<!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="API documentation for the Rust `DecoderHelpers` trait in crate `rustc_serialize`."> <meta name="keywords" content="rust, rustlang, rust-lang, DecoderHelpers"> <title>rustc_serialize::DecoderHelpers - Rust</title> <link rel="stylesheet" type="text/css" href="../normalize.css"> <link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle"> <link rel="stylesheet" type="text/css" href="../dark.css"> <link rel="stylesheet" type="text/css" href="../main.css" id="themeStyle"> <script src="../storage.js"></script> <link rel="shortcut icon" href="https://www.rust-lang.org/favicon.ico"> </head> <body class="rustdoc trait"> <!--[if lte IE 8]> <div class="warning"> This old browser is unsupported and will most likely display funky things. </div> <![endif]--> <nav class="sidebar"> <div class="sidebar-menu">☰</div> <a href='../rustc_serialize/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a> <p class='location'>Trait DecoderHelpers</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#required-methods">Required Methods</a><div class="sidebar-links"><a href="#tymethod.read_to_vec">read_to_vec</a></div><a class="sidebar-title" href="#implementors">Implementors</a></div><p class='location'><a href='index.html'>rustc_serialize</a></p><script>window.sidebarCurrent = {name: 'DecoderHelpers', ty: 'trait', relpath: ''};</script><script defer src="sidebar-items.js"></script></div> </nav> <div class="theme-picker"> <button id="theme-picker" aria-label="Pick another theme!"> <img src="../brush.svg" width="18" alt="Pick another theme!"> </button> <div id="theme-choices"></div> </div> <script src="../theme.js"></script> <nav class="sub"> <form class="search-form js-only"> <div class="search-container"> <input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"> </div> </form> </nav> <section id='main' class="content"> <h1 class='fqn'><span class='in-band'>Trait <a href='index.html'>rustc_serialize</a>::<wbr><a class="trait" href=''>DecoderHelpers</a></span><span class='out-of-band'><span id='render-detail'> <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs"> [<span class='inner'>−</span>] </a> </span><a class='srclink' href='../src/rustc_serialize/serialize.rs.html#1515-1548' title='goto source code'>[src]</a></span></h1> <pre class='rust trait'>pub trait DecoderHelpers: <a class="trait" href="../rustc_serialize/trait.Decoder.html" title="trait rustc_serialize::Decoder">Decoder</a> { fn <a href='#tymethod.read_to_vec' class='fnname'>read_to_vec</a><T, F>(&mut self, f: F) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/vec/struct.Vec.html" title="struct alloc::vec::Vec">Vec</a><T>, Self::<a class="type" href="../rustc_serialize/trait.Decoder.html#associatedtype.Error" title="type rustc_serialize::Decoder::Error">Error</a>><br> <span class="where">where<br> F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnMut.html" title="trait core::ops::function::FnMut">FnMut</a>(<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>Self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, Self::<a class="type" href="../rustc_serialize/trait.Decoder.html#associatedtype.Error" title="type rustc_serialize::Decoder::Error">Error</a>></span>; }</pre><div class='docblock'><p>Trait with helper functions for implementing <code>Decodable</code>.</p> <p>This trait is implemented for everything that implements <code>Decoder</code>. <code>Decodable</code> implementations can make use of it to make their implementations easier.</p> </div> <h2 id='required-methods' class='small-section-header'> Required Methods<a href='#required-methods' class='anchor'></a> </h2> <div class='methods'> <h3 id='tymethod.read_to_vec' class='method'><span id='read_to_vec.v' class='invisible'><code>fn <a href='#tymethod.read_to_vec' class='fnname'>read_to_vec</a><T, F>(&mut self, f: F) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/vec/struct.Vec.html" title="struct alloc::vec::Vec">Vec</a><T>, Self::<a class="type" href="../rustc_serialize/trait.Decoder.html#associatedtype.Error" title="type rustc_serialize::Decoder::Error">Error</a>> <span class="where fmt-newline">where<br> F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnMut.html" title="trait core::ops::function::FnMut">FnMut</a>(<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>Self) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><T, Self::<a class="type" href="../rustc_serialize/trait.Decoder.html#associatedtype.Error" title="type rustc_serialize::Decoder::Error">Error</a>>, </span></code></span></h3><div class='docblock'><p>Read a sequence into a vector.</p> <p>Storing sequences as vectors is a common pattern. This method makes deserializing such sequences easier by wrapping the calls to <code>Decoder::read_seq</code> and <code>Decoder::read_seq_elt</code>.</p> <h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1> <pre class="rust rust-example-rendered"> <span class="kw">use</span> <span class="ident">rustc_serialize</span>::<span class="ident">Decodable</span>; <span class="kw">use</span> <span class="ident">rustc_serialize</span>::<span class="ident">Decoder</span>; <span class="kw">use</span> <span class="ident">rustc_serialize</span>::<span class="ident">DecoderHelpers</span>; <span class="kw">struct</span> <span class="ident">NumberSequence</span> { <span class="ident">elements</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">i32</span><span class="op">></span>, } <span class="kw">impl</span> <span class="ident">Decodable</span> <span class="kw">for</span> <span class="ident">NumberSequence</span> { <span class="kw">fn</span> <span class="ident">decode</span><span class="op"><</span><span class="ident">D</span>: <span class="ident">Decoder</span><span class="op">></span>(<span class="ident">d</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">D</span>) <span class="op">-></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">NumberSequence</span>, <span class="ident">D</span>::<span class="ident">Error</span><span class="op">></span> { <span class="ident">d</span>.<span class="ident">read_struct</span>(<span class="string">"NumberSequence"</span>, <span class="number">2</span>, <span class="op">|</span><span class="ident">d</span><span class="op">|</span> { <span class="prelude-val">Ok</span>(<span class="ident">NumberSequence</span>{ <span class="ident">elements</span>: <span class="macro">try</span><span class="macro">!</span>(<span class="ident">d</span>.<span class="ident">read_struct_field</span>(<span class="string">"elements"</span>, <span class="number">0</span>, <span class="op">|</span><span class="ident">d</span><span class="op">|</span> { <span class="ident">d</span>.<span class="ident">read_to_vec</span>(<span class="op">|</span><span class="ident">d</span><span class="op">|</span> { <span class="ident">d</span>.<span class="ident">read_i32</span>() }) })) }) }) } }</pre> </div></div> <h2 id='implementors' class='small-section-header'> Implementors<a href='#implementors' class='anchor'></a> </h2> <ul class='item-list' id='implementors-list'> <li><div class='out-of-band'><a class='srclink' href='../src/rustc_serialize/serialize.rs.html#1550-1562' title='goto source code'>[src]</a></div><code>impl<D: <a class="trait" href="../rustc_serialize/trait.Decoder.html" title="trait rustc_serialize::Decoder">Decoder</a>> DecoderHelpers for D</code></li> </ul><script type="text/javascript" async src="../implementors/rustc_serialize/trait.DecoderHelpers.js"> </script></section> <section id='search' class="content hidden"></section> <section class="footer"></section> <aside id="help" class="hidden"> <div> <h1 class="hidden">Help</h1> <div class="shortcuts"> <h2>Keyboard Shortcuts</h2> <dl> <dt><kbd>?</kbd></dt> <dd>Show this help dialog</dd> <dt><kbd>S</kbd></dt> <dd>Focus the search field</dd> <dt><kbd>↑</kbd></dt> <dd>Move up in search results</dd> <dt><kbd>↓</kbd></dt> <dd>Move down in search results</dd> <dt><kbd>↹</kbd></dt> <dd>Switch tab</dd> <dt><kbd>⏎</kbd></dt> <dd>Go to active search result</dd> <dt><kbd>+</kbd></dt> <dd>Expand all sections</dd> <dt><kbd>-</kbd></dt> <dd>Collapse all sections</dd> </dl> </div> <div class="infos"> <h2>Search Tricks</h2> <p> Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type. </p> <p> Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>. </p> <p> Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>) </p> </div> </div> </aside> <script> window.rootPath = "../"; window.currentCrate = "rustc_serialize"; </script> <script src="../main.js"></script> <script defer src="../search-index.js"></script> </body> </html>