| <!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/async_seek_ext.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>async_seek_ext.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::seek::{seek, Seek}; |
| <span class="kw">use </span><span class="kw">crate</span>::io::AsyncSeek; |
| <span class="kw">use </span>std::io::SeekFrom; |
| |
| <span class="macro">cfg_io_util! </span>{ |
| <span class="doccomment">/// An extension trait that adds utility methods to [`AsyncSeek`] types. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::io::{self, Cursor, SeekFrom}; |
| /// use tokio::io::{AsyncSeekExt, AsyncReadExt}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() -> io::Result<()> { |
| /// let mut cursor = Cursor::new(b"abcdefg"); |
| /// |
| /// // the `seek` method is defined by this trait |
| /// cursor.seek(SeekFrom::Start(3)).await?; |
| /// |
| /// let mut buf = [0; 1]; |
| /// let n = cursor.read(&mut buf).await?; |
| /// assert_eq!(n, 1); |
| /// assert_eq!(buf, [b'd']); |
| /// |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// See [module][crate::io] documentation for more details. |
| /// |
| /// [`AsyncSeek`]: AsyncSeek |
| </span><span class="kw">pub trait </span>AsyncSeekExt: AsyncSeek { |
| <span class="doccomment">/// Creates a future which will seek an IO object, and then yield the |
| /// new position in the object and the object itself. |
| /// |
| /// Equivalent to: |
| /// |
| /// ```ignore |
| /// async fn seek(&mut self, pos: SeekFrom) -> io::Result<u64>; |
| /// ``` |
| /// |
| /// In the case of an error the buffer and the object will be discarded, with |
| /// the error yielded. |
| /// |
| /// # Examples |
| /// |
| /// ```no_run |
| /// use tokio::fs::File; |
| /// use tokio::io::{AsyncSeekExt, AsyncReadExt}; |
| /// |
| /// use std::io::SeekFrom; |
| /// |
| /// # async fn dox() -> std::io::Result<()> { |
| /// let mut file = File::open("foo.txt").await?; |
| /// file.seek(SeekFrom::Start(6)).await?; |
| /// |
| /// let mut contents = vec![0u8; 10]; |
| /// file.read_exact(&mut contents).await?; |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| </span><span class="kw">fn </span>seek(<span class="kw-2">&mut </span><span class="self">self</span>, pos: SeekFrom) -> Seek<<span class="lifetime">'_</span>, <span class="self">Self</span>> |
| <span class="kw">where |
| </span><span class="self">Self</span>: Unpin, |
| { |
| seek(<span class="self">self</span>, pos) |
| } |
| |
| <span class="doccomment">/// Creates a future which will rewind to the beginning of the stream. |
| /// |
| /// This is convenience method, equivalent to `self.seek(SeekFrom::Start(0))`. |
| </span><span class="kw">fn </span>rewind(<span class="kw-2">&mut </span><span class="self">self</span>) -> Seek<<span class="lifetime">'_</span>, <span class="self">Self</span>> |
| <span class="kw">where |
| </span><span class="self">Self</span>: Unpin, |
| { |
| <span class="self">self</span>.seek(SeekFrom::Start(<span class="number">0</span>)) |
| } |
| |
| <span class="doccomment">/// Creates a future which will return the current seek position from the |
| /// start of the stream. |
| /// |
| /// This is equivalent to `self.seek(SeekFrom::Current(0))`. |
| </span><span class="kw">fn </span>stream_position(<span class="kw-2">&mut </span><span class="self">self</span>) -> Seek<<span class="lifetime">'_</span>, <span class="self">Self</span>> |
| <span class="kw">where |
| </span><span class="self">Self</span>: Unpin, |
| { |
| <span class="self">self</span>.seek(SeekFrom::Current(<span class="number">0</span>)) |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><S: AsyncSeek + <span class="question-mark">?</span>Sized> AsyncSeekExt <span class="kw">for </span>S {} |
| </code></pre></div> |
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