-#![feature(pin_macro)]
-
use std::future::*;
use std::marker::PhantomPinned;
use std::pin::*;
}
}
+fn mk_waker() -> Waker {
+ use std::sync::Arc;
+
+ struct MyWaker;
+ impl Wake for MyWaker {
+ fn wake(self: Arc<Self>) {
+ unimplemented!()
+ }
+ }
+
+ Waker::from(Arc::new(MyWaker))
+}
+
async fn do_stuff() {
(&mut Delay::new(1)).await;
}
}
fn run_fut<T>(fut: impl Future<Output = T>) -> T {
- use std::sync::Arc;
-
- struct MyWaker;
- impl Wake for MyWaker {
- fn wake(self: Arc<Self>) {
- unimplemented!()
- }
- }
-
- let waker = Waker::from(Arc::new(MyWaker));
+ let waker = mk_waker();
let mut context = Context::from_waker(&waker);
let mut pinned = pin!(fut);
}
}
+fn self_referential_box() {
+ let waker = mk_waker();
+ let cx = &mut Context::from_waker(&waker);
+
+ async fn my_fut() -> i32 {
+ let val = 10;
+ let val_ref = &val;
+
+ let _ = Delay::new(1).await;
+
+ *val_ref
+ }
+
+ fn box_poll<F: Future>(
+ mut f: Pin<Box<F>>,
+ cx: &mut Context<'_>,
+ ) -> (Pin<Box<F>>, Poll<F::Output>) {
+ let p = f.as_mut().poll(cx);
+ (f, p)
+ }
+
+ let my_fut = Box::pin(my_fut());
+ let (my_fut, p1) = box_poll(my_fut, cx);
+ assert!(p1.is_pending());
+ let (my_fut, p2) = box_poll(my_fut, cx);
+ assert!(p2.is_ready());
+ drop(my_fut);
+}
+
fn main() {
run_fut(do_stuff());
run_fut(DoStuff::new());
+ self_referential_box();
}