| <!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-stream-0.1.14/src/stream_ext/throttle.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>throttle.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_stream/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_stream/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="doccomment">//! Slow down a stream by enforcing a delay between items. |
| |
| </span><span class="kw">use </span><span class="kw">crate</span>::Stream; |
| <span class="kw">use </span>tokio::time::{Duration, Instant, Sleep}; |
| |
| <span class="kw">use </span>std::future::Future; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{<span class="self">self</span>, Poll}; |
| |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>throttle<T>(duration: Duration, stream: T) -> Throttle<T> |
| <span class="kw">where |
| </span>T: Stream, |
| { |
| Throttle { |
| delay: tokio::time::sleep_until(Instant::now() + duration), |
| duration, |
| has_delayed: <span class="bool-val">true</span>, |
| stream, |
| } |
| } |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Stream for the [`throttle`](throttle) function. This object is `!Unpin`. If you need it to |
| /// implement `Unpin` you can pin your throttle like this: `Box::pin(your_throttle)`. |
| </span><span class="attribute">#[derive(Debug)] |
| #[must_use = <span class="string">"streams do nothing unless polled"</span>] |
| </span><span class="kw">pub struct </span>Throttle<T> { |
| <span class="attribute">#[pin] |
| </span>delay: Sleep, |
| duration: Duration, |
| |
| <span class="comment">// Set to true when `delay` has returned ready, but `stream` hasn't. |
| </span>has_delayed: bool, |
| |
| <span class="comment">// The stream to throttle |
| </span><span class="attribute">#[pin] |
| </span>stream: T, |
| } |
| } |
| |
| <span class="kw">impl</span><T> Throttle<T> { |
| <span class="doccomment">/// Acquires a reference to the underlying stream that this combinator is |
| /// pulling from. |
| </span><span class="kw">pub fn </span>get_ref(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>T { |
| <span class="kw-2">&</span><span class="self">self</span>.stream |
| } |
| |
| <span class="doccomment">/// Acquires a mutable reference to the underlying stream that this combinator |
| /// is pulling from. |
| /// |
| /// Note that care must be taken to avoid tampering with the state of the stream |
| /// which may otherwise confuse this combinator. |
| </span><span class="kw">pub fn </span>get_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>T { |
| <span class="kw-2">&mut </span><span class="self">self</span>.stream |
| } |
| |
| <span class="doccomment">/// Consumes this combinator, returning the underlying stream. |
| /// |
| /// Note that this may discard intermediate state of this combinator, so care |
| /// should be taken to avoid losing resources when this is called. |
| </span><span class="kw">pub fn </span>into_inner(<span class="self">self</span>) -> T { |
| <span class="self">self</span>.stream |
| } |
| } |
| |
| <span class="kw">impl</span><T: Stream> Stream <span class="kw">for </span>Throttle<T> { |
| <span class="kw">type </span>Item = T::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>task::Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Option</span><<span class="self">Self</span>::Item>> { |
| <span class="kw">let </span><span class="kw-2">mut </span>me = <span class="self">self</span>.project(); |
| <span class="kw">let </span>dur = <span class="kw-2">*</span>me.duration; |
| |
| <span class="kw">if </span>!<span class="kw-2">*</span>me.has_delayed && !is_zero(dur) { |
| <span class="macro">ready!</span>(me.delay.as_mut().poll(cx)); |
| <span class="kw-2">*</span>me.has_delayed = <span class="bool-val">true</span>; |
| } |
| |
| <span class="kw">let </span>value = <span class="macro">ready!</span>(me.stream.poll_next(cx)); |
| |
| <span class="kw">if </span>value.is_some() { |
| <span class="kw">if </span>!is_zero(dur) { |
| me.delay.reset(Instant::now() + dur); |
| } |
| |
| <span class="kw-2">*</span>me.has_delayed = <span class="bool-val">false</span>; |
| } |
| |
| Poll::Ready(value) |
| } |
| } |
| |
| <span class="kw">fn </span>is_zero(dur: Duration) -> bool { |
| dur == Duration::from_millis(<span class="number">0</span>) |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="tokio_stream" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |