| <!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/util/read_to_end.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>read_to_end.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> |
| <span id="118">118</span> |
| <span id="119">119</span> |
| <span id="120">120</span> |
| <span id="121">121</span> |
| <span id="122">122</span> |
| <span id="123">123</span> |
| <span id="124">124</span> |
| <span id="125">125</span> |
| <span id="126">126</span> |
| <span id="127">127</span> |
| <span id="128">128</span> |
| <span id="129">129</span> |
| <span id="130">130</span> |
| <span id="131">131</span> |
| <span id="132">132</span> |
| <span id="133">133</span> |
| <span id="134">134</span> |
| <span id="135">135</span> |
| <span id="136">136</span> |
| <span id="137">137</span> |
| <span id="138">138</span> |
| <span id="139">139</span> |
| <span id="140">140</span> |
| <span id="141">141</span> |
| <span id="142">142</span> |
| <span id="143">143</span> |
| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::io::util::vec_with_initialized::{into_read_buf_parts, VecU8, VecWithInitialized}; |
| <span class="kw">use </span><span class="kw">crate</span>::io::{AsyncRead, ReadBuf}; |
| |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| <span class="kw">use </span>std::future::Future; |
| <span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::marker::PhantomPinned; |
| <span class="kw">use </span>std::mem::{<span class="self">self</span>, MaybeUninit}; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="attribute">#[derive(Debug)] |
| #[must_use = <span class="string">"futures do nothing unless you `.await` or poll them"</span>] |
| </span><span class="kw">pub struct </span>ReadToEnd<<span class="lifetime">'a</span>, R: <span class="question-mark">?</span>Sized> { |
| reader: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>R, |
| buf: VecWithInitialized<<span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>Vec<u8>>, |
| <span class="comment">// The number of bytes appended to buf. This can be less than buf.len() if |
| // the buffer was not empty when the operation was started. |
| </span>read: usize, |
| <span class="comment">// Make this future `!Unpin` for compatibility with async trait methods. |
| </span><span class="attribute">#[pin] |
| </span>_pin: PhantomPinned, |
| } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>read_to_end<<span class="lifetime">'a</span>, R>(reader: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>R, buffer: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>Vec<u8>) -> ReadToEnd<<span class="lifetime">'a</span>, R> |
| <span class="kw">where |
| </span>R: AsyncRead + Unpin + <span class="question-mark">?</span>Sized, |
| { |
| ReadToEnd { |
| reader, |
| buf: VecWithInitialized::new(buffer), |
| read: <span class="number">0</span>, |
| _pin: PhantomPinned, |
| } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>read_to_end_internal<V: VecU8, R: AsyncRead + <span class="question-mark">?</span>Sized>( |
| buf: <span class="kw-2">&mut </span>VecWithInitialized<V>, |
| <span class="kw-2">mut </span>reader: Pin<<span class="kw-2">&mut </span>R>, |
| num_read: <span class="kw-2">&mut </span>usize, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| ) -> Poll<io::Result<usize>> { |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span>ret = <span class="macro">ready!</span>(poll_read_to_end(buf, reader.as_mut(), cx)); |
| <span class="kw">match </span>ret { |
| <span class="prelude-val">Err</span>(err) => <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(err)), |
| <span class="prelude-val">Ok</span>(<span class="number">0</span>) => <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(mem::replace(num_read, <span class="number">0</span>))), |
| <span class="prelude-val">Ok</span>(num) => { |
| <span class="kw-2">*</span>num_read += num; |
| } |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Tries to read from the provided AsyncRead. |
| /// |
| /// The length of the buffer is increased by the number of bytes read. |
| </span><span class="kw">fn </span>poll_read_to_end<V: VecU8, R: AsyncRead + <span class="question-mark">?</span>Sized>( |
| buf: <span class="kw-2">&mut </span>VecWithInitialized<V>, |
