Google Git
Sign in
apache / incubator-teaclave-website / refs/heads/asf-site / . / api-docs / crates-app / src / tokio / io / util / buf_reader.rs.html
blob: fe2334eb87ed6aa5a4e00f5e6b86bfaea44a7ee3 [file] [log] [blame]
<!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/buf_reader.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>buf_reader.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>
<span id="144">144</span>
<span id="145">145</span>
<span id="146">146</span>
<span id="147">147</span>
<span id="148">148</span>
<span id="149">149</span>
<span id="150">150</span>
<span id="151">151</span>
<span id="152">152</span>
<span id="153">153</span>
<span id="154">154</span>
<span id="155">155</span>
<span id="156">156</span>
<span id="157">157</span>
<span id="158">158</span>
<span id="159">159</span>
<span id="160">160</span>
<span id="161">161</span>
<span id="162">162</span>
<span id="163">163</span>
<span id="164">164</span>
<span id="165">165</span>
<span id="166">166</span>
<span id="167">167</span>
<span id="168">168</span>
<span id="169">169</span>
<span id="170">170</span>
<span id="171">171</span>
<span id="172">172</span>
<span id="173">173</span>
<span id="174">174</span>
<span id="175">175</span>
<span id="176">176</span>
<span id="177">177</span>
<span id="178">178</span>
<span id="179">179</span>
<span id="180">180</span>
<span id="181">181</span>
<span id="182">182</span>
<span id="183">183</span>
<span id="184">184</span>
<span id="185">185</span>
<span id="186">186</span>
<span id="187">187</span>
<span id="188">188</span>
<span id="189">189</span>
<span id="190">190</span>
<span id="191">191</span>
<span id="192">192</span>
<span id="193">193</span>
<span id="194">194</span>
<span id="195">195</span>
<span id="196">196</span>
<span id="197">197</span>
<span id="198">198</span>
<span id="199">199</span>
<span id="200">200</span>
<span id="201">201</span>
<span id="202">202</span>
<span id="203">203</span>
<span id="204">204</span>
<span id="205">205</span>
<span id="206">206</span>
<span id="207">207</span>
<span id="208">208</span>
<span id="209">209</span>
<span id="210">210</span>
<span id="211">211</span>
<span id="212">212</span>
<span id="213">213</span>
<span id="214">214</span>
<span id="215">215</span>
<span id="216">216</span>
<span id="217">217</span>
<span id="218">218</span>
<span id="219">219</span>
<span id="220">220</span>
<span id="221">221</span>
<span id="222">222</span>
<span id="223">223</span>
<span id="224">224</span>
<span id="225">225</span>
<span id="226">226</span>
<span id="227">227</span>
<span id="228">228</span>
<span id="229">229</span>
<span id="230">230</span>
<span id="231">231</span>
<span id="232">232</span>
<span id="233">233</span>
<span id="234">234</span>
<span id="235">235</span>
<span id="236">236</span>
<span id="237">237</span>
<span id="238">238</span>
<span id="239">239</span>
<span id="240">240</span>
<span id="241">241</span>
<span id="242">242</span>
<span id="243">243</span>
<span id="244">244</span>
<span id="245">245</span>
<span id="246">246</span>
<span id="247">247</span>
<span id="248">248</span>
<span id="249">249</span>
<span id="250">250</span>
<span id="251">251</span>
<span id="252">252</span>
<span id="253">253</span>
<span id="254">254</span>
<span id="255">255</span>
<span id="256">256</span>
<span id="257">257</span>
<span id="258">258</span>
<span id="259">259</span>
<span id="260">260</span>
<span id="261">261</span>
<span id="262">262</span>
<span id="263">263</span>
<span id="264">264</span>
<span id="265">265</span>
<span id="266">266</span>
<span id="267">267</span>
