| <!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/stream/stream/for_each_concurrent.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>for_each_concurrent.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>::stream::{FuturesUnordered, StreamExt}; |
| <span class="kw">use </span>core::fmt; |
| <span class="kw">use </span>core::num::NonZeroUsize; |
| <span class="kw">use </span>core::pin::Pin; |
| <span class="kw">use </span>futures_core::future::{FusedFuture, Future}; |
| <span class="kw">use </span>futures_core::stream::Stream; |
| <span class="kw">use </span>futures_core::task::{Context, Poll}; |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Future for the [`for_each_concurrent`](super::StreamExt::for_each_concurrent) |
| /// method. |
| </span><span class="attribute">#[must_use = <span class="string">"futures do nothing unless you `.await` or poll them"</span>] |
| </span><span class="kw">pub struct </span>ForEachConcurrent<St, Fut, F> { |
| <span class="attribute">#[pin] |
| </span>stream: <span class="prelude-ty">Option</span><St>, |
| f: F, |
| futures: FuturesUnordered<Fut>, |
| limit: <span class="prelude-ty">Option</span><NonZeroUsize>, |
| } |
| } |
| |
| <span class="kw">impl</span><St, Fut, F> fmt::Debug <span class="kw">for </span>ForEachConcurrent<St, Fut, F> |
| <span class="kw">where |
| </span>St: fmt::Debug, |
| Fut: fmt::Debug, |
| { |
| <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 { |
| f.debug_struct(<span class="string">"ForEachConcurrent"</span>) |
| .field(<span class="string">"stream"</span>, <span class="kw-2">&</span><span class="self">self</span>.stream) |
| .field(<span class="string">"futures"</span>, <span class="kw-2">&</span><span class="self">self</span>.futures) |
| .field(<span class="string">"limit"</span>, <span class="kw-2">&</span><span class="self">self</span>.limit) |
| .finish() |
| } |
| } |
| |
| <span class="kw">impl</span><St, Fut, F> ForEachConcurrent<St, Fut, F> |
| <span class="kw">where |
| </span>St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = ()>, |
| { |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>new(stream: St, limit: <span class="prelude-ty">Option</span><usize>, f: F) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| stream: <span class="prelude-val">Some</span>(stream), |
| <span class="comment">// Note: `limit` = 0 gets ignored. |
| </span>limit: limit.and_then(NonZeroUsize::new), |
| f, |
| futures: FuturesUnordered::new(), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><St, Fut, F> FusedFuture <span class="kw">for </span>ForEachConcurrent<St, Fut, F> |
| <span class="kw">where |
| </span>St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = ()>, |
| { |
| <span class="kw">fn </span>is_terminated(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.stream.is_none() && <span class="self">self</span>.futures.is_empty() |
| } |
| } |
| |
| <span class="kw">impl</span><St, Fut, F> Future <span class="kw">for </span>ForEachConcurrent<St, Fut, F> |
| <span class="kw">where |
| </span>St: Stream, |
| F: FnMut(St::Item) -> Fut, |
| Fut: Future<Output = ()>, |
| { |
| <span class="kw">type </span>Output = (); |
| |
| <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="kw">let </span><span class="kw-2">mut </span>this = <span class="self">self</span>.project(); |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>made_progress_this_iter = <span class="bool-val">false</span>; |
| |
| <span class="comment">// Check if we've already created a number of futures greater than `limit` |
| </span><span class="kw">if </span>this.limit.map(|limit| limit.get() > this.futures.len()).unwrap_or(<span class="bool-val">true</span>) { |
| <span class="kw">let </span><span class="kw-2">mut </span>stream_completed = <span class="bool-val">false</span>; |
| <span class="kw">let </span>elem = <span class="kw">if let </span><span class="prelude-val">Some</span>(stream) = this.stream.as_mut().as_pin_mut() { |
| <span class="kw">match </span>stream.poll_next(cx) { |
| Poll::Ready(<span class="prelude-val">Some</span>(elem)) => { |
| made_progress_this_iter = <span class="bool-val">true</span>; |
| <span class="prelude-val">Some</span>(elem) |
| } |
| Poll::Ready(<span class="prelude-val">None</span>) => { |
| stream_completed = <span class="bool-val">true</span>; |
| <span class="prelude-val">None |
| </span>} |
| Poll::Pending => <span class="prelude-val">None</span>, |
| } |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">None |
| </span>}; |
| <span class="kw">if </span>stream_completed { |
| this.stream.set(<span class="prelude-val">None</span>); |
| } |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(elem) = elem { |
| this.futures.push((this.f)(elem)); |
| } |
| } |
| |
| <span class="kw">match </span>this.futures.poll_next_unpin(cx) { |
| Poll::Ready(<span class="prelude-val">Some</span>(())) => made_progress_this_iter = <span class="bool-val">true</span>, |
| Poll::Ready(<span class="prelude-val">None</span>) => { |
| <span class="kw">if </span>this.stream.is_none() { |
| <span class="kw">return </span>Poll::Ready(()); |
| } |
| } |
| Poll::Pending => {} |
| } |
| |
| <span class="kw">if </span>!made_progress_this_iter { |
| <span class="kw">return </span>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> |
