| <!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/codec/lines_codec.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lines_codec.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="kw">use </span><span class="kw">crate</span>::codec::decoder::Decoder; |
| <span class="kw">use </span><span class="kw">crate</span>::codec::encoder::Encoder; |
| |
| <span class="kw">use </span>bytes::{Buf, BufMut, BytesMut}; |
| <span class="kw">use </span>std::{cmp, fmt, io, str, usize}; |
| |
| <span class="doccomment">/// A simple [`Decoder`] and [`Encoder`] implementation that splits up data into lines. |
| /// |
| /// [`Decoder`]: crate::codec::Decoder |
| /// [`Encoder`]: crate::codec::Encoder |
| </span><span class="attribute">#[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)] |
| </span><span class="kw">pub struct </span>LinesCodec { |
| <span class="comment">// Stored index of the next index to examine for a `\n` character. |
| // This is used to optimize searching. |
| // For example, if `decode` was called with `abc`, it would hold `3`, |
| // because that is the next index to examine. |
| // The next time `decode` is called with `abcde\n`, the method will |
| // only look at `de\n` before returning. |
| </span>next_index: usize, |
| |
| <span class="doccomment">/// The maximum length for a given line. If `usize::MAX`, lines will be |
| /// read until a `\n` character is reached. |
| </span>max_length: usize, |
| |
| <span class="doccomment">/// Are we currently discarding the remainder of a line which was over |
| /// the length limit? |
| </span>is_discarding: bool, |
| } |
| |
| <span class="kw">impl </span>LinesCodec { |
| <span class="doccomment">/// Returns a `LinesCodec` for splitting up data into lines. |
| /// |
| /// # Note |
| /// |
| /// The returned `LinesCodec` will not have an upper bound on the length |
| /// of a buffered line. See the documentation for [`new_with_max_length`] |
| /// for information on why this could be a potential security risk. |
| /// |
| /// [`new_with_max_length`]: crate::codec::LinesCodec::new_with_max_length() |
| </span><span class="kw">pub fn </span>new() -> LinesCodec { |
| LinesCodec { |
| next_index: <span class="number">0</span>, |
| max_length: usize::MAX, |
| is_discarding: <span class="bool-val">false</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Returns a `LinesCodec` with a maximum line length limit. |
| /// |
| /// If this is set, calls to `LinesCodec::decode` will return a |
| /// [`LinesCodecError`] when a line exceeds the length limit. Subsequent calls |
| /// will discard up to `limit` bytes from that line until a newline |
| /// character is reached, returning `None` until the line over the limit |
| /// has been fully discarded. After that point, calls to `decode` will |
| /// function as normal. |
| /// |
| /// # Note |
| /// |
| /// Setting a length limit is highly recommended for any `LinesCodec` which |
| /// will be exposed to untrusted input. Otherwise, the size of the buffer |
| /// that holds the line currently being read is unbounded. An attacker could |
| /// exploit this unbounded buffer by sending an unbounded amount of input |
| /// without any `\n` characters, causing unbounded memory consumption. |
| /// |
| /// [`LinesCodecError`]: crate::codec::LinesCodecError |
| </span><span class="kw">pub fn </span>new_with_max_length(max_length: usize) -> <span class="self">Self </span>{ |
| LinesCodec { |
| max_length, |
| ..LinesCodec::new() |
| } |
| } |
| |
| <span class="doccomment">/// Returns the maximum line length when decoding. |
| /// |
| /// ``` |
| /// use std::usize; |
| /// use tokio_util::codec::LinesCodec; |
| /// |
| /// let codec = LinesCodec::new(); |
| /// assert_eq!(codec.max_length(), usize::MAX); |
| /// ``` |
| /// ``` |
| /// use tokio_util::codec::LinesCodec; |
| /// |
| /// let codec = LinesCodec::new_with_max_length(256); |
| /// assert_eq!(codec.max_length(), 256); |
| /// ``` |
| </span><span class="kw">pub fn </span>max_length(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.max_length |
| } |
| } |
| |
| <span class="kw">fn </span>utf8(buf: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Result</span><<span class="kw-2">&</span>str, io::Error> { |
| str::from_utf8(buf) |
| .map_err(|<span class="kw">_</span>| io::Error::new(io::ErrorKind::InvalidData, <span class="string">"Unable to decode input as UTF8"</span>)) |
| } |
| |
| <span class="kw">fn </span>without_carriage_return(s: <span class="kw-2">&</span>[u8]) -> <span class="kw-2">&</span>[u8] { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="string">b'\r'</span>) = s.last() { |
| <span class="kw-2">&</span>s[..s.len() - <span class="number">1</span>] |
| } <span class="kw">else </span>{ |
| s |
| } |
| } |
| |
| <span class="kw">impl </span>Decoder <span class="kw">for </span>LinesCodec { |
| <span class="kw">type </span>Item = String; |
| <span class="kw">type </span>Error = LinesCodecError; |
| |
| <span class="kw">fn </span>decode(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&mut </span>BytesMut) -> <span class="prelude-ty">Result</span><<span class="prelude-ty">Option</span><String>, LinesCodecError> { |
| <span class="kw">loop </span>{ |
| <span class="comment">// Determine how far into the buffer we'll search for a newline. If |
| // there's no max_length set, we'll read to the end of the buffer. |
| </span><span class="kw">let </span>read_to = cmp::min(<span class="self">self</span>.max_length.saturating_add(<span class="number">1</span>), buf.len()); |
| |
| <span class="kw">let </span>newline_offset = buf[<span class="self">self</span>.next_index..read_to] |
| .iter() |
| .position(|b| <span class="kw-2">*</span>b == <span class="string">b'\n'</span>); |
| |
| <span class="kw">match </span>(<span class="self">self</span>.is_discarding, newline_offset) { |
| (<span class="bool-val">true</span>, <span class="prelude-val">Some</span>(offset)) => { |
| <span class="comment">// If we found a newline, discard up to that offset and |
| // then stop discarding. On the next iteration, we'll try |
| // to read a line normally. |
| </span>buf.advance(offset + <span class="self">self</span>.next_index + <span class="number">1</span>); |
| <span class="self">self</span>.is_discarding = <span class="bool-val">false</span>; |
| <span class="self">self</span>.next_index = <span class="number">0</span>; |
| } |
| (<span class="bool-val">true</span>, <span class="prelude-val">None</span>) => { |
| <span class="comment">// Otherwise, we didn't find a newline, so we'll discard |
| // everything we read. On the next iteration, we'll continue |
| // discarding up to max_len bytes unless we find a newline. |
| </span>buf.advance(read_to); |
| <span class="self">self</span>.next_index = <span class="number">0</span>; |
| <span class="kw">if </span>buf.is_empty() { |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>); |
| } |
| } |
| (<span class="bool-val">false</span>, <span class="prelude-val">Some</span>(offset)) => { |
| <span class="comment">// Found a line! |
| </span><span class="kw">let </span>newline_index = offset + <span class="self">self</span>.next_index; |
| <span class="self">self</span>.next_index = <span class="number">0</span>; |
| <span class="kw">let </span>line = buf.split_to(newline_index + <span class="number">1</span>); |
| <span class="kw">let </span>line = <span class="kw-2">&</span>line[..line.len() - <span class="number">1</span>]; |
| <span class="kw">let </span>line = without_carriage_return(line); |
| <span class="kw">let </span>line = utf8(line)<span class="question-mark">?</span>; |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(line.to_string())); |
| } |
| (<span class="bool-val">false</span>, <span class="prelude-val">None</span>) <span class="kw">if </span>buf.len() > <span class="self">self</span>.max_length => { |
| <span class="comment">// Reached the maximum length without finding a |
| // newline, return an error and start discarding on the |
| // next call. |
| </span><span class="self">self</span>.is_discarding = <span class="bool-val">true</span>; |
| <span class="kw">return </span><span class="prelude-val">Err</span>(LinesCodecError::MaxLineLengthExceeded); |
| } |
| (<span class="bool-val">false</span>, <span class="prelude-val">None</span>) => { |
| <span class="comment">// We didn't find a line or reach the length limit, so the next |
| // call will resume searching at the current offset. |
| </span><span class="self">self</span>.next_index = read_to; |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>); |
| } |
| } |
| } |
| } |
| |
| <span class="kw">fn </span>decode_eof(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&mut </span>BytesMut) -> <span class="prelude-ty">Result</span><<span class="prelude-ty">Option</span><String>, LinesCodecError> { |
| <span class="prelude-val">Ok</span>(<span class="kw">match </span><span class="self">self</span>.decode(buf)<span class="question-mark">? </span>{ |
| <span class="prelude-val">Some</span>(frame) => <span class="prelude-val">Some</span>(frame), |
| <span class="prelude-val">None </span>=> { |
| <span class="comment">// No terminating newline - return remaining data, if any |
| </span><span class="kw">if </span>buf.is_empty() || buf == <span class="kw-2">&</span><span class="string">b"\r"</span>[..] { |
| <span class="prelude-val">None |
| </span>} <span class="kw">else </span>{ |
| <span class="kw">let </span>line = buf.split_to(buf.len()); |
| <span class="kw">let </span>line = without_carriage_return(<span class="kw-2">&</span>line); |
| <span class="kw">let </span>line = utf8(line)<span class="question-mark">?</span>; |
| <span class="self">self</span>.next_index = <span class="number">0</span>; |
| <span class="prelude-val">Some</span>(line.to_string()) |
| } |
| } |
| }) |
| } |
| } |
| |
| <span class="kw">impl</span><T> Encoder<T> <span class="kw">for </span>LinesCodec |
| <span class="kw">where |
| </span>T: AsRef<str>, |
| { |
| <span class="kw">type </span>Error = LinesCodecError; |
| |
| <span class="kw">fn </span>encode(<span class="kw-2">&mut </span><span class="self">self</span>, line: T, buf: <span class="kw-2">&mut </span>BytesMut) -> <span class="prelude-ty">Result</span><(), LinesCodecError> { |
| <span class="kw">let </span>line = line.as_ref(); |
| buf.reserve(line.len() + <span class="number">1</span>); |
| buf.put(line.as_bytes()); |
| buf.put_u8(<span class="string">b'\n'</span>); |
| <span class="prelude-val">Ok</span>(()) |
| } |
| } |
| |
| <span class="kw">impl </span>Default <span class="kw">for </span>LinesCodec { |
| <span class="kw">fn </span>default() -> <span class="self">Self </span>{ |
| <span class="self">Self</span>::new() |
| } |
| } |
| |
| <span class="doccomment">/// An error occurred while encoding or decoding a line. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub enum </span>LinesCodecError { |
| <span class="doccomment">/// The maximum line length was exceeded. |
| </span>MaxLineLengthExceeded, |
| <span class="doccomment">/// An IO error occurred. |
| </span>Io(io::Error), |
| } |
| |
| <span class="kw">impl </span>fmt::Display <span class="kw">for </span>LinesCodecError { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| <span class="kw">match </span><span class="self">self </span>{ |
| LinesCodecError::MaxLineLengthExceeded => <span class="macro">write!</span>(f, <span class="string">"max line length exceeded"</span>), |
| LinesCodecError::Io(e) => <span class="macro">write!</span>(f, <span class="string">"{}"</span>, e), |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>From<io::Error> <span class="kw">for </span>LinesCodecError { |
| <span class="kw">fn </span>from(e: io::Error) -> LinesCodecError { |
| LinesCodecError::Io(e) |
| } |
| } |
| |
| <span class="kw">impl </span>std::error::Error <span class="kw">for </span>LinesCodecError {} |
| </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> |
