| <!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/futures-util-0.3.28/src/future/future/shared.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>shared.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="../../../../futures_util/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="../../../../futures_util/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>::task::{waker_ref, ArcWake}; |
| <span class="kw">use </span>futures_core::future::{FusedFuture, Future}; |
| <span class="kw">use </span>futures_core::task::{Context, Poll, Waker}; |
| <span class="kw">use </span>slab::Slab; |
| <span class="kw">use </span>std::cell::UnsafeCell; |
| <span class="kw">use </span>std::fmt; |
| <span class="kw">use </span>std::hash::Hasher; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::ptr; |
| <span class="kw">use </span>std::sync::atomic::AtomicUsize; |
| <span class="kw">use </span>std::sync::atomic::Ordering::{Acquire, SeqCst}; |
| <span class="kw">use </span>std::sync::{Arc, Mutex, Weak}; |
| |
| <span class="doccomment">/// Future for the [`shared`](super::FutureExt::shared) method. |
| </span><span class="attribute">#[must_use = <span class="string">"futures do nothing unless you `.await` or poll them"</span>] |
| </span><span class="kw">pub struct </span>Shared<Fut: Future> { |
| inner: <span class="prelude-ty">Option</span><Arc<Inner<Fut>>>, |
| waker_key: usize, |
| } |
| |
| <span class="kw">struct </span>Inner<Fut: Future> { |
| future_or_output: UnsafeCell<FutureOrOutput<Fut>>, |
| notifier: Arc<Notifier>, |
| } |
| |
| <span class="kw">struct </span>Notifier { |
| state: AtomicUsize, |
| wakers: Mutex<<span class="prelude-ty">Option</span><Slab<<span class="prelude-ty">Option</span><Waker>>>>, |
| } |
| |
| <span class="doccomment">/// A weak reference to a [`Shared`] that can be upgraded much like an `Arc`. |
| </span><span class="kw">pub struct </span>WeakShared<Fut: Future>(Weak<Inner<Fut>>); |
| |
| <span class="kw">impl</span><Fut: Future> Clone <span class="kw">for </span>WeakShared<Fut> { |
| <span class="kw">fn </span>clone(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self </span>{ |
| <span class="self">Self</span>(<span class="self">self</span>.<span class="number">0</span>.clone()) |
| } |
| } |
| |
| <span class="comment">// The future itself is polled behind the `Arc`, so it won't be moved |
| // when `Shared` is moved. |
| </span><span class="kw">impl</span><Fut: Future> Unpin <span class="kw">for </span>Shared<Fut> {} |
| |
| <span class="kw">impl</span><Fut: Future> fmt::Debug <span class="kw">for </span>Shared<Fut> { |
| <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">"Shared"</span>) |
| .field(<span class="string">"inner"</span>, <span class="kw-2">&</span><span class="self">self</span>.inner) |
| .field(<span class="string">"waker_key"</span>, <span class="kw-2">&</span><span class="self">self</span>.waker_key) |
| .finish() |
| } |
| } |
| |
| <span class="kw">impl</span><Fut: Future> fmt::Debug <span class="kw">for </span>Inner<Fut> { |
| <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">"Inner"</span>).finish() |
| } |
| } |
| |
| <span class="kw">impl</span><Fut: Future> fmt::Debug <span class="kw">for </span>WeakShared<Fut> { |
| <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">"WeakShared"</span>).finish() |
| } |
| } |
| |
| <span class="kw">enum </span>FutureOrOutput<Fut: Future> { |
| Future(Fut), |
| Output(Fut::Output), |
| } |
| |
| <span class="kw">unsafe impl</span><Fut> Send <span class="kw">for </span>Inner<Fut> |
| <span class="kw">where |
| </span>Fut: Future + Send, |
| Fut::Output: Send + Sync, |
| { |
| } |
| |
| <span class="kw">unsafe impl</span><Fut> Sync <span class="kw">for </span>Inner<Fut> |
| <span class="kw">where |
| </span>Fut: Future + Send, |
| Fut::Output: Send + Sync, |
| { |
| } |
| |
| <span class="kw">const </span>IDLE: usize = <span class="number">0</span>; |
| <span class="kw">const </span>POLLING: usize = <span class="number">1</span>; |
| <span class="kw">const </span>COMPLETE: usize = <span class="number">2</span>; |
| <span class="kw">const </span>POISONED: usize = <span class="number">3</span>; |
| |
| <span class="kw">const </span>NULL_WAKER_KEY: usize = usize::max_value(); |
| |
| <span class="kw">impl</span><Fut: Future> Shared<Fut> { |
| <span class="kw">pub</span>(<span class="kw">super</span>) <span class="kw">fn </span>new(future: Fut) -> <span class="self">Self </span>{ |
| <span class="kw">let </span>inner = Inner { |
| future_or_output: UnsafeCell::new(FutureOrOutput::Future(future)), |
| notifier: Arc::new(Notifier { |
| state: AtomicUsize::new(IDLE), |
| wakers: Mutex::new(<span class="prelude-val">Some</span>(Slab::new())), |
| }), |
| }; |
| |
| <span class="self">Self </span>{ inner: <span class="prelude-val">Some</span>(Arc::new(inner)), waker_key: NULL_WAKER_KEY } |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> Shared<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| { |
| <span class="doccomment">/// Returns [`Some`] containing a reference to this [`Shared`]'s output if |
| /// it has already been computed by a clone or [`None`] if it hasn't been |
| /// computed yet or this [`Shared`] already returned its output from |
| /// [`poll`](Future::poll). |
| </span><span class="kw">pub fn </span>peek(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>Fut::Output> { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(inner) = <span class="self">self</span>.inner.as_ref() { |
| <span class="kw">match </span>inner.notifier.state.load(SeqCst) { |
| COMPLETE => <span class="kw">unsafe </span>{ <span class="kw">return </span><span class="prelude-val">Some</span>(inner.output()) }, |
| POISONED => <span class="macro">panic!</span>(<span class="string">"inner future panicked during poll"</span>), |
| <span class="kw">_ </span>=> {} |
| } |
| } |
| <span class="prelude-val">None |
| </span>} |
| |
| <span class="doccomment">/// Creates a new [`WeakShared`] for this [`Shared`]. |
| /// |
| /// Returns [`None`] if it has already been polled to completion. |
| </span><span class="kw">pub fn </span>downgrade(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><WeakShared<Fut>> { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(inner) = <span class="self">self</span>.inner.as_ref() { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(WeakShared(Arc::downgrade(inner))); |
| } |
| <span class="prelude-val">None |
| </span>} |
| |
| <span class="doccomment">/// Gets the number of strong pointers to this allocation. |
| /// |
| /// Returns [`None`] if it has already been polled to completion. |
| /// |
| /// # Safety |
| /// |
| /// This method by itself is safe, but using it correctly requires extra care. Another thread |
| /// can change the strong count at any time, including potentially between calling this method |
| /// and acting on the result. |
| </span><span class="attribute">#[allow(clippy::unnecessary_safety_doc)] |
| </span><span class="kw">pub fn </span>strong_count(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="self">self</span>.inner.as_ref().map(|arc| Arc::strong_count(arc)) |
| } |
| |
| <span class="doccomment">/// Gets the number of weak pointers to this allocation. |
| /// |
| /// Returns [`None`] if it has already been polled to completion. |
| /// |
| /// # Safety |
| /// |
| /// This method by itself is safe, but using it correctly requires extra care. Another thread |
| /// can change the weak count at any time, including potentially between calling this method |
| /// and acting on the result. |
| </span><span class="attribute">#[allow(clippy::unnecessary_safety_doc)] |
| </span><span class="kw">pub fn </span>weak_count(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="self">self</span>.inner.as_ref().map(|arc| Arc::weak_count(arc)) |
| } |
| |
| <span class="doccomment">/// Hashes the internal state of this `Shared` in a way that's compatible with `ptr_eq`. |
| </span><span class="kw">pub fn </span>ptr_hash<H: Hasher>(<span class="kw-2">&</span><span class="self">self</span>, state: <span class="kw-2">&mut </span>H) { |
| <span class="kw">match </span><span class="self">self</span>.inner.as_ref() { |
| <span class="prelude-val">Some</span>(arc) => { |
| state.write_u8(<span class="number">1</span>); |
| ptr::hash(Arc::as_ptr(arc), state); |
| } |
| <span class="prelude-val">None </span>=> { |
| state.write_u8(<span class="number">0</span>); |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Returns `true` if the two `Shared`s point to the same future (in a vein similar to |
| /// `Arc::ptr_eq`). |
| /// |
| /// Returns `false` if either `Shared` has terminated. |
| </span><span class="kw">pub fn </span>ptr_eq(<span class="kw-2">&</span><span class="self">self</span>, rhs: <span class="kw-2">&</span><span class="self">Self</span>) -> bool { |
| <span class="kw">let </span>lhs = <span class="kw">match </span><span class="self">self</span>.inner.as_ref() { |
| <span class="prelude-val">Some</span>(lhs) => lhs, |
| <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="bool-val">false</span>, |
| }; |
| <span class="kw">let </span>rhs = <span class="kw">match </span>rhs.inner.as_ref() { |
| <span class="prelude-val">Some</span>(rhs) => rhs, |
| <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="bool-val">false</span>, |
| }; |
| Arc::ptr_eq(lhs, rhs) |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> Inner<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| { |
| <span class="doccomment">/// Safety: callers must first ensure that `self.inner.state` |
| /// is `COMPLETE` |
| </span><span class="kw">unsafe fn </span>output(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>Fut::Output { |
| <span class="kw">match </span><span class="kw-2">&*</span><span class="self">self</span>.future_or_output.get() { |
| FutureOrOutput::Output(<span class="kw-2">ref </span>item) => item, |
| FutureOrOutput::Future(<span class="kw">_</span>) => <span class="macro">unreachable!</span>(), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> Inner<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| Fut::Output: Clone, |
| { |
| <span class="doccomment">/// Registers the current task to receive a wakeup when we are awoken. |
| </span><span class="kw">fn </span>record_waker(<span class="kw-2">&</span><span class="self">self</span>, waker_key: <span class="kw-2">&mut </span>usize, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) { |
| <span class="kw">let </span><span class="kw-2">mut </span>wakers_guard = <span class="self">self</span>.notifier.wakers.lock().unwrap(); |
| |
| <span class="kw">let </span>wakers = <span class="kw">match </span>wakers_guard.as_mut() { |
| <span class="prelude-val">Some</span>(wakers) => wakers, |
| <span class="prelude-val">None </span>=> <span class="kw">return</span>, |
| }; |
| |
| <span class="kw">let </span>new_waker = cx.waker(); |
| |
| <span class="kw">if </span><span class="kw-2">*</span>waker_key == NULL_WAKER_KEY { |
| <span class="kw-2">*</span>waker_key = wakers.insert(<span class="prelude-val">Some</span>(new_waker.clone())); |
| } <span class="kw">else </span>{ |
| <span class="kw">match </span>wakers[<span class="kw-2">*</span>waker_key] { |
| <span class="prelude-val">Some</span>(<span class="kw-2">ref </span>old_waker) <span class="kw">if </span>new_waker.will_wake(old_waker) => {} |
| <span class="comment">// Could use clone_from here, but Waker doesn't specialize it. |
| </span><span class="kw-2">ref mut </span>slot => <span class="kw-2">*</span>slot = <span class="prelude-val">Some</span>(new_waker.clone()), |
| } |
| } |
| <span class="macro">debug_assert!</span>(<span class="kw-2">*</span>waker_key != NULL_WAKER_KEY); |
| } |
| |
| <span class="doccomment">/// Safety: callers must first ensure that `inner.state` |
| /// is `COMPLETE` |
| </span><span class="kw">unsafe fn </span>take_or_clone_output(<span class="self">self</span>: Arc<<span class="self">Self</span>>) -> Fut::Output { |
| <span class="kw">match </span>Arc::try_unwrap(<span class="self">self</span>) { |
| <span class="prelude-val">Ok</span>(inner) => <span class="kw">match </span>inner.future_or_output.into_inner() { |
| FutureOrOutput::Output(item) => item, |
| FutureOrOutput::Future(<span class="kw">_</span>) => <span class="macro">unreachable!</span>(), |
| }, |
| <span class="prelude-val">Err</span>(inner) => inner.output().clone(), |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> FusedFuture <span class="kw">for </span>Shared<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| Fut::Output: Clone, |
| { |
| <span class="kw">fn </span>is_terminated(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.inner.is_none() |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> Future <span class="kw">for </span>Shared<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| Fut::Output: Clone, |
| { |
| <span class="kw">type </span>Output = Fut::Output; |
| |
| <span class="kw">fn </span>poll(<span class="kw-2">mut </span><span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, cx: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="self">Self</span>::Output> { |
| <span class="kw">let </span>this = <span class="kw-2">&mut *</span><span class="self">self</span>; |
| |
| <span class="kw">let </span>inner = this.inner.take().expect(<span class="string">"Shared future polled again after completion"</span>); |
| |
| <span class="comment">// Fast path for when the wrapped future has already completed |
| </span><span class="kw">if </span>inner.notifier.state.load(Acquire) == COMPLETE { |
| <span class="comment">// Safety: We're in the COMPLETE state |
| </span><span class="kw">return unsafe </span>{ Poll::Ready(inner.take_or_clone_output()) }; |
| } |
| |
| inner.record_waker(<span class="kw-2">&mut </span>this.waker_key, cx); |
| |
| <span class="kw">match </span>inner |
| .notifier |
| .state |
| .compare_exchange(IDLE, POLLING, SeqCst, SeqCst) |
| .unwrap_or_else(|x| x) |
| { |
| IDLE => { |
| <span class="comment">// Lock acquired, fall through |
| </span>} |
| POLLING => { |
| <span class="comment">// Another task is currently polling, at this point we just want |
| // to ensure that the waker for this task is registered |
| </span>this.inner = <span class="prelude-val">Some</span>(inner); |
| <span class="kw">return </span>Poll::Pending; |
| } |
| COMPLETE => { |
| <span class="comment">// Safety: We're in the COMPLETE state |
| </span><span class="kw">return unsafe </span>{ Poll::Ready(inner.take_or_clone_output()) }; |
| } |
| POISONED => <span class="macro">panic!</span>(<span class="string">"inner future panicked during poll"</span>), |
| <span class="kw">_ </span>=> <span class="macro">unreachable!</span>(), |
| } |
| |
| <span class="kw">let </span>waker = waker_ref(<span class="kw-2">&</span>inner.notifier); |
| <span class="kw">let </span><span class="kw-2">mut </span>cx = Context::from_waker(<span class="kw-2">&</span>waker); |
| |
| <span class="kw">struct </span>Reset<<span class="lifetime">'a</span>> { |
| state: <span class="kw-2">&</span><span class="lifetime">'a </span>AtomicUsize, |
| did_not_panic: bool, |
| } |
| |
| <span class="kw">impl </span>Drop <span class="kw">for </span>Reset<<span class="lifetime">'_</span>> { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="kw">if </span>!<span class="self">self</span>.did_not_panic { |
| <span class="self">self</span>.state.store(POISONED, SeqCst); |
| } |
| } |
| } |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>reset = Reset { state: <span class="kw-2">&</span>inner.notifier.state, did_not_panic: <span class="bool-val">false </span>}; |
| |
| <span class="kw">let </span>output = { |
| <span class="kw">let </span>future = <span class="kw">unsafe </span>{ |
| <span class="kw">match </span><span class="kw-2">&mut *</span>inner.future_or_output.get() { |
| FutureOrOutput::Future(fut) => Pin::new_unchecked(fut), |
| <span class="kw">_ </span>=> <span class="macro">unreachable!</span>(), |
| } |
| }; |
| |
| <span class="kw">let </span>poll_result = future.poll(<span class="kw-2">&mut </span>cx); |
| reset.did_not_panic = <span class="bool-val">true</span>; |
| |
| <span class="kw">match </span>poll_result { |
| Poll::Pending => { |
| <span class="kw">if </span>inner.notifier.state.compare_exchange(POLLING, IDLE, SeqCst, SeqCst).is_ok() |
| { |
| <span class="comment">// Success |
| </span>drop(reset); |
| this.inner = <span class="prelude-val">Some</span>(inner); |
| <span class="kw">return </span>Poll::Pending; |
| } <span class="kw">else </span>{ |
| <span class="macro">unreachable!</span>() |
| } |
| } |
| Poll::Ready(output) => output, |
| } |
| }; |
| |
| <span class="kw">unsafe </span>{ |
| <span class="kw-2">*</span>inner.future_or_output.get() = FutureOrOutput::Output(output); |
| } |
| |
| inner.notifier.state.store(COMPLETE, SeqCst); |
| |
| <span class="comment">// Wake all tasks and drop the slab |
| </span><span class="kw">let </span><span class="kw-2">mut </span>wakers_guard = inner.notifier.wakers.lock().unwrap(); |
| <span class="kw">let </span><span class="kw-2">mut </span>wakers = wakers_guard.take().unwrap(); |
| <span class="kw">for </span>waker <span class="kw">in </span>wakers.drain().flatten() { |
| waker.wake(); |
| } |
| |
| drop(reset); <span class="comment">// Make borrow checker happy |
| </span>drop(wakers_guard); |
| |
| <span class="comment">// Safety: We're in the COMPLETE state |
| </span><span class="kw">unsafe </span>{ Poll::Ready(inner.take_or_clone_output()) } |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> Clone <span class="kw">for </span>Shared<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| { |
| <span class="kw">fn </span>clone(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ inner: <span class="self">self</span>.inner.clone(), waker_key: NULL_WAKER_KEY } |
| } |
| } |
| |
| <span class="kw">impl</span><Fut> Drop <span class="kw">for </span>Shared<Fut> |
| <span class="kw">where |
| </span>Fut: Future, |
| { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="kw">if </span><span class="self">self</span>.waker_key != NULL_WAKER_KEY { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref </span>inner) = <span class="self">self</span>.inner { |
| <span class="kw">if let </span><span class="prelude-val">Ok</span>(<span class="kw-2">mut </span>wakers) = inner.notifier.wakers.lock() { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(wakers) = wakers.as_mut() { |
| wakers.remove(<span class="self">self</span>.waker_key); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>ArcWake <span class="kw">for </span>Notifier { |
| <span class="kw">fn </span>wake_by_ref(arc_self: <span class="kw-2">&</span>Arc<<span class="self">Self</span>>) { |
| <span class="kw">let </span>wakers = <span class="kw-2">&mut *</span>arc_self.wakers.lock().unwrap(); |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(wakers) = wakers.as_mut() { |
| <span class="kw">for </span>(_key, opt_waker) <span class="kw">in </span>wakers { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(waker) = opt_waker.take() { |
| waker.wake(); |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><Fut: Future> WeakShared<Fut> { |
| <span class="doccomment">/// Attempts to upgrade this [`WeakShared`] into a [`Shared`]. |
| /// |
| /// Returns [`None`] if all clones of the [`Shared`] have been dropped or polled |
| /// to completion. |
| </span><span class="kw">pub fn </span>upgrade(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><Shared<Fut>> { |
| <span class="prelude-val">Some</span>(Shared { inner: <span class="prelude-val">Some</span>(<span class="self">self</span>.<span class="number">0</span>.upgrade()<span class="question-mark">?</span>), waker_key: NULL_WAKER_KEY }) |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="futures_util" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |