| <!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-1.28.2/src/io/async_buf_read.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>async_buf_read.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/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/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> |
| <span id="2">2</span> |
| <span id="3">3</span> |
| <span id="4">4</span> |
| <span id="5">5</span> |
| <span id="6">6</span> |
| <span id="7">7</span> |
| <span id="8">8</span> |
| <span id="9">9</span> |
| <span id="10">10</span> |
| <span id="11">11</span> |
| <span id="12">12</span> |
| <span id="13">13</span> |
| <span id="14">14</span> |
| <span id="15">15</span> |
| <span id="16">16</span> |
| <span id="17">17</span> |
| <span id="18">18</span> |
| <span id="19">19</span> |
| <span id="20">20</span> |
| <span id="21">21</span> |
| <span id="22">22</span> |
| <span id="23">23</span> |
| <span id="24">24</span> |
| <span id="25">25</span> |
| <span id="26">26</span> |
| <span id="27">27</span> |
| <span id="28">28</span> |
| <span id="29">29</span> |
| <span id="30">30</span> |
| <span id="31">31</span> |
| <span id="32">32</span> |
| <span id="33">33</span> |
| <span id="34">34</span> |
| <span id="35">35</span> |
| <span id="36">36</span> |
| <span id="37">37</span> |
| <span id="38">38</span> |
| <span id="39">39</span> |
| <span id="40">40</span> |
| <span id="41">41</span> |
| <span id="42">42</span> |
| <span id="43">43</span> |
| <span id="44">44</span> |
| <span id="45">45</span> |
| <span id="46">46</span> |
| <span id="47">47</span> |
| <span id="48">48</span> |
| <span id="49">49</span> |
| <span id="50">50</span> |
| <span id="51">51</span> |
| <span id="52">52</span> |
| <span id="53">53</span> |
| <span id="54">54</span> |
| <span id="55">55</span> |
| <span id="56">56</span> |
| <span id="57">57</span> |
| <span id="58">58</span> |
| <span id="59">59</span> |
| <span id="60">60</span> |
| <span id="61">61</span> |
| <span id="62">62</span> |
| <span id="63">63</span> |
| <span id="64">64</span> |
| <span id="65">65</span> |
| <span id="66">66</span> |
| <span id="67">67</span> |
| <span id="68">68</span> |
| <span id="69">69</span> |
| <span id="70">70</span> |
| <span id="71">71</span> |
| <span id="72">72</span> |
| <span id="73">73</span> |
| <span id="74">74</span> |
| <span id="75">75</span> |
| <span id="76">76</span> |
| <span id="77">77</span> |
| <span id="78">78</span> |
| <span id="79">79</span> |
| <span id="80">80</span> |
| <span id="81">81</span> |
| <span id="82">82</span> |
| <span id="83">83</span> |
| <span id="84">84</span> |
| <span id="85">85</span> |
| <span id="86">86</span> |
| <span id="87">87</span> |
| <span id="88">88</span> |
| <span id="89">89</span> |
| <span id="90">90</span> |
| <span id="91">91</span> |
| <span id="92">92</span> |
| <span id="93">93</span> |
| <span id="94">94</span> |
| <span id="95">95</span> |
| <span id="96">96</span> |
| <span id="97">97</span> |
| <span id="98">98</span> |
| <span id="99">99</span> |
| <span id="100">100</span> |
| <span id="101">101</span> |
| <span id="102">102</span> |
| <span id="103">103</span> |
| <span id="104">104</span> |
| <span id="105">105</span> |
| <span id="106">106</span> |
| <span id="107">107</span> |
| <span id="108">108</span> |
| <span id="109">109</span> |
| <span id="110">110</span> |
| <span id="111">111</span> |
| <span id="112">112</span> |
| <span id="113">113</span> |
| <span id="114">114</span> |
| <span id="115">115</span> |
| <span id="116">116</span> |
| <span id="117">117</span> |
| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::io::AsyncRead; |
| |
| <span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::ops::DerefMut; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| |
| <span class="doccomment">/// Reads bytes asynchronously. |
| /// |
| /// This trait is analogous to [`std::io::BufRead`], but integrates with |
| /// the asynchronous task system. In particular, the [`poll_fill_buf`] method, |
| /// unlike [`BufRead::fill_buf`], will automatically queue the current task for wakeup |
| /// and return if data is not yet available, rather than blocking the calling |
| /// thread. |
| /// |
| /// Utilities for working with `AsyncBufRead` values are provided by |
| /// [`AsyncBufReadExt`]. |
| /// |
| /// [`std::io::BufRead`]: std::io::BufRead |
| /// [`poll_fill_buf`]: AsyncBufRead::poll_fill_buf |
| /// [`BufRead::fill_buf`]: std::io::BufRead::fill_buf |
| /// [`AsyncBufReadExt`]: crate::io::AsyncBufReadExt |
| </span><span class="kw">pub trait </span>AsyncBufRead: AsyncRead { |
| <span class="doccomment">/// Attempts to return the contents of the internal buffer, filling it with more data |
| /// from the inner reader if it is empty. |
| /// |
| /// On success, returns `Poll::Ready(Ok(buf))`. |
| /// |
| /// If no data is available for reading, the method returns |
| /// `Poll::Pending` and arranges for the current task (via |
| /// `cx.waker().wake_by_ref()`) to receive a notification when the object becomes |
| /// readable or is closed. |
| /// |
| /// This function is a lower-level call. It needs to be paired with the |
| /// [`consume`] method to function properly. When calling this |
| /// method, none of the contents will be "read" in the sense that later |
| /// calling [`poll_read`] may return the same contents. As such, [`consume`] must |
| /// be called with the number of bytes that are consumed from this buffer to |
| /// ensure that the bytes are never returned twice. |
| /// |
| /// An empty buffer returned indicates that the stream has reached EOF. |
| /// |
| /// [`poll_read`]: AsyncRead::poll_read |
| /// [`consume`]: AsyncBufRead::consume |
| </span><span class="kw">fn </span>poll_fill_buf(<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<io::Result<<span class="kw-2">&</span>[u8]>>; |
| |
| <span class="doccomment">/// Tells this buffer that `amt` bytes have been consumed from the buffer, |
| /// so they should no longer be returned in calls to [`poll_read`]. |
| /// |
| /// This function is a lower-level call. It needs to be paired with the |
| /// [`poll_fill_buf`] method to function properly. This function does |
| /// not perform any I/O, it simply informs this object that some amount of |
| /// its buffer, returned from [`poll_fill_buf`], has been consumed and should |
| /// no longer be returned. As such, this function may do odd things if |
| /// [`poll_fill_buf`] isn't called before calling it. |
| /// |
| /// The `amt` must be `<=` the number of bytes in the buffer returned by |
| /// [`poll_fill_buf`]. |
| /// |
| /// [`poll_read`]: AsyncRead::poll_read |
| /// [`poll_fill_buf`]: AsyncBufRead::poll_fill_buf |
| </span><span class="kw">fn </span>consume(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, amt: usize); |
| } |
| |
| <span class="macro">macro_rules! </span>deref_async_buf_read { |
| () => { |
| <span class="kw">fn </span>poll_fill_buf(<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<io::Result<<span class="kw-2">&</span>[u8]>> { |
| Pin::new(<span class="kw-2">&mut **</span><span class="self">self</span>.get_mut()).poll_fill_buf(cx) |
| } |
| |
| <span class="kw">fn </span>consume(<span class="kw-2">mut </span><span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, amt: usize) { |
| Pin::new(<span class="kw-2">&mut **</span><span class="self">self</span>).consume(amt) |
| } |
| }; |
| } |
| |
| <span class="kw">impl</span><T: <span class="question-mark">?</span>Sized + AsyncBufRead + Unpin> AsyncBufRead <span class="kw">for </span>Box<T> { |
| <span class="macro">deref_async_buf_read!</span>(); |
| } |
| |
| <span class="kw">impl</span><T: <span class="question-mark">?</span>Sized + AsyncBufRead + Unpin> AsyncBufRead <span class="kw">for </span><span class="kw-2">&mut </span>T { |
| <span class="macro">deref_async_buf_read!</span>(); |
| } |
| |
| <span class="kw">impl</span><P> AsyncBufRead <span class="kw">for </span>Pin<P> |
| <span class="kw">where |
| </span>P: DerefMut + Unpin, |
| P::Target: AsyncBufRead, |
| { |
| <span class="kw">fn </span>poll_fill_buf(<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<io::Result<<span class="kw-2">&</span>[u8]>> { |
| <span class="self">self</span>.get_mut().as_mut().poll_fill_buf(cx) |
| } |
| |
| <span class="kw">fn </span>consume(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, amt: usize) { |
| <span class="self">self</span>.get_mut().as_mut().consume(amt) |
| } |
| } |
| |
| <span class="kw">impl </span>AsyncBufRead <span class="kw">for </span><span class="kw-2">&</span>[u8] { |
| <span class="kw">fn </span>poll_fill_buf(<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<io::Result<<span class="kw-2">&</span>[u8]>> { |
| Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">*</span><span class="self">self</span>)) |
| } |
| |
| <span class="kw">fn </span>consume(<span class="kw-2">mut </span><span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, amt: usize) { |
| <span class="kw-2">*</span><span class="self">self </span>= <span class="kw-2">&</span><span class="self">self</span>[amt..]; |
| } |
| } |
| |
| <span class="kw">impl</span><T: AsRef<[u8]> + Unpin> AsyncBufRead <span class="kw">for </span>io::Cursor<T> { |
| <span class="kw">fn </span>poll_fill_buf(<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<io::Result<<span class="kw-2">&</span>[u8]>> { |
| Poll::Ready(io::BufRead::fill_buf(<span class="self">self</span>.get_mut())) |
| } |
| |
| <span class="kw">fn </span>consume(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, amt: usize) { |
| io::BufRead::consume(<span class="self">self</span>.get_mut(), amt) |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
