| <!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-util-0.7.8/src/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.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_util/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_util/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="attribute">#![allow(clippy::needless_doctest_main)] |
| #![warn( |
| missing_debug_implementations, |
| missing_docs, |
| rust_2018_idioms, |
| unreachable_pub |
| )] |
| #![doc(test( |
| no_crate_inject, |
| attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables)) |
| ))] |
| #![cfg_attr(docsrs, feature(doc_cfg))] |
| |
| </span><span class="doccomment">//! Utilities for working with Tokio. |
| //! |
| //! This crate is not versioned in lockstep with the core |
| //! [`tokio`] crate. However, `tokio-util` _will_ respect Rust's |
| //! semantic versioning policy, especially with regard to breaking changes. |
| //! |
| //! [`tokio`]: https://docs.rs/tokio |
| |
| </span><span class="attribute">#[macro_use] |
| </span><span class="kw">mod </span>cfg; |
| |
| <span class="kw">mod </span>loom; |
| |
| <span class="macro">cfg_codec! </span>{ |
| <span class="kw">pub mod </span>codec; |
| } |
| |
| <span class="macro">cfg_net! </span>{ |
| <span class="attribute">#[cfg(not(target_arch = <span class="string">"wasm32"</span>))] |
| </span><span class="kw">pub mod </span>udp; |
| <span class="kw">pub mod </span>net; |
| } |
| |
| <span class="macro">cfg_compat! </span>{ |
| <span class="kw">pub mod </span>compat; |
| } |
| |
| <span class="macro">cfg_io! </span>{ |
| <span class="kw">pub mod </span>io; |
| } |
| |
| <span class="macro">cfg_rt! </span>{ |
| <span class="kw">pub mod </span>context; |
| <span class="kw">pub mod </span>task; |
| } |
| |
| <span class="macro">cfg_time! </span>{ |
| <span class="kw">pub mod </span>time; |
| } |
| |
| <span class="kw">pub mod </span>sync; |
| |
| <span class="kw">pub mod </span>either; |
| |
| <span class="attribute">#[cfg(any(feature = <span class="string">"io"</span>, feature = <span class="string">"codec"</span>))] |
| </span><span class="kw">mod </span>util { |
| <span class="kw">use </span>tokio::io::{AsyncRead, AsyncWrite, ReadBuf}; |
| |
| <span class="kw">use </span>bytes::{Buf, BufMut}; |
| <span class="kw">use </span>futures_core::ready; |
| <span class="kw">use </span>std::io::{<span class="self">self</span>, IoSlice}; |
| <span class="kw">use </span>std::mem::MaybeUninit; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::task::{Context, Poll}; |
| |
| <span class="doccomment">/// Try to read data from an `AsyncRead` into an implementer of the [`BufMut`] trait. |
| /// |
| /// [`BufMut`]: bytes::Buf |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// use bytes::{Bytes, BytesMut}; |
| /// use tokio_stream as stream; |
| /// use tokio::io::Result; |
| /// use tokio_util::io::{StreamReader, poll_read_buf}; |
| /// use futures::future::poll_fn; |
| /// use std::pin::Pin; |
| /// # #[tokio::main] |
| /// # async fn main() -> std::io::Result<()> { |
| /// |
| /// // Create a reader from an iterator. This particular reader will always be |
| /// // ready. |
| /// let mut read = StreamReader::new(stream::iter(vec![Result::Ok(Bytes::from_static(&[0, 1, 2, 3]))])); |
| /// |
| /// let mut buf = BytesMut::new(); |
| /// let mut reads = 0; |
| /// |
| /// loop { |
| /// reads += 1; |
| /// let n = poll_fn(|cx| poll_read_buf(Pin::new(&mut read), cx, &mut buf)).await?; |
| /// |
| /// if n == 0 { |
| /// break; |
| /// } |
| /// } |
| /// |
| /// // one or more reads might be necessary. |
| /// assert!(reads >= 1); |
| /// assert_eq!(&buf[..], &[0, 1, 2, 3]); |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| </span><span class="attribute">#[cfg_attr(not(feature = <span class="string">"io"</span>), allow(unreachable_pub))] |
| </span><span class="kw">pub fn </span>poll_read_buf<T: AsyncRead, B: BufMut>( |
| io: Pin<<span class="kw-2">&mut </span>T>, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| buf: <span class="kw-2">&mut </span>B, |
| ) -> Poll<io::Result<usize>> { |
| <span class="kw">if </span>!buf.has_remaining_mut() { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="number">0</span>)); |
| } |
| |
| <span class="kw">let </span>n = { |
| <span class="kw">let </span>dst = buf.chunk_mut(); |
| |
| <span class="comment">// Safety: `chunk_mut()` returns a `&mut UninitSlice`, and `UninitSlice` is a |
| // transparent wrapper around `[MaybeUninit<u8>]`. |
| </span><span class="kw">let </span>dst = <span class="kw">unsafe </span>{ <span class="kw-2">&mut *</span>(dst <span class="kw">as </span><span class="kw-2">*mut </span><span class="kw">_ as </span><span class="kw-2">*mut </span>[MaybeUninit<u8>]) }; |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = ReadBuf::uninit(dst); |
| <span class="kw">let </span>ptr = buf.filled().as_ptr(); |
| <span class="macro">ready!</span>(io.poll_read(cx, <span class="kw-2">&mut </span>buf)<span class="question-mark">?</span>); |
| |
| <span class="comment">// Ensure the pointer does not change from under us |
| </span><span class="macro">assert_eq!</span>(ptr, buf.filled().as_ptr()); |
| buf.filled().len() |
| }; |
| |
| <span class="comment">// Safety: This is guaranteed to be the number of initialized (and read) |
| // bytes due to the invariants provided by `ReadBuf::filled`. |
| </span><span class="kw">unsafe </span>{ |
| buf.advance_mut(n); |
| } |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>(n)) |
| } |
| |
| <span class="doccomment">/// Try to write data from an implementer of the [`Buf`] trait to an |
| /// [`AsyncWrite`], advancing the buffer's internal cursor. |
| /// |
| /// This function will use [vectored writes] when the [`AsyncWrite`] supports |
| /// vectored writes. |
| /// |
| /// # Examples |
| /// |
| /// [`File`] implements [`AsyncWrite`] and [`Cursor<&[u8]>`] implements |
| /// [`Buf`]: |
| /// |
| /// ```no_run |
| /// use tokio_util::io::poll_write_buf; |
| /// use tokio::io; |
| /// use tokio::fs::File; |
| /// |
| /// use bytes::Buf; |
| /// use std::io::Cursor; |
| /// use std::pin::Pin; |
| /// use futures::future::poll_fn; |
| /// |
| /// #[tokio::main] |
| /// async fn main() -> io::Result<()> { |
| /// let mut file = File::create("foo.txt").await?; |
| /// let mut buf = Cursor::new(b"data to write"); |
| /// |
| /// // Loop until the entire contents of the buffer are written to |
| /// // the file. |
| /// while buf.has_remaining() { |
| /// poll_fn(|cx| poll_write_buf(Pin::new(&mut file), cx, &mut buf)).await?; |
| /// } |
| /// |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// [`Buf`]: bytes::Buf |
| /// [`AsyncWrite`]: tokio::io::AsyncWrite |
| /// [`File`]: tokio::fs::File |
| /// [vectored writes]: tokio::io::AsyncWrite::poll_write_vectored |
| </span><span class="attribute">#[cfg_attr(not(feature = <span class="string">"io"</span>), allow(unreachable_pub))] |
| </span><span class="kw">pub fn </span>poll_write_buf<T: AsyncWrite, B: Buf>( |
| io: Pin<<span class="kw-2">&mut </span>T>, |
| cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>, |
| buf: <span class="kw-2">&mut </span>B, |
| ) -> Poll<io::Result<usize>> { |
| <span class="kw">const </span>MAX_BUFS: usize = <span class="number">64</span>; |
| |
| <span class="kw">if </span>!buf.has_remaining() { |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(<span class="number">0</span>)); |
| } |
| |
| <span class="kw">let </span>n = <span class="kw">if </span>io.is_write_vectored() { |
| <span class="kw">let </span><span class="kw-2">mut </span>slices = [IoSlice::new(<span class="kw-2">&</span>[]); MAX_BUFS]; |
| <span class="kw">let </span>cnt = buf.chunks_vectored(<span class="kw-2">&mut </span>slices); |
| <span class="macro">ready!</span>(io.poll_write_vectored(cx, <span class="kw-2">&</span>slices[..cnt]))<span class="question-mark">? |
| </span>} <span class="kw">else </span>{ |
| <span class="macro">ready!</span>(io.poll_write(cx, buf.chunk()))<span class="question-mark">? |
| </span>}; |
| |
| buf.advance(n); |
| |
| Poll::Ready(<span class="prelude-val">Ok</span>(n)) |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="tokio_util" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
