| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/git/checkouts/tokio-377c595163f99a10/dfe252d/tokio/src/io/util/copy.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>copy.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../../normalize.css"><link rel="stylesheet" href="../../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../../ayu.css" disabled><link rel="stylesheet" href="../../../../dark.css" disabled><link rel="stylesheet" href="../../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../../storage.js"></script><script defer src="../../../../source-script.js"></script><script defer src="../../../../source-files.js"></script><script defer src="../../../../main.js"></script><noscript><link rel="stylesheet" href="../../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../../tokio/index.html"><img class="rust-logo" src="../../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::io::{AsyncRead, AsyncWrite, ReadBuf}; |
| |
| <span class="kw">use </span>std::future::Future; |
| <span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">struct </span>CopyBuffer { |
| read_done: bool, |
| need_flush: bool, |
| pos: usize, |
| cap: usize, |
| amt: u64, |
| buf: Box<[u8]>, |
| } |
| |
| <span class="kw">impl </span>CopyBuffer { |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>new() -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| read_done: <span class="bool-val">false</span>, |
| need_flush: <span class="bool-val">false</span>, |
| pos: <span class="number">0</span>, |
| cap: <span class="number">0</span>, |
| amt: <span class="number">0</span>, |
| buf: <span class="macro">vec!</span>[<span class="number">0</span>; <span class="kw">super</span>::DEFAULT_BUF_SIZE].into_boxed_slice(), |
| } |
| } |
| |
| <span class="kw">fn </span>poll_fill_buf<R>( |
| <span class="kw-2">&mut </span><span class="self">self</span>, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| reader: Pin<<span class="kw-2">&mut </span>R>, |
| ) -> Poll<io::Result<()>> |
| <span class="kw">where |
| </span>R: AsyncRead + <span class="question-mark">?</span>Sized, |
| { |
| <span class="kw">let </span>me = <span class="kw-2">&mut *</span><span class="self">self</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = ReadBuf::new(<span class="kw-2">&mut </span>me.buf); |
| buf.set_filled(me.cap); |
| |
| <span class="kw">let </span>res = reader.poll_read(cx, <span class="kw-2">&mut </span>buf); |
| <span class="kw">if let </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw">_</span>)) = res { |
| <span class="kw">let </span>filled_len = buf.filled().len(); |
| me.read_done = me.cap == filled_len; |
| me.cap = filled_len; |
| } |
| res |
| } |
| |
| <span class="kw">fn </span>poll_write_buf<R, W>( |
| <span class="kw-2">&mut </span><span class="self">self</span>, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| <span class="kw-2">mut </span>reader: Pin<<span class="kw-2">&mut </span>R>, |
| <span class="kw-2">mut </span>writer: Pin<<span class="kw-2">&mut </span>W>, |
| ) -> Poll<io::Result<usize>> |
| <span class="kw">where |
| </span>R: AsyncRead + <span class="question-mark">?</span>Sized, |
| W: AsyncWrite + <span class="question-mark">?</span>Sized, |
| { |
| <span class="kw">let </span>me = <span class="kw-2">&mut *</span><span class="self">self</span>; |
| <span class="kw">match </span>writer.as_mut().poll_write(cx, <span class="kw-2">&</span>me.buf[me.pos..me.cap]) { |
| Poll::Pending => { |
| <span class="comment">// Top up the buffer towards full if we can read a bit more |
| // data - this should improve the chances of a large write |
| </span><span class="kw">if </span>!me.read_done && me.cap < me.buf.len() { |
| <span class="macro">ready!</span>(me.poll_fill_buf(cx, reader.as_mut()))<span class="question-mark">?</span>; |
| } |
| Poll::Pending |
| } |
| res => res, |
| } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>poll_copy<R, W>( |
| <span class="kw-2">&mut </span><span class="self">self</span>, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| <span class="kw-2">mut </span>reader: Pin<<span class="kw-2">&mut </span>R>, |
| <span class="kw-2">mut </span>writer: Pin<<span class="kw-2">&mut </span>W>, |
| ) -> Poll<io::Result<u64>> |
| <span class="kw">where |
| </span>R: AsyncRead + <span class="question-mark">?</span>Sized, |
| W: AsyncWrite + <span class="question-mark">?</span>Sized, |
| { |
| <span class="kw">loop </span>{ |
| <span class="comment">// If our buffer is empty, then we need to read some data to |
| // continue. |
| </span><span class="kw">if </span><span class="self">self</span>.pos == <span class="self">self</span>.cap && !<span class="self">self</span>.read_done { |
| <span class="self">self</span>.pos = <span class="number">0</span>; |
| <span class="self">self</span>.cap = <span class="number">0</span>; |
| |
| <span class="kw">match </span><span class="self">self</span>.poll_fill_buf(cx, reader.as_mut()) { |
| Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw">_</span>)) => (), |
| Poll::Ready(<span class="prelude-val">Err</span>(err)) => <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(err)), |
| Poll::Pending => { |
| <span class="comment">// Try flushing when the reader has no progress to avoid deadlock |
| // when the reader depends on buffered writer. |
| </span><span class="kw">if </span><span class="self">self</span>.need_flush { |
| <span class="macro">ready!</span>(writer.as_mut().poll_flush(cx))<span class="question-mark">?</span>; |
| <span class="self">self</span>.need_flush = <span class="bool-val">false</span>; |
| } |
| |
| <span class="kw">return </span>Poll::Pending; |
| } |
| } |
| } |
| |
| <span class="comment">// If our buffer has some data, let's write it out! |
| </span><span class="kw">while </span><span class="self">self</span>.pos < <span class="self">self</span>.cap { |
| <span class="kw">let </span>i = <span class="macro">ready!</span>(<span class="self">self</span>.poll_write_buf(cx, reader.as_mut(), writer.as_mut()))<span class="question-mark">?</span>; |
| <span class="kw">if </span>i == <span class="number">0 </span>{ |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(io::Error::new( |
| io::ErrorKind::WriteZero, |
| <span class="string">"write zero byte into writer"</span>, |
| ))); |
| } <span class="kw">else </span>{ |
| <span class="self">self</span>.pos += i; |
| <span class="self">self</span>.amt += i <span class="kw">as </span>u64; |
| <span class="self">self</span>.need_flush = <span class="bool-val">true</span>; |
| } |
| } |
| |
| <span class="comment">// If pos larger than cap, this loop will never stop. |
| // In particular, user's wrong poll_write implementation returning |
| // incorrect written length may lead to thread blocking. |
| </span><span class="macro">debug_assert!</span>( |
| <span class="self">self</span>.pos <= <span class="self">self</span>.cap, |
| <span class="string">"writer returned length larger than input slice" |
| </span>); |
| |
| <span class="comment">// If we've written all the data and we've seen EOF, flush out the |
| // data and finish the transfer. |
| </span><span class="kw">if </span><span class="self">self</span>.pos == <span class="self">self</span>.cap && <span class="self">self</span>.read_done { |
| <span class="macro">ready!</span>(writer.as_mut().poll_flush(cx))<span class="question-mark">?</span>; |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="self">self</span>.amt)); |
| } |
| } |
| } |
| } |
| |
| <span class="doccomment">/// A future that asynchronously copies the entire contents of a reader into a |
| /// writer. |
| </span><span class="attribute">#[derive(Debug)] |
| #[must_use = <span class="string">"futures do nothing unless you `.await` or poll them"</span>] |
| </span><span class="kw">struct </span>Copy<<span class="lifetime">'a</span>, R: <span class="question-mark">?</span>Sized, W: <span class="question-mark">?</span>Sized> { |
| reader: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>R, |
| writer: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>W, |
| buf: CopyBuffer, |
| } |
| |
| <span class="macro">cfg_io_util! </span>{ |
| <span class="doccomment">/// Asynchronously copies the entire contents of a reader into a writer. |
| /// |
| /// This function returns a future that 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. |
| /// |
| /// This is an asynchronous version of [`std::io::copy`][std]. |
| /// |
| /// [std]: std::io::copy |
| /// |
| /// # Errors |
| /// |
| /// The returned future will return an error immediately if any call to |
| /// `poll_read` or `poll_write` returns an error. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use tokio::io; |
| /// |
| /// # async fn dox() -> std::io::Result<()> { |
| /// let mut reader: &[u8] = b"hello"; |
| /// let mut writer: Vec<u8> = vec![]; |
| /// |
| /// io::copy(&mut reader, &mut writer).await?; |
| /// |
| /// assert_eq!(&b"hello"[..], &writer[..]); |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| </span><span class="kw">pub async fn </span>copy<<span class="lifetime">'a</span>, R, W>(reader: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>R, writer: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>W) -> io::Result<u64> |
| <span class="kw">where |
| </span>R: AsyncRead + Unpin + <span class="question-mark">?</span>Sized, |
| W: AsyncWrite + Unpin + <span class="question-mark">?</span>Sized, |
| { |
| Copy { |
| reader, |
| writer, |
| buf: CopyBuffer::new() |
| }.<span class="kw">await |
| </span>} |
| } |
| |
| <span class="kw">impl</span><R, W> Future <span class="kw">for </span>Copy<<span class="lifetime">'_</span>, R, W> |
| <span class="kw">where |
| </span>R: AsyncRead + Unpin + <span class="question-mark">?</span>Sized, |
| W: AsyncWrite + Unpin + <span class="question-mark">?</span>Sized, |
| { |
| <span class="kw">type </span>Output = io::Result<u64>; |
| |
| <span class="kw">fn </span>poll(<span class="kw-2">mut </span><span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<io::Result<u64>> { |
| <span class="kw">let </span>me = <span class="kw-2">&mut *</span><span class="self">self</span>; |
| |
| me.buf |
| .poll_copy(cx, Pin::new(<span class="kw-2">&mut *</span>me.reader), Pin::new(<span class="kw-2">&mut *</span>me.writer)) |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