<span id="268">268</span>
<span id="269">269</span>
<span id="270">270</span>
<span id="271">271</span>
<span id="272">272</span>
<span id="273">273</span>
<span id="274">274</span>
<span id="275">275</span>
<span id="276">276</span>
<span id="277">277</span>
<span id="278">278</span>
<span id="279">279</span>
<span id="280">280</span>
<span id="281">281</span>
<span id="282">282</span>
<span id="283">283</span>
<span id="284">284</span>
<span id="285">285</span>
<span id="286">286</span>
<span id="287">287</span>
<span id="288">288</span>
<span id="289">289</span>
<span id="290">290</span>
<span id="291">291</span>
<span id="292">292</span>
<span id="293">293</span>
<span id="294">294</span>
<span id="295">295</span>
<span id="296">296</span>
<span id="297">297</span>
<span id="298">298</span>
<span id="299">299</span>
<span id="300">300</span>
<span id="301">301</span>
<span id="302">302</span>
<span id="303">303</span>
<span id="304">304</span>
<span id="305">305</span>
<span id="306">306</span>
<span id="307">307</span>
<span id="308">308</span>
<span id="309">309</span>
<span id="310">310</span>
<span id="311">311</span>
</pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::io::util::DEFAULT_BUF_SIZE;
<span class="kw">use </span><span class="kw">crate</span>::io::{AsyncBufRead, AsyncRead, AsyncSeek, AsyncWrite, ReadBuf};
<span class="kw">use </span>pin_project_lite::pin_project;
<span class="kw">use </span>std::io::{<span class="self">self</span>, IoSlice, SeekFrom};
<span class="kw">use </span>std::pin::Pin;
<span class="kw">use </span>std::task::{Context, Poll};
<span class="kw">use </span>std::{cmp, fmt, mem};
<span class="macro">pin_project! </span>{
<span class="doccomment">/// The `BufReader` struct adds buffering to any reader.
///
/// It can be excessively inefficient to work directly with a [`AsyncRead`]
/// instance. A `BufReader` performs large, infrequent reads on the underlying
/// [`AsyncRead`] and maintains an in-memory buffer of the results.
///
/// `BufReader` can improve the speed of programs that make *small* and
/// *repeated* read calls to the same file or network socket. It does not
/// help when reading very large amounts at once, or reading just one or a few
/// times. It also provides no advantage when reading from a source that is
/// already in memory, like a `Vec&lt;u8&gt;`.
///
/// When the `BufReader` is dropped, the contents of its buffer will be
/// discarded. Creating multiple instances of a `BufReader` on the same
/// stream can cause data loss.
</span><span class="attribute">#[cfg_attr(docsrs, doc(cfg(feature = <span class="string">&quot;io-util&quot;</span>)))]
</span><span class="kw">pub struct </span>BufReader&lt;R&gt; {
<span class="attribute">#[pin]
</span><span class="kw">pub</span>(<span class="kw">super</span>) inner: R,
<span class="kw">pub</span>(<span class="kw">super</span>) buf: Box&lt;[u8]&gt;,
<span class="kw">pub</span>(<span class="kw">super</span>) pos: usize,
<span class="kw">pub</span>(<span class="kw">super</span>) cap: usize,
<span class="kw">pub</span>(<span class="kw">super</span>) seek_state: SeekState,
}
}
<span class="kw">impl</span>&lt;R: AsyncRead&gt; BufReader&lt;R&gt; {
<span class="doccomment">/// Creates a new `BufReader` with a default buffer capacity. The default is currently 8 KB,
/// but may change in the future.
</span><span class="kw">pub fn </span>new(inner: R) -&gt; <span class="self">Self </span>{
<span class="self">Self</span>::with_capacity(DEFAULT_BUF_SIZE, inner)
}
<span class="doccomment">/// Creates a new `BufReader` with the specified buffer capacity.
</span><span class="kw">pub fn </span>with_capacity(capacity: usize, inner: R) -&gt; <span class="self">Self </span>{
<span class="kw">let </span>buffer = <span class="macro">vec!</span>[<span class="number">0</span>; capacity];
<span class="self">Self </span>{
inner,
buf: buffer.into_boxed_slice(),
pos: <span class="number">0</span>,
cap: <span class="number">0</span>,
seek_state: SeekState::Init,
}
}
<span class="doccomment">/// Gets a reference to the underlying reader.
///
/// It is inadvisable to directly read from the underlying reader.
</span><span class="kw">pub fn </span>get_ref(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="kw-2">&amp;</span>R {
<span class="kw-2">&amp;</span><span class="self">self</span>.inner
}
<span class="doccomment">/// Gets a mutable reference to the underlying reader.
///
/// It is inadvisable to directly read from the underlying reader.
</span><span class="kw">pub fn </span>get_mut(<span class="kw-2">&amp;mut </span><span class="self">self</span>) -&gt; <span class="kw-2">&amp;mut </span>R {
<span class="kw-2">&amp;mut </span><span class="self">self</span>.inner
}
<span class="doccomment">/// Gets a pinned mutable reference to the underlying reader.
///
/// It is inadvisable to directly read from the underlying reader.
</span><span class="kw">pub fn </span>get_pin_mut(<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;) -&gt; Pin&lt;<span class="kw-2">&amp;mut </span>R&gt; {
<span class="self">self</span>.project().inner
}
<span class="doccomment">/// Consumes this `BufReader`, returning the underlying reader.
///
/// Note that any leftover data in the internal buffer is lost.
</span><span class="kw">pub fn </span>into_inner(<span class="self">self</span>) -&gt; R {
<span class="self">self</span>.inner
}
<span class="doccomment">/// Returns a reference to the internally buffered data.
///
/// Unlike `fill_buf`, this will not attempt to fill the buffer if it is empty.
</span><span class="kw">pub fn </span>buffer(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="kw-2">&amp;</span>[u8] {
<span class="kw-2">&amp;</span><span class="self">self</span>.buf[<span class="self">self</span>.pos..<span class="self">self</span>.cap]
}
<span class="doccomment">/// Invalidates all data in the internal buffer.
</span><span class="attribute">#[inline]
</span><span class="kw">fn </span>discard_buffer(<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;) {
<span class="kw">let </span>me = <span class="self">self</span>.project();
<span class="kw-2">*</span>me.pos = <span class="number">0</span>;
<span class="kw-2">*</span>me.cap = <span class="number">0</span>;
}
}
<span class="kw">impl</span>&lt;R: AsyncRead&gt; AsyncRead <span class="kw">for </span>BufReader&lt;R&gt; {
<span class="kw">fn </span>poll_read(
<span class="kw-2">mut </span><span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;,
cx: <span class="kw-2">&amp;mut </span>Context&lt;<span class="lifetime">&#39;_</span>&gt;,
buf: <span class="kw-2">&amp;mut </span>ReadBuf&lt;<span class="lifetime">&#39;_</span>&gt;,
) -&gt; Poll&lt;io::Result&lt;()&gt;&gt; {
<span class="comment">// If we don&#39;t have any buffered data and we&#39;re doing a massive read
// (larger than our internal buffer), bypass our internal buffer
// entirely.
</span><span class="kw">if </span><span class="self">self</span>.pos == <span class="self">self</span>.cap &amp;&amp; buf.remaining() &gt;= <span class="self">self</span>.buf.len() {
<span class="kw">let </span>res = <span class="macro">ready!</span>(<span class="self">self</span>.as_mut().get_pin_mut().poll_read(cx, buf));
<span class="self">self</span>.discard_buffer();
<span class="kw">return </span>Poll::Ready(res);
}
<span class="kw">let </span>rem = <span class="macro">ready!</span>(<span class="self">self</span>.as_mut().poll_fill_buf(cx))<span class="question-mark">?</span>;
<span class="kw">let </span>amt = std::cmp::min(rem.len(), buf.remaining());
buf.put_slice(<span class="kw-2">&amp;</span>rem[..amt]);
<span class="self">self</span>.consume(amt);
Poll::Ready(<span class="prelude-val">Ok</span>(()))
}
}
<span class="kw">impl</span>&lt;R: AsyncRead&gt; AsyncBufRead <span class="kw">for </span>BufReader&lt;R&gt; {
<span class="kw">fn </span>poll_fill_buf(<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;, cx: <span class="kw-2">&amp;mut </span>Context&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; Poll&lt;io::Result&lt;<span class="kw-2">&amp;</span>[u8]&gt;&gt; {
<span class="kw">let </span>me = <span class="self">self</span>.project();
<span class="comment">// If we&#39;ve reached the end of our internal buffer then we need to fetch
// some more data from the underlying reader.
// Branch using `&gt;=` instead of the more correct `==`
// to tell the compiler that the pos..cap slice is always valid.
</span><span class="kw">if </span><span class="kw-2">*</span>me.pos &gt;= <span class="kw-2">*</span>me.cap {
<span class="macro">debug_assert!</span>(<span class="kw-2">*</span>me.pos == <span class="kw-2">*</span>me.cap);
<span class="kw">let </span><span class="kw-2">mut </span>buf = ReadBuf::new(me.buf);
<span class="macro">ready!</span>(me.inner.poll_read(cx, <span class="kw-2">&amp;mut </span>buf))<span class="question-mark">?</span>;
<span class="kw-2">*</span>me.cap = buf.filled().len();
<span class="kw-2">*</span>me.pos = <span class="number">0</span>;
}
Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">&amp;</span>me.buf[<span class="kw-2">*</span>me.pos..<span class="kw-2">*</span>me.cap]))
}
<span class="kw">fn </span>consume(<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;, amt: usize) {
<span class="kw">let </span>me = <span class="self">self</span>.project();
<span class="kw-2">*</span>me.pos = cmp::min(<span class="kw-2">*</span>me.pos + amt, <span class="kw-2">*</span>me.cap);
}
}
<span class="attribute">#[derive(Debug, Clone, Copy)]
</span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">enum </span>SeekState {
<span class="doccomment">/// start_seek has not been called.
</span>Init,
<span class="doccomment">/// start_seek has been called, but poll_complete has not yet been called.
</span>Start(SeekFrom),
<span class="doccomment">/// Waiting for completion of the first poll_complete in the `n.checked_sub(remainder).is_none()` branch.
</span>PendingOverflowed(i64),
<span class="doccomment">/// Waiting for completion of poll_complete.
</span>Pending,
}
<span class="doccomment">/// Seeks to an offset, in bytes, in the underlying reader.
///
/// The position used for seeking with `SeekFrom::Current(_)` is the
/// position the underlying reader would be at if the `BufReader` had no
/// internal buffer.
///
/// Seeking always discards the internal buffer, even if the seek position
/// would otherwise fall within it. This guarantees that calling
/// `.into_inner()` immediately after a seek yields the underlying reader
/// at the same position.
///
/// See [`AsyncSeek`] for more details.
///
/// Note: In the edge case where you&#39;re seeking with `SeekFrom::Current(n)`
/// where `n` minus the internal buffer length overflows an `i64`, two
/// seeks will be performed instead of one. If the second seek returns
/// `Err`, the underlying reader will be left at the same position it would
/// have if you called `seek` with `SeekFrom::Current(0)`.
</span><span class="kw">impl</span>&lt;R: AsyncRead + AsyncSeek&gt; AsyncSeek <span class="kw">for </span>BufReader&lt;R&gt; {
<span class="kw">fn </span>start_seek(<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;, pos: SeekFrom) -&gt; io::Result&lt;()&gt; {
<span class="comment">// We needs to call seek operation multiple times.
// And we should always call both start_seek and poll_complete,
// as start_seek alone cannot guarantee that the operation will be completed.
// poll_complete receives a Context and returns a Poll, so it cannot be called
// inside start_seek.
</span><span class="kw-2">*</span><span class="self">self</span>.project().seek_state = SeekState::Start(pos);
<span class="prelude-val">Ok</span>(())
}
<span class="kw">fn </span>poll_complete(<span class="kw-2">mut </span><span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;, cx: <span class="kw-2">&amp;mut </span>Context&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; Poll&lt;io::Result&lt;u64&gt;&gt; {
<span class="kw">let </span>res = <span class="kw">match </span>mem::replace(<span class="self">self</span>.as_mut().project().seek_state, SeekState::Init) {
SeekState::Init =&gt; {
<span class="comment">// 1.x AsyncSeek recommends calling poll_complete before start_seek.
// We don&#39;t have to guarantee that the value returned by
// poll_complete called without start_seek is correct,
// so we&#39;ll return 0.
</span><span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="number">0</span>));
}
SeekState::Start(SeekFrom::Current(n)) =&gt; {
<span class="kw">let </span>remainder = (<span class="self">self</span>.cap - <span class="self">self</span>.pos) <span class="kw">as </span>i64;
<span class="comment">// it should be safe to assume that remainder fits within an i64 as the alternative
// means we managed to allocate 8 exbibytes and that&#39;s absurd.
// But it&#39;s not out of the realm of possibility for some weird underlying reader to
// support seeking by i64::MIN so we need to handle underflow when subtracting
// remainder.
</span><span class="kw">if let </span><span class="prelude-val">Some</span>(offset) = n.checked_sub(remainder) {
<span class="self">self</span>.as_mut()
.get_pin_mut()
.start_seek(SeekFrom::Current(offset))<span class="question-mark">?</span>;
} <span class="kw">else </span>{
<span class="comment">// seek backwards by our remainder, and then by the offset
</span><span class="self">self</span>.as_mut()
.get_pin_mut()
.start_seek(SeekFrom::Current(-remainder))<span class="question-mark">?</span>;
<span class="kw">if </span><span class="self">self</span>.as_mut().get_pin_mut().poll_complete(cx)<span class="question-mark">?</span>.is_pending() {
<span class="kw-2">*</span><span class="self">self</span>.as_mut().project().seek_state = SeekState::PendingOverflowed(n);
<span class="kw">return </span>Poll::Pending;
}
<span class="comment">// https://github.com/rust-lang/rust/pull/61157#issuecomment-495932676
</span><span class="self">self</span>.as_mut().discard_buffer();
<span class="self">self</span>.as_mut()
.get_pin_mut()
.start_seek(SeekFrom::Current(n))<span class="question-mark">?</span>;
}
<span class="self">self</span>.as_mut().get_pin_mut().poll_complete(cx)<span class="question-mark">?
</span>}
SeekState::PendingOverflowed(n) =&gt; {
<span class="kw">if </span><span class="self">self</span>.as_mut().get_pin_mut().poll_complete(cx)<span class="question-mark">?</span>.is_pending() {
<span class="kw-2">*</span><span class="self">self</span>.as_mut().project().seek_state = SeekState::PendingOverflowed(n);
<span class="kw">return </span>Poll::Pending;
}
<span class="comment">// https://github.com/rust-lang/rust/pull/61157#issuecomment-495932676
</span><span class="self">self</span>.as_mut().discard_buffer();
<span class="self">self</span>.as_mut()
.get_pin_mut()
.start_seek(SeekFrom::Current(n))<span class="question-mark">?</span>;
<span class="self">self</span>.as_mut().get_pin_mut().poll_complete(cx)<span class="question-mark">?
</span>}
SeekState::Start(pos) =&gt; {
<span class="comment">// Seeking with Start/End doesn&#39;t care about our buffer length.
