106 lines
2.7 KiB
Rust
106 lines
2.7 KiB
Rust
//@ run-pass
|
|
//@ aux-build:arc_wake.rs
|
|
//@ edition:2018
|
|
|
|
extern crate arc_wake;
|
|
|
|
use std::pin::Pin;
|
|
use std::future::Future;
|
|
use std::sync::{
|
|
Arc,
|
|
atomic::{self, AtomicUsize},
|
|
};
|
|
use std::task::{Context, Poll};
|
|
use arc_wake::ArcWake;
|
|
|
|
struct Counter {
|
|
wakes: AtomicUsize,
|
|
}
|
|
|
|
impl ArcWake for Counter {
|
|
fn wake(self: Arc<Self>) {
|
|
Self::wake_by_ref(&self)
|
|
}
|
|
fn wake_by_ref(arc_self: &Arc<Self>) {
|
|
arc_self.wakes.fetch_add(1, atomic::Ordering::SeqCst);
|
|
}
|
|
}
|
|
|
|
struct WakeOnceThenComplete(bool, u8);
|
|
|
|
impl Future for WakeOnceThenComplete {
|
|
type Output = u8;
|
|
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<u8> {
|
|
if self.0 {
|
|
Poll::Ready(self.1)
|
|
} else {
|
|
cx.waker().wake_by_ref();
|
|
self.0 = true;
|
|
Poll::Pending
|
|
}
|
|
}
|
|
}
|
|
|
|
fn wait(fut: impl Future<Output = u8>) -> u8 {
|
|
let mut fut = Box::pin(fut);
|
|
let counter = Arc::new(Counter { wakes: AtomicUsize::new(0) });
|
|
let waker = ArcWake::into_waker(counter.clone());
|
|
let mut cx = Context::from_waker(&waker);
|
|
loop {
|
|
match fut.as_mut().poll(&mut cx) {
|
|
Poll::Ready(out) => return out,
|
|
Poll::Pending => (),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn base() -> WakeOnceThenComplete { WakeOnceThenComplete(false, 1) }
|
|
|
|
async fn await1_level1() -> u8 {
|
|
base().await
|
|
}
|
|
|
|
async fn await2_level1() -> u8 {
|
|
base().await + base().await
|
|
}
|
|
|
|
async fn await3_level1() -> u8 {
|
|
base().await + base().await + base().await
|
|
}
|
|
|
|
async fn await3_level2() -> u8 {
|
|
await3_level1().await + await3_level1().await + await3_level1().await
|
|
}
|
|
|
|
async fn await3_level3() -> u8 {
|
|
await3_level2().await + await3_level2().await + await3_level2().await
|
|
}
|
|
|
|
async fn await3_level4() -> u8 {
|
|
await3_level3().await + await3_level3().await + await3_level3().await
|
|
}
|
|
|
|
async fn await3_level5() -> u8 {
|
|
await3_level4().await + await3_level4().await + await3_level4().await
|
|
}
|
|
|
|
fn main() {
|
|
assert_eq!(2, std::mem::size_of_val(&base()));
|
|
assert_eq!(3, std::mem::size_of_val(&await1_level1()));
|
|
assert_eq!(4, std::mem::size_of_val(&await2_level1()));
|
|
assert_eq!(5, std::mem::size_of_val(&await3_level1()));
|
|
assert_eq!(8, std::mem::size_of_val(&await3_level2()));
|
|
assert_eq!(11, std::mem::size_of_val(&await3_level3()));
|
|
assert_eq!(14, std::mem::size_of_val(&await3_level4()));
|
|
assert_eq!(17, std::mem::size_of_val(&await3_level5()));
|
|
|
|
assert_eq!(1, wait(base()));
|
|
assert_eq!(1, wait(await1_level1()));
|
|
assert_eq!(2, wait(await2_level1()));
|
|
assert_eq!(3, wait(await3_level1()));
|
|
assert_eq!(9, wait(await3_level2()));
|
|
assert_eq!(27, wait(await3_level3()));
|
|
assert_eq!(81, wait(await3_level4()));
|
|
assert_eq!(243, wait(await3_level5()));
|
|
}
|