| <!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/take.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>take.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> |
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| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::io::{AsyncBufRead, AsyncRead, ReadBuf}; |
| |
| <span class="kw">use </span>pin_project_lite::pin_project; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| <span class="kw">use </span>std::{cmp, io}; |
| |
| <span class="macro">pin_project! </span>{ |
| <span class="doccomment">/// Stream for the [`take`](super::AsyncReadExt::take) method. |
| </span><span class="attribute">#[derive(Debug)] |
| #[must_use = <span class="string">"streams do nothing unless you `.await` or poll them"</span>] |
| #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"io-util"</span>)))] |
| </span><span class="kw">pub struct </span>Take<R> { |
| <span class="attribute">#[pin] |
| </span>inner: R, |
| <span class="comment">// Add '_' to avoid conflicts with `limit` method. |
| </span>limit_: u64, |
| } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>take<R: AsyncRead>(inner: R, limit: u64) -> Take<R> { |
| Take { |
| inner, |
| limit_: limit, |
| } |
| } |
| |
| <span class="kw">impl</span><R: AsyncRead> Take<R> { |
| <span class="doccomment">/// Returns the remaining number of bytes that can be |
| /// read before this instance will return EOF. |
| /// |
| /// # Note |
| /// |
| /// This instance may reach `EOF` after reading fewer bytes than indicated by |
| /// this method if the underlying [`AsyncRead`] instance reaches EOF. |
| </span><span class="kw">pub fn </span>limit(<span class="kw-2">&</span><span class="self">self</span>) -> u64 { |
| <span class="self">self</span>.limit_ |
| } |
| |
| <span class="doccomment">/// Sets the number of bytes that can be read before this instance will |
| /// return EOF. This is the same as constructing a new `Take` instance, so |
| /// the amount of bytes read and the previous limit value don't matter when |
| /// calling this method. |
| </span><span class="kw">pub fn </span>set_limit(<span class="kw-2">&mut </span><span class="self">self</span>, limit: u64) { |
| <span class="self">self</span>.limit_ = limit |
| } |
| |
| <span class="doccomment">/// Gets a reference to the underlying reader. |
| </span><span class="kw">pub fn </span>get_ref(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>R { |
| <span class="kw-2">&</span><span class="self">self</span>.inner |
| } |
| |
| <span class="doccomment">/// Gets a mutable reference to the underlying reader. |
| /// |
| /// Care should be taken to avoid modifying the internal I/O state of the |
| /// underlying reader as doing so may corrupt the internal limit of this |
| /// `Take`. |
| </span><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>R { |
| <span class="kw-2">&mut </span><span class="self">self</span>.inner |
| } |
| |
| <span class="doccomment">/// Gets a pinned mutable reference to the underlying reader. |
| /// |
| /// Care should be taken to avoid modifying the internal I/O state of the |
| /// underlying reader as doing so may corrupt the internal limit of this |
| /// `Take`. |
| </span><span class="kw">pub fn </span>get_pin_mut(<span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>) -> Pin<<span class="kw-2">&mut </span>R> { |
| <span class="self">self</span>.project().inner |
| } |
| |
| <span class="doccomment">/// Consumes the `Take`, returning the wrapped reader. |
| </span><span class="kw">pub fn </span>into_inner(<span class="self">self</span>) -> R { |
| <span class="self">self</span>.inner |
| } |
| } |
| |
| <span class="kw">impl</span><R: AsyncRead> AsyncRead <span class="kw">for </span>Take<R> { |
| <span class="kw">fn </span>poll_read( |
| <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<<span class="lifetime">'_</span>>, |
| ) -> Poll<<span class="prelude-ty">Result</span><(), io::Error>> { |
| <span class="kw">if </span><span class="self">self</span>.limit_ == <span class="number">0 </span>{ |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(())); |
| } |
| |
| <span class="kw">let </span>me = <span class="self">self</span>.project(); |
| <span class="kw">let </span><span class="kw-2">mut </span>b = buf.take(<span class="kw-2">*</span>me.limit_ <span class="kw">as </span>usize); |
| |
| <span class="kw">let </span>buf_ptr = b.filled().as_ptr(); |
| <span class="macro">ready!</span>(me.inner.poll_read(cx, <span class="kw-2">&mut </span>b))<span class="question-mark">?</span>; |
| <span class="macro">assert_eq!</span>(b.filled().as_ptr(), buf_ptr); |
| |
| <span class="kw">let </span>n = b.filled().len(); |
| |
| <span class="comment">// We need to update the original ReadBuf |
| </span><span class="kw">unsafe </span>{ |
| buf.assume_init(n); |
| } |
| buf.advance(n); |
| <span class="kw-2">*</span>me.limit_ -= n <span class="kw">as </span>u64; |
| Poll::Ready(<span class="prelude-val">Ok</span>(())) |
| } |
| } |
| |
| <span class="kw">impl</span><R: AsyncBufRead> AsyncBufRead <span class="kw">for </span>Take<R> { |
| <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="kw">let </span>me = <span class="self">self</span>.project(); |
| |
| <span class="comment">// Don't call into inner reader at all at EOF because it may still block |
| </span><span class="kw">if </span><span class="kw-2">*</span>me.limit_ == <span class="number">0 </span>{ |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">&</span>[])); |
| } |
| |
| <span class="kw">let </span>buf = <span class="macro">ready!</span>(me.inner.poll_fill_buf(cx)<span class="question-mark">?</span>); |
| <span class="kw">let </span>cap = cmp::min(buf.len() <span class="kw">as </span>u64, <span class="kw-2">*</span>me.limit_) <span class="kw">as </span>usize; |
| Poll::Ready(<span class="prelude-val">Ok</span>(<span class="kw-2">&</span>buf[..cap])) |
| } |
| |
| <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="kw">let </span>me = <span class="self">self</span>.project(); |
| <span class="comment">// Don't let callers reset the limit by passing an overlarge value |
| </span><span class="kw">let </span>amt = cmp::min(amt <span class="kw">as </span>u64, <span class="kw-2">*</span>me.limit_) <span class="kw">as </span>usize; |
| <span class="kw-2">*</span>me.limit_ -= amt <span class="kw">as </span>u64; |
| me.inner.consume(amt); |
| } |
| } |
| |
| <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::<Take<()>>(); |
| } |
| } |
| </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> |