</span><span class="self">self</span>.as_mut().get_pin_mut().start_seek(pos)<span class="question-mark">?</span>;
<span class="self">self</span>.as_mut().get_pin_mut().poll_complete(cx)<span class="question-mark">?
</span>}
SeekState::Pending =&gt; <span class="self">self</span>.as_mut().get_pin_mut().poll_complete(cx)<span class="question-mark">?</span>,
};
<span class="kw">match </span>res {
Poll::Ready(res) =&gt; {
<span class="self">self</span>.discard_buffer();
Poll::Ready(<span class="prelude-val">Ok</span>(res))
}
Poll::Pending =&gt; {
<span class="kw-2">*</span><span class="self">self</span>.as_mut().project().seek_state = SeekState::Pending;
Poll::Pending
}
}
}
}
<span class="kw">impl</span>&lt;R: AsyncRead + AsyncWrite&gt; AsyncWrite <span class="kw">for </span>BufReader&lt;R&gt; {
<span class="kw">fn </span>poll_write(
<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;,
cx: <span class="kw-2">&amp;mut </span>Context&lt;<span class="lifetime">&#39;_</span>&gt;,
buf: <span class="kw-2">&amp;</span>[u8],
) -&gt; Poll&lt;io::Result&lt;usize&gt;&gt; {
<span class="self">self</span>.get_pin_mut().poll_write(cx, buf)
}
<span class="kw">fn </span>poll_write_vectored(
<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;,
cx: <span class="kw-2">&amp;mut </span>Context&lt;<span class="lifetime">&#39;_</span>&gt;,
bufs: <span class="kw-2">&amp;</span>[IoSlice&lt;<span class="lifetime">&#39;_</span>&gt;],
) -&gt; Poll&lt;io::Result&lt;usize&gt;&gt; {
<span class="self">self</span>.get_pin_mut().poll_write_vectored(cx, bufs)
}
<span class="kw">fn </span>is_write_vectored(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; bool {
<span class="self">self</span>.get_ref().is_write_vectored()
}
<span class="kw">fn </span>poll_flush(<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;, cx: <span class="kw-2">&amp;mut </span>Context&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; Poll&lt;io::Result&lt;()&gt;&gt; {
<span class="self">self</span>.get_pin_mut().poll_flush(cx)
}
<span class="kw">fn </span>poll_shutdown(<span class="self">self</span>: Pin&lt;<span class="kw-2">&amp;mut </span><span class="self">Self</span>&gt;, cx: <span class="kw-2">&amp;mut </span>Context&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; Poll&lt;io::Result&lt;()&gt;&gt; {
<span class="self">self</span>.get_pin_mut().poll_shutdown(cx)
}
}
<span class="kw">impl</span>&lt;R: fmt::Debug&gt; fmt::Debug <span class="kw">for </span>BufReader&lt;R&gt; {
<span class="kw">fn </span>fmt(<span class="kw-2">&amp;</span><span class="self">self</span>, f: <span class="kw-2">&amp;mut </span>fmt::Formatter&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; fmt::Result {
f.debug_struct(<span class="string">&quot;BufReader&quot;</span>)
.field(<span class="string">&quot;reader&quot;</span>, <span class="kw-2">&amp;</span><span class="self">self</span>.inner)
.field(
<span class="string">&quot;buffer&quot;</span>,
<span class="kw-2">&amp;</span><span class="macro">format_args!</span>(<span class="string">&quot;{}/{}&quot;</span>, <span class="self">self</span>.cap - <span class="self">self</span>.pos, <span class="self">self</span>.buf.len()),
)
.finish()
}
}
<span class="attribute">#[cfg(test)]
</span><span class="kw">mod </span>tests {
<span class="kw">use super</span>::<span class="kw-2">*</span>;
<span class="attribute">#[test]
</span><span class="kw">fn </span>assert_unpin() {
<span class="kw">crate</span>::is_unpin::&lt;BufReader&lt;()&gt;&gt;();
}
}
</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>