| <!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/git/checkouts/rayon-3b3b152053499ede/a07ce2e/src/iter/collect/mod.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>mod.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="../../../../rayon/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="../../../../rayon/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 super</span>::{IndexedParallelIterator, ParallelIterator}; |
| |
| <span class="kw">mod </span>consumer; |
| <span class="kw">use </span><span class="self">self</span>::consumer::CollectConsumer; |
| <span class="kw">use </span><span class="self">self</span>::consumer::CollectResult; |
| <span class="kw">use </span><span class="kw">super</span>::unzip::unzip_indexed; |
| |
| <span class="kw">mod </span>test; |
| |
| <span class="doccomment">/// Collects the results of the exact iterator into the specified vector. |
| /// |
| /// This is called by `IndexedParallelIterator::collect_into_vec`. |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>collect_into_vec<I, T>(pi: I, v: <span class="kw-2">&mut </span>Vec<T>) |
| <span class="kw">where |
| </span>I: IndexedParallelIterator<Item = T>, |
| T: Send, |
| { |
| v.truncate(<span class="number">0</span>); <span class="comment">// clear any old data |
| </span><span class="kw">let </span>len = pi.len(); |
| collect_with_consumer(v, len, |consumer| pi.drive(consumer)); |
| } |
| |
| <span class="doccomment">/// Collects the results of the iterator into the specified vector. |
| /// |
| /// Technically, this only works for `IndexedParallelIterator`, but we're faking a |
| /// bit of specialization here until Rust can do that natively. Callers are |
| /// using `opt_len` to find the length before calling this, and only exact |
| /// iterators will return anything but `None` there. |
| /// |
| /// Since the type system doesn't understand that contract, we have to allow |
| /// *any* `ParallelIterator` here, and `CollectConsumer` has to also implement |
| /// `UnindexedConsumer`. That implementation panics `unreachable!` in case |
| /// there's a bug where we actually do try to use this unindexed. |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>special_extend<I, T>(pi: I, len: usize, v: <span class="kw-2">&mut </span>Vec<T>) |
| <span class="kw">where |
| </span>I: ParallelIterator<Item = T>, |
| T: Send, |
| { |
| collect_with_consumer(v, len, |consumer| pi.drive_unindexed(consumer)); |
| } |
| |
| <span class="doccomment">/// Unzips the results of the exact iterator into the specified vectors. |
| /// |
| /// This is called by `IndexedParallelIterator::unzip_into_vecs`. |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>unzip_into_vecs<I, A, B>(pi: I, left: <span class="kw-2">&mut </span>Vec<A>, right: <span class="kw-2">&mut </span>Vec<B>) |
| <span class="kw">where |
| </span>I: IndexedParallelIterator<Item = (A, B)>, |
| A: Send, |
| B: Send, |
| { |
| <span class="comment">// clear any old data |
| </span>left.truncate(<span class="number">0</span>); |
| right.truncate(<span class="number">0</span>); |
| |
| <span class="kw">let </span>len = pi.len(); |
| collect_with_consumer(right, len, |right_consumer| { |
| <span class="kw">let </span><span class="kw-2">mut </span>right_result = <span class="prelude-val">None</span>; |
| collect_with_consumer(left, len, |left_consumer| { |
| <span class="kw">let </span>(left_r, right_r) = unzip_indexed(pi, left_consumer, right_consumer); |
| right_result = <span class="prelude-val">Some</span>(right_r); |
| left_r |
| }); |
| right_result.unwrap() |
| }); |
| } |
| |
| <span class="doccomment">/// Create a consumer on the slice of memory we are collecting into. |
| /// |
| /// The consumer needs to be used inside the scope function, and the |
| /// complete collect result passed back. |
| /// |
| /// This method will verify the collect result, and panic if the slice |
| /// was not fully written into. Otherwise, in the successful case, |
| /// the vector is complete with the collected result. |
| </span><span class="kw">fn </span>collect_with_consumer<T, F>(vec: <span class="kw-2">&mut </span>Vec<T>, len: usize, scope_fn: F) |
| <span class="kw">where |
| </span>T: Send, |
| F: FnOnce(CollectConsumer<<span class="lifetime">'_</span>, T>) -> CollectResult<<span class="lifetime">'_</span>, T>, |
| { |
| <span class="comment">// Reserve space for `len` more elements in the vector, |
| </span>vec.reserve(len); |
| |
| <span class="comment">// Create the consumer and run the callback for collection. |
| </span><span class="kw">let </span>result = scope_fn(CollectConsumer::appender(vec, len)); |
| |
| <span class="comment">// The `CollectResult` represents a contiguous part of the slice, that has |
| // been written to. On unwind here, the `CollectResult` will be dropped. If |
| // some producers on the way did not produce enough elements, partial |
| // `CollectResult`s may have been dropped without being reduced to the final |
| // result, and we will see that as the length coming up short. |
| // |
| // Here, we assert that added length is fully initialized. This is checked |
| // by the following assert, which verifies if a complete `CollectResult` |
| // was produced; if the length is correct, it is necessarily covering the |
| // target slice. Since we know that the consumer cannot have escaped from |
| // `drive` (by parametricity, essentially), we know that any stores that |
| // will happen, have happened. Unless some code is buggy, that means we |
| // should have seen `len` total writes. |
| </span><span class="kw">let </span>actual_writes = result.len(); |
| <span class="macro">assert!</span>( |
| actual_writes == len, |
| <span class="string">"expected {} total writes, but got {}"</span>, |
| len, |
| actual_writes |
| ); |
| |
| <span class="comment">// Release the result's mutable borrow and "proxy ownership" |
| // of the elements, before the vector takes it over. |
| </span>result.release_ownership(); |
| |
| <span class="kw">let </span>new_len = vec.len() + len; |
| |
| <span class="kw">unsafe </span>{ |
| vec.set_len(new_len); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="rayon" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |