+ fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+ (**self).read_to_string(buf)
+ }
+
+ #[inline]
+ fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+ (**self).read_exact(buf)
+ }
+}
+impl<'a, W: Write + ?Sized> Write for &'a mut W {
+ #[inline]
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+ #[inline]
+ fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+ #[inline]
+ fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+ (**self).write_all(buf)
+ }
+
+ #[inline]
+ fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+ (**self).write_fmt(fmt)
+ }
+}
+impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+ #[inline]
+ fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[cfg(feature="collections")]
+impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+ #[inline]
+ fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+ #[inline]
+ fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+ #[inline]
+ fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+ (**self).read_until(byte, buf)
+ }
+
+ #[inline]
+ fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+ (**self).read_line(buf)
+ }
+}
+
+#[cfg(feature="alloc")]
+impl<R: Read + ?Sized> Read for Box<R> {
+ #[inline]
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ (**self).read(buf)
+ }
+
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ (**self).initializer()
+ }
+
+ #[cfg(feature="collections")]
+ #[inline]
+ fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+ (**self).read_to_end(buf)
+ }
+
+ #[cfg(feature="collections")]
+ #[inline]
+ fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+ (**self).read_to_string(buf)
+ }
+
+ #[inline]
+ fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+ (**self).read_exact(buf)
+ }
+}
+#[cfg(feature="alloc")]
+impl<W: Write + ?Sized> Write for Box<W> {
+ #[inline]
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
+
+ #[inline]
+ fn flush(&mut self) -> io::Result<()> { (**self).flush() }
+
+ #[inline]
+ fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+ (**self).write_all(buf)
+ }
+
+ #[inline]
+ fn write_fmt(&mut self, fmt: fmt::Arguments) -> io::Result<()> {
+ (**self).write_fmt(fmt)
+ }
+}
+#[cfg(feature="alloc")]
+impl<S: Seek + ?Sized> Seek for Box<S> {
+ #[inline]
+ fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
+}
+#[cfg(feature="collections")]
+impl<B: BufRead + ?Sized> BufRead for Box<B> {
+ #[inline]
+ fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
+
+ #[inline]
+ fn consume(&mut self, amt: usize) { (**self).consume(amt) }
+
+ #[inline]
+ fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> io::Result<usize> {
+ (**self).read_until(byte, buf)
+ }
+
+ #[inline]
+ fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
+ (**self).read_line(buf)
+ }
+}
+
+// =============================================================================
+// In-memory buffer implementations
+
+/// Read is implemented for `&[u8]` by copying from the slice.
+///
+/// Note that reading updates the slice to point to the yet unread part.
+/// The slice will be empty when EOF is reached.
+impl<'a> Read for &'a [u8] {
+ #[inline]
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ let amt = cmp::min(buf.len(), self.len());
+ let (a, b) = self.split_at(amt);
+
+ // First check if the amount of bytes we want to read is small:
+ // `copy_from_slice` will generally expand to a call to `memcpy`, and
+ // for a single byte the overhead is significant.
+ if amt == 1 {
+ buf[0] = a[0];
+ } else {
+ buf[..amt].copy_from_slice(a);
+ }
+
+ *self = b;
+ Ok(amt)
+ }
+
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ Initializer::nop()
+ }
+
+ #[inline]
+ fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+ if buf.len() > self.len() {
+ return Err(Error::new(ErrorKind::UnexpectedEof,
+ "failed to fill whole buffer"));
+ }
+ let (a, b) = self.split_at(buf.len());
+
+ // First check if the amount of bytes we want to read is small:
+ // `copy_from_slice` will generally expand to a call to `memcpy`, and
+ // for a single byte the overhead is significant.
+ if buf.len() == 1 {
+ buf[0] = a[0];
+ } else {
+ buf.copy_from_slice(a);
+ }
+
+ *self = b;
+ Ok(())
+ }
+
+ #[cfg(feature="collections")]
+ #[inline]
+ fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+ buf.extend_from_slice(*self);
+ let len = self.len();
+ *self = &self[len..];
+ Ok(len)
+ }
+}
+
+#[cfg(feature="collections")]
+impl<'a> BufRead for &'a [u8] {
+ #[inline]
+ fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
+
+ #[inline]
+ fn consume(&mut self, amt: usize) { *self = &self[amt..]; }
+}
+
+/// Write is implemented for `&mut [u8]` by copying into the slice, overwriting
+/// its data.
+///
+/// Note that writing updates the slice to point to the yet unwritten part.
+/// The slice will be empty when it has been completely overwritten.
+impl<'a> Write for &'a mut [u8] {
+ #[inline]
+ fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+ let amt = cmp::min(data.len(), self.len());
+ let (a, b) = mem::replace(self, &mut []).split_at_mut(amt);
+ a.copy_from_slice(&data[..amt]);
+ *self = b;
+ Ok(amt)
+ }
+
+ #[inline]
+ fn write_all(&mut self, data: &[u8]) -> io::Result<()> {
+ if self.write(data)? == data.len() {
+ Ok(())
+ } else {
+ Err(Error::new(ErrorKind::WriteZero, "failed to write whole buffer"))
+ }
+ }
+
+ #[inline]
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+/// Write is implemented for `Vec<u8>` by appending to the vector.
+/// The vector will grow as needed.
+#[cfg(feature="collections")]
+impl Write for Vec<u8> {
+ #[inline]
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ self.extend_from_slice(buf);
+ Ok(buf.len())
+ }
+
+ #[inline]
+ fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
+ self.extend_from_slice(buf);
+ Ok(())
+ }
+
+ #[inline]
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+#[cfg(test)]
+mod tests {
+ use io::prelude::*;
+ use test;
+
+ #[bench]
+ fn bench_read_slice(b: &mut test::Bencher) {
+ let buf = [5; 1024];
+ let mut dst = [0; 128];
+
+ b.iter(|| {
+ let mut rd = &buf[..];
+ for _ in 0..8 {
+ let _ = rd.read(&mut dst);
+ test::black_box(&dst);
+ }
+ })
+ }
+
+ #[bench]
+ fn bench_write_slice(b: &mut test::Bencher) {
+ let mut buf = [0; 1024];
+ let src = [5; 128];
+
+ b.iter(|| {
+ let mut wr = &mut buf[..];
+ for _ in 0..8 {
+ let _ = wr.write_all(&src);
+ test::black_box(&wr);
+ }
+ })
+ }
+
+ #[bench]
+ fn bench_read_vec(b: &mut test::Bencher) {
+ let buf = vec![5; 1024];
+ let mut dst = [0; 128];
+
+ b.iter(|| {
+ let mut rd = &buf[..];
+ for _ in 0..8 {
+ let _ = rd.read(&mut dst);
+ test::black_box(&dst);
+ }
+ })
+ }
+
+ #[bench]
+ fn bench_write_vec(b: &mut test::Bencher) {
+ let mut buf = Vec::with_capacity(1024);
+ let src = [5; 128];
+
+ b.iter(|| {
+ let mut wr = &mut buf[..];
+ for _ in 0..8 {
+ let _ = wr.write_all(&src);
+ test::black_box(&wr);
+ }
+ })
+ }
+}
diff --git a/src/b81da278623d9dcda1776008612bd42e1922e9c3/mod.rs b/src/b81da278623d9dcda1776008612bd42e1922e9c3/mod.rs
new file mode 100644
index 0000000..a5706ec
--- /dev/null
+++ b/src/b81da278623d9dcda1776008612bd42e1922e9c3/mod.rs
@@ -0,0 +1,2310 @@
+// Copyright 2015 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, helpers, and type definitions for core I/O functionality.
+//!
+//! The `std::io` module contains a number of common things you'll need
+//! when doing input and output. The most core part of this module is
+//! the [`Read`] and [`Write`] traits, which provide the
+//! most general interface for reading and writing input and output.
+//!
+//! # Read and Write
+//!
+//! Because they are traits, [`Read`] and [`Write`] are implemented by a number
+//! of other types, and you can implement them for your types too. As such,
+//! you'll see a few different types of I/O throughout the documentation in
+//! this module: [`File`]s, [`TcpStream`]s, and sometimes even [`Vec<T>`]s. For
+//! example, [`Read`] adds a [`read`][`Read::read`] method, which we can use on
+//! [`File`]s:
+//!
+//! ```no_run
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::fs::File;
+//!
+//! fn main() -> io::Result<()> {
+//! let mut f = File::open("foo.txt")?;
+//! let mut buffer = [0; 10];
+//!
+//! // read up to 10 bytes
+//! f.read(&mut buffer)?;
+//!
+//! println!("The bytes: {:?}", buffer);
+//! Ok(())
+//! }
+//! ```
+//!
+//! [`Read`] and [`Write`] are so important, implementors of the two traits have a
+//! nickname: readers and writers. So you'll sometimes see 'a reader' instead
+//! of 'a type that implements the [`Read`] trait'. Much easier!
+//!
+//! ## Seek and BufRead
+//!
+//! Beyond that, there are two important traits that are provided: [`Seek`]
+//! and [`BufRead`]. Both of these build on top of a reader to control
+//! how the reading happens. [`Seek`] lets you control where the next byte is
+//! coming from:
+//!
+//! ```no_run
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::SeekFrom;
+//! use std::fs::File;
+//!
+//! fn main() -> io::Result<()> {
+//! let mut f = File::open("foo.txt")?;
+//! let mut buffer = [0; 10];
+//!
+//! // skip to the last 10 bytes of the file
+//! f.seek(SeekFrom::End(-10))?;
+//!
+//! // read up to 10 bytes
+//! f.read(&mut buffer)?;
+//!
+//! println!("The bytes: {:?}", buffer);
+//! Ok(())
+//! }
+//! ```
+//!
+//! [`BufRead`] uses an internal buffer to provide a number of other ways to read, but
+//! to show it off, we'll need to talk about buffers in general. Keep reading!
+//!
+//! ## BufReader and BufWriter
+//!
+//! Byte-based interfaces are unwieldy and can be inefficient, as we'd need to be
+//! making near-constant calls to the operating system. To help with this,
+//! `std::io` comes with two structs, [`BufReader`] and [`BufWriter`], which wrap
+//! readers and writers. The wrapper uses a buffer, reducing the number of
+//! calls and providing nicer methods for accessing exactly what you want.
+//!
+//! For example, [`BufReader`] works with the [`BufRead`] trait to add extra
+//! methods to any reader:
+//!
+//! ```no_run
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! fn main() -> io::Result<()> {
+//! let f = File::open("foo.txt")?;
+//! let mut reader = BufReader::new(f);
+//! let mut buffer = String::new();
+//!
+//! // read a line into buffer
+//! reader.read_line(&mut buffer)?;
+//!
+//! println!("{}", buffer);
+//! Ok(())
+//! }
+//! ```
+//!
+//! [`BufWriter`] doesn't add any new ways of writing; it just buffers every call
+//! to [`write`][`Write::write`]:
+//!
+//! ```no_run
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufWriter;
+//! use std::fs::File;
+//!
+//! fn main() -> io::Result<()> {
+//! let f = File::create("foo.txt")?;
+//! {
+//! let mut writer = BufWriter::new(f);
+//!
+//! // write a byte to the buffer
+//! writer.write(&[42])?;
+//!
+//! } // the buffer is flushed once writer goes out of scope
+//!
+//! Ok(())
+//! }
+//! ```
+//!
+//! ## Standard input and output
+//!
+//! A very common source of input is standard input:
+//!
+//! ```no_run
+//! use std::io;
+//!
+//! fn main() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! io::stdin().read_line(&mut input)?;
+//!
+//! println!("You typed: {}", input.trim());
+//! Ok(())
+//! }
+//! ```
+//!
+//! Note that you cannot use the [`?` operator] in functions that do not return
+//! a [`Result<T, E>`][`Result`] (e.g. `main`). Instead, you can call [`.unwrap()`]
+//! or `match` on the return value to catch any possible errors:
+//!
+//! ```no_run
+//! use std::io;
+//!
+//! let mut input = String::new();
+//!
+//! io::stdin().read_line(&mut input).unwrap();
+//! ```
+//!
+//! And a very common source of output is standard output:
+//!
+//! ```no_run
+//! use std::io;
+//! use std::io::prelude::*;
+//!
+//! fn main() -> io::Result<()> {
+//! io::stdout().write(&[42])?;
+//! Ok(())
+//! }
+//! ```
+//!
+//! Of course, using [`io::stdout`] directly is less common than something like
+//! [`println!`].
+//!
+//! ## Iterator types
+//!
+//! A large number of the structures provided by `std::io` are for various
+//! ways of iterating over I/O. For example, [`Lines`] is used to split over
+//! lines:
+//!
+//! ```no_run
+//! use std::io;
+//! use std::io::prelude::*;
+//! use std::io::BufReader;
+//! use std::fs::File;
+//!
+//! fn main() -> io::Result<()> {
+//! let f = File::open("foo.txt")?;
+//! let reader = BufReader::new(f);
+//!
+//! for line in reader.lines() {
+//! println!("{}", line?);
+//! }
+//! Ok(())
+//! }
+//! ```
+//!
+//! ## Functions
+//!
+//! There are a number of [functions][functions-list] that offer access to various
+//! features. For example, we can use three of these functions to copy everything
+//! from standard input to standard output:
+//!
+//! ```no_run
+//! use std::io;
+//!
+//! fn main() -> io::Result<()> {
+//! io::copy(&mut io::stdin(), &mut io::stdout())?;
+//! Ok(())
+//! }
+//! ```
+//!
+//! [functions-list]: #functions-1
+//!
+//! ## io::Result
+//!
+//! Last, but certainly not least, is [`io::Result`]. This type is used
+//! as the return type of many `std::io` functions that can cause an error, and
+//! can be returned from your own functions as well. Many of the examples in this
+//! module use the [`?` operator]:
+//!
+//! ```
+//! use std::io;
+//!
+//! fn read_input() -> io::Result<()> {
+//! let mut input = String::new();
+//!
+//! io::stdin().read_line(&mut input)?;
+//!
+//! println!("You typed: {}", input.trim());
+//!
+//! Ok(())
+//! }
+//! ```
+//!
+//! The return type of `read_input()`, [`io::Result<()>`][`io::Result`], is a very
+//! common type for functions which don't have a 'real' return value, but do want to
+//! return errors if they happen. In this case, the only purpose of this function is
+//! to read the line and print it, so we use `()`.
+//!
+//! ## Platform-specific behavior
+//!
+//! Many I/O functions throughout the standard library are documented to indicate
+//! what various library or syscalls they are delegated to. This is done to help
+//! applications both understand what's happening under the hood as well as investigate
+//! any possibly unclear semantics. Note, however, that this is informative, not a binding
+//! contract. The implementation of many of these functions are subject to change over
+//! time and may call fewer or more syscalls/library functions.
+//!
+//! [`Read`]: trait.Read.html
+//! [`Write`]: trait.Write.html
+//! [`Seek`]: trait.Seek.html
+//! [`BufRead`]: trait.BufRead.html
+//! [`File`]: ../fs/struct.File.html
+//! [`TcpStream`]: ../net/struct.TcpStream.html
+//! [`Vec<T>`]: ../vec/struct.Vec.html
+//! [`BufReader`]: struct.BufReader.html
+//! [`BufWriter`]: struct.BufWriter.html
+//! [`Write::write`]: trait.Write.html#tymethod.write
+//! [`io::stdout`]: fn.stdout.html
+//! [`println!`]: ../macro.println.html
+//! [`Lines`]: struct.Lines.html
+//! [`io::Result`]: type.Result.html
+//! [`?` operator]: ../../book/first-edition/syntax-index.html
+//! [`Read::read`]: trait.Read.html#tymethod.read
+//! [`Result`]: ../result/enum.Result.html
+//! [`.unwrap()`]: ../result/enum.Result.html#method.unwrap
+
+use core::cmp;
+use core::str as core_str;
+use core::fmt;
+use core::result;
+#[cfg(feature="collections")] use collections::string::String;
+use core::str;
+#[cfg(feature="collections")] use collections::vec::Vec;
+#[cfg(not(core_memchr))]
+mod memchr;
+#[cfg(all(feature="collections",core_memchr))]
+use core::slice::memchr;
+use core::ptr;
+
+#[cfg(feature="collections")] pub use self::buffered::{BufReader, BufWriter, LineWriter};
+#[cfg(feature="collections")] pub use self::buffered::IntoInnerError;
+pub use self::cursor::Cursor;
+pub use self::error::{Result, Error, ErrorKind};
+pub use self::util::{copy, sink, Sink, empty, Empty, repeat, Repeat};
+
+pub mod prelude;
+#[cfg(feature="collections")] mod buffered;
+mod cursor;
+mod error;
+mod impls;
+mod util;
+
+const DEFAULT_BUF_SIZE: usize = 8 * 1024;
+
+#[cfg(feature="collections")]
+struct Guard<'a> { buf: &'a mut Vec<u8>, len: usize }
+
+#[cfg(feature="collections")]
+impl<'a> Drop for Guard<'a> {
+ fn drop(&mut self) {
+ unsafe { self.buf.set_len(self.len); }
+ }
+}
+
+// A few methods below (read_to_string, read_line) will append data into a
+// `String` buffer, but we need to be pretty careful when doing this. The
+// implementation will just call `.as_mut_vec()` and then delegate to a
+// byte-oriented reading method, but we must ensure that when returning we never
+// leave `buf` in a state such that it contains invalid UTF-8 in its bounds.
+//
+// To this end, we use an RAII guard (to protect against panics) which updates
+// the length of the string when it is dropped. This guard initially truncates
+// the string to the prior length and only after we've validated that the
+// new contents are valid UTF-8 do we allow it to set a longer length.
+//
+// The unsafety in this function is twofold:
+//
+// 1. We're looking at the raw bytes of `buf`, so we take on the burden of UTF-8
+// checks.
+// 2. We're passing a raw buffer to the function `f`, and it is expected that
+// the function only *appends* bytes to the buffer. We'll get undefined
+// behavior if existing bytes are overwritten to have non-UTF-8 data.
+#[cfg(feature="collections")]
+fn append_to_string<F>(buf: &mut String, f: F) -> Result<usize>
+ where F: FnOnce(&mut Vec<u8>) -> Result<usize>
+{
+ unsafe {
+ let mut g = Guard { len: buf.len(), buf: buf.as_mut_vec() };
+ let ret = f(g.buf);
+ if str::from_utf8(&g.buf[g.len..]).is_err() {
+ ret.and_then(|_| {
+ Err(Error::new(ErrorKind::InvalidData,
+ "stream did not contain valid UTF-8"))
+ })
+ } else {
+ g.len = g.buf.len();
+ ret
+ }
+ }
+}
+
+// This uses an adaptive system to extend the vector when it fills. We want to
+// avoid paying to allocate and zero a huge chunk of memory if the reader only
+// has 4 bytes while still making large reads if the reader does have a ton
+// of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every
+// time is 4,500 times (!) slower than this if the reader has a very small
+// amount of data to return.
+//
+// Because we're extending the buffer with uninitialized data for trusted
+// readers, we need to make sure to truncate that if any of this panics.
+#[cfg(feature="collections")]
+fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize> {
+ let start_len = buf.len();
+ let mut g = Guard { len: buf.len(), buf: buf };
+ let ret;
+ loop {
+ if g.len == g.buf.len() {
+ unsafe {
+ g.buf.reserve(32);
+ let capacity = g.buf.capacity();
+ g.buf.set_len(capacity);
+ r.initializer().initialize(&mut g.buf[g.len..]);
+ }
+ }
+
+ match r.read(&mut g.buf[g.len..]) {
+ Ok(0) => {
+ ret = Ok(g.len - start_len);
+ break;
+ }
+ Ok(n) => g.len += n,
+ Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+ Err(e) => {
+ ret = Err(e);
+ break;
+ }
+ }
+ }
+
+ ret
+}
+
+/// The `Read` trait allows for reading bytes from a source.
+///
+/// Implementors of the `Read` trait are called 'readers'.
+///
+/// Readers are defined by one required method, [`read()`]. Each call to [`read()`]
+/// will attempt to pull bytes from this source into a provided buffer. A
+/// number of other methods are implemented in terms of [`read()`], giving
+/// implementors a number of ways to read bytes while only needing to implement
+/// a single method.
+///
+/// Readers are intended to be composable with one another. Many implementors
+/// throughout [`std::io`] take and provide types which implement the `Read`
+/// trait.
+///
+/// Please note that each call to [`read()`] may involve a system call, and
+/// therefore, using something that implements [`BufRead`], such as
+/// [`BufReader`], will be more efficient.
+///
+/// # Examples
+///
+/// [`File`]s implement `Read`:
+///
+/// ```no_run
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// fn main() -> io::Result<()> {
+/// let mut f = File::open("foo.txt")?;
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// f.read(&mut buffer)?;
+///
+/// let mut buffer = vec![0; 10];
+/// // read the whole file
+/// f.read_to_end(&mut buffer)?;
+///
+/// // read into a String, so that you don't need to do the conversion.
+/// let mut buffer = String::new();
+/// f.read_to_string(&mut buffer)?;
+///
+/// // and more! See the other methods for more details.
