<!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/stream/or_else.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>or_else.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>
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<span class="kw">use</span> {<span class="ident">IntoFuture</span>, <span class="ident">Future</span>, <span class="ident">Poll</span>, <span class="ident">Async</span>};
<span class="kw">use</span> <span class="ident">stream</span>::<span class="ident">Stream</span>;
<span class="doccomment">/// A stream combinator which chains a computation onto errors produced by a</span>
<span class="doccomment">/// stream.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This structure is produced by the `Stream::or_else` method.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span>
<span class="attribute">#[<span class="ident">must_use</span> <span class="op">=</span> <span class="string">"streams do nothing unless polled"</span>]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">OrElse</span><span class="op"><</span><span class="ident">S</span>, <span class="ident">F</span>, <span class="ident">U</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">U</span>: <span class="ident">IntoFuture</span>,
{
<span class="ident">stream</span>: <span class="ident">S</span>,
<span class="ident">future</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">U</span>::<span class="ident">Future</span><span class="op">></span>,
<span class="ident">f</span>: <span class="ident">F</span>,
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span><span class="op"><</span><span class="ident">S</span>, <span class="ident">F</span>, <span class="ident">U</span><span class="op">></span>(<span class="ident">s</span>: <span class="ident">S</span>, <span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-></span> <span class="ident">OrElse</span><span class="op"><</span><span class="ident">S</span>, <span class="ident">F</span>, <span class="ident">U</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">S</span>: <span class="ident">Stream</span>,
<span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">S</span>::<span class="ident">Error</span>) <span class="op">-></span> <span class="ident">U</span>,
<span class="ident">U</span>: <span class="ident">IntoFuture</span><span class="op"><</span><span class="ident">Item</span><span class="op">=</span><span class="ident">S</span>::<span class="ident">Item</span><span class="op">></span>,
{
<span class="ident">OrElse</span> {
<span class="ident">stream</span>: <span class="ident">s</span>,
<span class="ident">future</span>: <span class="prelude-val">None</span>,
<span class="ident">f</span>: <span class="ident">f</span>,
}
}
<span class="comment">// Forwarding impl of Sink from the underlying stream</span>
<span class="kw">impl</span><span class="op"><</span><span class="ident">S</span>, <span class="ident">F</span>, <span class="ident">U</span><span class="op">></span> ::<span class="ident">sink</span>::<span class="ident">Sink</span> <span class="kw">for</span> <span class="ident">OrElse</span><span class="op"><</span><span class="ident">S</span>, <span class="ident">F</span>, <span class="ident">U</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">S</span>: ::<span class="ident">sink</span>::<span class="ident">Sink</span>, <span class="ident">U</span>: <span class="ident">IntoFuture</span>
{
<span class="kw">type</span> <span class="ident">SinkItem</span> <span class="op">=</span> <span class="ident">S</span>::<span class="ident">SinkItem</span>;
<span class="kw">type</span> <span class="ident">SinkError</span> <span class="op">=</span> <span class="ident">S</span>::<span class="ident">SinkError</span>;
<span class="kw">fn</span> <span class="ident">start_send</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">item</span>: <span class="ident">S</span>::<span class="ident">SinkItem</span>) <span class="op">-></span> ::<span class="ident">StartSend</span><span class="op"><</span><span class="ident">S</span>::<span class="ident">SinkItem</span>, <span class="ident">S</span>::<span class="ident">SinkError</span><span class="op">></span> {
<span class="self">self</span>.<span class="ident">stream</span>.<span class="ident">start_send</span>(<span class="ident">item</span>)
}
<span class="kw">fn</span> <span class="ident">poll_complete</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="ident">S</span>::<span class="ident">SinkError</span><span class="op">></span> {
<span class="self">self</span>.<span class="ident">stream</span>.<span class="ident">poll_complete</span>()
}
<span class="kw">fn</span> <span class="ident">close</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="ident">S</span>::<span class="ident">SinkError</span><span class="op">></span> {
<span class="self">self</span>.<span class="ident">stream</span>.<span class="ident">close</span>()
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">S</span>, <span class="ident">F</span>, <span class="ident">U</span><span class="op">></span> <span class="ident">Stream</span> <span class="kw">for</span> <span class="ident">OrElse</span><span class="op"><</span><span class="ident">S</span>, <span class="ident">F</span>, <span class="ident">U</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">S</span>: <span class="ident">Stream</span>,
<span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">S</span>::<span class="ident">Error</span>) <span class="op">-></span> <span class="ident">U</span>,
<span class="ident">U</span>: <span class="ident">IntoFuture</span><span class="op"><</span><span class="ident">Item</span><span class="op">=</span><span class="ident">S</span>::<span class="ident">Item</span><span class="op">></span>,
{
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">S</span>::<span class="ident">Item</span>;
<span class="kw">type</span> <span class="ident">Error</span> <span class="op">=</span> <span class="ident">U</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="prelude-ty">Option</span><span class="op"><</span><span class="ident">S</span>::<span class="ident">Item</span><span class="op">></span>, <span class="ident">U</span>::<span class="ident">Error</span><span class="op">></span> {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">future</span>.<span class="ident">is_none</span>() {
<span class="kw">let</span> <span class="ident">item</span> <span class="op">=</span> <span class="kw">match</span> <span class="self">self</span>.<span class="ident">stream</span>.<span class="ident">poll</span>() {
<span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">Ready</span>(<span class="ident">e</span>)) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">Ready</span>(<span class="ident">e</span>)),
<span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">NotReady</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">NotReady</span>),
<span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> <span class="ident">e</span>,
};
<span class="self">self</span>.<span class="ident">future</span> <span class="op">=</span> <span class="prelude-val">Some</span>((<span class="self">self</span>.<span class="ident">f</span>)(<span class="ident">item</span>).<span class="ident">into_future</span>());
}
<span class="macro">assert</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">future</span>.<span class="ident">is_some</span>());
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">future</span>.<span class="ident">as_mut</span>().<span class="ident">unwrap</span>().<span class="ident">poll</span>() {
<span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">Ready</span>(<span class="ident">e</span>)) <span class="op">=></span> {
<span class="self">self</span>.<span class="ident">future</span> <span class="op">=</span> <span class="prelude-val">None</span>;
<span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">Ready</span>(<span class="prelude-val">Some</span>(<span class="ident">e</span>)))
}
<span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> {
<span class="self">self</span>.<span class="ident">future</span> <span class="op">=</span> <span class="prelude-val">None</span>;
<span class="prelude-val">Err</span>(<span class="ident">e</span>)
}
<span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">NotReady</span>) <span class="op">=></span> <span class="prelude-val">Ok</span>(<span class="ident">Async</span>::<span class="ident">NotReady</span>)
}
}
}
</pre>
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