| <!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/itertools-0.10.5/src/flatten_ok.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>flatten_ok.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="../../itertools/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="../../itertools/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>::size_hint; |
| <span class="kw">use </span>std::{ |
| fmt, |
| iter::{DoubleEndedIterator, FusedIterator}, |
| }; |
| |
| <span class="kw">pub fn </span>flatten_ok<I, T, E>(iter: I) -> FlattenOk<I, T, E> |
| <span class="kw">where |
| </span>I: Iterator<Item = <span class="prelude-ty">Result</span><T, E>>, |
| T: IntoIterator, |
| { |
| FlattenOk { |
| iter, |
| inner_front: <span class="prelude-val">None</span>, |
| inner_back: <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="doccomment">/// An iterator adaptor that flattens `Result::Ok` values and |
| /// allows `Result::Err` values through unchanged. |
| /// |
| /// See [`.flatten_ok()`](crate::Itertools::flatten_ok) for more information. |
| </span><span class="attribute">#[must_use = <span class="string">"iterator adaptors are lazy and do nothing unless consumed"</span>] |
| </span><span class="kw">pub struct </span>FlattenOk<I, T, E> |
| <span class="kw">where |
| </span>I: Iterator<Item = <span class="prelude-ty">Result</span><T, E>>, |
| T: IntoIterator, |
| { |
| iter: I, |
| inner_front: <span class="prelude-ty">Option</span><T::IntoIter>, |
| inner_back: <span class="prelude-ty">Option</span><T::IntoIter>, |
| } |
| |
| <span class="kw">impl</span><I, T, E> Iterator <span class="kw">for </span>FlattenOk<I, T, E> |
| <span class="kw">where |
| </span>I: Iterator<Item = <span class="prelude-ty">Result</span><T, E>>, |
| T: IntoIterator, |
| { |
| <span class="kw">type </span>Item = <span class="prelude-ty">Result</span><T::Item, E>; |
| |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>::Item> { |
| <span class="kw">loop </span>{ |
| <span class="comment">// Handle the front inner iterator. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(inner) = <span class="kw-2">&mut </span><span class="self">self</span>.inner_front { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(item) = inner.next() { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(item)); |
| } |
| |
| <span class="comment">// This is necessary for the iterator to implement `FusedIterator` |
| // with only the original iterator being fused. |
| </span><span class="self">self</span>.inner_front = <span class="prelude-val">None</span>; |
| } |
| |
| <span class="kw">match </span><span class="self">self</span>.iter.next() { |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(ok)) => <span class="self">self</span>.inner_front = <span class="prelude-val">Some</span>(ok.into_iter()), |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(e)) => <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(e)), |
| <span class="prelude-val">None </span>=> { |
| <span class="comment">// Handle the back inner iterator. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(inner) = <span class="kw-2">&mut </span><span class="self">self</span>.inner_back { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(item) = inner.next() { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(item)); |
| } |
| |
| <span class="comment">// This is necessary for the iterator to implement `FusedIterator` |
| // with only the original iterator being fused. |
| </span><span class="self">self</span>.inner_back = <span class="prelude-val">None</span>; |
| } <span class="kw">else </span>{ |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="kw">fn </span>size_hint(<span class="kw-2">&</span><span class="self">self</span>) -> (usize, <span class="prelude-ty">Option</span><usize>) { |
| <span class="kw">let </span>inner_hint = |inner: <span class="kw-2">&</span><span class="prelude-ty">Option</span><T::IntoIter>| { |
| inner |
| .as_ref() |
| .map(Iterator::size_hint) |
| .unwrap_or((<span class="number">0</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>))) |
| }; |
| <span class="kw">let </span>inner_front = inner_hint(<span class="kw-2">&</span><span class="self">self</span>.inner_front); |
| <span class="kw">let </span>inner_back = inner_hint(<span class="kw-2">&</span><span class="self">self</span>.inner_back); |
| <span class="comment">// The outer iterator `Ok` case could be (0, None) as we don't know its size_hint yet. |
| </span><span class="kw">let </span>outer = <span class="kw">match </span><span class="self">self</span>.iter.size_hint() { |
| (<span class="number">0</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>)) => (<span class="number">0</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| <span class="kw">_ </span>=> (<span class="number">0</span>, <span class="prelude-val">None</span>), |
| }; |
| |
| size_hint::add(size_hint::add(inner_front, inner_back), outer) |
| } |
| } |
| |
| <span class="kw">impl</span><I, T, E> DoubleEndedIterator <span class="kw">for </span>FlattenOk<I, T, E> |
| <span class="kw">where |
| </span>I: DoubleEndedIterator<Item = <span class="prelude-ty">Result</span><T, E>>, |
| T: IntoIterator, |
| T::IntoIter: DoubleEndedIterator, |
| { |
| <span class="kw">fn </span>next_back(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>::Item> { |
| <span class="kw">loop </span>{ |
| <span class="comment">// Handle the back inner iterator. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(inner) = <span class="kw-2">&mut </span><span class="self">self</span>.inner_back { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(item) = inner.next_back() { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(item)); |
| } |
| |
| <span class="comment">// This is necessary for the iterator to implement `FusedIterator` |
| // with only the original iterator being fused. |
| </span><span class="self">self</span>.inner_back = <span class="prelude-val">None</span>; |
| } |
| |
| <span class="kw">match </span><span class="self">self</span>.iter.next_back() { |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(ok)) => <span class="self">self</span>.inner_back = <span class="prelude-val">Some</span>(ok.into_iter()), |
| <span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(e)) => <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(e)), |
| <span class="prelude-val">None </span>=> { |
| <span class="comment">// Handle the front inner iterator. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(inner) = <span class="kw-2">&mut </span><span class="self">self</span>.inner_front { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(item) = inner.next_back() { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(item)); |
| } |
| |
| <span class="comment">// This is necessary for the iterator to implement `FusedIterator` |
| // with only the original iterator being fused. |
| </span><span class="self">self</span>.inner_front = <span class="prelude-val">None</span>; |
| } <span class="kw">else </span>{ |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><I, T, E> Clone <span class="kw">for </span>FlattenOk<I, T, E> |
| <span class="kw">where |
| </span>I: Iterator<Item = <span class="prelude-ty">Result</span><T, E>> + Clone, |
| T: IntoIterator, |
| T::IntoIter: Clone, |
| { |
| <span class="macro">clone_fields!</span>(iter, inner_front, inner_back); |
| } |
| |
| <span class="kw">impl</span><I, T, E> fmt::Debug <span class="kw">for </span>FlattenOk<I, T, E> |
| <span class="kw">where |
| </span>I: Iterator<Item = <span class="prelude-ty">Result</span><T, E>> + fmt::Debug, |
| T: IntoIterator, |
| T::IntoIter: fmt::Debug, |
| { |
| <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 { |
| f.debug_struct(<span class="string">"FlattenOk"</span>) |
| .field(<span class="string">"iter"</span>, <span class="kw-2">&</span><span class="self">self</span>.iter) |
| .field(<span class="string">"inner_front"</span>, <span class="kw-2">&</span><span class="self">self</span>.inner_front) |
| .field(<span class="string">"inner_back"</span>, <span class="kw-2">&</span><span class="self">self</span>.inner_back) |
| .finish() |
| } |
| } |
| |
| <span class="doccomment">/// Only the iterator being flattened needs to implement [`FusedIterator`]. |
| </span><span class="kw">impl</span><I, T, E> FusedIterator <span class="kw">for </span>FlattenOk<I, T, E> |
| <span class="kw">where |
| </span>I: FusedIterator<Item = <span class="prelude-ty">Result</span><T, E>>, |
| T: IntoIterator, |
| { |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="itertools" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