+/// Ok(())
+/// }
+/// ```
+///
+/// Read from [`&str`] because [`&[u8]`][slice] implements `Read`:
+///
+/// ```no_run
+/// # use std::io;
+/// use std::io::prelude::*;
+///
+/// fn main() -> io::Result<()> {
+/// let mut b = "This string will be read".as_bytes();
+/// let mut buffer = [0; 10];
+///
+/// // read up to 10 bytes
+/// b.read(&mut buffer)?;
+///
+/// // etc... it works exactly as a File does!
+/// Ok(())
+/// }
+/// ```
+///
+/// [`read()`]: trait.Read.html#tymethod.read
+/// [`std::io`]: ../../std/io/index.html
+/// [`File`]: ../fs/struct.File.html
+/// [`BufRead`]: trait.BufRead.html
+/// [`BufReader`]: struct.BufReader.html
+/// [`&str`]: ../../std/primitive.str.html
+/// [slice]: ../../std/primitive.slice.html
+#[doc(spotlight)]
+pub trait Read {
+ /// Pull some bytes from this source into the specified buffer, returning
+ /// how many bytes were read.
+ ///
+ /// This function does not provide any guarantees about whether it blocks
+ /// waiting for data, but if an object needs to block for a read but cannot
+ /// it will typically signal this via an [`Err`] return value.
+ ///
+ /// If the return value of this method is [`Ok(n)`], then it must be
+ /// guaranteed that `0 <= n <= buf.len()`. A nonzero `n` value indicates
+ /// that the buffer `buf` has been filled in with `n` bytes of data from this
+ /// source. If `n` is `0`, then it can indicate one of two scenarios:
+ ///
+ /// 1. This reader has reached its "end of file" and will likely no longer
+ /// be able to produce bytes. Note that this does not mean that the
+ /// reader will *always* no longer be able to produce bytes.
+ /// 2. The buffer specified was 0 bytes in length.
+ ///
+ /// No guarantees are provided about the contents of `buf` when this
+ /// function is called, implementations cannot rely on any property of the
+ /// contents of `buf` being true. It is recommended that implementations
+ /// only write data to `buf` instead of reading its contents.
+ ///
+ /// # Errors
+ ///
+ /// If this function encounters any form of I/O or other error, an error
+ /// variant will be returned. If an error is returned then it must be
+ /// guaranteed that no bytes were read.
+ ///
+ /// An error of the [`ErrorKind::Interrupted`] kind is non-fatal and the read
+ /// operation should be retried if there is nothing else to do.
+ ///
+ /// # Examples
+ ///
+ /// [`File`]s implement `Read`:
+ ///
+ /// [`Err`]: ../../std/result/enum.Result.html#variant.Err
+ /// [`Ok(n)`]: ../../std/result/enum.Result.html#variant.Ok
+ /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
+ /// [`File`]: ../fs/struct.File.html
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ /// let mut buffer = [0; 10];
+ ///
+ /// // read up to 10 bytes
+ /// f.read(&mut buffer[..])?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
+
+ /// Determines if this `Read`er can work with buffers of uninitialized
+ /// memory.
+ ///
+ /// The default implementation returns an initializer which will zero
+ /// buffers.
+ ///
+ /// If a `Read`er guarantees that it can work properly with uninitialized
+ /// memory, it should call [`Initializer::nop()`]. See the documentation for
+ /// [`Initializer`] for details.
+ ///
+ /// The behavior of this method must be independent of the state of the
+ /// `Read`er - the method only takes `&self` so that it can be used through
+ /// trait objects.
+ ///
+ /// # Safety
+ ///
+ /// This method is unsafe because a `Read`er could otherwise return a
+ /// non-zeroing `Initializer` from another `Read` type without an `unsafe`
+ /// block.
+ ///
+ /// [`Initializer::nop()`]: ../../std/io/struct.Initializer.html#method.nop
+ /// [`Initializer`]: ../../std/io/struct.Initializer.html
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ Initializer::zeroing()
+ }
+
+ /// Read all bytes until EOF in this source, placing them into `buf`.
+ ///
+ /// All bytes read from this source will be appended to the specified buffer
+ /// `buf`. This function will continuously call [`read()`] to append more data to
+ /// `buf` until [`read()`] returns either [`Ok(0)`] or an error of
+ /// non-[`ErrorKind::Interrupted`] kind.
+ ///
+ /// If successful, this function will return the total number of bytes read.
+ ///
+ /// # Errors
+ ///
+ /// If this function encounters an error of the kind
+ /// [`ErrorKind::Interrupted`] then the error is ignored and the operation
+ /// will continue.
+ ///
+ /// If any other read error is encountered then this function immediately
+ /// returns. Any bytes which have already been read will be appended to
+ /// `buf`.
+ ///
+ /// # Examples
+ ///
+ /// [`File`]s implement `Read`:
+ ///
+ /// [`read()`]: trait.Read.html#tymethod.read
+ /// [`Ok(0)`]: ../../std/result/enum.Result.html#variant.Ok
+ /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
+ /// [`File`]: ../fs/struct.File.html
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ /// let mut buffer = Vec::new();
+ ///
+ /// // read the whole file
+ /// f.read_to_end(&mut buffer)?;
+ /// Ok(())
+ /// }
+ /// ```
+ ///
+ /// (See also the [`std::fs::read`] convenience function for reading from a
+ /// file.)
+ ///
+ /// [`std::fs::read`]: ../fs/fn.read.html
+ #[cfg(feature = "collections")]
+ fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
+ read_to_end(self, buf)
+ }
+
+ /// Read all bytes until EOF in this source, appending them to `buf`.
+ ///
+ /// If successful, this function returns the number of bytes which were read
+ /// and appended to `buf`.
+ ///
+ /// # Errors
+ ///
+ /// If the data in this stream is *not* valid UTF-8 then an error is
+ /// returned and `buf` is unchanged.
+ ///
+ /// See [`read_to_end`][readtoend] for other error semantics.
+ ///
+ /// [readtoend]: #method.read_to_end
+ ///
+ /// # Examples
+ ///
+ /// [`File`][file]s implement `Read`:
+ ///
+ /// [file]: ../fs/struct.File.html
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ /// let mut buffer = String::new();
+ ///
+ /// f.read_to_string(&mut buffer)?;
+ /// Ok(())
+ /// }
+ /// ```
+ ///
+ /// (See also the [`std::fs::read_to_string`] convenience function for
+ /// reading from a file.)
+ ///
+ /// [`std::fs::read_to_string`]: ../fs/fn.read_to_string.html
+ #[cfg(feature = "collections")]
+ fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
+ // Note that we do *not* call `.read_to_end()` here. We are passing
+ // `&mut Vec<u8>` (the raw contents of `buf`) into the `read_to_end`
+ // method to fill it up. An arbitrary implementation could overwrite the
+ // entire contents of the vector, not just append to it (which is what
+ // we are expecting).
+ //
+ // To prevent extraneously checking the UTF-8-ness of the entire buffer
+ // we pass it to our hardcoded `read_to_end` implementation which we
+ // know is guaranteed to only read data into the end of the buffer.
+ append_to_string(buf, |b| read_to_end(self, b))
+ }
+
+ /// Read the exact number of bytes required to fill `buf`.
+ ///
+ /// This function reads as many bytes as necessary to completely fill the
+ /// specified buffer `buf`.
+ ///
+ /// No guarantees are provided about the contents of `buf` when this
+ /// function is called, implementations cannot rely on any property of the
+ /// contents of `buf` being true. It is recommended that implementations
+ /// only write data to `buf` instead of reading its contents.
+ ///
+ /// # Errors
+ ///
+ /// If this function encounters an error of the kind
+ /// [`ErrorKind::Interrupted`] then the error is ignored and the operation
+ /// will continue.
+ ///
+ /// If this function encounters an "end of file" before completely filling
+ /// the buffer, it returns an error of the kind [`ErrorKind::UnexpectedEof`].
+ /// The contents of `buf` are unspecified in this case.
+ ///
+ /// If any other read error is encountered then this function immediately
+ /// returns. The contents of `buf` are unspecified in this case.
+ ///
+ /// If this function returns an error, it is unspecified how many bytes it
+ /// has read, but it will never read more than would be necessary to
+ /// completely fill the buffer.
+ ///
+ /// # Examples
+ ///
+ /// [`File`]s implement `Read`:
+ ///
+ /// [`File`]: ../fs/struct.File.html
+ /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
+ /// [`ErrorKind::UnexpectedEof`]: ../../std/io/enum.ErrorKind.html#variant.UnexpectedEof
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ /// let mut buffer = [0; 10];
+ ///
+ /// // read exactly 10 bytes
+ /// f.read_exact(&mut buffer)?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
+ while !buf.is_empty() {
+ match self.read(buf) {
+ Ok(0) => break,
+ Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
+ Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+ Err(e) => return Err(e),
+ }
+ }
+ if !buf.is_empty() {
+ Err(Error::new(ErrorKind::UnexpectedEof,
+ "failed to fill whole buffer"))
+ } else {
+ Ok(())
+ }
+ }
+
+ /// Creates a "by reference" adaptor for this instance of `Read`.
+ ///
+ /// The returned adaptor also implements `Read` and will simply borrow this
+ /// current reader.
+ ///
+ /// # Examples
+ ///
+ /// [`File`][file]s implement `Read`:
+ ///
+ /// [file]: ../fs/struct.File.html
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::Read;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ /// let mut buffer = Vec::new();
+ /// let mut other_buffer = Vec::new();
+ ///
+ /// {
+ /// let reference = f.by_ref();
+ ///
+ /// // read at most 5 bytes
+ /// reference.take(5).read_to_end(&mut buffer)?;
+ ///
+ /// } // drop our &mut reference so we can use f again
+ ///
+ /// // original file still usable, read the rest
+ /// f.read_to_end(&mut other_buffer)?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+
+ /// Transforms this `Read` instance to an [`Iterator`] over its bytes.
+ ///
+ /// The returned type implements [`Iterator`] where the `Item` is
+ /// [`Result`]`<`[`u8`]`, `[`io::Error`]`>`.
+ /// The yielded item is [`Ok`] if a byte was successfully read and [`Err`]
+ /// otherwise. EOF is mapped to returning [`None`] from this iterator.
+ ///
+ /// # Examples
+ ///
+ /// [`File`][file]s implement `Read`:
+ ///
+ /// [file]: ../fs/struct.File.html
+ /// [`Iterator`]: ../../std/iter/trait.Iterator.html
+ /// [`Result`]: ../../std/result/enum.Result.html
+ /// [`io::Error`]: ../../std/io/struct.Error.html
+ /// [`u8`]: ../../std/primitive.u8.html
+ /// [`Ok`]: ../../std/result/enum.Result.html#variant.Ok
+ /// [`Err`]: ../../std/result/enum.Result.html#variant.Err
+ /// [`None`]: ../../std/option/enum.Option.html#variant.None
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ ///
+ /// for byte in f.bytes() {
+ /// println!("{}", byte.unwrap());
+ /// }
+ /// Ok(())
+ /// }
+ /// ```
+ fn bytes(self) -> Bytes<Self> where Self: Sized {
+ Bytes { inner: self }
+ }
+
+ /// Transforms this `Read` instance to an [`Iterator`] over [`char`]s.
+ ///
+ /// This adaptor will attempt to interpret this reader as a UTF-8 encoded
+ /// sequence of characters. The returned iterator will return [`None`] once
+ /// EOF is reached for this reader. Otherwise each element yielded will be a
+ /// [`Result`]`<`[`char`]`, E>` where `E` may contain information about what I/O error
+ /// occurred or where decoding failed.
+ ///
+ /// Currently this adaptor will discard intermediate data read, and should
+ /// be avoided if this is not desired.
+ ///
+ /// # Examples
+ ///
+ /// [`File`]s implement `Read`:
+ ///
+ /// [`File`]: ../fs/struct.File.html
+ /// [`Iterator`]: ../../std/iter/trait.Iterator.html
+ /// [`Result`]: ../../std/result/enum.Result.html
+ /// [`char`]: ../../std/primitive.char.html
+ /// [`None`]: ../../std/option/enum.Option.html#variant.None
+ ///
+ /// ```no_run
+ /// #![feature(io)]
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ ///
+ /// for c in f.chars() {
+ /// println!("{}", c.unwrap());
+ /// }
+ /// Ok(())
+ /// }
+ /// ```
+ #[allow(deprecated)]
+ fn chars(self) -> Chars<Self> where Self: Sized {
+ Chars { inner: self }
+ }
+
+ /// Creates an adaptor which will chain this stream with another.
+ ///
+ /// The returned `Read` instance will first read all bytes from this object
+ /// until EOF is encountered. Afterwards the output is equivalent to the
+ /// output of `next`.
+ ///
+ /// # Examples
+ ///
+ /// [`File`][file]s implement `Read`:
+ ///
+ /// [file]: ../fs/struct.File.html
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f1 = File::open("foo.txt")?;
+ /// let mut f2 = File::open("bar.txt")?;
+ ///
+ /// let mut handle = f1.chain(f2);
+ /// let mut buffer = String::new();
+ ///
+ /// // read the value into a String. We could use any Read method here,
+ /// // this is just one example.
+ /// handle.read_to_string(&mut buffer)?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
+ Chain { first: self, second: next, done_first: false }
+ }
+
+ /// Creates an adaptor which will read at most `limit` bytes from it.
+ ///
+ /// This function returns a new instance of `Read` which will read at most
+ /// `limit` bytes, after which it will always return EOF ([`Ok(0)`]). Any
+ /// read errors will not count towards the number of bytes read and future
+ /// calls to [`read()`] may succeed.
+ ///
+ /// # Examples
+ ///
+ /// [`File`]s implement `Read`:
+ ///
+ /// [`File`]: ../fs/struct.File.html
+ /// [`Ok(0)`]: ../../std/result/enum.Result.html#variant.Ok
+ /// [`read()`]: trait.Read.html#tymethod.read
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut f = File::open("foo.txt")?;
+ /// let mut buffer = [0; 5];
+ ///
+ /// // read at most five bytes
+ /// let mut handle = f.take(5);
+ ///
+ /// handle.read(&mut buffer)?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn take(self, limit: u64) -> Take<Self> where Self: Sized {
+ Take { inner: self, limit: limit }
+ }
+}
+
+/// A type used to conditionally initialize buffers passed to `Read` methods.
+#[derive(Debug)]
+pub struct Initializer(bool);
+
+impl Initializer {
+ /// Returns a new `Initializer` which will zero out buffers.
+ #[inline]
+ pub fn zeroing() -> Initializer {
+ Initializer(true)
+ }
+
+ /// Returns a new `Initializer` which will not zero out buffers.
+ ///
+ /// # Safety
+ ///
+ /// This may only be called by `Read`ers which guarantee that they will not
+ /// read from buffers passed to `Read` methods, and that the return value of
+ /// the method accurately reflects the number of bytes that have been
+ /// written to the head of the buffer.
+ #[inline]
+ pub unsafe fn nop() -> Initializer {
+ Initializer(false)
+ }
+
+ /// Indicates if a buffer should be initialized.
+ #[inline]
+ pub fn should_initialize(&self) -> bool {
+ self.0
+ }
+
+ /// Initializes a buffer if necessary.
+ #[inline]
+ pub fn initialize(&self, buf: &mut [u8]) {
+ if self.should_initialize() {
+ unsafe { ptr::write_bytes(buf.as_mut_ptr(), 0, buf.len()) }
+ }
+ }
+}
+
+/// A trait for objects which are byte-oriented sinks.
+///
+/// Implementors of the `Write` trait are sometimes called 'writers'.
+///
+/// Writers are defined by two required methods, [`write`] and [`flush`]:
+///
+/// * The [`write`] method will attempt to write some data into the object,
+/// returning how many bytes were successfully written.
+///
+/// * The [`flush`] method is useful for adaptors and explicit buffers
+/// themselves for ensuring that all buffered data has been pushed out to the
+/// 'true sink'.
+///
+/// Writers are intended to be composable with one another. Many implementors
+/// throughout [`std::io`] take and provide types which implement the `Write`
+/// trait.
+///
+/// [`write`]: #tymethod.write
+/// [`flush`]: #tymethod.flush
+/// [`std::io`]: index.html
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// fn main() -> std::io::Result<()> {
+/// let mut buffer = File::create("foo.txt")?;
+///
+/// buffer.write(b"some bytes")?;
+/// Ok(())
+/// }
+/// ```
+#[doc(spotlight)]
+pub trait Write {
+ /// Write a buffer into this object, returning how many bytes were written.
+ ///
+ /// This function will attempt to write the entire contents of `buf`, but
+ /// the entire write may not succeed, or the write may also generate an
+ /// error. A call to `write` represents *at most one* attempt to write to
+ /// any wrapped object.
+ ///
+ /// Calls to `write` are not guaranteed to block waiting for data to be
+ /// written, and a write which would otherwise block can be indicated through
+ /// an [`Err`] variant.
+ ///
+ /// If the return value is [`Ok(n)`] then it must be guaranteed that
+ /// `0 <= n <= buf.len()`. A return value of `0` typically means that the
+ /// underlying object is no longer able to accept bytes and will likely not
+ /// be able to in the future as well, or that the buffer provided is empty.
+ ///
+ /// # Errors
+ ///
+ /// Each call to `write` may generate an I/O error indicating that the
+ /// operation could not be completed. If an error is returned then no bytes
+ /// in the buffer were written to this writer.
+ ///
+ /// It is **not** considered an error if the entire buffer could not be
+ /// written to this writer.
+ ///
+ /// An error of the [`ErrorKind::Interrupted`] kind is non-fatal and the
+ /// write operation should be retried if there is nothing else to do.
+ ///
+ /// [`Err`]: ../../std/result/enum.Result.html#variant.Err
+ /// [`Ok(n)`]: ../../std/result/enum.Result.html#variant.Ok
+ /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let mut buffer = File::create("foo.txt")?;
+ ///
+ /// // Writes some prefix of the byte string, not necessarily all of it.
+ /// buffer.write(b"some bytes")?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn write(&mut self, buf: &[u8]) -> Result<usize>;
+
+ /// Flush this output stream, ensuring that all intermediately buffered
+ /// contents reach their destination.
+ ///
+ /// # Errors
+ ///
+ /// It is considered an error if not all bytes could be written due to
+ /// I/O errors or EOF being reached.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::prelude::*;
+ /// use std::io::BufWriter;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let mut buffer = BufWriter::new(File::create("foo.txt")?);
+ ///
+ /// buffer.write(b"some bytes")?;
+ /// buffer.flush()?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn flush(&mut self) -> Result<()>;
+
+ /// Attempts to write an entire buffer into this write.
+ ///
+ /// This method will continuously call [`write`] until there is no more data
+ /// to be written or an error of non-[`ErrorKind::Interrupted`] kind is
+ /// returned. This method will not return until the entire buffer has been
+ /// successfully written or such an error occurs. The first error that is
+ /// not of [`ErrorKind::Interrupted`] kind generated from this method will be
+ /// returned.
+ ///
+ /// # Errors
+ ///
+ /// This function will return the first error of
+ /// non-[`ErrorKind::Interrupted`] kind that [`write`] returns.
+ ///
+ /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
+ /// [`write`]: #tymethod.write
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let mut buffer = File::create("foo.txt")?;
+ ///
+ /// buffer.write_all(b"some bytes")?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
+ while !buf.is_empty() {
+ match self.write(buf) {
+ Ok(0) => return Err(Error::new(ErrorKind::WriteZero,
+ "failed to write whole buffer")),
+ Ok(n) => buf = &buf[n..],
+ Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+ Err(e) => return Err(e),
+ }
+ }
+ Ok(())
+ }
+
+ /// Writes a formatted string into this writer, returning any error
+ /// encountered.
+ ///
+ /// This method is primarily used to interface with the
+ /// [`format_args!`][formatargs] macro, but it is rare that this should
+ /// explicitly be called. The [`write!`][write] macro should be favored to
+ /// invoke this method instead.
+ ///
+ /// [formatargs]: ../macro.format_args.html
+ /// [write]: ../macro.write.html
+ ///
+ /// This function internally uses the [`write_all`][writeall] method on
+ /// this trait and hence will continuously write data so long as no errors
+ /// are received. This also means that partial writes are not indicated in
+ /// this signature.
+ ///
+ /// [writeall]: #method.write_all
+ ///
+ /// # Errors
+ ///
+ /// This function will return any I/O error reported while formatting.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let mut buffer = File::create("foo.txt")?;
+ ///
+ /// // this call
+ /// write!(buffer, "{:.*}", 2, 1.234567)?;
+ /// // turns into this:
+ /// buffer.write_fmt(format_args!("{:.*}", 2, 1.234567))?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
+ // Create a shim which translates a Write to a fmt::Write and saves
+ // off I/O errors. instead of discarding them
+ struct Adaptor<'a, T: ?Sized + 'a> {
+ inner: &'a mut T,
+ error: Result<()>,
+ }
+
+ impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+ fn write_str(&mut self, s: &str) -> fmt::Result {
+ match self.inner.write_all(s.as_bytes()) {
+ Ok(()) => Ok(()),
+ Err(e) => {
+ self.error = Err(e);
+ Err(fmt::Error)
+ }
+ }
+ }
+ }
+
+ let mut output = Adaptor { inner: self, error: Ok(()) };
+ match fmt::write(&mut output, fmt) {
+ Ok(()) => Ok(()),
+ Err(..) => {
+ // check if the error came from the underlying `Write` or not
+ if output.error.is_err() {
+ output.error
+ } else {
+ Err(Error::new(ErrorKind::Other, "formatter error"))
+ }
+ }
+ }
+ }
+
+ /// Creates a "by reference" adaptor for this instance of `Write`.
