| <!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-util-0.7.8/src/codec/framed_impl.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>framed_impl.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_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="../../../tokio_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>::codec::decoder::Decoder; |
| <span class="kw">use </span><span class="kw">crate</span>::codec::encoder::Encoder; |
| |
| <span class="kw">use </span>futures_core::Stream; |
| <span class="kw">use </span>tokio::io::{AsyncRead, AsyncWrite}; |
| |
| <span class="kw">use </span>bytes::BytesMut; |
| <span class="kw">use </span>futures_core::ready; |
| <span class="kw">use </span>futures_sink::Sink; |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| <span class="kw">use </span>std::borrow::{Borrow, BorrowMut}; |
| <span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| <span class="kw">use </span>tracing::trace; |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>FramedImpl<T, U, State> { |
| <span class="attribute">#[pin] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) inner: T, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) state: State, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) codec: U, |
| } |
| } |
| |
| <span class="kw">const </span>INITIAL_CAPACITY: usize = <span class="number">8 </span>* <span class="number">1024</span>; |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>ReadFrame { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) eof: bool, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) is_readable: bool, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) buffer: BytesMut, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) has_errored: bool, |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>WriteFrame { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) buffer: BytesMut, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) backpressure_boundary: usize, |
| } |
| |
| <span class="attribute">#[derive(Default)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>RWFrames { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) read: ReadFrame, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) write: WriteFrame, |
| } |
| |
| <span class="kw">impl </span>Default <span class="kw">for </span>ReadFrame { |
| <span class="kw">fn </span>default() -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| eof: <span class="bool-val">false</span>, |
| is_readable: <span class="bool-val">false</span>, |
| buffer: BytesMut::with_capacity(INITIAL_CAPACITY), |
| has_errored: <span class="bool-val">false</span>, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>Default <span class="kw">for </span>WriteFrame { |
| <span class="kw">fn </span>default() -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| buffer: BytesMut::with_capacity(INITIAL_CAPACITY), |
| backpressure_boundary: INITIAL_CAPACITY, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>From<BytesMut> <span class="kw">for </span>ReadFrame { |
| <span class="kw">fn </span>from(<span class="kw-2">mut </span>buffer: BytesMut) -> <span class="self">Self </span>{ |
| <span class="kw">let </span>size = buffer.capacity(); |
| <span class="kw">if </span>size < INITIAL_CAPACITY { |
| buffer.reserve(INITIAL_CAPACITY - size); |
| } |
| |
| <span class="self">Self </span>{ |
| buffer, |
| is_readable: size > <span class="number">0</span>, |
| eof: <span class="bool-val">false</span>, |
| has_errored: <span class="bool-val">false</span>, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>From<BytesMut> <span class="kw">for </span>WriteFrame { |
| <span class="kw">fn </span>from(<span class="kw-2">mut </span>buffer: BytesMut) -> <span class="self">Self </span>{ |
| <span class="kw">let </span>size = buffer.capacity(); |
| <span class="kw">if </span>size < INITIAL_CAPACITY { |
| buffer.reserve(INITIAL_CAPACITY - size); |
| } |
| |
| <span class="self">Self </span>{ |
| buffer, |
| backpressure_boundary: INITIAL_CAPACITY, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>Borrow<ReadFrame> <span class="kw">for </span>RWFrames { |
| <span class="kw">fn </span>borrow(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>ReadFrame { |
| <span class="kw-2">&</span><span class="self">self</span>.read |
| } |
| } |
| <span class="kw">impl </span>BorrowMut<ReadFrame> <span class="kw">for </span>RWFrames { |
| <span class="kw">fn </span>borrow_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>ReadFrame { |
| <span class="kw-2">&mut </span><span class="self">self</span>.read |
| } |
| } |
| <span class="kw">impl </span>Borrow<WriteFrame> <span class="kw">for </span>RWFrames { |
| <span class="kw">fn </span>borrow(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>WriteFrame { |
| <span class="kw-2">&</span><span class="self">self</span>.write |
| } |
| } |
| <span class="kw">impl </span>BorrowMut<WriteFrame> <span class="kw">for </span>RWFrames { |
| <span class="kw">fn </span>borrow_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>WriteFrame { |
| <span class="kw-2">&mut </span><span class="self">self</span>.write |
| } |
| } |
| <span class="kw">impl</span><T, U, R> Stream <span class="kw">for </span>FramedImpl<T, U, R> |
| <span class="kw">where |
| </span>T: AsyncRead, |
| U: Decoder, |
| R: BorrowMut<ReadFrame>, |
| { |
| <span class="kw">type </span>Item = <span class="prelude-ty">Result</span><U::Item, U::Error>; |
| |
| <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="kw">use </span><span class="kw">crate</span>::util::poll_read_buf; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>pinned = <span class="self">self</span>.project(); |
| <span class="kw">let </span>state: <span class="kw-2">&mut </span>ReadFrame = pinned.state.borrow_mut(); |
| <span class="comment">// The following loops implements a state machine with each state corresponding |
| // to a combination of the `is_readable` and `eof` flags. States persist across |
| // loop entries and most state transitions occur with a return. |
| // |
| // The initial state is `reading`. |
| // |
| // | state | eof | is_readable | has_errored | |
| // |---------|-------|-------------|-------------| |
| // | reading | false | false | false | |
| // | framing | false | true | false | |
| // | pausing | true | true | false | |
| // | paused | true | false | false | |
| // | errored | <any> | <any> | true | |
| // `decode_eof` returns Err |
| // ┌────────────────────────────────────────────────────────┐ |
| // `decode_eof` returns │ │ |
| // `Ok(Some)` │ │ |
| // ┌─────┐ │ `decode_eof` returns After returning │ |
| // Read 0 bytes ├─────▼──┴┐ `Ok(None)` ┌────────┐ ◄───┐ `None` ┌───▼─────┐ |
| // ┌────────────────►│ Pausing ├───────────────────────►│ Paused ├─┐ └───────────┤ Errored │ |
| // │ └─────────┘ └─┬──▲───┘ │ └───▲───▲─┘ |
| // Pending read │ │ │ │ │ │ |
| // ┌──────┐ │ `decode` returns `Some` │ └─────┘ │ │ |
| // │ │ │ ┌──────┐ │ Pending │ │ |
| // │ ┌────▼──┴─┐ Read n>0 bytes ┌┴──────▼─┐ read n>0 bytes │ read │ │ |
| // └─┤ Reading ├───────────────►│ Framing │◄────────────────────────┘ │ │ |
| // └──┬─▲────┘ └─────┬──┬┘ │ │ |
| // │ │ │ │ `decode` returns Err │ │ |
| // │ └───decode` returns `None`──┘ └───────────────────────────────────────────────────────┘ │ |
| // │ read returns Err │ |
| // └────────────────────────────────────────────────────────────────────────────────────────────┘ |
| </span><span class="kw">loop </span>{ |
| <span class="comment">// Return `None` if we have encountered an error from the underlying decoder |
| // See: https://github.com/tokio-rs/tokio/issues/3976 |
| </span><span class="kw">if </span>state.has_errored { |
| <span class="comment">// preparing has_errored -> paused |
| </span><span class="macro">trace!</span>(<span class="string">"Returning None and setting paused"</span>); |
| state.is_readable = <span class="bool-val">false</span>; |
| state.has_errored = <span class="bool-val">false</span>; |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">None</span>); |
| } |
| |
| <span class="comment">// Repeatedly call `decode` or `decode_eof` while the buffer is "readable", |
| // i.e. it _might_ contain data consumable as a frame or closing frame. |
| // Both signal that there is no such data by returning `None`. |
| // |
| // If `decode` couldn't read a frame and the upstream source has returned eof, |
| // `decode_eof` will attempt to decode the remaining bytes as closing frames. |
| // |
| // If the underlying AsyncRead is resumable, we may continue after an EOF, |
| // but must finish emitting all of it's associated `decode_eof` frames. |
| // Furthermore, we don't want to emit any `decode_eof` frames on retried |
| // reads after an EOF unless we've actually read more data. |
| </span><span class="kw">if </span>state.is_readable { |
| <span class="comment">// pausing or framing |
| </span><span class="kw">if </span>state.eof { |
| <span class="comment">// pausing |
| </span><span class="kw">let </span>frame = pinned.codec.decode_eof(<span class="kw-2">&mut </span>state.buffer).map_err(|err| { |
| <span class="macro">trace!</span>(<span class="string">"Got an error, going to errored state"</span>); |
| state.has_errored = <span class="bool-val">true</span>; |
| err |
| })<span class="question-mark">?</span>; |
| <span class="kw">if </span>frame.is_none() { |
| state.is_readable = <span class="bool-val">false</span>; <span class="comment">// prepare pausing -> paused |
| </span>} |
| <span class="comment">// implicit pausing -> pausing or pausing -> paused |
| </span><span class="kw">return </span>Poll::Ready(frame.map(<span class="prelude-val">Ok</span>)); |
| } |
| |
| <span class="comment">// framing |
| </span><span class="macro">trace!</span>(<span class="string">"attempting to decode a frame"</span>); |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(frame) = pinned.codec.decode(<span class="kw-2">&mut </span>state.buffer).map_err(|op| { |
| <span class="macro">trace!</span>(<span class="string">"Got an error, going to errored state"</span>); |
| state.has_errored = <span class="bool-val">true</span>; |
| op |
| })<span class="question-mark">? </span>{ |
| <span class="macro">trace!</span>(<span class="string">"frame decoded from buffer"</span>); |
| <span class="comment">// implicit framing -> framing |
| </span><span class="kw">return </span>Poll::Ready(<span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(frame))); |
| } |
| |
| <span class="comment">// framing -> reading |
| </span>state.is_readable = <span class="bool-val">false</span>; |
| } |
| <span class="comment">// reading or paused |
| // If we can't build a frame yet, try to read more data and try again. |
| // Make sure we've got room for at least one byte to read to ensure |
| // that we don't get a spurious 0 that looks like EOF. |
| </span>state.buffer.reserve(<span class="number">1</span>); |
| <span class="kw">let </span>bytect = <span class="kw">match </span>poll_read_buf(pinned.inner.as_mut(), cx, <span class="kw-2">&mut </span>state.buffer).map_err( |
| |err| { |
| <span class="macro">trace!</span>(<span class="string">"Got an error, going to errored state"</span>); |
| state.has_errored = <span class="bool-val">true</span>; |
| err |
| }, |
| )<span class="question-mark">? </span>{ |
| Poll::Ready(ct) => ct, |
| <span class="comment">// implicit reading -> reading or implicit paused -> paused |
| </span>Poll::Pending => <span class="kw">return </span>Poll::Pending, |
| }; |
| <span class="kw">if </span>bytect == <span class="number">0 </span>{ |
| <span class="kw">if </span>state.eof { |
| <span class="comment">// We're already at an EOF, and since we've reached this path |
| // we're also not readable. This implies that we've already finished |
| // our `decode_eof` handling, so we can simply return `None`. |
| // implicit paused -> paused |
| </span><span class="kw">return </span>Poll::Ready(<span class="prelude-val">None</span>); |
| } |
| <span class="comment">// prepare reading -> paused |
| </span>state.eof = <span class="bool-val">true</span>; |
| } <span class="kw">else </span>{ |
| <span class="comment">// prepare paused -> framing or noop reading -> framing |
| </span>state.eof = <span class="bool-val">false</span>; |
| } |
| |
| <span class="comment">// paused -> framing or reading -> framing or reading -> pausing |
| </span>state.is_readable = <span class="bool-val">true</span>; |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><T, I, U, W> Sink<I> <span class="kw">for </span>FramedImpl<T, U, W> |
| <span class="kw">where |
| </span>T: AsyncWrite, |
| U: Encoder<I>, |
| U::Error: From<io::Error>, |
| W: BorrowMut<WriteFrame>, |
| { |
| <span class="kw">type </span>Error = U::Error; |
| |
| <span class="kw">fn </span>poll_ready(<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="prelude-ty">Result</span><(), <span class="self">Self</span>::Error>> { |
| <span class="kw">if </span><span class="self">self</span>.state.borrow().buffer.len() >= <span class="self">self</span>.state.borrow().backpressure_boundary { |
| <span class="self">self</span>.as_mut().poll_flush(cx) |
| } <span class="kw">else </span>{ |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| } |
| |
| <span class="kw">fn </span>start_send(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, item: I) -> <span class="prelude-ty">Result</span><(), <span class="self">Self</span>::Error> { |
| <span class="kw">let </span>pinned = <span class="self">self</span>.project(); |
| pinned |
| .codec |
| .encode(item, <span class="kw-2">&mut </span>pinned.state.borrow_mut().buffer)<span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">fn </span>poll_flush(<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">Result</span><(), <span class="self">Self</span>::Error>> { |
| <span class="kw">use </span><span class="kw">crate</span>::util::poll_write_buf; |
| <span class="macro">trace!</span>(<span class="string">"flushing framed transport"</span>); |
| <span class="kw">let </span><span class="kw-2">mut </span>pinned = <span class="self">self</span>.project(); |
| |
| <span class="kw">while </span>!pinned.state.borrow_mut().buffer.is_empty() { |
| <span class="kw">let </span>WriteFrame { buffer, .. } = pinned.state.borrow_mut(); |
| <span class="macro">trace!</span>(remaining = buffer.len(), <span class="string">"writing;"</span>); |
| |
| <span class="kw">let </span>n = <span class="macro">ready!</span>(poll_write_buf(pinned.inner.as_mut(), cx, buffer))<span class="question-mark">?</span>; |
| |
| <span class="kw">if </span>n == <span class="number">0 </span>{ |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(io::Error::new( |
| io::ErrorKind::WriteZero, |
| <span class="string">"failed to \ |
| write frame to transport"</span>, |
| ) |
| .into())); |
| } |
| } |
| |
| <span class="comment">// Try flushing the underlying IO |
| </span><span class="macro">ready!</span>(pinned.inner.poll_flush(cx))<span class="question-mark">?</span>; |
| |
| <span class="macro">trace!</span>(<span class="string">"framed transport flushed"</span>); |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| |
| <span class="kw">fn </span>poll_close(<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="prelude-ty">Result</span><(), <span class="self">Self</span>::Error>> { |
| <span class="macro">ready!</span>(<span class="self">self</span>.as_mut().poll_flush(cx))<span class="question-mark">?</span>; |
| <span class="macro">ready!</span>(<span class="self">self</span>.project().inner.poll_shutdown(cx))<span class="question-mark">?</span>; |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="tokio_util" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
