| <!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/codec/framed_write.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>framed_write.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::UserError; |
| <span class="kw">use </span><span class="kw">crate</span>::codec::UserError::<span class="kw-2">*</span>; |
| <span class="kw">use </span><span class="kw">crate</span>::frame::{<span class="self">self</span>, Frame, FrameSize}; |
| <span class="kw">use </span><span class="kw">crate</span>::hpack; |
| |
| <span class="kw">use </span>bytes::{Buf, BufMut, BytesMut}; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| <span class="kw">use </span>tokio::io::{AsyncRead, AsyncWrite, ReadBuf}; |
| |
| <span class="kw">use </span>std::io::{<span class="self">self</span>, Cursor, IoSlice}; |
| |
| <span class="comment">// A macro to get around a method needing to borrow &mut self |
| </span><span class="macro">macro_rules! </span>limited_write_buf { |
| (<span class="macro-nonterminal">$self</span>:expr) => {{ |
| <span class="kw">let </span>limit = <span class="macro-nonterminal">$self</span>.max_frame_size() + frame::HEADER_LEN; |
| <span class="macro-nonterminal">$self</span>.buf.get_mut().limit(limit) |
| }}; |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>FramedWrite<T, B> { |
| <span class="doccomment">/// Upstream `AsyncWrite` |
| </span>inner: T, |
| |
| encoder: Encoder<B>, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">struct </span>Encoder<B> { |
| <span class="doccomment">/// HPACK encoder |
| </span>hpack: hpack::Encoder, |
| |
| <span class="doccomment">/// Write buffer |
| /// |
| /// TODO: Should this be a ring buffer? |
| </span>buf: Cursor<BytesMut>, |
| |
| <span class="doccomment">/// Next frame to encode |
| </span>next: <span class="prelude-ty">Option</span><Next<B>>, |
| |
| <span class="doccomment">/// Last data frame |
| </span>last_data_frame: <span class="prelude-ty">Option</span><frame::Data<B>>, |
| |
| <span class="doccomment">/// Max frame size, this is specified by the peer |
| </span>max_frame_size: FrameSize, |
| |
| <span class="doccomment">/// Whether or not the wrapped `AsyncWrite` supports vectored IO. |
| </span>is_write_vectored: bool, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">enum </span>Next<B> { |
| Data(frame::Data<B>), |
| Continuation(frame::Continuation), |
| } |
| |
| <span class="doccomment">/// Initialize the connection with this amount of write buffer. |
| /// |
| /// The minimum MAX_FRAME_SIZE is 16kb, so always be able to send a HEADERS |
| /// frame that big. |
| </span><span class="kw">const </span>DEFAULT_BUFFER_CAPACITY: usize = <span class="number">16 </span>* <span class="number">1_024</span>; |
| |
| <span class="doccomment">/// Min buffer required to attempt to write a frame |
| </span><span class="kw">const </span>MIN_BUFFER_CAPACITY: usize = frame::HEADER_LEN + CHAIN_THRESHOLD; |
| |
| <span class="doccomment">/// Chain payloads bigger than this. The remote will never advertise a max frame |
| /// size less than this (well, the spec says the max frame size can't be less |
| /// than 16kb, so not even close). |
| </span><span class="kw">const </span>CHAIN_THRESHOLD: usize = <span class="number">256</span>; |
| |
| <span class="comment">// TODO: Make generic |
| </span><span class="kw">impl</span><T, B> FramedWrite<T, B> |
| <span class="kw">where |
| </span>T: AsyncWrite + Unpin, |
| B: Buf, |
| { |
| <span class="kw">pub fn </span>new(inner: T) -> FramedWrite<T, B> { |
| <span class="kw">let </span>is_write_vectored = inner.is_write_vectored(); |
| FramedWrite { |
| inner, |
| encoder: Encoder { |
| hpack: hpack::Encoder::default(), |
| buf: Cursor::new(BytesMut::with_capacity(DEFAULT_BUFFER_CAPACITY)), |
| next: <span class="prelude-val">None</span>, |
| last_data_frame: <span class="prelude-val">None</span>, |
| max_frame_size: frame::DEFAULT_MAX_FRAME_SIZE, |
| is_write_vectored, |
| }, |
| } |
| } |
| |
| <span class="doccomment">/// Returns `Ready` when `send` is able to accept a frame |
| /// |
| /// Calling this function may result in the current contents of the buffer |
| /// to be flushed to `T`. |
| </span><span class="kw">pub fn </span>poll_ready(<span class="kw-2">&mut </span><span class="self">self</span>, cx: <span class="kw-2">&mut </span>Context) -> Poll<io::Result<()>> { |
| <span class="kw">if </span>!<span class="self">self</span>.encoder.has_capacity() { |
| <span class="comment">// Try flushing |
| </span><span class="macro">ready!</span>(<span class="self">self</span>.flush(cx))<span class="question-mark">?</span>; |
| |
| <span class="kw">if </span>!<span class="self">self</span>.encoder.has_capacity() { |
| <span class="kw">return </span>Poll::Pending; |
| } |
| } |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| |
| <span class="doccomment">/// Buffer a frame. |
| /// |
| /// `poll_ready` must be called first to ensure that a frame may be |
| /// accepted. |
| </span><span class="kw">pub fn </span>buffer(<span class="kw-2">&mut </span><span class="self">self</span>, item: Frame<B>) -> <span class="prelude-ty">Result</span><(), UserError> { |
| <span class="self">self</span>.encoder.buffer(item) |
| } |
| |
| <span class="doccomment">/// Flush buffered data to the wire |
| </span><span class="kw">pub fn </span>flush(<span class="kw-2">&mut </span><span class="self">self</span>, cx: <span class="kw-2">&mut </span>Context) -> Poll<io::Result<()>> { |
| <span class="kw">let </span>span = <span class="macro">tracing::trace_span!</span>(<span class="string">"FramedWrite::flush"</span>); |
| <span class="kw">let </span>_e = span.enter(); |
| |
| <span class="kw">loop </span>{ |
| <span class="kw">while </span>!<span class="self">self</span>.encoder.is_empty() { |
| <span class="kw">match </span><span class="self">self</span>.encoder.next { |
| <span class="prelude-val">Some</span>(Next::Data(<span class="kw-2">ref mut </span>frame)) => { |
| <span class="macro">tracing::trace!</span>(queued_data_frame = <span class="bool-val">true</span>); |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = (<span class="kw-2">&mut </span><span class="self">self</span>.encoder.buf).chain(frame.payload_mut()); |
| <span class="macro">ready!</span>(write( |
| <span class="kw-2">&mut </span><span class="self">self</span>.inner, |
| <span class="self">self</span>.encoder.is_write_vectored, |
| <span class="kw-2">&mut </span>buf, |
| cx, |
| ))<span class="question-mark">? |
| </span>} |
| <span class="kw">_ </span>=> { |
| <span class="macro">tracing::trace!</span>(queued_data_frame = <span class="bool-val">false</span>); |
| <span class="macro">ready!</span>(write( |
| <span class="kw-2">&mut </span><span class="self">self</span>.inner, |
| <span class="self">self</span>.encoder.is_write_vectored, |
| <span class="kw-2">&mut </span><span class="self">self</span>.encoder.buf, |
| cx, |
| ))<span class="question-mark">? |
| </span>} |
| } |
| } |
| |
| <span class="kw">match </span><span class="self">self</span>.encoder.unset_frame() { |
| ControlFlow::Continue => (), |
| ControlFlow::Break => <span class="kw">break</span>, |
| } |
| } |
| |
| <span class="macro">tracing::trace!</span>(<span class="string">"flushing buffer"</span>); |
| <span class="comment">// Flush the upstream |
| </span><span class="macro">ready!</span>(Pin::new(<span class="kw-2">&mut </span><span class="self">self</span>.inner).poll_flush(cx))<span class="question-mark">?</span>; |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| |
| <span class="doccomment">/// Close the codec |
| </span><span class="kw">pub fn </span>shutdown(<span class="kw-2">&mut </span><span class="self">self</span>, cx: <span class="kw-2">&mut </span>Context) -> Poll<io::Result<()>> { |
| <span class="macro">ready!</span>(<span class="self">self</span>.flush(cx))<span class="question-mark">?</span>; |
| Pin::new(<span class="kw-2">&mut </span><span class="self">self</span>.inner).poll_shutdown(cx) |
| } |
| } |
| |
| <span class="kw">fn </span>write<T, B>( |
| writer: <span class="kw-2">&mut </span>T, |
| is_write_vectored: bool, |
| buf: <span class="kw-2">&mut </span>B, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| ) -> Poll<io::Result<()>> |
| <span class="kw">where |
| </span>T: AsyncWrite + Unpin, |
| B: Buf, |
| { |
| <span class="comment">// TODO(eliza): when tokio-util 0.5.1 is released, this |
| // could just use `poll_write_buf`... |
| </span><span class="kw">const </span>MAX_IOVS: usize = <span class="number">64</span>; |
| <span class="kw">let </span>n = <span class="kw">if </span>is_write_vectored { |
| <span class="kw">let </span><span class="kw-2">mut </span>bufs = [IoSlice::new(<span class="kw-2">&</span>[]); MAX_IOVS]; |
| <span class="kw">let </span>cnt = buf.chunks_vectored(<span class="kw-2">&mut </span>bufs); |
| <span class="macro">ready!</span>(Pin::new(writer).poll_write_vectored(cx, <span class="kw-2">&</span>bufs[..cnt]))<span class="question-mark">? |
| </span>} <span class="kw">else </span>{ |
| <span class="macro">ready!</span>(Pin::new(writer).poll_write(cx, buf.chunk()))<span class="question-mark">? |
| </span>}; |
| buf.advance(n); |
| <span class="prelude-val">Ok</span>(()).into() |
| } |
| |
| <span class="attribute">#[must_use] |
| </span><span class="kw">enum </span>ControlFlow { |
| Continue, |
| Break, |
| } |
| |
| <span class="kw">impl</span><B> Encoder<B> |
| <span class="kw">where |
| </span>B: Buf, |
| { |
| <span class="kw">fn </span>unset_frame(<span class="kw-2">&mut </span><span class="self">self</span>) -> ControlFlow { |
| <span class="comment">// Clear internal buffer |
| </span><span class="self">self</span>.buf.set_position(<span class="number">0</span>); |
| <span class="self">self</span>.buf.get_mut().clear(); |
| |
| <span class="comment">// The data frame has been written, so unset it |
| </span><span class="kw">match </span><span class="self">self</span>.next.take() { |
| <span class="prelude-val">Some</span>(Next::Data(frame)) => { |
| <span class="self">self</span>.last_data_frame = <span class="prelude-val">Some</span>(frame); |
| <span class="macro">debug_assert!</span>(<span class="self">self</span>.is_empty()); |
| ControlFlow::Break |
| } |
| <span class="prelude-val">Some</span>(Next::Continuation(frame)) => { |
| <span class="comment">// Buffer the continuation frame, then try to write again |
| </span><span class="kw">let </span><span class="kw-2">mut </span>buf = <span class="macro">limited_write_buf!</span>(<span class="self">self</span>); |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(continuation) = frame.encode(<span class="kw-2">&mut </span>buf) { |
| <span class="self">self</span>.next = <span class="prelude-val">Some</span>(Next::Continuation(continuation)); |
| } |
| ControlFlow::Continue |
| } |
| <span class="prelude-val">None </span>=> ControlFlow::Break, |
| } |
| } |
| |
| <span class="kw">fn </span>buffer(<span class="kw-2">&mut </span><span class="self">self</span>, item: Frame<B>) -> <span class="prelude-ty">Result</span><(), UserError> { |
| <span class="comment">// Ensure that we have enough capacity to accept the write. |
| </span><span class="macro">assert!</span>(<span class="self">self</span>.has_capacity()); |
| <span class="kw">let </span>span = <span class="macro">tracing::trace_span!</span>(<span class="string">"FramedWrite::buffer"</span>, frame = <span class="question-mark">?</span>item); |
| <span class="kw">let </span>_e = span.enter(); |
| |
| <span class="macro">tracing::debug!</span>(frame = <span class="question-mark">?</span>item, <span class="string">"send"</span>); |
| |
| <span class="kw">match </span>item { |
| Frame::Data(<span class="kw-2">mut </span>v) => { |
| <span class="comment">// Ensure that the payload is not greater than the max frame. |
| </span><span class="kw">let </span>len = v.payload().remaining(); |
| |
| <span class="kw">if </span>len > <span class="self">self</span>.max_frame_size() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(PayloadTooBig); |
| } |
| |
| <span class="kw">if </span>len >= CHAIN_THRESHOLD { |
| <span class="kw">let </span>head = v.head(); |
| |
| <span class="comment">// Encode the frame head to the buffer |
| </span>head.encode(len, <span class="self">self</span>.buf.get_mut()); |
| |
| <span class="comment">// Save the data frame |
| </span><span class="self">self</span>.next = <span class="prelude-val">Some</span>(Next::Data(v)); |
| } <span class="kw">else </span>{ |
| v.encode_chunk(<span class="self">self</span>.buf.get_mut()); |
| |
| <span class="comment">// The chunk has been fully encoded, so there is no need to |
| // keep it around |
| </span><span class="macro">assert_eq!</span>(v.payload().remaining(), <span class="number">0</span>, <span class="string">"chunk not fully encoded"</span>); |
| |
| <span class="comment">// Save off the last frame... |
| </span><span class="self">self</span>.last_data_frame = <span class="prelude-val">Some</span>(v); |
| } |
| } |
| Frame::Headers(v) => { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = <span class="macro">limited_write_buf!</span>(<span class="self">self</span>); |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(continuation) = v.encode(<span class="kw-2">&mut </span><span class="self">self</span>.hpack, <span class="kw-2">&mut </span>buf) { |
| <span class="self">self</span>.next = <span class="prelude-val">Some</span>(Next::Continuation(continuation)); |
| } |
| } |
| Frame::PushPromise(v) => { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = <span class="macro">limited_write_buf!</span>(<span class="self">self</span>); |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(continuation) = v.encode(<span class="kw-2">&mut </span><span class="self">self</span>.hpack, <span class="kw-2">&mut </span>buf) { |
| <span class="self">self</span>.next = <span class="prelude-val">Some</span>(Next::Continuation(continuation)); |
| } |
| } |
| Frame::Settings(v) => { |
| v.encode(<span class="self">self</span>.buf.get_mut()); |
| <span class="macro">tracing::trace!</span>(rem = <span class="self">self</span>.buf.remaining(), <span class="string">"encoded settings"</span>); |
| } |
| Frame::GoAway(v) => { |
| v.encode(<span class="self">self</span>.buf.get_mut()); |
| <span class="macro">tracing::trace!</span>(rem = <span class="self">self</span>.buf.remaining(), <span class="string">"encoded go_away"</span>); |
| } |
| Frame::Ping(v) => { |
| v.encode(<span class="self">self</span>.buf.get_mut()); |
| <span class="macro">tracing::trace!</span>(rem = <span class="self">self</span>.buf.remaining(), <span class="string">"encoded ping"</span>); |
| } |
| Frame::WindowUpdate(v) => { |
| v.encode(<span class="self">self</span>.buf.get_mut()); |
| <span class="macro">tracing::trace!</span>(rem = <span class="self">self</span>.buf.remaining(), <span class="string">"encoded window_update"</span>); |
| } |
| |
| Frame::Priority(<span class="kw">_</span>) => { |
| <span class="comment">/* |
| v.encode(self.buf.get_mut()); |
| tracing::trace!("encoded priority; rem={:?}", self.buf.remaining()); |
| */ |
| </span><span class="macro">unimplemented!</span>(); |
| } |
| Frame::Reset(v) => { |
| v.encode(<span class="self">self</span>.buf.get_mut()); |
| <span class="macro">tracing::trace!</span>(rem = <span class="self">self</span>.buf.remaining(), <span class="string">"encoded reset"</span>); |
| } |
| } |
| |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">fn </span>has_capacity(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.next.is_none() && <span class="self">self</span>.buf.get_ref().remaining_mut() >= MIN_BUFFER_CAPACITY |
| } |
| |
| <span class="kw">fn </span>is_empty(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="kw">match </span><span class="self">self</span>.next { |
| <span class="prelude-val">Some</span>(Next::Data(<span class="kw-2">ref </span>frame)) => !frame.payload().has_remaining(), |
| <span class="kw">_ </span>=> !<span class="self">self</span>.buf.has_remaining(), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><B> Encoder<B> { |
| <span class="kw">fn </span>max_frame_size(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.max_frame_size <span class="kw">as </span>usize |
| } |
| } |
| |
| <span class="kw">impl</span><T, B> FramedWrite<T, B> { |
| <span class="doccomment">/// Returns the max frame size that can be sent |
| </span><span class="kw">pub fn </span>max_frame_size(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.encoder.max_frame_size() |
| } |
| |
| <span class="doccomment">/// Set the peer's max frame size. |
| </span><span class="kw">pub fn </span>set_max_frame_size(<span class="kw-2">&mut </span><span class="self">self</span>, val: usize) { |
| <span class="macro">assert!</span>(val <= frame::MAX_MAX_FRAME_SIZE <span class="kw">as </span>usize); |
| <span class="self">self</span>.encoder.max_frame_size = val <span class="kw">as </span>FrameSize; |
| } |
| |
| <span class="doccomment">/// Set the peer's header table size. |
| </span><span class="kw">pub fn </span>set_header_table_size(<span class="kw-2">&mut </span><span class="self">self</span>, val: usize) { |
| <span class="self">self</span>.encoder.hpack.update_max_size(val); |
| } |
| |
| <span class="doccomment">/// Retrieve the last data frame that has been sent |
| </span><span class="kw">pub fn </span>take_last_data_frame(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><frame::Data<B>> { |
| <span class="self">self</span>.encoder.last_data_frame.take() |
| } |
| |
| <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>.inner |
| } |
| } |
| |
| <span class="kw">impl</span><T: AsyncRead + Unpin, B> AsyncRead <span class="kw">for </span>FramedWrite<T, B> { |
| <span class="kw">fn </span>poll_read( |
| <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>>, |
| buf: <span class="kw-2">&mut </span>ReadBuf, |
| ) -> Poll<io::Result<()>> { |
| Pin::new(<span class="kw-2">&mut </span><span class="self">self</span>.inner).poll_read(cx, buf) |
| } |
| } |
| |
| <span class="comment">// We never project the Pin to `B`. |
| </span><span class="kw">impl</span><T: Unpin, B> Unpin <span class="kw">for </span>FramedWrite<T, B> {} |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"unstable"</span>)] |
| </span><span class="kw">mod </span>unstable { |
| <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| |
| <span class="kw">impl</span><T, B> FramedWrite<T, B> { |
| <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>.inner |
| } |
| } |
| } |
| </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> |
