| <!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/h2-0.3.19/src/proto/ping_pong.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>ping_pong.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="../../../h2/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="../../../h2/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>::codec::Codec; |
| <span class="kw">use </span><span class="kw">crate</span>::frame::Ping; |
| <span class="kw">use </span><span class="kw">crate</span>::proto::{<span class="self">self</span>, PingPayload}; |
| |
| <span class="kw">use </span>bytes::Buf; |
| <span class="kw">use </span>futures_util::task::AtomicWaker; |
| <span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::sync::atomic::{AtomicUsize, Ordering}; |
| <span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| <span class="kw">use </span>tokio::io::AsyncWrite; |
| |
| <span class="doccomment">/// Acknowledges ping requests from the remote. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>PingPong { |
| pending_ping: <span class="prelude-ty">Option</span><PendingPing>, |
| pending_pong: <span class="prelude-ty">Option</span><PingPayload>, |
| user_pings: <span class="prelude-ty">Option</span><UserPingsRx>, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>UserPings(Arc<UserPingsInner>); |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>UserPingsRx(Arc<UserPingsInner>); |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>UserPingsInner { |
| state: AtomicUsize, |
| <span class="doccomment">/// Task to wake up the main `Connection`. |
| </span>ping_task: AtomicWaker, |
| <span class="doccomment">/// Task to wake up `share::PingPong::poll_pong`. |
| </span>pong_task: AtomicWaker, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>PendingPing { |
| payload: PingPayload, |
| sent: bool, |
| } |
| |
| <span class="doccomment">/// Status returned from `PingPong::recv_ping`. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">enum </span>ReceivedPing { |
| MustAck, |
| Unknown, |
| Shutdown, |
| } |
| |
| <span class="doccomment">/// No user ping pending. |
| </span><span class="kw">const </span>USER_STATE_EMPTY: usize = <span class="number">0</span>; |
| <span class="doccomment">/// User has called `send_ping`, but PING hasn't been written yet. |
| </span><span class="kw">const </span>USER_STATE_PENDING_PING: usize = <span class="number">1</span>; |
| <span class="doccomment">/// User PING has been written, waiting for PONG. |
| </span><span class="kw">const </span>USER_STATE_PENDING_PONG: usize = <span class="number">2</span>; |
| <span class="doccomment">/// We've received user PONG, waiting for user to `poll_pong`. |
| </span><span class="kw">const </span>USER_STATE_RECEIVED_PONG: usize = <span class="number">3</span>; |
| <span class="doccomment">/// The connection is closed. |
| </span><span class="kw">const </span>USER_STATE_CLOSED: usize = <span class="number">4</span>; |
| |
| <span class="comment">// ===== impl PingPong ===== |
| |
| </span><span class="kw">impl </span>PingPong { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new() -> <span class="self">Self </span>{ |
| PingPong { |
| pending_ping: <span class="prelude-val">None</span>, |
| pending_pong: <span class="prelude-val">None</span>, |
| user_pings: <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Can only be called once. If called a second time, returns `None`. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>take_user_pings(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><UserPings> { |
| <span class="kw">if </span><span class="self">self</span>.user_pings.is_some() { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| |
| <span class="kw">let </span>user_pings = Arc::new(UserPingsInner { |
| state: AtomicUsize::new(USER_STATE_EMPTY), |
| ping_task: AtomicWaker::new(), |
| pong_task: AtomicWaker::new(), |
| }); |
| <span class="self">self</span>.user_pings = <span class="prelude-val">Some</span>(UserPingsRx(user_pings.clone())); |
| <span class="prelude-val">Some</span>(UserPings(user_pings)) |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>ping_shutdown(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="macro">assert!</span>(<span class="self">self</span>.pending_ping.is_none()); |
| |
| <span class="self">self</span>.pending_ping = <span class="prelude-val">Some</span>(PendingPing { |
| payload: Ping::SHUTDOWN, |
| sent: <span class="bool-val">false</span>, |
| }); |
| } |
| |
| <span class="doccomment">/// Process a ping |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>recv_ping(<span class="kw-2">&mut </span><span class="self">self</span>, ping: Ping) -> ReceivedPing { |
| <span class="comment">// The caller should always check that `send_pongs` returns ready before |
| // calling `recv_ping`. |
| </span><span class="macro">assert!</span>(<span class="self">self</span>.pending_pong.is_none()); |
| |
| <span class="kw">if </span>ping.is_ack() { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(pending) = <span class="self">self</span>.pending_ping.take() { |
| <span class="kw">if </span><span class="kw-2">&</span>pending.payload == ping.payload() { |
| <span class="macro">assert_eq!</span>( |
| <span class="kw-2">&</span>pending.payload, |
| <span class="kw-2">&</span>Ping::SHUTDOWN, |
| <span class="string">"pending_ping should be for shutdown"</span>, |
| ); |
| <span class="macro">tracing::trace!</span>(<span class="string">"recv PING SHUTDOWN ack"</span>); |
| <span class="kw">return </span>ReceivedPing::Shutdown; |
| } |
| |
| <span class="comment">// if not the payload we expected, put it back. |
| </span><span class="self">self</span>.pending_ping = <span class="prelude-val">Some</span>(pending); |
| } |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref </span>users) = <span class="self">self</span>.user_pings { |
| <span class="kw">if </span>ping.payload() == <span class="kw-2">&</span>Ping::USER && users.receive_pong() { |
| <span class="macro">tracing::trace!</span>(<span class="string">"recv PING USER ack"</span>); |
| <span class="kw">return </span>ReceivedPing::Unknown; |
| } |
| } |
| |
| <span class="comment">// else we were acked a ping we didn't send? |
| // The spec doesn't require us to do anything about this, |
| // so for resiliency, just ignore it for now. |
| </span><span class="macro">tracing::warn!</span>(<span class="string">"recv PING ack that we never sent: {:?}"</span>, ping); |
| ReceivedPing::Unknown |
| } <span class="kw">else </span>{ |
| <span class="comment">// Save the ping's payload to be sent as an acknowledgement. |
| </span><span class="self">self</span>.pending_pong = <span class="prelude-val">Some</span>(ping.into_payload()); |
| ReceivedPing::MustAck |
| } |
| } |
| |
| <span class="doccomment">/// Send any pending pongs. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>send_pending_pong<T, B>( |
| <span class="kw-2">&mut </span><span class="self">self</span>, |
| cx: <span class="kw-2">&mut </span>Context, |
| dst: <span class="kw-2">&mut </span>Codec<T, B>, |
| ) -> Poll<io::Result<()>> |
| <span class="kw">where |
| </span>T: AsyncWrite + Unpin, |
| B: Buf, |
| { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(pong) = <span class="self">self</span>.pending_pong.take() { |
| <span class="kw">if </span>!dst.poll_ready(cx)<span class="question-mark">?</span>.is_ready() { |
| <span class="self">self</span>.pending_pong = <span class="prelude-val">Some</span>(pong); |
| <span class="kw">return </span>Poll::Pending; |
| } |
| |
| dst.buffer(Ping::pong(pong).into()) |
| .expect(<span class="string">"invalid pong frame"</span>); |
| } |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| |
| <span class="doccomment">/// Send any pending pings. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>send_pending_ping<T, B>( |
| <span class="kw-2">&mut </span><span class="self">self</span>, |
| cx: <span class="kw-2">&mut </span>Context, |
| dst: <span class="kw-2">&mut </span>Codec<T, B>, |
| ) -> Poll<io::Result<()>> |
| <span class="kw">where |
| </span>T: AsyncWrite + Unpin, |
| B: Buf, |
| { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref mut </span>ping) = <span class="self">self</span>.pending_ping { |
| <span class="kw">if </span>!ping.sent { |
| <span class="kw">if </span>!dst.poll_ready(cx)<span class="question-mark">?</span>.is_ready() { |
| <span class="kw">return </span>Poll::Pending; |
| } |
| |
| dst.buffer(Ping::new(ping.payload).into()) |
| .expect(<span class="string">"invalid ping frame"</span>); |
| ping.sent = <span class="bool-val">true</span>; |
| } |
| } <span class="kw">else if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref </span>users) = <span class="self">self</span>.user_pings { |
| <span class="kw">if </span>users.<span class="number">0</span>.state.load(Ordering::Acquire) == USER_STATE_PENDING_PING { |
| <span class="kw">if </span>!dst.poll_ready(cx)<span class="question-mark">?</span>.is_ready() { |
| <span class="kw">return </span>Poll::Pending; |
| } |
| |
| dst.buffer(Ping::new(Ping::USER).into()) |
| .expect(<span class="string">"invalid ping frame"</span>); |
| users |
| .<span class="number">0 |
| </span>.state |
| .store(USER_STATE_PENDING_PONG, Ordering::Release); |
| } <span class="kw">else </span>{ |
| users.<span class="number">0</span>.ping_task.register(cx.waker()); |
| } |
| } |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| } |
| |
| <span class="kw">impl </span>ReceivedPing { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>is_shutdown(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="macro">matches!</span>(<span class="kw-2">*</span><span class="self">self</span>, <span class="self">Self</span>::Shutdown) |
| } |
| } |
| |
| <span class="comment">// ===== impl UserPings ===== |
| |
| </span><span class="kw">impl </span>UserPings { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>send_ping(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><(), <span class="prelude-ty">Option</span><proto::Error>> { |
| <span class="kw">let </span>prev = <span class="self">self |
| </span>.<span class="number">0 |
| </span>.state |
| .compare_exchange( |
| USER_STATE_EMPTY, <span class="comment">// current |
| </span>USER_STATE_PENDING_PING, <span class="comment">// new |
| </span>Ordering::AcqRel, |
| Ordering::Acquire, |
| ) |
| .unwrap_or_else(|v| v); |
| |
| <span class="kw">match </span>prev { |
| USER_STATE_EMPTY => { |
| <span class="self">self</span>.<span class="number">0</span>.ping_task.wake(); |
| <span class="prelude-val">Ok</span>(()) |
| } |
| USER_STATE_CLOSED => <span class="prelude-val">Err</span>(<span class="prelude-val">Some</span>(broken_pipe().into())), |
| <span class="kw">_ </span>=> { |
| <span class="comment">// Was already pending, user error! |
| </span><span class="prelude-val">Err</span>(<span class="prelude-val">None</span>) |
| } |
| } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>poll_pong(<span class="kw-2">&</span><span class="self">self</span>, cx: <span class="kw-2">&mut </span>Context) -> Poll<<span class="prelude-ty">Result</span><(), proto::Error>> { |
| <span class="comment">// Must register before checking state, in case state were to change |
| // before we could register, and then the ping would just be lost. |
| </span><span class="self">self</span>.<span class="number">0</span>.pong_task.register(cx.waker()); |
| <span class="kw">let </span>prev = <span class="self">self |
| </span>.<span class="number">0 |
| </span>.state |
| .compare_exchange( |
| USER_STATE_RECEIVED_PONG, <span class="comment">// current |
| </span>USER_STATE_EMPTY, <span class="comment">// new |
| </span>Ordering::AcqRel, |
| Ordering::Acquire, |
| ) |
| .unwrap_or_else(|v| v); |
| |
| <span class="kw">match </span>prev { |
| USER_STATE_RECEIVED_PONG => Poll::Ready(<span class="prelude-val">Ok</span>(())), |
| USER_STATE_CLOSED => Poll::Ready(<span class="prelude-val">Err</span>(broken_pipe().into())), |
| <span class="kw">_ </span>=> Poll::Pending, |
| } |
| } |
| } |
| |
| <span class="comment">// ===== impl UserPingsRx ===== |
| |
| </span><span class="kw">impl </span>UserPingsRx { |
| <span class="kw">fn </span>receive_pong(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="kw">let </span>prev = <span class="self">self |
| </span>.<span class="number">0 |
| </span>.state |
| .compare_exchange( |
| USER_STATE_PENDING_PONG, <span class="comment">// current |
| </span>USER_STATE_RECEIVED_PONG, <span class="comment">// new |
| </span>Ordering::AcqRel, |
| Ordering::Acquire, |
| ) |
| .unwrap_or_else(|v| v); |
| |
| <span class="kw">if </span>prev == USER_STATE_PENDING_PONG { |
| <span class="self">self</span>.<span class="number">0</span>.pong_task.wake(); |
| <span class="bool-val">true |
| </span>} <span class="kw">else </span>{ |
| <span class="bool-val">false |
| </span>} |
| } |
| } |
| |
| <span class="kw">impl </span>Drop <span class="kw">for </span>UserPingsRx { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="self">self</span>.<span class="number">0</span>.state.store(USER_STATE_CLOSED, Ordering::Release); |
| <span class="self">self</span>.<span class="number">0</span>.pong_task.wake(); |
| } |
| } |
| |
| <span class="kw">fn </span>broken_pipe() -> io::Error { |
| io::ErrorKind::BrokenPipe.into() |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="h2" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