+ ///
+ /// The returned adaptor also implements `Write` and will simply borrow this
+ /// current writer.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io::Write;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> std::io::Result<()> {
+ /// let mut buffer = File::create("foo.txt")?;
+ ///
+ /// let reference = buffer.by_ref();
+ ///
+ /// // we can use reference just like our original buffer
+ /// reference.write_all(b"some bytes")?;
+ /// Ok(())
+ /// }
+ /// ```
+ fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
+}
+
+/// The `Seek` trait provides a cursor which can be moved within a stream of
+/// bytes.
+///
+/// The stream typically has a fixed size, allowing seeking relative to either
+/// end or the current offset.
+///
+/// # Examples
+///
+/// [`File`][file]s implement `Seek`:
+///
+/// [file]: ../fs/struct.File.html
+///
+/// ```no_run
+/// use std::io;
+/// use std::io::prelude::*;
+/// use std::fs::File;
+/// use std::io::SeekFrom;
+///
+/// fn main() -> io::Result<()> {
+/// let mut f = File::open("foo.txt")?;
+///
+/// // move the cursor 42 bytes from the start of the file
+/// f.seek(SeekFrom::Start(42))?;
+/// Ok(())
+/// }
+/// ```
+pub trait Seek {
+ /// Seek to an offset, in bytes, in a stream.
+ ///
+ /// A seek beyond the end of a stream is allowed, but implementation
+ /// defined.
+ ///
+ /// If the seek operation completed successfully,
+ /// this method returns the new position from the start of the stream.
+ /// That position can be used later with [`SeekFrom::Start`].
+ ///
+ /// # Errors
+ ///
+ /// Seeking to a negative offset is considered an error.
+ ///
+ /// [`SeekFrom::Start`]: enum.SeekFrom.html#variant.Start
+ fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
+}
+
+/// Enumeration of possible methods to seek within an I/O object.
+///
+/// It is used by the [`Seek`] trait.
+///
+/// [`Seek`]: trait.Seek.html
+#[derive(Copy, PartialEq, Eq, Clone, Debug)]
+pub enum SeekFrom {
+ /// Set the offset to the provided number of bytes.
+ Start(u64),
+
+ /// Set the offset to the size of this object plus the specified number of
+ /// bytes.
+ ///
+ /// It is possible to seek beyond the end of an object, but it's an error to
+ /// seek before byte 0.
+ End(i64),
+
+ /// Set the offset to the current position plus the specified number of
+ /// bytes.
+ ///
+ /// It is possible to seek beyond the end of an object, but it's an error to
+ /// seek before byte 0.
+ Current(i64),
+}
+
+#[cfg(feature="collections")]
+fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
+ -> Result<usize> {
+ let mut read = 0;
+ loop {
+ let (done, used) = {
+ let available = match r.fill_buf() {
+ Ok(n) => n,
+ Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+ Err(e) => return Err(e)
+ };
+ match memchr::memchr(delim, available) {
+ Some(i) => {
+ buf.extend_from_slice(&available[..i + 1]);
+ (true, i + 1)
+ }
+ None => {
+ buf.extend_from_slice(available);
+ (false, available.len())
+ }
+ }
+ };
+ r.consume(used);
+ read += used;
+ if done || used == 0 {
+ return Ok(read);
+ }
+ }
+}
+
+/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
+/// to perform extra ways of reading.
+///
+/// For example, reading line-by-line is inefficient without using a buffer, so
+/// if you want to read by line, you'll need `BufRead`, which includes a
+/// [`read_line`] method as well as a [`lines`] iterator.
+///
+/// # Examples
+///
+/// A locked standard input implements `BufRead`:
+///
+/// ```no_run
+/// use std::io;
+/// use std::io::prelude::*;
+///
+/// let stdin = io::stdin();
+/// for line in stdin.lock().lines() {
+/// println!("{}", line.unwrap());
+/// }
+/// ```
+///
+/// If you have something that implements [`Read`], you can use the [`BufReader`
+/// type][`BufReader`] to turn it into a `BufRead`.
+///
+/// For example, [`File`] implements [`Read`], but not `BufRead`.
+/// [`BufReader`] to the rescue!
+///
+/// [`BufReader`]: struct.BufReader.html
+/// [`File`]: ../fs/struct.File.html
+/// [`read_line`]: #method.read_line
+/// [`lines`]: #method.lines
+/// [`Read`]: trait.Read.html
+///
+/// ```no_run
+/// use std::io::{self, BufReader};
+/// use std::io::prelude::*;
+/// use std::fs::File;
+///
+/// fn main() -> io::Result<()> {
+/// let f = File::open("foo.txt")?;
+/// let f = BufReader::new(f);
+///
+/// for line in f.lines() {
+/// println!("{}", line.unwrap());
+/// }
+///
+/// Ok(())
+/// }
+/// ```
+///
+#[cfg(feature="collections")]
+pub trait BufRead: Read {
+ /// Fills the internal buffer of this object, returning the buffer contents.
+ ///
+ /// This function is a lower-level call. It needs to be paired with the
+ /// [`consume`] method to function properly. When calling this
+ /// method, none of the contents will be "read" in the sense that later
+ /// calling `read` may return the same contents. As such, [`consume`] must
+ /// be called with the number of bytes that are consumed from this buffer to
+ /// ensure that the bytes are never returned twice.
+ ///
+ /// [`consume`]: #tymethod.consume
+ ///
+ /// An empty buffer returned indicates that the stream has reached EOF.
+ ///
+ /// # Errors
+ ///
+ /// This function will return an I/O error if the underlying reader was
+ /// read, but returned an error.
+ ///
+ /// # Examples
+ ///
+ /// A locked standard input implements `BufRead`:
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ ///
+ /// let stdin = io::stdin();
+ /// let mut stdin = stdin.lock();
+ ///
+ /// // we can't have two `&mut` references to `stdin`, so use a block
+ /// // to end the borrow early.
+ /// let length = {
+ /// let buffer = stdin.fill_buf().unwrap();
+ ///
+ /// // work with buffer
+ /// println!("{:?}", buffer);
+ ///
+ /// buffer.len()
+ /// };
+ ///
+ /// // ensure the bytes we worked with aren't returned again later
+ /// stdin.consume(length);
+ /// ```
+ fn fill_buf(&mut self) -> Result<&[u8]>;
+
+ /// Tells this buffer that `amt` bytes have been consumed from the buffer,
+ /// so they should no longer be returned in calls to `read`.
+ ///
+ /// This function is a lower-level call. It needs to be paired with the
+ /// [`fill_buf`] method to function properly. This function does
+ /// not perform any I/O, it simply informs this object that some amount of
+ /// its buffer, returned from [`fill_buf`], has been consumed and should
+ /// no longer be returned. As such, this function may do odd things if
+ /// [`fill_buf`] isn't called before calling it.
+ ///
+ /// The `amt` must be `<=` the number of bytes in the buffer returned by
+ /// [`fill_buf`].
+ ///
+ /// # Examples
+ ///
+ /// Since `consume()` is meant to be used with [`fill_buf`],
+ /// that method's example includes an example of `consume()`.
+ ///
+ /// [`fill_buf`]: #tymethod.fill_buf
+ fn consume(&mut self, amt: usize);
+
+ /// Read all bytes into `buf` until the delimiter `byte` or EOF is reached.
+ ///
+ /// This function will read bytes from the underlying stream until the
+ /// delimiter or EOF is found. Once found, all bytes up to, and including,
+ /// the delimiter (if found) will be appended to `buf`.
+ ///
+ /// If successful, this function will return the total number of bytes read.
+ ///
+ /// # Errors
+ ///
+ /// This function will ignore all instances of [`ErrorKind::Interrupted`] and
+ /// will otherwise return any errors returned by [`fill_buf`].
+ ///
+ /// If an I/O error is encountered then all bytes read so far will be
+ /// present in `buf` and its length will have been adjusted appropriately.
+ ///
+ /// [`fill_buf`]: #tymethod.fill_buf
+ /// [`ErrorKind::Interrupted`]: enum.ErrorKind.html#variant.Interrupted
+ ///
+ /// # Examples
+ ///
+ /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
+ /// this example, we use [`Cursor`] to read all the bytes in a byte slice
+ /// in hyphen delimited segments:
+ ///
+ /// [`Cursor`]: struct.Cursor.html
+ ///
+ /// ```
+ /// use std::io::{self, BufRead};
+ ///
+ /// let mut cursor = io::Cursor::new(b"lorem-ipsum");
+ /// let mut buf = vec![];
+ ///
+ /// // cursor is at 'l'
+ /// let num_bytes = cursor.read_until(b'-', &mut buf)
+ /// .expect("reading from cursor won't fail");
+ /// assert_eq!(num_bytes, 6);
+ /// assert_eq!(buf, b"lorem-");
+ /// buf.clear();
+ ///
+ /// // cursor is at 'i'
+ /// let num_bytes = cursor.read_until(b'-', &mut buf)
+ /// .expect("reading from cursor won't fail");
+ /// assert_eq!(num_bytes, 5);
+ /// assert_eq!(buf, b"ipsum");
+ /// buf.clear();
+ ///
+ /// // cursor is at EOF
+ /// let num_bytes = cursor.read_until(b'-', &mut buf)
+ /// .expect("reading from cursor won't fail");
+ /// assert_eq!(num_bytes, 0);
+ /// assert_eq!(buf, b"");
+ /// ```
+ fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
+ read_until(self, byte, buf)
+ }
+
+ /// Read all bytes until a newline (the 0xA byte) is reached, and append
+ /// them to the provided buffer.
+ ///
+ /// This function will read bytes from the underlying stream until the
+ /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
+ /// up to, and including, the delimiter (if found) will be appended to
+ /// `buf`.
+ ///
+ /// If successful, this function will return the total number of bytes read.
+ ///
+ /// An empty buffer returned indicates that the stream has reached EOF.
+ ///
+ /// # Errors
+ ///
+ /// This function has the same error semantics as [`read_until`] and will
+ /// also return an error if the read bytes are not valid UTF-8. If an I/O
+ /// error is encountered then `buf` may contain some bytes already read in
+ /// the event that all data read so far was valid UTF-8.
+ ///
+ /// [`read_until`]: #method.read_until
+ ///
+ /// # Examples
+ ///
+ /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
+ /// this example, we use [`Cursor`] to read all the lines in a byte slice:
+ ///
+ /// [`Cursor`]: struct.Cursor.html
+ ///
+ /// ```
+ /// use std::io::{self, BufRead};
+ ///
+ /// let mut cursor = io::Cursor::new(b"foo\nbar");
+ /// let mut buf = String::new();
+ ///
+ /// // cursor is at 'f'
+ /// let num_bytes = cursor.read_line(&mut buf)
+ /// .expect("reading from cursor won't fail");
+ /// assert_eq!(num_bytes, 4);
+ /// assert_eq!(buf, "foo\n");
+ /// buf.clear();
+ ///
+ /// // cursor is at 'b'
+ /// let num_bytes = cursor.read_line(&mut buf)
+ /// .expect("reading from cursor won't fail");
+ /// assert_eq!(num_bytes, 3);
+ /// assert_eq!(buf, "bar");
+ /// buf.clear();
+ ///
+ /// // cursor is at EOF
+ /// let num_bytes = cursor.read_line(&mut buf)
+ /// .expect("reading from cursor won't fail");
+ /// assert_eq!(num_bytes, 0);
+ /// assert_eq!(buf, "");
+ /// ```
+ fn read_line(&mut self, buf: &mut String) -> Result<usize> {
+ // Note that we are not calling the `.read_until` method here, but
+ // rather our hardcoded implementation. For more details as to why, see
+ // the comments in `read_to_end`.
+ append_to_string(buf, |b| read_until(self, b'\n', b))
+ }
+
+ /// Returns an iterator over the contents of this reader split on the byte
+ /// `byte`.
+ ///
+ /// The iterator returned from this function will return instances of
+ /// [`io::Result`]`<`[`Vec<u8>`]`>`. Each vector returned will *not* have
+ /// the delimiter byte at the end.
+ ///
+ /// This function will yield errors whenever [`read_until`] would have
+ /// also yielded an error.
+ ///
+ /// [`io::Result`]: type.Result.html
+ /// [`Vec<u8>`]: ../vec/struct.Vec.html
+ /// [`read_until`]: #method.read_until
+ ///
+ /// # Examples
+ ///
+ /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
+ /// this example, we use [`Cursor`] to iterate over all hyphen delimited
+ /// segments in a byte slice
+ ///
+ /// [`Cursor`]: struct.Cursor.html
+ ///
+ /// ```
+ /// use std::io::{self, BufRead};
+ ///
+ /// let cursor = io::Cursor::new(b"lorem-ipsum-dolor");
+ ///
+ /// let mut split_iter = cursor.split(b'-').map(|l| l.unwrap());
+ /// assert_eq!(split_iter.next(), Some(b"lorem".to_vec()));
+ /// assert_eq!(split_iter.next(), Some(b"ipsum".to_vec()));
+ /// assert_eq!(split_iter.next(), Some(b"dolor".to_vec()));
+ /// assert_eq!(split_iter.next(), None);
+ /// ```
+ fn split(self, byte: u8) -> Split<Self> where Self: Sized {
+ Split { buf: self, delim: byte }
+ }
+
+ /// Returns an iterator over the lines of this reader.
+ ///
+ /// The iterator returned from this function will yield instances of
+ /// [`io::Result`]`<`[`String`]`>`. Each string returned will *not* have a newline
+ /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
+ ///
+ /// [`io::Result`]: type.Result.html
+ /// [`String`]: ../string/struct.String.html
+ ///
+ /// # Examples
+ ///
+ /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
+ /// this example, we use [`Cursor`] to iterate over all the lines in a byte
+ /// slice.
+ ///
+ /// [`Cursor`]: struct.Cursor.html
+ ///
+ /// ```
+ /// use std::io::{self, BufRead};
+ ///
+ /// let cursor = io::Cursor::new(b"lorem\nipsum\r\ndolor");
+ ///
+ /// let mut lines_iter = cursor.lines().map(|l| l.unwrap());
+ /// assert_eq!(lines_iter.next(), Some(String::from("lorem")));
+ /// assert_eq!(lines_iter.next(), Some(String::from("ipsum")));
+ /// assert_eq!(lines_iter.next(), Some(String::from("dolor")));
+ /// assert_eq!(lines_iter.next(), None);
+ /// ```
+ ///
+ /// # Errors
+ ///
+ /// Each line of the iterator has the same error semantics as [`BufRead::read_line`].
+ ///
+ /// [`BufRead::read_line`]: trait.BufRead.html#method.read_line
+ fn lines(self) -> Lines<Self> where Self: Sized {
+ Lines { buf: self }
+ }
+}
+
+/// Adaptor to chain together two readers.
+///
+/// This struct is generally created by calling [`chain`] on a reader.
+/// Please see the documentation of [`chain`] for more details.
+///
+/// [`chain`]: trait.Read.html#method.chain
+pub struct Chain<T, U> {
+ first: T,
+ second: U,
+ done_first: bool,
+}
+
+impl<T, U> Chain<T, U> {
+ /// Consumes the `Chain`, returning the wrapped readers.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut foo_file = File::open("foo.txt")?;
+ /// let mut bar_file = File::open("bar.txt")?;
+ ///
+ /// let chain = foo_file.chain(bar_file);
+ /// let (foo_file, bar_file) = chain.into_inner();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn into_inner(self) -> (T, U) {
+ (self.first, self.second)
+ }
+
+ /// Gets references to the underlying readers in this `Chain`.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut foo_file = File::open("foo.txt")?;
+ /// let mut bar_file = File::open("bar.txt")?;
+ ///
+ /// let chain = foo_file.chain(bar_file);
+ /// let (foo_file, bar_file) = chain.get_ref();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_ref(&self) -> (&T, &U) {
+ (&self.first, &self.second)
+ }
+
+ /// Gets mutable references to the underlying readers in this `Chain`.
+ ///
+ /// Care should be taken to avoid modifying the internal I/O state of the
+ /// underlying readers as doing so may corrupt the internal state of this
+ /// `Chain`.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut foo_file = File::open("foo.txt")?;
+ /// let mut bar_file = File::open("bar.txt")?;
+ ///
+ /// let mut chain = foo_file.chain(bar_file);
+ /// let (foo_file, bar_file) = chain.get_mut();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_mut(&mut self) -> (&mut T, &mut U) {
+ (&mut self.first, &mut self.second)
+ }
+}
+
+impl<T: fmt::Debug, U: fmt::Debug> fmt::Debug for Chain<T, U> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.debug_struct("Chain")
+ .field("t", &self.first)
+ .field("u", &self.second)
+ .finish()
+ }
+}
+
+impl<T: Read, U: Read> Read for Chain<T, U> {
+ fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+ if !self.done_first {
+ match self.first.read(buf)? {
+ 0 if buf.len() != 0 => { self.done_first = true; }
+ n => return Ok(n),
+ }
+ }
+ self.second.read(buf)
+ }
+
+ unsafe fn initializer(&self) -> Initializer {
+ let initializer = self.first.initializer();
+ if initializer.should_initialize() {
+ initializer
+ } else {
+ self.second.initializer()
+ }
+ }
+}
+
+#[cfg(feature="collections")]
+impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
+ fn fill_buf(&mut self) -> Result<&[u8]> {
+ if !self.done_first {
+ match self.first.fill_buf()? {
+ buf if buf.len() == 0 => { self.done_first = true; }
+ buf => return Ok(buf),
+ }
+ }
+ self.second.fill_buf()
+ }
+
+ fn consume(&mut self, amt: usize) {
+ if !self.done_first {
+ self.first.consume(amt)
+ } else {
+ self.second.consume(amt)
+ }
+ }
+}
+
+/// Reader adaptor which limits the bytes read from an underlying reader.
+///
+/// This struct is generally created by calling [`take`] on a reader.
+/// Please see the documentation of [`take`] for more details.
+///
+/// [`take`]: trait.Read.html#method.take
+#[derive(Debug)]
+pub struct Take<T> {
+ inner: T,
+ limit: u64,
+}
+
+impl<T> Take<T> {
+ /// Returns the number of bytes that can be read before this instance will
+ /// return EOF.
+ ///
+ /// # Note
+ ///
+ /// This instance may reach `EOF` after reading fewer bytes than indicated by
+ /// this method if the underlying [`Read`] instance reaches EOF.
+ ///
+ /// [`Read`]: ../../std/io/trait.Read.html
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let f = File::open("foo.txt")?;
+ ///
+ /// // read at most five bytes
+ /// let handle = f.take(5);
+ ///
+ /// println!("limit: {}", handle.limit());
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn limit(&self) -> u64 { self.limit }
+
+ /// Sets the number of bytes that can be read before this instance will
+ /// return EOF. This is the same as constructing a new `Take` instance, so
+ /// the amount of bytes read and the previous limit value don't matter when
+ /// calling this method.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let f = File::open("foo.txt")?;
+ ///
+ /// // read at most five bytes
+ /// let mut handle = f.take(5);
+ /// handle.set_limit(10);
+ ///
+ /// assert_eq!(handle.limit(), 10);
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn set_limit(&mut self, limit: u64) {
+ self.limit = limit;
+ }
+
+ /// Consumes the `Take`, returning the wrapped reader.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut file = File::open("foo.txt")?;
+ ///
+ /// let mut buffer = [0; 5];
+ /// let mut handle = file.take(5);
+ /// handle.read(&mut buffer)?;
+ ///
+ /// let file = handle.into_inner();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn into_inner(self) -> T {
+ self.inner
+ }
+
+ /// Gets a reference to the underlying reader.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut file = File::open("foo.txt")?;
+ ///
+ /// let mut buffer = [0; 5];
+ /// let mut handle = file.take(5);
+ /// handle.read(&mut buffer)?;
+ ///
+ /// let file = handle.get_ref();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_ref(&self) -> &T {
+ &self.inner
+ }
+
+ /// Gets a mutable reference to the underlying reader.
+ ///
+ /// Care should be taken to avoid modifying the internal I/O state of the
+ /// underlying reader as doing so may corrupt the internal limit of this
+ /// `Take`.
+ ///
+ /// # Examples
+ ///
+ /// ```no_run
+ /// use std::io;
+ /// use std::io::prelude::*;
+ /// use std::fs::File;
+ ///
+ /// fn main() -> io::Result<()> {
+ /// let mut file = File::open("foo.txt")?;
+ ///
+ /// let mut buffer = [0; 5];
+ /// let mut handle = file.take(5);
+ /// handle.read(&mut buffer)?;
+ ///
+ /// let file = handle.get_mut();
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn get_mut(&mut self) -> &mut T {
+ &mut self.inner
+ }
+}
+
+impl<T: Read> Read for Take<T> {
+ fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
+ // Don't call into inner reader at all at EOF because it may still block
+ if self.limit == 0 {
+ return Ok(0);
+ }
+
+ let max = cmp::min(buf.len() as u64, self.limit) as usize;
+ let n = self.inner.read(&mut buf[..max])?;
+ self.limit -= n as u64;
+ Ok(n)
+ }
+
+ unsafe fn initializer(&self) -> Initializer {
+ self.inner.initializer()
+ }
+}
+
+#[cfg(feature="collections")]
+impl<T: BufRead> BufRead for Take<T> {
+ fn fill_buf(&mut self) -> Result<&[u8]> {
+ // Don't call into inner reader at all at EOF because it may still block
+ if self.limit == 0 {
+ return Ok(&[]);
+ }
+
+ let buf = self.inner.fill_buf()?;
+ let cap = cmp::min(buf.len() as u64, self.limit) as usize;
+ Ok(&buf[..cap])
+ }
+
+ fn consume(&mut self, amt: usize) {
+ // Don't let callers reset the limit by passing an overlarge value
+ let amt = cmp::min(amt as u64, self.limit) as usize;
+ self.limit -= amt as u64;
+ self.inner.consume(amt);
+ }
+}
+
+fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
+ let mut buf = [0];
+ loop {
+ return match reader.read(&mut buf) {
+ Ok(0) => None,
+ Ok(..) => Some(Ok(buf[0])),
+ Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+ Err(e) => Some(Err(e)),
+ };
+ }
+}
+
+/// An iterator over `u8` values of a reader.
+///
+/// This struct is generally created by calling [`bytes`] on a reader.
+/// Please see the documentation of [`bytes`] for more details.
+///
+/// [`bytes`]: trait.Read.html#method.bytes
+#[derive(Debug)]
+pub struct Bytes<R> {
+ inner: R,
+}
+
+impl<R: Read> Iterator for Bytes<R> {
+ type Item = Result<u8>;
+
+ fn next(&mut self) -> Option<Result<u8>> {
+ read_one_byte(&mut self.inner)
+ }
+}
+
+/// An iterator over the `char`s of a reader.
+///
+/// This struct is generally created by calling [`chars`][chars] on a reader.
+/// Please see the documentation of `chars()` for more details.
+///
+/// [chars]: trait.Read.html#method.chars
+#[derive(Debug)]
+#[allow(deprecated)]
+pub struct Chars<R> {
+ inner: R,
+}
+
+/// An enumeration of possible errors that can be generated from the `Chars`
+/// adapter.
+#[derive(Debug)]
+#[allow(deprecated)]
+pub enum CharsError {
+ /// Variant representing that the underlying stream was read successfully
+ /// but it did not contain valid utf8 data.
+ NotUtf8,
+
+ /// Variant representing that an I/O error occurred.
+ Other(Error),
+}
+
+#[allow(deprecated)]
+impl<R: Read> Iterator for Chars<R> {
+ type Item = result::Result<char, CharsError>;
+
+ fn next(&mut self) -> Option<result::Result<char, CharsError>> {
+ let first_byte = match read_one_byte(&mut self.inner)? {
+ Ok(b) => b,
+ Err(e) => return Some(Err(CharsError::Other(e))),
+ };
+ let width = core_str::utf8_char_width(first_byte);
+ if width == 1 { return Some(Ok(first_byte as char)) }
+ if width == 0 { return Some(Err(CharsError::NotUtf8)) }
+ let mut buf = [first_byte, 0, 0, 0];
+ {
+ let mut start = 1;
+ while start < width {
+ match self.inner.read(&mut buf[start..width]) {
+ Ok(0) => return Some(Err(CharsError::NotUtf8)),
+ Ok(n) => start += n,
+ Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+ Err(e) => return Some(Err(CharsError::Other(e))),
+ }
+ }
+ }
+ Some(match str::from_utf8(&buf[..width]).ok() {
+ Some(s) => Ok(s.chars().next().unwrap()),
+ None => Err(CharsError::NotUtf8),
+ })
+ }
+}
+
+#[allow(deprecated)]
+impl fmt::Display for CharsError {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ match *self {
+ CharsError::NotUtf8 => {
+ "byte stream did not contain valid utf8".fmt(f)
+ }
+ CharsError::Other(ref e) => e.fmt(f),
+ }
+ }
+}
+
+/// An iterator over the contents of an instance of `BufRead` split on a
+/// particular byte.
+///
+/// This struct is generally created by calling [`split`][split] on a
+/// `BufRead`. Please see the documentation of `split()` for more details.
+///
+/// [split]: trait.BufRead.html#method.split
+#[cfg(feature="collections")]
+#[derive(Debug)]
+pub struct Split<B> {
+ buf: B,
+ delim: u8,
+}
+
+#[cfg(feature="collections")]
+impl<B: BufRead> Iterator for Split<B> {
+ type Item = Result<Vec<u8>>;
+
+ fn next(&mut self) -> Option<Result<Vec<u8>>> {
+ let mut buf = Vec::new();
+ match self.buf.read_until(self.delim, &mut buf) {
+ Ok(0) => None,
+ Ok(_n) => {
+ if buf[buf.len() - 1] == self.delim {
+ buf.pop();
+ }
+ Some(Ok(buf))
+ }
+ Err(e) => Some(Err(e))
+ }
+ }
+}
+
+/// An iterator over the lines of an instance of `BufRead`.
+///
+/// This struct is generally created by calling [`lines`][lines] on a
+/// `BufRead`. Please see the documentation of `lines()` for more details.
+///
+/// [lines]: trait.BufRead.html#method.lines
+#[cfg(feature="collections")]
+#[derive(Debug)]
+pub struct Lines<B> {
+ buf: B,
+}
+
+#[cfg(feature="collections")]
+impl<B: BufRead> Iterator for Lines<B> {
+ type Item = Result<String>;
+
+ fn next(&mut self) -> Option<Result<String>> {
+ let mut buf = String::new();
+ match self.buf.read_line(&mut buf) {
+ Ok(0) => None,
+ Ok(_n) => {
+ if buf.ends_with("\n") {
+ buf.pop();
+ if buf.ends_with("\r") {
+ buf.pop();
+ }
+ }
+ Some(Ok(buf))
+ }
+ Err(e) => Some(Err(e))
+ }
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use io::prelude::*;
+ use io;
+ use super::Cursor;
+ use test;
+ use super::repeat;
+
+ #[test]
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ fn read_until() {
+ let mut buf = Cursor::new(&b"12"[..]);
+ let mut v = Vec::new();
+ assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
+ assert_eq!(v, b"12");
+
+ let mut buf = Cursor::new(&b"1233"[..]);
+ let mut v = Vec::new();
+ assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
+ assert_eq!(v, b"123");
+ v.truncate(0);
+ assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
+ assert_eq!(v, b"3");
+ v.truncate(0);
+ assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
+ assert_eq!(v, []);
+ }
+
+ #[test]
+ fn split() {
+ let buf = Cursor::new(&b"12"[..]);
+ let mut s = buf.split(b'3');
+ assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+ assert!(s.next().is_none());
+
+ let buf = Cursor::new(&b"1233"[..]);
+ let mut s = buf.split(b'3');
+ assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+ assert_eq!(s.next().unwrap().unwrap(), vec![]);
+ assert!(s.next().is_none());
+ }
+
+ #[test]
+ fn read_line() {
+ let mut buf = Cursor::new(&b"12"[..]);
+ let mut v = String::new();
+ assert_eq!(buf.read_line(&mut v).unwrap(), 2);
+ assert_eq!(v, "12");
+
+ let mut buf = Cursor::new(&b"12\n\n"[..]);
+ let mut v = String::new();
+ assert_eq!(buf.read_line(&mut v).unwrap(), 3);
+ assert_eq!(v, "12\n");
+ v.truncate(0);
+ assert_eq!(buf.read_line(&mut v).unwrap(), 1);
+ assert_eq!(v, "\n");
+ v.truncate(0);
+ assert_eq!(buf.read_line(&mut v).unwrap(), 0);
+ assert_eq!(v, "");
+ }
+
+ #[test]
+ fn lines() {
+ let buf = Cursor::new(&b"12\r"[..]);
+ let mut s = buf.lines();
+ assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
+ assert!(s.next().is_none());
+
+ let buf = Cursor::new(&b"12\r\n\n"[..]);
+ let mut s = buf.lines();
+ assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+ assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+ assert!(s.next().is_none());
+ }
+
+ #[test]
+ fn read_to_end() {
+ let mut c = Cursor::new(&b""[..]);
+ let mut v = Vec::new();
+ assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
+ assert_eq!(v, []);
+
+ let mut c = Cursor::new(&b"1"[..]);
+ let mut v = Vec::new();
+ assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
+ assert_eq!(v, b"1");
+
+ let cap = 1024 * 1024;
+ let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
+ let mut v = Vec::new();
+ let (a, b) = data.split_at(data.len() / 2);
+ assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
+ assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
+ assert_eq!(v, data);
+ }
+
+ #[test]
+ fn read_to_string() {
+ let mut c = Cursor::new(&b""[..]);
+ let mut v = String::new();
+ assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
+ assert_eq!(v, "");
+
+ let mut c = Cursor::new(&b"1"[..]);
+ let mut v = String::new();
+ assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
+ assert_eq!(v, "1");
+
+ let mut c = Cursor::new(&b"\xff"[..]);
+ let mut v = String::new();
+ assert!(c.read_to_string(&mut v).is_err());
+ }
+
+ #[test]
+ fn read_exact() {
+ let mut buf = [0; 4];
+
+ let mut c = Cursor::new(&b""[..]);
+ assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+ io::ErrorKind::UnexpectedEof);
+
+ let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
+ c.read_exact(&mut buf).unwrap();
+ assert_eq!(&buf, b"1234");
+ c.read_exact(&mut buf).unwrap();
+ assert_eq!(&buf, b"5678");
+ assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+ io::ErrorKind::UnexpectedEof);
+ }
+
+ #[test]
+ fn read_exact_slice() {
+ let mut buf = [0; 4];
+
+ let mut c = &b""[..];
+ assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+ io::ErrorKind::UnexpectedEof);
+
+ let mut c = &b"123"[..];
+ assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(),
+ io::ErrorKind::UnexpectedEof);
+ // make sure the optimized (early returning) method is being used
+ assert_eq!(&buf, &[0; 4]);
+
+ let mut c = &b"1234"[..];
+ c.read_exact(&mut buf).unwrap();
+ assert_eq!(&buf, b"1234");
+
+ let mut c = &b"56789"[..];
+ c.read_exact(&mut buf).unwrap();
+ assert_eq!(&buf, b"5678");
+ assert_eq!(c, b"9");
+ }
+
+ #[test]
+ fn take_eof() {
+ struct R;
+
+ impl Read for R {
+ fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
+ Err(io::Error::new(io::ErrorKind::Other, ""))
+ }
+ }
+ impl BufRead for R {
+ fn fill_buf(&mut self) -> io::Result<&[u8]> {
+ Err(io::Error::new(io::ErrorKind::Other, ""))
+ }
+ fn consume(&mut self, _amt: usize) { }
+ }
+
+ let mut buf = [0; 1];
+ assert_eq!(0, R.take(0).read(&mut buf).unwrap());
+ assert_eq!(b"", R.take(0).fill_buf().unwrap());
+ }
+
+ fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
+ let mut cat = Vec::new();
+ loop {
+ let consume = {
+ let buf1 = br1.fill_buf().unwrap();
+ let buf2 = br2.fill_buf().unwrap();
+ let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
+ assert_eq!(buf1[..minlen], buf2[..minlen]);
+ cat.extend_from_slice(&buf1[..minlen]);
+ minlen
+ };
+ if consume == 0 {
+ break;
+ }
+ br1.consume(consume);
+ br2.consume(consume);
+ }
+ assert_eq!(br1.fill_buf().unwrap().len(), 0);
+ assert_eq!(br2.fill_buf().unwrap().len(), 0);
+ assert_eq!(&cat[..], &exp[..])
