<!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 to the Rust file `/home/mrh/.cargo/registry/src/github.com-1ecc6299db9ec823/rayon-1.1.0/src/iter/empty.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>empty.rs.html -- source</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="../../../light.css" id="themeStyle"><script src="../../../storage.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="shortcut icon" href="../../../favicon.ico"><style type="text/css">#crate-search{background-image:url("../../../down-arrow.svg");}</style></head><body class="rustdoc source"><!--[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='../../../rayon/index.html'><div class='logo-container'><img src='../../../rust-logo.png' alt='logo'></div></a></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"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span>
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</pre><div class="example-wrap"><pre class="rust ">
<span class="kw">use</span> <span class="ident">iter</span>::<span class="ident">plumbing</span>::<span class="kw-2">*</span>;
<span class="kw">use</span> <span class="ident">iter</span>::<span class="kw-2">*</span>;
<span class="kw">use</span> <span class="ident">std</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">fmt</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">marker</span>::<span class="ident">PhantomData</span>;
<span class="doccomment">/// Creates a parallel iterator that produces nothing.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This admits no parallelism on its own, but it could be used for code that</span>
<span class="doccomment">/// deals with generic parallel iterators.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Examples</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use rayon::prelude::*;</span>
<span class="doccomment">/// use rayon::iter::empty;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let pi = (0..1234).into_par_iter()</span>
<span class="doccomment">/// .chain(empty())</span>
<span class="doccomment">/// .chain(1234..10_000);</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(pi.count(), 10_000);</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">empty</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span>() <span class="op">-</span><span class="op">></span> <span class="ident">Empty</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">Empty</span> {
<span class="ident">marker</span>: <span class="ident">PhantomData</span>,
}
}
<span class="doccomment">/// Iterator adaptor for [the `empty()` function](fn.empty.html).</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Empty</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> {
<span class="ident">marker</span>: <span class="ident">PhantomData</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Clone</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">clone</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">empty</span>()
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="ident">f</span>.<span class="ident">pad</span>(<span class="string">"Empty"</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">ParallelIterator</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">T</span>;
<span class="kw">fn</span> <span class="ident">drive_unindexed</span><span class="op"><</span><span class="ident">C</span><span class="op">></span>(<span class="self">self</span>, <span class="ident">consumer</span>: <span class="ident">C</span>) <span class="op">-</span><span class="op">></span> <span class="ident">C</span>::<span class="prelude-ty">Result</span>
<span class="kw">where</span>
<span class="ident">C</span>: <span class="ident">UnindexedConsumer</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span>,
{
<span class="self">self</span>.<span class="ident">drive</span>(<span class="ident">consumer</span>)
}
<span class="kw">fn</span> <span class="ident">opt_len</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> {
<span class="prelude-val">Some</span>(<span class="number">0</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">IndexedParallelIterator</span> <span class="kw">for</span> <span class="ident">Empty</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">drive</span><span class="op"><</span><span class="ident">C</span><span class="op">></span>(<span class="self">self</span>, <span class="ident">consumer</span>: <span class="ident">C</span>) <span class="op">-</span><span class="op">></span> <span class="ident">C</span>::<span class="prelude-ty">Result</span>
<span class="kw">where</span>
<span class="ident">C</span>: <span class="ident">Consumer</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span>,
{
<span class="ident">consumer</span>.<span class="ident">into_folder</span>().<span class="ident">complete</span>()
}
<span class="kw">fn</span> <span class="ident">len</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">usize</span> {
<span class="number">0</span>
}
<span class="kw">fn</span> <span class="ident">with_producer</span><span class="op"><</span><span class="ident">CB</span><span class="op">></span>(<span class="self">self</span>, <span class="ident">callback</span>: <span class="ident">CB</span>) <span class="op">-</span><span class="op">></span> <span class="ident">CB</span>::<span class="ident">Output</span>
<span class="kw">where</span>
<span class="ident">CB</span>: <span class="ident">ProducerCallback</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span>,
{
<span class="ident">callback</span>.<span class="ident">callback</span>(<span class="ident">EmptyProducer</span>(<span class="ident">PhantomData</span>))
}
}
<span class="doccomment">/// Private empty producer</span>
<span class="kw">struct</span> <span class="ident">EmptyProducer</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span>(<span class="ident">PhantomData</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>);
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span> <span class="ident">Producer</span> <span class="kw">for</span> <span class="ident">EmptyProducer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">T</span>;
<span class="kw">type</span> <span class="ident">IntoIter</span> <span class="op">=</span> <span class="ident">std</span>::<span class="ident">iter</span>::<span class="ident">Empty</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>;
<span class="kw">fn</span> <span class="ident">into_iter</span>(<span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span>::<span class="ident">IntoIter</span> {
<span class="ident">std</span>::<span class="ident">iter</span>::<span class="ident">empty</span>()
}
<span class="kw">fn</span> <span class="ident">split_at</span>(<span class="self">self</span>, <span class="ident">index</span>: <span class="ident">usize</span>) <span class="op">-</span><span class="op">></span> (<span class="self">Self</span>, <span class="self">Self</span>) {
<span class="macro">debug_assert_eq</span><span class="macro">!</span>(<span class="ident">index</span>, <span class="number">0</span>);
(<span class="self">self</span>, <span class="ident">EmptyProducer</span>(<span class="ident">PhantomData</span>))
}
<span class="kw">fn</span> <span class="ident">fold_with</span><span class="op"><</span><span class="ident">F</span><span class="op">></span>(<span class="self">self</span>, <span class="ident">folder</span>: <span class="ident">F</span>) <span class="op">-</span><span class="op">></span> <span class="ident">F</span>
<span class="kw">where</span>
<span class="ident">F</span>: <span class="ident">Folder</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span><span class="op">></span>,
{
<span class="ident">folder</span>
}
}
</pre></div>
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