diff options
Diffstat (limited to 'tests/ui/async-await/async-fn-size.rs')
-rw-r--r-- | tests/ui/async-await/async-fn-size.rs | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/tests/ui/async-await/async-fn-size.rs b/tests/ui/async-await/async-fn-size.rs new file mode 100644 index 000000000..0c1f36364 --- /dev/null +++ b/tests/ui/async-await/async-fn-size.rs @@ -0,0 +1,105 @@ +// 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())); +} |