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#![feature(arbitrary_self_types, futures_api)]
#![allow(unused)]
use std::future::Future;
use std::pin::Pin;
use std::rc::Rc;
use std::sync::{
Arc,
atomic::{self, AtomicUsize},
};
use std::task::{
Poll, Wake, Waker, LocalWaker,
local_waker, local_waker_from_nonlocal,
};
struct Counter {
local_wakes: AtomicUsize,
nonlocal_wakes: AtomicUsize,
}
impl Wake for Counter {
fn wake(this: &Arc<Self>) {
this.nonlocal_wakes.fetch_add(1, atomic::Ordering::SeqCst);
}
unsafe fn wake_local(this: &Arc<Self>) {
this.local_wakes.fetch_add(1, atomic::Ordering::SeqCst);
}
}
struct MyFuture;
impl Future for MyFuture {
type Output = ();
fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
// Wake once locally
lw.wake();
// Wake twice non-locally
let waker = lw.clone().into_waker();
waker.wake();
waker.wake();
Poll::Ready(())
}
}
fn test_local_waker() {
let counter = Arc::new(Counter {
local_wakes: AtomicUsize::new(0),
nonlocal_wakes: AtomicUsize::new(0),
});
let waker = unsafe { local_waker(counter.clone()) };
assert_eq!(Poll::Ready(()), Pin::new(&mut MyFuture).poll(&waker));
assert_eq!(1, counter.local_wakes.load(atomic::Ordering::SeqCst));
assert_eq!(2, counter.nonlocal_wakes.load(atomic::Ordering::SeqCst));
}
fn test_local_as_nonlocal_waker() {
let counter = Arc::new(Counter {
local_wakes: AtomicUsize::new(0),
nonlocal_wakes: AtomicUsize::new(0),
});
let waker: LocalWaker = local_waker_from_nonlocal(counter.clone());
assert_eq!(Poll::Ready(()), Pin::new(&mut MyFuture).poll(&waker));
assert_eq!(0, counter.local_wakes.load(atomic::Ordering::SeqCst));
assert_eq!(3, counter.nonlocal_wakes.load(atomic::Ordering::SeqCst));
}
fn main() {
test_local_waker();
test_local_as_nonlocal_waker();
}
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