| <!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/abortable.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>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>::task::AtomicWaker; |
| <span class="kw">use </span>alloc::sync::Arc; |
| <span class="kw">use </span>core::fmt; |
| <span class="kw">use </span>core::pin::Pin; |
| <span class="kw">use </span>core::sync::atomic::{AtomicBool, Ordering}; |
| <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_core::Stream; |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// A future/stream which can be remotely short-circuited using an `AbortHandle`. |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| #[must_use = <span class="string">"futures/streams do nothing unless you poll them"</span>] |
| </span><span class="kw">pub struct </span>Abortable<T> { |
| <span class="attribute">#[pin] |
| </span>task: T, |
| inner: Arc<AbortInner>, |
| } |
| } |
| |
| <span class="kw">impl</span><T> Abortable<T> { |
| <span class="doccomment">/// Creates a new `Abortable` future/stream using an existing `AbortRegistration`. |
| /// `AbortRegistration`s can be acquired through `AbortHandle::new`. |
| /// |
| /// When `abort` is called on the handle tied to `reg` or if `abort` has |
| /// already been called, the future/stream will complete immediately without making |
| /// any further progress. |
| /// |
| /// # Examples: |
| /// |
| /// Usage with futures: |
| /// |
| /// ``` |
| /// # futures::executor::block_on(async { |
| /// use futures::future::{Abortable, AbortHandle, Aborted}; |
| /// |
| /// let (abort_handle, abort_registration) = AbortHandle::new_pair(); |
| /// let future = Abortable::new(async { 2 }, abort_registration); |
| /// abort_handle.abort(); |
| /// assert_eq!(future.await, Err(Aborted)); |
| /// # }); |
| /// ``` |
| /// |
| /// Usage with streams: |
| /// |
| /// ``` |
| /// # futures::executor::block_on(async { |
| /// # use futures::future::{Abortable, AbortHandle}; |
| /// # use futures::stream::{self, StreamExt}; |
| /// |
| /// let (abort_handle, abort_registration) = AbortHandle::new_pair(); |
| /// let mut stream = Abortable::new(stream::iter(vec![1, 2, 3]), abort_registration); |
| /// abort_handle.abort(); |
| /// assert_eq!(stream.next().await, None); |
| /// # }); |
| /// ``` |
| </span><span class="kw">pub fn </span>new(task: T, reg: AbortRegistration) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ task, inner: reg.inner } |
| } |
| |
| <span class="doccomment">/// Checks whether the task has been aborted. Note that all this |
| /// method indicates is whether [`AbortHandle::abort`] was *called*. |
| /// This means that it will return `true` even if: |
| /// * `abort` was called after the task had completed. |
| /// * `abort` was called while the task was being polled - the task may still be running and |
| /// will not be stopped until `poll` returns. |
| </span><span class="kw">pub fn </span>is_aborted(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.inner.aborted.load(Ordering::Relaxed) |
| } |
| } |
| |
| <span class="doccomment">/// A registration handle for an `Abortable` task. |
| /// Values of this type can be acquired from `AbortHandle::new` and are used |
| /// in calls to `Abortable::new`. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>AbortRegistration { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) inner: Arc<AbortInner>, |
| } |
| |
| <span class="kw">impl </span>AbortRegistration { |
| <span class="doccomment">/// Create an [`AbortHandle`] from the given [`AbortRegistration`]. |
| /// |
| /// The created [`AbortHandle`] is functionally the same as any other |
| /// [`AbortHandle`]s that are associated with the same [`AbortRegistration`], |
| /// such as the one created by [`AbortHandle::new_pair`]. |
| </span><span class="kw">pub fn </span>handle(<span class="kw-2">&</span><span class="self">self</span>) -> AbortHandle { |
| AbortHandle { inner: <span class="self">self</span>.inner.clone() } |
| } |
| } |
| |
| <span class="doccomment">/// A handle to an `Abortable` task. |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">pub struct </span>AbortHandle { |
| inner: Arc<AbortInner>, |
| } |
| |
| <span class="kw">impl </span>AbortHandle { |
| <span class="doccomment">/// Creates an (`AbortHandle`, `AbortRegistration`) pair which can be used |
| /// to abort a running future or stream. |
| /// |
| /// This function is usually paired with a call to [`Abortable::new`]. |
| </span><span class="kw">pub fn </span>new_pair() -> (<span class="self">Self</span>, AbortRegistration) { |
| <span class="kw">let </span>inner = |
| Arc::new(AbortInner { waker: AtomicWaker::new(), aborted: AtomicBool::new(<span class="bool-val">false</span>) }); |
| |
| (<span class="self">Self </span>{ inner: inner.clone() }, AbortRegistration { inner }) |
