3 // aux-build:arc_wake.rs
7 use std::future::Future;
11 atomic::{self, AtomicUsize},
16 use arc_wake::ArcWake;
22 impl ArcWake for Counter {
23 fn wake(self: Arc<Self>) {
24 Self::wake_by_ref(&self)
26 fn wake_by_ref(arc_self: &Arc<Self>) {
27 arc_self.wakes.fetch_add(1, atomic::Ordering::SeqCst);
33 impl Future for MyFuture {
35 fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
37 let waker = cx.waker();
45 let counter = Arc::new(Counter {
46 wakes: AtomicUsize::new(0),
48 let waker = ArcWake::into_waker(counter.clone());
49 assert_eq!(2, Arc::strong_count(&counter));
51 let mut context = Context::from_waker(&waker);
52 assert_eq!(Poll::Ready(()), Pin::new(&mut MyFuture).poll(&mut context));
53 assert_eq!(2, counter.wakes.load(atomic::Ordering::SeqCst));
56 assert_eq!(1, Arc::strong_count(&counter));