+ }
+
+ #[test]
+ fn chain_bufread() {
+ let testdata = b"ABCDEFGHIJKL";
+ let chain1 = (&testdata[..3]).chain(&testdata[3..6])
+ .chain(&testdata[6..9])
+ .chain(&testdata[9..]);
+ let chain2 = (&testdata[..4]).chain(&testdata[4..8])
+ .chain(&testdata[8..]);
+ cmp_bufread(chain1, chain2, &testdata[..]);
+ }
+
+ #[test]
+ fn chain_zero_length_read_is_not_eof() {
+ let a = b"A";
+ let b = b"B";
+ let mut s = String::new();
+ let mut chain = (&a[..]).chain(&b[..]);
+ chain.read(&mut []).unwrap();
+ chain.read_to_string(&mut s).unwrap();
+ assert_eq!("AB", s);
+ }
+
+ #[bench]
+ #[cfg_attr(target_os = "emscripten", ignore)]
+ fn bench_read_to_end(b: &mut test::Bencher) {
+ b.iter(|| {
+ let mut lr = repeat(1).take(10000000);
+ let mut vec = Vec::with_capacity(1024);
+ super::read_to_end(&mut lr, &mut vec)
+ });
+ }
+}
diff --git a/src/b81da278623d9dcda1776008612bd42e1922e9c3/prelude.rs b/src/b81da278623d9dcda1776008612bd42e1922e9c3/prelude.rs
new file mode 100644
index 0000000..49d66c9
--- /dev/null
+++ b/src/b81da278623d9dcda1776008612bd42e1922e9c3/prelude.rs
@@ -0,0 +1,25 @@
+// Copyright 2015 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.
+
+//! The I/O Prelude
+//!
+//! The purpose of this module is to alleviate imports of many common I/O traits
+//! by adding a glob import to the top of I/O heavy modules:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use std::io::prelude::*;
+//! ```
+
+pub use super::{Read, Write, Seek};
+#[cfg(feature="collections")] pub use super::BufRead;
+
+#[cfg(feature="collections")] pub use alloc::boxed::Box;
+#[cfg(feature="collections")] pub use collections::vec::Vec;
diff --git a/src/b81da278623d9dcda1776008612bd42e1922e9c3/util.rs b/src/b81da278623d9dcda1776008612bd42e1922e9c3/util.rs
new file mode 100644
index 0000000..20755b7
--- /dev/null
+++ b/src/b81da278623d9dcda1776008612bd42e1922e9c3/util.rs
@@ -0,0 +1,250 @@
+// 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.
+
+#![allow(missing_copy_implementations)]
+
+use core::fmt;
+use io::{self, Read, Initializer, Write, ErrorKind};
+use core::mem;
+#[cfg(feature="collections")] use io::BufRead;
+
+/// Copies the entire contents of a reader into a writer.
+///
+/// This function will continuously read data from `reader` and then
+/// write it into `writer` in a streaming fashion until `reader`
+/// returns EOF.
+///
+/// On success, the total number of bytes that were copied from
+/// `reader` to `writer` is returned.
+///
+/// # Errors
+///
+/// This function will return an error immediately if any call to `read` or
+/// `write` returns an error. All instances of `ErrorKind::Interrupted` are
+/// handled by this function and the underlying operation is retried.
+///
+/// # Examples
+///
+/// ```
+/// use std::io;
+///
+/// fn main() -> io::Result<()> {
+/// let mut reader: &[u8] = b"hello";
+/// let mut writer: Vec<u8> = vec![];
+///
+/// io::copy(&mut reader, &mut writer)?;
+///
+/// assert_eq!(&b"hello"[..], &writer[..]);
+/// Ok(())
+/// }
+/// ```
+pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>
+ where R: Read, W: Write
+{
+ let mut buf = unsafe {
+ let mut buf: [u8; super::DEFAULT_BUF_SIZE] = mem::uninitialized();
+ reader.initializer().initialize(&mut buf);
+ buf
+ };
+
+ let mut written = 0;
+ loop {
+ let len = match reader.read(&mut buf) {
+ Ok(0) => return Ok(written),
+ Ok(len) => len,
+ Err(ref e) if e.kind() == ErrorKind::Interrupted => continue,
+ Err(e) => return Err(e),
+ };
+ writer.write_all(&buf[..len])?;
+ written += len as u64;
+ }
+}
+
+/// A reader which is always at EOF.
+///
+/// This struct is generally created by calling [`empty`]. Please see
+/// the documentation of [`empty()`][`empty`] for more details.
+///
+/// [`empty`]: fn.empty.html
+pub struct Empty { _priv: () }
+
+/// Constructs a new handle to an empty reader.
+///
+/// All reads from the returned reader will return [`Ok`]`(0)`.
+///
+/// [`Ok`]: ../result/enum.Result.html#variant.Ok
+///
+/// # Examples
+///
+/// A slightly sad example of not reading anything into a buffer:
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = String::new();
+/// io::empty().read_to_string(&mut buffer).unwrap();
+/// assert!(buffer.is_empty());
+/// ```
+pub fn empty() -> Empty { Empty { _priv: () } }
+
+impl Read for Empty {
+ #[inline]
+ fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) }
+
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ Initializer::nop()
+ }
+}
+
+#[cfg(feature="collections")]
+impl BufRead for Empty {
+ #[inline]
+ fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) }
+ #[inline]
+ fn consume(&mut self, _n: usize) {}
+}
+
+impl fmt::Debug for Empty {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.pad("Empty { .. }")
+ }
+}
+
+/// A reader which yields one byte over and over and over and over and over and...
+///
+/// This struct is generally created by calling [`repeat`][repeat]. Please
+/// see the documentation of `repeat()` for more details.
+///
+/// [repeat]: fn.repeat.html
+pub struct Repeat { byte: u8 }
+
+/// Creates an instance of a reader that infinitely repeats one byte.
+///
+/// All reads from this reader will succeed by filling the specified buffer with
+/// the given byte.
+///
+/// # Examples
+///
+/// ```
+/// use std::io::{self, Read};
+///
+/// let mut buffer = [0; 3];
+/// io::repeat(0b101).read_exact(&mut buffer).unwrap();
+/// assert_eq!(buffer, [0b101, 0b101, 0b101]);
+/// ```
+pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } }
+
+impl Read for Repeat {
+ #[inline]
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ for slot in &mut *buf {
+ *slot = self.byte;
+ }
+ Ok(buf.len())
+ }
+
+ #[inline]
+ unsafe fn initializer(&self) -> Initializer {
+ Initializer::nop()
+ }
+}
+
+impl fmt::Debug for Repeat {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.pad("Repeat { .. }")
+ }
+}
+
+/// A writer which will move data into the void.
+///
+/// This struct is generally created by calling [`sink`][sink]. Please
+/// see the documentation of `sink()` for more details.
+///
+/// [sink]: fn.sink.html
+pub struct Sink { _priv: () }
+
+/// Creates an instance of a writer which will successfully consume all data.
+///
+/// All calls to `write` on the returned instance will return `Ok(buf.len())`
+/// and the contents of the buffer will not be inspected.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::io::{self, Write};
+///
+/// let buffer = vec![1, 2, 3, 5, 8];
+/// let num_bytes = io::sink().write(&buffer).unwrap();
+/// assert_eq!(num_bytes, 5);
+/// ```
+pub fn sink() -> Sink { Sink { _priv: () } }
+
+impl Write for Sink {
+ #[inline]
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) }
+ #[inline]
+ fn flush(&mut self) -> io::Result<()> { Ok(()) }
+}
+
+impl fmt::Debug for Sink {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.pad("Sink { .. }")
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use io::prelude::*;
+ use io::{copy, sink, empty, repeat};
+
+ #[test]
+ fn copy_copies() {
+ let mut r = repeat(0).take(4);
+ let mut w = sink();
+ assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
+
+ let mut r = repeat(0).take(1 << 17);
+ assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17);
+ }
+
+ #[test]
+ fn sink_sinks() {
+ let mut s = sink();
+ assert_eq!(s.write(&[]).unwrap(), 0);
+ assert_eq!(s.write(&[0]).unwrap(), 1);
+ assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+ assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
+ }
+
+ #[test]
+ fn empty_reads() {
+ let mut e = empty();
+ assert_eq!(e.read(&mut []).unwrap(), 0);
+ assert_eq!(e.read(&mut [0]).unwrap(), 0);
+ assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+ assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
+ }
+
+ #[test]
+ fn repeat_repeats() {
+ let mut r = repeat(4);
+ let mut b = [0; 1024];
+ assert_eq!(r.read(&mut b).unwrap(), 1024);
+ assert!(b.iter().all(|b| *b == 4));
+ }
+
+ #[test]
+ fn take_some_bytes() {
+ assert_eq!(repeat(4).take(100).bytes().count(), 100);
+ assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
+ assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
+ }
+}
--
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