| } |
| } |
| |
| <span class="comment">// Inner type storing the waker to awaken and a bool indicating that it |
| // should be aborted. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>AbortInner { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) waker: AtomicWaker, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) aborted: AtomicBool, |
| } |
| |
| <span class="doccomment">/// Indicator that the `Abortable` task was aborted. |
| </span><span class="attribute">#[derive(Copy, Clone, Debug, Eq, PartialEq)] |
| </span><span class="kw">pub struct </span>Aborted; |
| |
| <span class="kw">impl </span>fmt::Display <span class="kw">for </span>Aborted { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <span class="macro">write!</span>(f, <span class="string">"`Abortable` future has been aborted"</span>) |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| </span><span class="kw">impl </span>std::error::Error <span class="kw">for </span>Aborted {} |
| |
| <span class="kw">impl</span><T> Abortable<T> { |
| <span class="kw">fn </span>try_poll<I>( |
| <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: <span class="kw">impl </span>Fn(Pin<<span class="kw-2">&mut </span>T>, <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<I>, |
| ) -> Poll<<span class="prelude-ty">Result</span><I, Aborted>> { |
| <span class="comment">// Check if the task has been aborted |
| </span><span class="kw">if </span><span class="self">self</span>.is_aborted() { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(Aborted)); |
| } |
| |
| <span class="comment">// attempt to complete the task |
| </span><span class="kw">if let </span>Poll::Ready(x) = poll(<span class="self">self</span>.as_mut().project().task, cx) { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(x)); |
| } |
| |
| <span class="comment">// Register to receive a wakeup if the task is aborted in the future |
| </span><span class="self">self</span>.inner.waker.register(cx.waker()); |
| |
| <span class="comment">// Check to see if the task was aborted between the first check and |
| // registration. |
| // Checking with `is_aborted` which uses `Relaxed` is sufficient because |
| // `register` introduces an `AcqRel` barrier. |
| </span><span class="kw">if </span><span class="self">self</span>.is_aborted() { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(Aborted)); |
| } |
| |
| Poll::Pending |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> Future <span class="kw">for </span>Abortable<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| { |
| <span class="kw">type </span>Output = <span class="prelude-ty">Result</span><Fut::Output, Aborted>; |
| |
| <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="self">self</span>.try_poll(cx, |fut, cx| fut.poll(cx)) |
| } |
| } |
| |
| <span class="kw">impl</span><St> Stream <span class="kw">for </span>Abortable<St> |
| <span class="kw">where |
| </span>St: Stream, |
| { |
| <span class="kw">type </span>Item = St::Item; |
| |
| <span class="kw">fn </span>poll_next(<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="prelude-ty">Option</span><<span class="self">Self</span>::Item>> { |
| <span class="self">self</span>.try_poll(cx, |stream, cx| stream.poll_next(cx)).map(Result::ok).map(Option::flatten) |
| } |
| } |
| |
| <span class="kw">impl </span>AbortHandle { |
| <span class="doccomment">/// Abort the `Abortable` stream/future associated with this handle. |
| /// |
| /// Notifies the Abortable task associated with this handle that it |
| /// should abort. Note that if the task is currently being polled on |
| /// another thread, it will not immediately stop running. Instead, it will |
| /// continue to run until its poll method returns. |
| </span><span class="kw">pub fn </span>abort(<span class="kw-2">&</span><span class="self">self</span>) { |
| <span class="self">self</span>.inner.aborted.store(<span class="bool-val">true</span>, Ordering::Relaxed); |
| <span class="self">self</span>.inner.waker.wake(); |
| } |
| |
| <span class="doccomment">/// Checks whether [`AbortHandle::abort`] was *called* on any associated |
| /// [`AbortHandle`]s, which includes all the [`AbortHandle`]s linked with |
| /// the same [`AbortRegistration`]. This means that it will return `true` |
| /// even if: |
| /// * `abort` was called after the task had completed. |
| /// * `abort` was called while the task was being polled - the task may still be running and |
| /// will not be stopped until `poll` returns. |
| /// |
| /// This operation has a Relaxed ordering. |
| </span><span class="kw">pub fn </span>is_aborted(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.inner.aborted.load(Ordering::Relaxed) |
| } |
| } |
| </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> |