| read: Pin<<span class="kw-2">&mut </span>R>, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| ) -> Poll<io::Result<usize>> { |
| <span class="comment">// This uses an adaptive system to extend the vector when it fills. We want to |
| // avoid paying to allocate and zero a huge chunk of memory if the reader only |
| // has 4 bytes while still making large reads if the reader does have a ton |
| // of data to return. Simply tacking on an extra DEFAULT_BUF_SIZE space every |
| // time is 4,500 times (!) slower than this if the reader has a very small |
| // amount of data to return. When the vector is full with its starting |
| // capacity, we first try to read into a small buffer to see if we reached |
| // an EOF. This only happens when the starting capacity is >= NUM_BYTES, since |
| // we allocate at least NUM_BYTES each time. This avoids the unnecessary |
| // allocation that we attempt before reading into the vector. |
| |
| </span><span class="kw">const </span>NUM_BYTES: usize = <span class="number">32</span>; |
| <span class="kw">let </span>try_small_read = buf.try_small_read_first(NUM_BYTES); |
| |
| <span class="comment">// Get a ReadBuf into the vector. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>read_buf; |
| <span class="kw">let </span>poll_result; |
| |
| <span class="kw">let </span>n = <span class="kw">if </span>try_small_read { |
| <span class="comment">// Read some bytes using a small read. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>small_buf: [MaybeUninit<u8>; NUM_BYTES] = [MaybeUninit::uninit(); NUM_BYTES]; |
| <span class="kw">let </span><span class="kw-2">mut </span>small_read_buf = ReadBuf::uninit(<span class="kw-2">&mut </span>small_buf); |
| poll_result = read.poll_read(cx, <span class="kw-2">&mut </span>small_read_buf); |
| <span class="kw">let </span>to_write = small_read_buf.filled(); |
| |
| <span class="comment">// Ensure we have enough space to fill our vector with what we read. |
| </span>read_buf = buf.get_read_buf(); |
| <span class="kw">if </span>to_write.len() > read_buf.remaining() { |
| buf.reserve(NUM_BYTES); |
| read_buf = buf.get_read_buf(); |
| } |
| read_buf.put_slice(to_write); |
| |
| to_write.len() |
| } <span class="kw">else </span>{ |
| <span class="comment">// Ensure we have enough space for reading. |
| </span>buf.reserve(NUM_BYTES); |
| read_buf = buf.get_read_buf(); |
| |
| <span class="comment">// Read data directly into vector. |
| </span><span class="kw">let </span>filled_before = read_buf.filled().len(); |
| poll_result = read.poll_read(cx, <span class="kw-2">&mut </span>read_buf); |
| |
| <span class="comment">// Compute the number of bytes read. |
| </span>read_buf.filled().len() - filled_before |
| }; |
| |
| <span class="comment">// Update the length of the vector using the result of poll_read. |
| </span><span class="kw">let </span>read_buf_parts = into_read_buf_parts(read_buf); |
| buf.apply_read_buf(read_buf_parts); |
| |
| <span class="kw">match </span>poll_result { |
| Poll::Pending => { |
| <span class="comment">// In this case, nothing should have been read. However we still |
| // update the vector in case the poll_read call initialized parts of |
| // the vector's unused capacity. |
| </span><span class="macro">debug_assert_eq!</span>(n, <span class="number">0</span>); |
| Poll::Pending |
| } |
| Poll::Ready(<span class="prelude-val">Err</span>(err)) => { |
| <span class="macro">debug_assert_eq!</span>(n, <span class="number">0</span>); |
| Poll::Ready(<span class="prelude-val">Err</span>(err)) |
| } |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) => Poll::Ready(<span class="prelude-val">Ok</span>(n)), |
| } |
| } |
| |
| <span class="kw">impl</span><A> Future <span class="kw">for </span>ReadToEnd<<span class="lifetime">'_</span>, A> |
| <span class="kw">where |
| </span>A: AsyncRead + <span class="question-mark">?</span>Sized + Unpin, |
| { |
| <span class="kw">type </span>Output = io::Result<usize>; |
| |
| <span class="kw">fn </span>poll(<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="self">Self</span>::Output> { |
| <span class="kw">let </span>me = <span class="self">self</span>.project(); |
| |
| read_to_end_internal(me.buf, Pin::new(<span class="kw-2">*</span>me.reader), me.read, cx) |
| } |
| } |
| </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> |
