AsyncDrop implementation using shim codegen of async_drop_in_place::{closure}, scoped async drop added.

1 files changed, 110 insertions, 0 deletions

diff --git a/tests/ui/async-await/async-drop/async-drop-middle-drop.rs b/tests/ui/async-await/async-drop/async-drop-middle-drop.rs
new file mode 100644
index 00000000000..772a853fe1e
--- /dev/null
+++ b/tests/ui/async-await/async-drop/async-drop-middle-drop.rs
@@ -0,0 +1,110 @@
+//@ run-pass
+//@ check-run-results
+// Test async drop of coroutine `bar` (with internal async drop),
+// stopped at the middle of execution, with AsyncDrop object Foo active.
+
+#![feature(async_drop)]
+#![allow(incomplete_features)]
+
+//@ edition: 2021
+
+use std::mem::ManuallyDrop;
+
+use std::{
+    future::{Future, async_drop_in_place, AsyncDrop},
+    pin::{pin, Pin},
+    sync::{mpsc, Arc},
+    task::{Context, Poll, Wake, Waker},
+};
+
+struct Foo {
+    my_resource_handle: usize,
+}
+
+impl Foo {
+    fn new(my_resource_handle: usize) -> Self {
+        let out = Foo {
+            my_resource_handle,
+        };
+        println!("Foo::new({})", my_resource_handle);
+        out
+    }
+}
+
+impl Drop for Foo {
+    fn drop(&mut self) {
+        println!("Foo::drop({})", self.my_resource_handle);
+    }
+}
+
+impl AsyncDrop for Foo {
+    async fn drop(self: Pin<&mut Self>) {
+        println!("Foo::async drop({})", self.my_resource_handle);
+    }
+}
+
+fn main() {
+    block_on_and_drop_in_the_middle(bar(10));
+    println!("done")
+}
+
+pub struct MiddleFuture {
+    first_call: bool,
+}
+impl Future for MiddleFuture {
+    type Output = ();
+    fn poll(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
+        if self.first_call {
+            println!("MiddleFuture first poll");
+            self.first_call = false;
+            Poll::Pending
+        } else {
+            println!("MiddleFuture Ready");
+            Poll::Ready(())
+        }
+    }
+}
+
+async fn bar(ident_base: usize) {
+    let middle = MiddleFuture { first_call: true };
+    let mut _first = Foo::new(ident_base);
+    middle.await; // Hanging `bar` future before Foo drop
+}
+
+fn block_on_and_drop_in_the_middle<F>(fut_unpin: F) -> F::Output
+where
+    F: Future<Output = ()>,
+{
+    let mut fut_pin = pin!(ManuallyDrop::new(fut_unpin));
+    let mut fut: Pin<&mut F> = unsafe {
+        Pin::map_unchecked_mut(fut_pin.as_mut(), |x| &mut **x)
+    };
+    let (waker, rx) = simple_waker();
+    let mut context = Context::from_waker(&waker);
+    let poll1 = fut.as_mut().poll(&mut context);
+    assert!(poll1.is_pending());
+
+    let drop_fut_unpin = unsafe { async_drop_in_place(fut.get_unchecked_mut()) };
+    let mut drop_fut: Pin<&mut _> = pin!(drop_fut_unpin);
+    loop {
+        match drop_fut.as_mut().poll(&mut context) {
+            Poll::Ready(()) => break,
+            Poll::Pending => rx.try_recv().unwrap(),
+        }
+    }
+}
+
+fn simple_waker() -> (Waker, mpsc::Receiver<()>) {
+    struct SimpleWaker {
+        tx: std::sync::mpsc::Sender<()>,
+    }
+
+    impl Wake for SimpleWaker {
+        fn wake(self: Arc<Self>) {
+            self.tx.send(()).unwrap();
+        }
+    }
+
+    let (tx, rx) = mpsc::channel();
+    (Waker::from(Arc::new(SimpleWaker { tx })), rx)
+}