| <!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/consumer.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>consumer.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 </span><span class="kw">super</span>::<span class="kw">super</span>::plumbing::<span class="kw-2">*</span>; |
| <span class="kw">use </span><span class="kw">crate</span>::SendPtr; |
| <span class="kw">use </span>std::marker::PhantomData; |
| <span class="kw">use </span>std::ptr; |
| <span class="kw">use </span>std::slice; |
| |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">struct </span>CollectConsumer<<span class="lifetime">'c</span>, T: Send> { |
| <span class="doccomment">/// See `CollectResult` for explanation of why this is not a slice |
| </span>start: SendPtr<T>, |
| len: usize, |
| marker: PhantomData<<span class="kw-2">&</span><span class="lifetime">'c </span><span class="kw-2">mut </span>T>, |
| } |
| |
| <span class="kw">impl</span><T: Send> CollectConsumer<<span class="lifetime">'_</span>, T> { |
| <span class="doccomment">/// Create a collector for `len` items in the unused capacity of the vector. |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>appender(vec: <span class="kw-2">&mut </span>Vec<T>, len: usize) -> CollectConsumer<<span class="lifetime">'_</span>, T> { |
| <span class="kw">let </span>start = vec.len(); |
| <span class="macro">assert!</span>(vec.capacity() - start >= len); |
| |
| <span class="comment">// SAFETY: We already made sure to have the additional space allocated. |
| // The pointer is derived from `Vec` directly, not through a `Deref`, |
| // so it has provenance over the whole allocation. |
| </span><span class="kw">unsafe </span>{ CollectConsumer::new(vec.as_mut_ptr().add(start), len) } |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'c</span>, T: Send + <span class="lifetime">'c</span>> CollectConsumer<<span class="lifetime">'c</span>, T> { |
| <span class="doccomment">/// The target memory is considered uninitialized, and will be |
| /// overwritten without reading or dropping existing values. |
| </span><span class="kw">unsafe fn </span>new(start: <span class="kw-2">*mut </span>T, len: usize) -> <span class="self">Self </span>{ |
| CollectConsumer { |
| start: SendPtr(start), |
| len, |
| marker: PhantomData, |
| } |
| } |
| } |
| |
| <span class="doccomment">/// CollectResult represents an initialized part of the target slice. |
| /// |
| /// This is a proxy owner of the elements in the slice; when it drops, |
| /// the elements will be dropped, unless its ownership is released before then. |
| </span><span class="attribute">#[must_use] |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">struct </span>CollectResult<<span class="lifetime">'c</span>, T> { |
| <span class="doccomment">/// This pointer and length has the same representation as a slice, |
| /// but retains the provenance of the entire array so that we can merge |
| /// these regions together in `CollectReducer`. |
| </span>start: SendPtr<T>, |
| total_len: usize, |
| <span class="doccomment">/// The current initialized length after `start` |
| </span>initialized_len: usize, |
| <span class="doccomment">/// Lifetime invariance guarantees that the data flows from consumer to result, |
| /// especially for the `scope_fn` callback in `Collect::with_consumer`. |
| </span>invariant_lifetime: PhantomData<<span class="kw-2">&</span><span class="lifetime">'c </span><span class="kw-2">mut &</span><span class="lifetime">'c </span><span class="kw-2">mut </span>[T]>, |
| } |
| |
| <span class="kw">unsafe impl</span><<span class="lifetime">'c</span>, T> Send <span class="kw">for </span>CollectResult<<span class="lifetime">'c</span>, T> <span class="kw">where </span>T: Send {} |
| |
| <span class="kw">impl</span><<span class="lifetime">'c</span>, T> CollectResult<<span class="lifetime">'c</span>, T> { |
| <span class="doccomment">/// The current length of the collect result |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>len(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.initialized_len |
| } |
| |
| <span class="doccomment">/// Release ownership of the slice of elements, and return the length |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>release_ownership(<span class="kw-2">mut </span><span class="self">self</span>) -> usize { |
| <span class="kw">let </span>ret = <span class="self">self</span>.initialized_len; |
| <span class="self">self</span>.initialized_len = <span class="number">0</span>; |
| ret |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'c</span>, T> Drop <span class="kw">for </span>CollectResult<<span class="lifetime">'c</span>, T> { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="comment">// Drop the first `self.initialized_len` elements, which have been recorded |
| // to be initialized by the folder. |
| </span><span class="kw">unsafe </span>{ |
| ptr::drop_in_place(slice::from_raw_parts_mut( |
| <span class="self">self</span>.start.<span class="number">0</span>, |
| <span class="self">self</span>.initialized_len, |
| )); |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'c</span>, T: Send + <span class="lifetime">'c</span>> Consumer<T> <span class="kw">for </span>CollectConsumer<<span class="lifetime">'c</span>, T> { |
| <span class="kw">type </span>Folder = CollectResult<<span class="lifetime">'c</span>, T>; |
| <span class="kw">type </span>Reducer = CollectReducer; |
| <span class="kw">type </span><span class="prelude-ty">Result </span>= CollectResult<<span class="lifetime">'c</span>, T>; |
| |
| <span class="kw">fn </span>split_at(<span class="self">self</span>, index: usize) -> (<span class="self">Self</span>, <span class="self">Self</span>, CollectReducer) { |
| <span class="kw">let </span>CollectConsumer { start, len, .. } = <span class="self">self</span>; |
| |
| <span class="comment">// Produce new consumers. |
| // SAFETY: This assert checks that `index` is a valid offset for `start` |
| </span><span class="kw">unsafe </span>{ |
| <span class="macro">assert!</span>(index <= len); |
| ( |
| CollectConsumer::new(start.<span class="number">0</span>, index), |
| CollectConsumer::new(start.<span class="number">0</span>.add(index), len - index), |
| CollectReducer, |
| ) |
| } |
| } |
| |
| <span class="kw">fn </span>into_folder(<span class="self">self</span>) -> <span class="self">Self</span>::Folder { |
| <span class="comment">// Create a result/folder that consumes values and writes them |
| // into the region after start. The initial result has length 0. |
| </span>CollectResult { |
| start: <span class="self">self</span>.start, |
| total_len: <span class="self">self</span>.len, |
| initialized_len: <span class="number">0</span>, |
| invariant_lifetime: PhantomData, |
| } |
| } |
| |
| <span class="kw">fn </span>full(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="bool-val">false |
| </span>} |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'c</span>, T: Send + <span class="lifetime">'c</span>> Folder<T> <span class="kw">for </span>CollectResult<<span class="lifetime">'c</span>, T> { |
| <span class="kw">type </span><span class="prelude-ty">Result </span>= <span class="self">Self</span>; |
| |
| <span class="kw">fn </span>consume(<span class="kw-2">mut </span><span class="self">self</span>, item: T) -> <span class="self">Self </span>{ |
| <span class="macro">assert!</span>( |
| <span class="self">self</span>.initialized_len < <span class="self">self</span>.total_len, |
| <span class="string">"too many values pushed to consumer" |
| </span>); |
| |
| <span class="comment">// SAFETY: The assert above is a bounds check for this write, and we |
| // avoid assignment here so we do not drop an uninitialized T. |
| </span><span class="kw">unsafe </span>{ |
| <span class="comment">// Write item and increase the initialized length |
| </span><span class="self">self</span>.start.<span class="number">0</span>.add(<span class="self">self</span>.initialized_len).write(item); |
| <span class="self">self</span>.initialized_len += <span class="number">1</span>; |
| } |
| |
| <span class="self">self |
| </span>} |
| |
| <span class="kw">fn </span>complete(<span class="self">self</span>) -> <span class="self">Self</span>::Result { |
| <span class="comment">// NB: We don't explicitly check that the local writes were complete, |
| // but Collect will assert the total result length in the end. |
| </span><span class="self">self |
| </span>} |
| |
| <span class="kw">fn </span>full(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="bool-val">false |
| </span>} |
| } |
| |
| <span class="doccomment">/// Pretend to be unindexed for `special_collect_into_vec`, |
| /// but we should never actually get used that way... |
| </span><span class="kw">impl</span><<span class="lifetime">'c</span>, T: Send + <span class="lifetime">'c</span>> UnindexedConsumer<T> <span class="kw">for </span>CollectConsumer<<span class="lifetime">'c</span>, T> { |
| <span class="kw">fn </span>split_off_left(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self </span>{ |
| <span class="macro">unreachable!</span>(<span class="string">"CollectConsumer must be indexed!"</span>) |
| } |
| <span class="kw">fn </span>to_reducer(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self</span>::Reducer { |
| CollectReducer |
| } |
| } |
| |
| <span class="doccomment">/// CollectReducer combines adjacent chunks; the result must always |
| /// be contiguous so that it is one combined slice. |
| </span><span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">struct </span>CollectReducer; |
| |
| <span class="kw">impl</span><<span class="lifetime">'c</span>, T> Reducer<CollectResult<<span class="lifetime">'c</span>, T>> <span class="kw">for </span>CollectReducer { |
| <span class="kw">fn </span>reduce( |
| <span class="self">self</span>, |
| <span class="kw-2">mut </span>left: CollectResult<<span class="lifetime">'c</span>, T>, |
| right: CollectResult<<span class="lifetime">'c</span>, T>, |
| ) -> CollectResult<<span class="lifetime">'c</span>, T> { |
| <span class="comment">// Merge if the CollectResults are adjacent and in left to right order |
| // else: drop the right piece now and total length will end up short in the end, |
| // when the correctness of the collected result is asserted. |
| </span><span class="kw">unsafe </span>{ |
| <span class="kw">let </span>left_end = left.start.<span class="number">0</span>.add(left.initialized_len); |
| <span class="kw">if </span>left_end == right.start.<span class="number">0 </span>{ |
| left.total_len += right.total_len; |
| left.initialized_len += right.release_ownership(); |
| } |
| left |
| } |
| } |
| } |
| </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> |
