| <!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/want-0.3.0/src/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.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="../../want/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="../../want/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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| <span id="583">583</span> |
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| <span id="585">585</span> |
| </pre><pre class="rust"><code><span class="attribute">#![doc(html_root_url = <span class="string">"https://docs.rs/want/0.3.0"</span>)] |
| #![deny(warnings)] |
| #![deny(missing_docs)] |
| #![deny(missing_debug_implementations)] |
| |
| </span><span class="doccomment">//! A Futures channel-like utility to signal when a value is wanted. |
| //! |
| //! Futures are supposed to be lazy, and only starting work if `Future::poll` |
| //! is called. The same is true of `Stream`s, but when using a channel as |
| //! a `Stream`, it can be hard to know if the receiver is ready for the next |
| //! value. |
| //! |
| //! Put another way, given a `(tx, rx)` from `futures::sync::mpsc::channel()`, |
| //! how can the sender (`tx`) know when the receiver (`rx`) actually wants more |
| //! work to be produced? Just because there is room in the channel buffer |
| //! doesn't mean the work would be used by the receiver. |
| //! |
| //! This is where something like `want` comes in. Added to a channel, you can |
| //! make sure that the `tx` only creates the message and sends it when the `rx` |
| //! has `poll()` for it, and the buffer was empty. |
| //! |
| //! # Example |
| //! |
| //! ```nightly |
| //! # //#![feature(async_await)] |
| //! extern crate want; |
| //! |
| //! # fn spawn<T>(_t: T) {} |
| //! # fn we_still_want_message() -> bool { true } |
| //! # fn mpsc_channel() -> (Tx, Rx) { (Tx, Rx) } |
| //! # struct Tx; |
| //! # impl Tx { fn send<T>(&mut self, _: T) {} } |
| //! # struct Rx; |
| //! # impl Rx { async fn recv(&mut self) -> Option<Expensive> { Some(Expensive) } } |
| //! |
| //! // Some message that is expensive to produce. |
| //! struct Expensive; |
| //! |
| //! // Some futures-aware MPSC channel... |
| //! let (mut tx, mut rx) = mpsc_channel(); |
| //! |
| //! // And our `want` channel! |
| //! let (mut gv, mut tk) = want::new(); |
| //! |
| //! |
| //! // Our receiving task... |
| //! spawn(async move { |
| //! // Maybe something comes up that prevents us from ever |
| //! // using the expensive message. |
| //! // |
| //! // Without `want`, the "send" task may have started to |
| //! // produce the expensive message even though we wouldn't |
| //! // be able to use it. |
| //! if !we_still_want_message() { |
| //! return; |
| //! } |
| //! |
| //! // But we can use it! So tell the `want` channel. |
| //! tk.want(); |
| //! |
| //! match rx.recv().await { |
| //! Some(_msg) => println!("got a message"), |
| //! None => println!("DONE"), |
| //! } |
| //! }); |
| //! |
| //! // Our sending task |
| //! spawn(async move { |
| //! // It's expensive to create a new message, so we wait until the |
| //! // receiving end truly *wants* the message. |
| //! if let Err(_closed) = gv.want().await { |
| //! // Looks like they will never want it... |
| //! return; |
| //! } |
| //! |
| //! // They want it, let's go! |
| //! tx.send(Expensive); |
| //! }); |
| //! |
| //! # fn main() {} |
| //! ``` |
| |
| </span><span class="attribute">#[macro_use] |
| </span><span class="kw">extern crate </span>log; |
| |
| <span class="kw">use </span>std::fmt; |
| <span class="kw">use </span>std::future::Future; |
| <span class="kw">use </span>std::mem; |
| <span class="kw">use </span>std::pin::Pin; |
| <span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>std::sync::atomic::AtomicUsize; |
| <span class="comment">// SeqCst is the only ordering used to ensure accessing the state and |
| // TryLock are never re-ordered. |
| </span><span class="kw">use </span>std::sync::atomic::Ordering::SeqCst; |
| <span class="kw">use </span>std::task::{<span class="self">self</span>, Poll, Waker}; |
| |
| |
| <span class="kw">use </span>try_lock::TryLock; |
| |
| <span class="doccomment">/// Create a new `want` channel. |
| </span><span class="kw">pub fn </span>new() -> (Giver, Taker) { |
| <span class="kw">let </span>inner = Arc::new(Inner { |
| state: AtomicUsize::new(State::Idle.into()), |
| task: TryLock::new(<span class="prelude-val">None</span>), |
| }); |
| <span class="kw">let </span>inner2 = inner.clone(); |
| ( |
| Giver { |
| inner: inner, |
| }, |
| Taker { |
| inner: inner2, |
| }, |
| ) |
| } |
| |
| <span class="doccomment">/// An entity that gives a value when wanted. |
| </span><span class="kw">pub struct </span>Giver { |
| inner: Arc<Inner>, |
| } |
| |
| <span class="doccomment">/// An entity that wants a value. |
| </span><span class="kw">pub struct </span>Taker { |
| inner: Arc<Inner>, |
| } |
| |
| <span class="doccomment">/// A cloneable `Giver`. |
| /// |
| /// It differs from `Giver` in that you cannot poll for `want`. It's only |
| /// usable as a cancellation watcher. |
| </span><span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>SharedGiver { |
| inner: Arc<Inner>, |
| } |
| |
| <span class="doccomment">/// The `Taker` has canceled its interest in a value. |
| </span><span class="kw">pub struct </span>Closed { |
| _inner: (), |
| } |
| |
| <span class="attribute">#[derive(Clone, Copy, Debug)] |
| </span><span class="kw">enum </span>State { |
| Idle, |
| Want, |
| Give, |
| Closed, |
| } |
| |
| <span class="kw">impl </span>From<State> <span class="kw">for </span>usize { |
| <span class="kw">fn </span>from(s: State) -> usize { |
| <span class="kw">match </span>s { |
| State::Idle => <span class="number">0</span>, |
| State::Want => <span class="number">1</span>, |
| State::Give => <span class="number">2</span>, |
| State::Closed => <span class="number">3</span>, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>From<usize> <span class="kw">for </span>State { |
| <span class="kw">fn </span>from(num: usize) -> State { |
| <span class="kw">match </span>num { |
| <span class="number">0 </span>=> State::Idle, |
| <span class="number">1 </span>=> State::Want, |
| <span class="number">2 </span>=> State::Give, |
| <span class="number">3 </span>=> State::Closed, |
| <span class="kw">_ </span>=> <span class="macro">unreachable!</span>(<span class="string">"unknown state: {}"</span>, num), |
| } |
| } |
| } |
| |
| <span class="kw">struct </span>Inner { |
| state: AtomicUsize, |
| task: TryLock<<span class="prelude-ty">Option</span><Waker>>, |
| } |
| |
| <span class="comment">// ===== impl Giver ====== |
| |
| </span><span class="kw">impl </span>Giver { |
| <span class="doccomment">/// Returns a `Future` that fulfills when the `Taker` has done some action. |
| </span><span class="kw">pub fn </span>want<<span class="lifetime">'a</span>>(<span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span><span class="self">self</span>) -> <span class="kw">impl </span>Future<Output = <span class="prelude-ty">Result</span><(), Closed>> + <span class="lifetime">'a </span>{ |
| Want(<span class="self">self</span>) |
| } |
| |
| <span class="doccomment">/// Poll whether the `Taker` has registered interest in another value. |
| /// |
| /// - If the `Taker` has called `want()`, this returns `Async::Ready(())`. |
| /// - If the `Taker` has not called `want()` since last poll, this |
| /// returns `Async::NotReady`, and parks the current task to be notified |
| /// when the `Taker` does call `want()`. |
| /// - If the `Taker` has canceled (or dropped), this returns `Closed`. |
| /// |
| /// After knowing that the Taker is wanting, the state can be reset by |
| /// calling [`give`](Giver::give). |
| </span><span class="kw">pub fn </span>poll_want(<span class="kw-2">&mut </span><span class="self">self</span>, cx: <span class="kw-2">&mut </span>task::Context<<span class="lifetime">'_</span>>) -> Poll<<span class="prelude-ty">Result</span><(), Closed>> { |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span>state = <span class="self">self</span>.inner.state.load(SeqCst).into(); |
| <span class="kw">match </span>state { |
| State::Want => { |
| <span class="macro">trace!</span>(<span class="string">"poll_want: taker wants!"</span>); |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Ok</span>(())); |
| }, |
| State::Closed => { |
| <span class="macro">trace!</span>(<span class="string">"poll_want: closed"</span>); |
| <span class="kw">return </span>Poll::Ready(<span class="prelude-val">Err</span>(Closed { _inner: () })); |
| }, |
| State::Idle | State::Give => { |
| <span class="comment">// Taker doesn't want anything yet, so park. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">mut </span>locked) = <span class="self">self</span>.inner.task.try_lock_order(SeqCst, SeqCst) { |
| |
| <span class="comment">// While we have the lock, try to set to GIVE. |
| </span><span class="kw">let </span>old = <span class="self">self</span>.inner.state.compare_and_swap( |
| state.into(), |
| State::Give.into(), |
| SeqCst, |
| ); |
| <span class="comment">// If it's still the first state (Idle or Give), park current task. |
| </span><span class="kw">if </span>old == state.into() { |
| <span class="kw">let </span>park = locked.as_ref() |
| .map(|w| !w.will_wake(cx.waker())) |
| .unwrap_or(<span class="bool-val">true</span>); |
| <span class="kw">if </span>park { |
| <span class="kw">let </span>old = mem::replace(<span class="kw-2">&mut *</span>locked, <span class="prelude-val">Some</span>(cx.waker().clone())); |
| drop(locked); |
| old.map(|prev_task| { |
| <span class="comment">// there was an old task parked here. |
| // it might be waiting to be notified, |
| // so poke it before dropping. |
| </span>prev_task.wake(); |
| }); |
| } |
| <span class="kw">return </span>Poll::Pending; |
| } |
| <span class="comment">// Otherwise, something happened! Go around the loop again. |
| </span>} <span class="kw">else </span>{ |
| <span class="comment">// if we couldn't take the lock, then a Taker has it. |
| // The *ONLY* reason is because it is in the process of notifying us |
| // of its want. |
| // |
| // We need to loop again to see what state it was changed to. |
| </span>} |
| }, |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Mark the state as idle, if the Taker currently is wanting. |
| /// |
| /// Returns true if Taker was wanting, false otherwise. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>give(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="comment">// only set to IDLE if it is still Want |
| </span><span class="self">self</span>.inner.state.compare_and_swap( |
| State::Want.into(), |
| State::Idle.into(), |
| SeqCst, |
| ) == State::Want.into() |
| } |
| |
| <span class="doccomment">/// Check if the `Taker` has called `want()` without parking a task. |
| /// |
| /// This is safe to call outside of a futures task context, but other |
| /// means of being notified is left to the user. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>is_wanting(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.inner.state.load(SeqCst) == State::Want.into() |
| } |
| |
| |
| <span class="doccomment">/// Check if the `Taker` has canceled interest without parking a task. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>is_canceled(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.inner.state.load(SeqCst) == State::Closed.into() |
| } |
| |
| <span class="doccomment">/// Converts this into a `SharedGiver`. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>shared(<span class="self">self</span>) -> SharedGiver { |
| SharedGiver { |
| inner: <span class="self">self</span>.inner, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>fmt::Debug <span class="kw">for </span>Giver { |
| <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) -> fmt::Result { |
| f.debug_struct(<span class="string">"Giver"</span>) |
| .field(<span class="string">"state"</span>, <span class="kw-2">&</span><span class="self">self</span>.inner.state()) |
| .finish() |
| } |
| } |
| |
| <span class="comment">// ===== impl SharedGiver ====== |
| |
| </span><span class="kw">impl </span>SharedGiver { |
| <span class="doccomment">/// Check if the `Taker` has called `want()` without parking a task. |
| /// |
| /// This is safe to call outside of a futures task context, but other |
| /// means of being notified is left to the user. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>is_wanting(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.inner.state.load(SeqCst) == State::Want.into() |
| } |
| |
| |
| <span class="doccomment">/// Check if the `Taker` has canceled interest without parking a task. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>is_canceled(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.inner.state.load(SeqCst) == State::Closed.into() |
| } |
| } |
| |
| <span class="kw">impl </span>fmt::Debug <span class="kw">for </span>SharedGiver { |
| <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) -> fmt::Result { |
| f.debug_struct(<span class="string">"SharedGiver"</span>) |
| .field(<span class="string">"state"</span>, <span class="kw-2">&</span><span class="self">self</span>.inner.state()) |
| .finish() |
| } |
| } |
| |
| <span class="comment">// ===== impl Taker ====== |
| |
| </span><span class="kw">impl </span>Taker { |
| <span class="doccomment">/// Signal to the `Giver` that the want is canceled. |
| /// |
| /// This is useful to tell that the channel is closed if you cannot |
| /// drop the value yet. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>cancel(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="macro">trace!</span>(<span class="string">"signal: {:?}"</span>, State::Closed); |
| <span class="self">self</span>.signal(State::Closed) |
| } |
| |
| <span class="doccomment">/// Signal to the `Giver` that a value is wanted. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>want(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="macro">debug_assert!</span>( |
| <span class="self">self</span>.inner.state.load(SeqCst) != State::Closed.into(), |
| <span class="string">"want called after cancel" |
| </span>); |
| <span class="macro">trace!</span>(<span class="string">"signal: {:?}"</span>, State::Want); |
| <span class="self">self</span>.signal(State::Want) |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>signal(<span class="kw-2">&mut </span><span class="self">self</span>, state: State) { |
| <span class="kw">let </span>old_state = <span class="self">self</span>.inner.state.swap(state.into(), SeqCst).into(); |
| <span class="kw">match </span>old_state { |
| State::Idle | State::Want | State::Closed => (), |
| State::Give => { |
| <span class="kw">loop </span>{ |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">mut </span>locked) = <span class="self">self</span>.inner.task.try_lock_order(SeqCst, SeqCst) { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(task) = locked.take() { |
| drop(locked); |
| <span class="macro">trace!</span>(<span class="string">"signal found waiting giver, notifying"</span>); |
| task.wake(); |
| } |
| <span class="kw">return</span>; |
| } <span class="kw">else </span>{ |
| <span class="comment">// if we couldn't take the lock, then a Giver has it. |
| // The *ONLY* reason is because it is in the process of parking. |
| // |
| // We need to loop and take the lock so we can notify this task. |
| </span>} |
| } |
| }, |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>Drop <span class="kw">for </span>Taker { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="self">self</span>.signal(State::Closed); |
| } |
| } |
| |
| <span class="kw">impl </span>fmt::Debug <span class="kw">for </span>Taker { |
| <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) -> fmt::Result { |
| f.debug_struct(<span class="string">"Taker"</span>) |
| .field(<span class="string">"state"</span>, <span class="kw-2">&</span><span class="self">self</span>.inner.state()) |
| .finish() |
| } |
| } |
| |
| <span class="comment">// ===== impl Closed ====== |
| |
| </span><span class="kw">impl </span>fmt::Debug <span class="kw">for </span>Closed { |
| <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) -> fmt::Result { |
| f.debug_struct(<span class="string">"Closed"</span>) |
| .finish() |
| } |
| } |
| |
| <span class="comment">// ===== impl Inner ====== |
| |
| </span><span class="kw">impl </span>Inner { |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>state(<span class="kw-2">&</span><span class="self">self</span>) -> State { |
| <span class="self">self</span>.state.load(SeqCst).into() |
| } |
| } |
| |
| <span class="comment">// ===== impl PollFn ====== |
| |
| </span><span class="kw">struct </span>Want<<span class="lifetime">'a</span>>(<span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>Giver); |
| |
| |
| <span class="kw">impl </span>Future <span class="kw">for </span>Want<<span class="lifetime">'_</span>> { |
| <span class="kw">type </span>Output = <span class="prelude-ty">Result</span><(), Closed>; |
| |
| <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>task::Context<<span class="lifetime">'_</span>>) -> Poll<<span class="self">Self</span>::Output> { |
| <span class="self">self</span>.<span class="number">0</span>.poll_want(cx) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use </span>std::thread; |
| <span class="kw">use </span>tokio_sync::oneshot; |
| <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| |
| <span class="kw">fn </span>block_on<F: Future>(f: F) -> F::Output { |
| tokio_executor::enter() |
| .expect(<span class="string">"block_on enter"</span>) |
| .block_on(f) |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>want_ready() { |
| <span class="kw">let </span>(<span class="kw-2">mut </span>gv, <span class="kw-2">mut </span>tk) = new(); |
| |
| tk.want(); |
| |
| block_on(gv.want()).unwrap(); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>want_notify_0() { |
| <span class="kw">let </span>(<span class="kw-2">mut </span>gv, <span class="kw-2">mut </span>tk) = new(); |
| <span class="kw">let </span>(tx, rx) = oneshot::channel(); |
| |
| thread::spawn(<span class="kw">move </span>|| { |
| tk.want(); |
| <span class="comment">// use a oneshot to keep this thread alive |
| // until other thread was notified of want |
| </span>block_on(rx).expect(<span class="string">"rx"</span>); |
| }); |
| |
| block_on(gv.want()).expect(<span class="string">"want"</span>); |
| |
| <span class="macro">assert!</span>(gv.is_wanting(), <span class="string">"still wanting after poll_want success"</span>); |
| <span class="macro">assert!</span>(gv.give(), <span class="string">"give is true when wanting"</span>); |
| |
| <span class="macro">assert!</span>(!gv.is_wanting(), <span class="string">"no longer wanting after give"</span>); |
| <span class="macro">assert!</span>(!gv.is_canceled(), <span class="string">"give doesn't cancel"</span>); |
| |
| <span class="macro">assert!</span>(!gv.give(), <span class="string">"give is false if not wanting"</span>); |
| |
| tx.send(()).expect(<span class="string">"tx"</span>); |
| } |
| |
| <span class="comment">/* |
| /// This tests that if the Giver moves tasks after parking, |
| /// it will still wake up the correct task. |
| #[test] |
| fn want_notify_moving_tasks() { |
| use std::sync::Arc; |
| use futures::executor::{spawn, Notify, NotifyHandle}; |
| |
| struct WantNotify; |
| |
| impl Notify for WantNotify { |
| fn notify(&self, _id: usize) { |
| } |
| } |
| |
| fn n() -> NotifyHandle { |
| Arc::new(WantNotify).into() |
| } |
| |
| let (mut gv, mut tk) = new(); |
| |
| let mut s = spawn(poll_fn(move || { |
| gv.poll_want() |
| })); |
| |
| // Register with t1 as the task::current() |
| let t1 = n(); |
| assert!(s.poll_future_notify(&t1, 1).unwrap().is_not_ready()); |
| |
| thread::spawn(move || { |
| thread::sleep(::std::time::Duration::from_millis(100)); |
| tk.want(); |
| }); |
| |
| // And now, move to a ThreadNotify task. |
| s.into_inner().wait().expect("poll_want"); |
| } |
| */ |
| |
| </span><span class="attribute">#[test] |
| </span><span class="kw">fn </span>cancel() { |
| <span class="comment">// explicit |
| </span><span class="kw">let </span>(<span class="kw-2">mut </span>gv, <span class="kw-2">mut </span>tk) = new(); |
| |
| <span class="macro">assert!</span>(!gv.is_canceled()); |
| |
| tk.cancel(); |
| |
| <span class="macro">assert!</span>(gv.is_canceled()); |
| block_on(gv.want()).unwrap_err(); |
| |
| <span class="comment">// implicit |
| </span><span class="kw">let </span>(<span class="kw-2">mut </span>gv, tk) = new(); |
| |
| <span class="macro">assert!</span>(!gv.is_canceled()); |
| |
| drop(tk); |
| |
| <span class="macro">assert!</span>(gv.is_canceled()); |
| block_on(gv.want()).unwrap_err(); |
| |
| <span class="comment">// notifies |
| </span><span class="kw">let </span>(<span class="kw-2">mut </span>gv, tk) = new(); |
| |
| thread::spawn(<span class="kw">move </span>|| { |
| <span class="kw">let </span>_tk = tk; |
| <span class="comment">// and dropped |
| </span>}); |
| |
| block_on(gv.want()).unwrap_err(); |
| } |
| |
| <span class="comment">/* |
| #[test] |
| fn stress() { |
| let nthreads = 5; |
| let nwants = 100; |
| |
| for _ in 0..nthreads { |
| let (mut gv, mut tk) = new(); |
| let (mut tx, mut rx) = mpsc::channel(0); |
| |
| // rx thread |
| thread::spawn(move || { |
| let mut cnt = 0; |
| poll_fn(move || { |
| while cnt < nwants { |
| let n = match rx.poll().expect("rx poll") { |
| Async::Ready(n) => n.expect("rx opt"), |
| Async::NotReady => { |
| tk.want(); |
| return Ok(Async::NotReady); |
| }, |
| }; |
| assert_eq!(cnt, n); |
| cnt += 1; |
| } |
| Ok::<_, ()>(Async::Ready(())) |
| }).wait().expect("rx wait"); |
| }); |
| |
| // tx thread |
| thread::spawn(move || { |
| let mut cnt = 0; |
| let nsent = poll_fn(move || { |
| loop { |
| while let Ok(()) = tx.try_send(cnt) { |
| cnt += 1; |
| } |
| match gv.poll_want() { |
| Ok(Async::Ready(_)) => (), |
| Ok(Async::NotReady) => return Ok::<_, ()>(Async::NotReady), |
| Err(_) => return Ok(Async::Ready(cnt)), |
| } |
| } |
| }).wait().expect("tx wait"); |
| |
| assert_eq!(nsent, nwants); |
| }).join().expect("thread join"); |
| } |
| } |
| */ |
| </span>} |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="want" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |