use std::cell::Cell;
use std::future::Future;
use std::panic::{catch_unwind, AssertUnwindSafe};
use std::pin::Pin;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::task::{Context, Poll};
use std::thread;
use std::time::Duration;
use async_task::Runnable;
use atomic_waker::AtomicWaker;
use easy_parallel::Parallel;
use smol::future;
// Creates a future with event counters.
//
// Usage: `future!(f, get_waker, POLL, DROP)`
//
// The future `f` always sleeps for 200 ms, and panics the second time it is polled.
// When it gets polled, `POLL` is incremented.
// When it gets dropped, `DROP` is incremented.
//
// Every time the future is run, it stores the waker into a global variable.
// This waker can be extracted using the `get_waker()` function.
macro_rules! future {
($name:pat, $get_waker:pat, $poll:ident, $drop:ident) => {
static $poll: AtomicUsize = AtomicUsize::new(0 );
static $drop: AtomicUsize = AtomicUsize::new(0 );
static WAKER: AtomicWaker = AtomicWaker::new();
let ($name, $get_waker) = {
struct Fut(Cell<bool>, Box <i32>);
impl Future for Fut {
type Output = ();
fn poll(self : Pin<&mut Self >, cx: &mut Context<'_>) -> Poll<Self::Output> {
WAKER.register(cx.waker());
$poll.fetch_add(1 , Ordering::SeqCst);
thread::sleep(ms(400 ));
if self .0 .get() {
panic!()
} else {
self .0 .set(true );
Poll::Pending
}
}
}
impl Drop for Fut {
fn drop(&mut self ) {
$drop.fetch_add(1 , Ordering::SeqCst);
}
}
(Fut(Cell::new(false ), Box ::new(0 )), || WAKER.take().unwrap())
};
};
}
// Creates a schedule function with event counters.
//
// Usage: `schedule!(s, chan, SCHED, DROP)`
//
// The schedule function `s` pushes the task into `chan`.
// When it gets invoked, `SCHED` is incremented.
// When it gets dropped, `DROP` is incremented.
//
// Receiver `chan` extracts the task when it is scheduled.
macro_rules! schedule {
($name:pat, $chan:pat, $sched:ident, $drop:ident) => {
static $drop: AtomicUsize = AtomicUsize::new(0 );
static $sched: AtomicUsize = AtomicUsize::new(0 );
let ($name, $chan) = {
let (s, r) = flume::unbounded();
struct Guard(Box <i32>);
impl Drop for Guard {
fn drop(&mut self ) {
$drop.fetch_add(1 , Ordering::SeqCst);
}
}
let guard = Guard(Box ::new(0 ));
let sched = move |runnable: Runnable| {
let _ = &guard;
$sched.fetch_add(1 , Ordering::SeqCst);
s.send(runnable).unwrap();
};
(sched, r)
};
};
}
fn ms(ms: u64) -> Duration {
Duration::from_millis(ms)
}
fn try_await<T>(f: impl Future<Output = T>) -> Option<T> {
future::block_on(future::poll_once(f))
}
#[ test]
fn wake_during_run() {
future!(f, get_waker, POLL, DROP_F);
schedule!(s, chan, SCHEDULE, DROP_S);
let (runnable, task) = async_task::spawn(f, s);
runnable.run();
let waker = get_waker();
waker.wake_by_ref();
let runnable = chan.recv().unwrap();
Parallel::new()
.add(|| {
assert!(catch_unwind(|| runnable.run()).is_err());
drop(get_waker());
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.add(|| {
thread::sleep(ms(200 ));
waker.wake();
task.detach();
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 0 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
assert_eq!(chan.len(), 0 );
thread::sleep(ms(400 ));
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.run();
}
#[ test]
fn cancel_during_run() {
future!(f, get_waker, POLL, DROP_F);
schedule!(s, chan, SCHEDULE, DROP_S);
let (runnable, task) = async_task::spawn(f, s);
runnable.run();
let waker = get_waker();
waker.wake();
let runnable = chan.recv().unwrap();
Parallel::new()
.add(|| {
assert!(catch_unwind(|| runnable.run()).is_err());
drop(get_waker());
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.add(|| {
thread::sleep(ms(200 ));
drop(task);
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 0 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
assert_eq!(chan.len(), 0 );
thread::sleep(ms(400 ));
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.run();
}
#[ test]
fn wake_and_cancel_during_run() {
future!(f, get_waker, POLL, DROP_F);
schedule!(s, chan, SCHEDULE, DROP_S);
let (runnable, task) = async_task::spawn(f, s);
runnable.run();
let waker = get_waker();
waker.wake_by_ref();
let runnable = chan.recv().unwrap();
Parallel::new()
.add(|| {
assert!(catch_unwind(|| runnable.run()).is_err());
drop(get_waker());
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.add(|| {
thread::sleep(ms(200 ));
waker.wake();
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 0 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
assert_eq!(chan.len(), 0 );
drop(task);
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 0 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
assert_eq!(chan.len(), 0 );
thread::sleep(ms(400 ));
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.run();
}
#[ flaky_test::flaky_test]
fn cancel_and_wake_during_run() {
future!(f, get_waker, POLL, DROP_F);
schedule!(s, chan, SCHEDULE, DROP_S);
POLL.store(0 , Ordering::SeqCst);
DROP_F.store(0 , Ordering::SeqCst);
SCHEDULE.store(0 , Ordering::SeqCst);
DROP_S.store(0 , Ordering::SeqCst);
let (runnable, task) = async_task::spawn(f, s);
runnable.run();
let waker = get_waker();
waker.wake_by_ref();
let runnable = chan.recv().unwrap();
Parallel::new()
.add(|| {
assert!(catch_unwind(|| runnable.run()).is_err());
drop(get_waker());
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.add(|| {
thread::sleep(ms(200 ));
drop(task);
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 0 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
assert_eq!(chan.len(), 0 );
waker.wake();
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 0 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
assert_eq!(chan.len(), 0 );
thread::sleep(ms(400 ));
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
assert_eq!(chan.len(), 0 );
})
.run();
}
#[ test]
fn panic_and_poll() {
future!(f, get_waker, POLL, DROP_F);
schedule!(s, chan, SCHEDULE, DROP_S);
let (runnable, task) = async_task::spawn(f, s);
runnable.run();
get_waker().wake();
assert_eq!(POLL.load(Ordering::SeqCst), 1 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 0 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
let mut task = task;
assert!(try_await(&mut task).is_none());
let runnable = chan.recv().unwrap();
assert!(catch_unwind(|| runnable.run()).is_err());
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
assert!(catch_unwind(AssertUnwindSafe(|| try_await(&mut task))).is_err());
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 0 );
drop(get_waker());
drop(task);
assert_eq!(POLL.load(Ordering::SeqCst), 2 );
assert_eq!(SCHEDULE.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_F.load(Ordering::SeqCst), 1 );
assert_eq!(DROP_S.load(Ordering::SeqCst), 1 );
}
Messung V0.5 in Prozent C=76 H=100 G=88
¤ Dauer der Verarbeitung: 0.12 Sekunden
(vorverarbeitet am 2026-06-22)
¤
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