| <!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/registry/src/github.com-1ecc6299db9ec823/tokio-1.28.2/src/io/util/copy_bidirectional.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>copy_bidirectional.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">super</span>::copy::CopyBuffer; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::future::poll_fn; |
| <span class="kw">use </span><span class="kw">crate</span>::io::{AsyncRead, AsyncWrite}; |
| |
| <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="kw">enum </span>TransferState { |
| Running(CopyBuffer), |
| ShuttingDown(u64), |
| Done(u64), |
| } |
| |
| <span class="kw">fn </span>transfer_one_direction<A, B>( |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| state: <span class="kw-2">&mut </span>TransferState, |
| r: <span class="kw-2">&mut </span>A, |
| w: <span class="kw-2">&mut </span>B, |
| ) -> Poll<io::Result<u64>> |
| <span class="kw">where |
| </span>A: AsyncRead + AsyncWrite + Unpin + <span class="question-mark">?</span>Sized, |
| B: AsyncRead + AsyncWrite + Unpin + <span class="question-mark">?</span>Sized, |
| { |
| <span class="kw">let </span><span class="kw-2">mut </span>r = Pin::new(r); |
| <span class="kw">let </span><span class="kw-2">mut </span>w = Pin::new(w); |
| |
| <span class="kw">loop </span>{ |
| <span class="kw">match </span>state { |
| TransferState::Running(buf) => { |
| <span class="kw">let </span>count = <span class="macro">ready!</span>(buf.poll_copy(cx, r.as_mut(), w.as_mut()))<span class="question-mark">?</span>; |
| <span class="kw-2">*</span>state = TransferState::ShuttingDown(count); |
| } |
| TransferState::ShuttingDown(count) => { |
| <span class="macro">ready!</span>(w.as_mut().poll_shutdown(cx))<span class="question-mark">?</span>; |
| |
| <span class="kw-2">*</span>state = TransferState::Done(<span class="kw-2">*</span>count); |
| } |
| TransferState::Done(count) => <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">*</span>count)), |
| } |
| } |
| } |
| <span class="doccomment">/// Copies data in both directions between `a` and `b`. |
| /// |
| /// This function returns a future that will read from both streams, |
| /// writing any data read to the opposing stream. |
| /// This happens in both directions concurrently. |
| /// |
| /// If an EOF is observed on one stream, [`shutdown()`] will be invoked on |
| /// the other, and reading from that stream will stop. Copying of data in |
| /// the other direction will continue. |
| /// |
| /// The future will complete successfully once both directions of communication has been shut down. |
| /// A direction is shut down when the reader reports EOF, |
| /// at which point [`shutdown()`] is called on the corresponding writer. When finished, |
| /// it will return a tuple of the number of bytes copied from a to b |
| /// and the number of bytes copied from b to a, in that order. |
| /// |
| /// [`shutdown()`]: crate::io::AsyncWriteExt::shutdown |
| /// |
| /// # Errors |
| /// |
| /// The future will immediately return an error if any IO operation on `a` |
| /// or `b` returns an error. Some data read from either stream may be lost (not |
| /// written to the other stream) in this case. |
| /// |
| /// # Return value |
| /// |
| /// Returns a tuple of bytes copied `a` to `b` and bytes copied `b` to `a`. |
| </span><span class="attribute">#[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"io-util"</span>)))] |
| </span><span class="kw">pub async fn </span>copy_bidirectional<A, B>(a: <span class="kw-2">&mut </span>A, b: <span class="kw-2">&mut </span>B) -> <span class="prelude-ty">Result</span><(u64, u64), std::io::Error> |
| <span class="kw">where |
| </span>A: AsyncRead + AsyncWrite + Unpin + <span class="question-mark">?</span>Sized, |
| B: AsyncRead + AsyncWrite + Unpin + <span class="question-mark">?</span>Sized, |
| { |
| <span class="kw">let </span><span class="kw-2">mut </span>a_to_b = TransferState::Running(CopyBuffer::new()); |
| <span class="kw">let </span><span class="kw-2">mut </span>b_to_a = TransferState::Running(CopyBuffer::new()); |
| poll_fn(|cx| { |
| <span class="kw">let </span>a_to_b = transfer_one_direction(cx, <span class="kw-2">&mut </span>a_to_b, a, b)<span class="question-mark">?</span>; |
| <span class="kw">let </span>b_to_a = transfer_one_direction(cx, <span class="kw-2">&mut </span>b_to_a, b, a)<span class="question-mark">?</span>; |
| |
| <span class="comment">// It is not a problem if ready! returns early because transfer_one_direction for the |
| // other direction will keep returning TransferState::Done(count) in future calls to poll |
| </span><span class="kw">let </span>a_to_b = <span class="macro">ready!</span>(a_to_b); |
| <span class="kw">let </span>b_to_a = <span class="macro">ready!</span>(b_to_a); |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>((a_to_b, b_to_a))) |
| }) |
| .<span class="kw">await |
| </span>} |
| </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> |
