| <!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/futures-util-0.3.28/src/io/copy_buf_abortable.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>copy_buf_abortable.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="../../../futures_util/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="../../../futures_util/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>::abortable::{AbortHandle, AbortInner, Aborted}; |
| <span class="kw">use </span>futures_core::future::Future; |
| <span class="kw">use </span>futures_core::task::{Context, Poll}; |
| <span class="kw">use </span>futures_io::{AsyncBufRead, AsyncWrite}; |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| <span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::sync::atomic::Ordering; |
| <span class="kw">use </span>std::sync::Arc; |
| |
| <span class="doccomment">/// Creates a future which copies all the bytes from one object to another, with its `AbortHandle`. |
| /// |
| /// The returned future will copy all the bytes read from this `AsyncBufRead` into the |
| /// `writer` specified. This future will only complete once abort has been requested or the `reader` has hit |
| /// EOF and all bytes have been written to and flushed from the `writer` |
| /// provided. |
| /// |
| /// On success the number of bytes is returned. If aborted, `Aborted` is returned. Otherwise, the underlying error is returned. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # futures::executor::block_on(async { |
| /// use futures::io::{self, AsyncWriteExt, Cursor}; |
| /// use futures::future::Aborted; |
| /// |
| /// let reader = Cursor::new([1, 2, 3, 4]); |
| /// let mut writer = Cursor::new(vec![0u8; 5]); |
| /// |
| /// let (fut, abort_handle) = io::copy_buf_abortable(reader, &mut writer); |
| /// let bytes = fut.await; |
| /// abort_handle.abort(); |
| /// writer.close().await.unwrap(); |
| /// match bytes { |
| /// Ok(Ok(n)) => { |
| /// assert_eq!(n, 4); |
| /// assert_eq!(writer.into_inner(), [1, 2, 3, 4, 0]); |
| /// Ok(n) |
| /// }, |
| /// Ok(Err(a)) => { |
| /// Err::<u64, Aborted>(a) |
| /// } |
| /// Err(e) => panic!("{}", e) |
| /// } |
| /// # }).unwrap(); |
| /// ``` |
| </span><span class="kw">pub fn </span>copy_buf_abortable<R, W>( |
| reader: R, |
| writer: <span class="kw-2">&mut </span>W, |
| ) -> (CopyBufAbortable<<span class="lifetime">'_</span>, R, W>, AbortHandle) |
| <span class="kw">where |
| </span>R: AsyncBufRead, |
| W: AsyncWrite + Unpin + <span class="question-mark">?</span>Sized, |
| { |
| <span class="kw">let </span>(handle, reg) = AbortHandle::new_pair(); |
| (CopyBufAbortable { reader, writer, amt: <span class="number">0</span>, inner: reg.inner }, handle) |
| } |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Future for the [`copy_buf()`] function. |
| </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">pub struct </span>CopyBufAbortable<<span class="lifetime">'a</span>, R, W: <span class="question-mark">?</span>Sized> { |
| <span class="attribute">#[pin] |
| </span>reader: R, |
| writer: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>W, |
| amt: u64, |
| inner: Arc<AbortInner> |
| } |
| } |
| |
| <span class="macro">macro_rules! </span>ready_or_break { |
| (<span class="macro-nonterminal">$e</span>:expr $(,)<span class="question-mark">?</span>) => { |
| <span class="kw">match </span><span class="macro-nonterminal">$e </span>{ |
| <span class="macro-nonterminal">$crate::task::Poll::Ready</span>(t) => t, |
| <span class="macro-nonterminal">$crate::task::Poll::Pending </span>=> <span class="kw">break</span>, |
| } |
| }; |
| } |
| |
| <span class="kw">impl</span><R, W> Future <span class="kw">for </span>CopyBufAbortable<<span class="lifetime">'_</span>, R, W> |
| <span class="kw">where |
| </span>R: AsyncBufRead, |
| W: AsyncWrite + Unpin + Sized, |
| { |
| <span class="kw">type </span>Output = <span class="prelude-ty">Result</span><<span class="prelude-ty">Result</span><u64, Aborted>, io::Error>; |
| |
| <span class="kw">fn </span>poll(<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<<span class="self">Self</span>::Output> { |
| <span class="kw">let </span><span class="kw-2">mut </span>this = <span class="self">self</span>.project(); |
| <span class="kw">loop </span>{ |
| <span class="comment">// Check if the task has been aborted |
| </span><span class="kw">if </span>this.inner.aborted.load(Ordering::Relaxed) { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="prelude-val">Err</span>(Aborted))); |
| } |
| |
| <span class="comment">// Read some bytes from the reader, and if we have reached EOF, return total bytes read |
| </span><span class="kw">let </span>buffer = <span class="macro">ready_or_break!</span>(this.reader.as_mut().poll_fill_buf(cx))<span class="question-mark">?</span>; |
| <span class="kw">if </span>buffer.is_empty() { |
| <span class="macro">ready_or_break!</span>(Pin::new(<span class="kw-2">&mut </span>this.writer).poll_flush(cx))<span class="question-mark">?</span>; |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="prelude-val">Ok</span>(<span class="kw-2">*</span>this.amt))); |
| } |
| |
| <span class="comment">// Pass the buffer to the writer, and update the amount written |
| </span><span class="kw">let </span>i = <span class="macro">ready_or_break!</span>(Pin::new(<span class="kw-2">&mut </span>this.writer).poll_write(cx, buffer))<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::ErrorKind::WriteZero.into())); |
| } |
| <span class="kw-2">*</span>this.amt += i <span class="kw">as </span>u64; |
| this.reader.as_mut().consume(i); |
| } |
| <span class="comment">// Schedule the task to be woken up again. |
| // Never called unless Poll::Pending is returned from io objects. |
| </span>this.inner.waker.register(cx.waker()); |
| |
| <span class="comment">// Check to see if the task was aborted between the first check and |
| // registration. |
| // Checking with `Relaxed` is sufficient because |
| // `register` introduces an `AcqRel` barrier. |
| </span><span class="kw">if </span>this.inner.aborted.load(Ordering::Relaxed) { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="prelude-val">Err</span>(Aborted))); |
| } |
| Poll::Pending |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="futures_util" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |