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|
use async_io::block_on;
use std::{
future::Future,
pin::Pin,
task::{Context, Poll, Waker},
time::{Duration, Instant},
};
#[test]
fn doesnt_poll_after_ready() {
#[derive(Default)]
struct Bomb {
returned_ready: bool,
}
impl Future for Bomb {
type Output = ();
fn poll(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
if self.returned_ready {
panic!("Future was polled again after returning Poll::Ready");
} else {
self.returned_ready = true;
Poll::Ready(())
}
}
}
block_on(Bomb::default())
}
#[test]
fn recursive_wakers_are_different() {
struct Outer;
impl Future for Outer {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let outer_waker = cx.waker();
block_on(Inner { outer_waker });
Poll::Ready(())
}
}
struct Inner<'a> {
pub outer_waker: &'a Waker,
}
impl Future for Inner<'_> {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let inner_waker = cx.waker();
assert!(!inner_waker.will_wake(self.outer_waker));
Poll::Ready(())
}
}
block_on(Outer);
}
#[test]
fn inner_cannot_wake_outer() {
#[derive(Default)]
struct Outer {
elapsed: Option<Instant>,
}
impl Future for Outer {
type Output = ();
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
if let Some(elapsed) = self.elapsed {
assert!(elapsed.elapsed() >= Duration::from_secs(1));
Poll::Ready(())
} else {
let outer_waker = cx.waker().clone();
block_on(Inner);
std::thread::spawn(|| {
std::thread::sleep(Duration::from_secs(1));
outer_waker.wake();
});
self.elapsed = Some(Instant::now());
Poll::Pending
}
}
}
struct Inner;
impl Future for Inner {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let inner_waker = cx.waker();
inner_waker.wake_by_ref();
Poll::Ready(())
}
}
block_on(Outer::default());
}
#[test]
fn outer_cannot_wake_inner() {
struct Outer;
impl Future for Outer {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let outer_waker = cx.waker();
outer_waker.wake_by_ref();
block_on(Inner::default());
Poll::Ready(())
}
}
#[derive(Default)]
struct Inner {
elapsed: Option<Instant>,
}
impl Future for Inner {
type Output = ();
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
if let Some(elapsed) = self.elapsed {
assert!(elapsed.elapsed() >= Duration::from_secs(1));
Poll::Ready(())
} else {
let inner_waker = cx.waker().clone();
std::thread::spawn(|| {
std::thread::sleep(Duration::from_secs(1));
inner_waker.wake();
});
self.elapsed = Some(Instant::now());
Poll::Pending
}
}
}
block_on(Outer);
}
#[test]
fn first_cannot_wake_second() {
struct First;
impl Future for First {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let first_waker = cx.waker();
first_waker.wake_by_ref();
Poll::Ready(())
}
}
#[derive(Default)]
struct Second {
elapsed: Option<Instant>,
}
impl Future for Second {
type Output = ();
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
if let Some(elapsed) = self.elapsed {
assert!(elapsed.elapsed() >= Duration::from_secs(1));
Poll::Ready(())
} else {
let second_waker = cx.waker().clone();
std::thread::spawn(|| {
std::thread::sleep(Duration::from_secs(1));
second_waker.wake();
});
self.elapsed = Some(Instant::now());
Poll::Pending
}
}
}
block_on(First);
block_on(Second::default());
}
|
