<!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 `/Users/travis/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.23/src/future/flatten.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>flatten.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></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></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"><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>
<span id="2"> 2</span>
<span id="3"> 3</span>
<span id="4"> 4</span>
<span id="5"> 5</span>
<span id="6"> 6</span>
<span id="7"> 7</span>
<span id="8"> 8</span>
<span id="9"> 9</span>
<span id="10">10</span>
<span id="11">11</span>
<span id="12">12</span>
<span id="13">13</span>
<span id="14">14</span>
<span id="15">15</span>
<span id="16">16</span>
<span id="17">17</span>
<span id="18">18</span>
<span id="19">19</span>
<span id="20">20</span>
<span id="21">21</span>
<span id="22">22</span>
<span id="23">23</span>
<span id="24">24</span>
<span id="25">25</span>
<span id="26">26</span>
<span id="27">27</span>
<span id="28">28</span>
<span id="29">29</span>
<span id="30">30</span>
<span id="31">31</span>
<span id="32">32</span>
<span id="33">33</span>
<span id="34">34</span>
<span id="35">35</span>
<span id="36">36</span>
<span id="37">37</span>
<span id="38">38</span>
<span id="39">39</span>
<span id="40">40</span>
<span id="41">41</span>
<span id="42">42</span>
<span id="43">43</span>
<span id="44">44</span>
<span id="45">45</span>
<span id="46">46</span>
<span id="47">47</span>
<span id="48">48</span>
<span id="49">49</span>
</pre><pre class="rust ">
<span class="kw">use</span> {<span class="ident">Future</span>, <span class="ident">IntoFuture</span>, <span class="ident">Poll</span>};
<span class="kw">use</span> <span class="ident">core</span>::<span class="ident">fmt</span>;
<span class="kw">use</span> <span class="kw">super</span>::<span class="ident">chain</span>::<span class="ident">Chain</span>;
<span class="doccomment">/// Future for the `flatten` combinator, flattening a future-of-a-future to get just</span>
<span class="doccomment">/// the result of the final future.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is created by the `Future::flatten` method.</span>
<span class="attribute">#[<span class="ident">must_use</span> <span class="op">=</span> <span class="string">"futures do nothing unless polled"</span>]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Flatten</span><span class="op"><</span><span class="ident">A</span><span class="op">></span> <span class="kw">where</span> <span class="ident">A</span>: <span class="ident">Future</span>, <span class="ident">A</span>::<span class="ident">Item</span>: <span class="ident">IntoFuture</span> {
<span class="ident">state</span>: <span class="ident">Chain</span><span class="op"><</span><span class="ident">A</span>, <span class="op"><</span><span class="ident">A</span>::<span class="ident">Item</span> <span class="kw">as</span> <span class="ident">IntoFuture</span><span class="op">></span>::<span class="ident">Future</span>, ()<span class="op">></span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">A</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Flatten</span><span class="op"><</span><span class="ident">A</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">Future</span> <span class="op">+</span> <span class="ident">fmt</span>::<span class="ident">Debug</span>,
<span class="ident">A</span>::<span class="ident">Item</span>: <span class="ident">IntoFuture</span>,
<span class="op"><<</span><span class="ident">A</span> <span class="kw">as</span> <span class="ident">IntoFuture</span><span class="op">></span>::<span class="ident">Item</span> <span class="kw">as</span> <span class="ident">IntoFuture</span><span class="op">></span>::<span class="ident">Future</span>: <span class="ident">fmt</span>::<span class="ident">Debug</span>,
{
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">fmt</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="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="ident">fmt</span>.<span class="ident">debug_struct</span>(<span class="string">"Flatten"</span>)
.<span class="ident">field</span>(<span class="string">"state"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">state</span>)
.<span class="ident">finish</span>()
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span><span class="op"><</span><span class="ident">A</span><span class="op">></span>(<span class="ident">future</span>: <span class="ident">A</span>) <span class="op">-></span> <span class="ident">Flatten</span><span class="op"><</span><span class="ident">A</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">Future</span>,
<span class="ident">A</span>::<span class="ident">Item</span>: <span class="ident">IntoFuture</span>,
{
<span class="ident">Flatten</span> {
<span class="ident">state</span>: <span class="ident">Chain</span>::<span class="ident">new</span>(<span class="ident">future</span>, ()),
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">A</span><span class="op">></span> <span class="ident">Future</span> <span class="kw">for</span> <span class="ident">Flatten</span><span class="op"><</span><span class="ident">A</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">A</span>: <span class="ident">Future</span>,
<span class="ident">A</span>::<span class="ident">Item</span>: <span class="ident">IntoFuture</span>,
<span class="op"><<</span><span class="ident">A</span> <span class="kw">as</span> <span class="ident">Future</span><span class="op">></span>::<span class="ident">Item</span> <span class="kw">as</span> <span class="ident">IntoFuture</span><span class="op">></span>::<span class="ident">Error</span>: <span class="ident">From</span><span class="op"><<</span><span class="ident">A</span> <span class="kw">as</span> <span class="ident">Future</span><span class="op">></span>::<span class="ident">Error</span><span class="op">></span>
{
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="op"><<</span><span class="ident">A</span> <span class="kw">as</span> <span class="ident">Future</span><span class="op">></span>::<span class="ident">Item</span> <span class="kw">as</span> <span class="ident">IntoFuture</span><span class="op">></span>::<span class="ident">Item</span>;
<span class="kw">type</span> <span class="ident">Error</span> <span class="op">=</span> <span class="op"><<</span><span class="ident">A</span> <span class="kw">as</span> <span class="ident">Future</span><span class="op">></span>::<span class="ident">Item</span> <span class="kw">as</span> <span class="ident">IntoFuture</span><span class="op">></span>::<span class="ident">Error</span>;
<span class="kw">fn</span> <span class="ident">poll</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">Poll</span><span class="op"><</span><span class="self">Self</span>::<span class="ident">Item</span>, <span class="self">Self</span>::<span class="ident">Error</span><span class="op">></span> {
<span class="self">self</span>.<span class="ident">state</span>.<span class="ident">poll</span>(<span class="op">|</span><span class="ident">a</span>, ()<span class="op">|</span> {
<span class="kw">let</span> <span class="ident">future</span> <span class="op">=</span> <span class="ident">a</span><span class="question-mark">?</span>.<span class="ident">into_future</span>();
<span class="prelude-val">Ok</span>(<span class="prelude-val">Err</span>(<span class="ident">future</span>))
})
}
}
</pre>
</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><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../../";window.currentCrate = "futures";</script><script src="../../../aliases.js"></script><script src="../../../main.js"></script><script defer src="../../../search-index.js"></script></body></html>