1 files changed, 496 insertions, 0 deletions
diff --git a/third_party/rust/futures-executor/tests/local_pool.rs b/third_party/rust/futures-executor/tests/local_pool.rs
new file mode 100644
index 0000000000..72ce74b744
--- /dev/null
+++ b/third_party/rust/futures-executor/tests/local_pool.rs
@@ -0,0 +1,496 @@
+use futures::channel::oneshot;
+use futures::executor::LocalPool;
+use futures::future::{self, lazy, poll_fn, Future};
+use futures::task::{Context, LocalSpawn, LocalSpawnExt, Poll, Spawn, SpawnExt, Waker};
+use std::cell::{Cell, RefCell};
+use std::pin::Pin;
+use std::rc::Rc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+use std::thread;
+use std::time::Duration;
+
+struct Pending(Rc<()>);
+
+impl Future for Pending {
+    type Output = ();
+
+    fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<()> {
+        Poll::Pending
+    }
+}
+
+fn pending() -> Pending {
+    Pending(Rc::new(()))
+}
+
+#[test]
+fn run_until_single_future() {
+    let mut cnt = 0;
+
+    {
+        let mut pool = LocalPool::new();
+        let fut = lazy(|_| {
+            cnt += 1;
+        });
+        pool.run_until(fut);
+    }
+
+    assert_eq!(cnt, 1);
+}
+
+#[test]
+fn run_until_ignores_spawned() {
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+    spawn.spawn_local_obj(Box::pin(pending()).into()).unwrap();
+    pool.run_until(lazy(|_| ()));
+}
+
+#[test]
+fn run_until_executes_spawned() {
+    let (tx, rx) = oneshot::channel();
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+    spawn
+        .spawn_local_obj(
+            Box::pin(lazy(move |_| {
+                tx.send(()).unwrap();
+            }))
+            .into(),
+        )
+        .unwrap();
+    pool.run_until(rx).unwrap();
+}
+
+#[test]
+fn run_returns_if_empty() {
+    let mut pool = LocalPool::new();
+    pool.run();
+    pool.run();
+}
+
+#[test]
+fn run_executes_spawned() {
+    let cnt = Rc::new(Cell::new(0));
+    let cnt2 = cnt.clone();
+
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+    let spawn2 = pool.spawner();
+
+    spawn
+        .spawn_local_obj(
+            Box::pin(lazy(move |_| {
+                spawn2
+                    .spawn_local_obj(
+                        Box::pin(lazy(move |_| {
+                            cnt2.set(cnt2.get() + 1);
+                        }))
+                        .into(),
+                    )
+                    .unwrap();
+            }))
+            .into(),
+        )
+        .unwrap();
+
+    pool.run();
+
+    assert_eq!(cnt.get(), 1);
+}
+
+#[test]
+fn run_spawn_many() {
+    const ITER: usize = 200;
+
+    let cnt = Rc::new(Cell::new(0));
+
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+
+    for _ in 0..ITER {
+        let cnt = cnt.clone();
+        spawn
+            .spawn_local_obj(
+                Box::pin(lazy(move |_| {
+                    cnt.set(cnt.get() + 1);
+                }))
+                .into(),
+            )
+            .unwrap();
+    }
+
+    pool.run();
+
+    assert_eq!(cnt.get(), ITER);
+}
+
+#[test]
+fn try_run_one_returns_if_empty() {
+    let mut pool = LocalPool::new();
+    assert!(!pool.try_run_one());
+}
+
+#[test]
+fn try_run_one_executes_one_ready() {
+    const ITER: usize = 200;
+
+    let cnt = Rc::new(Cell::new(0));
+
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+
+    for _ in 0..ITER {
+        spawn.spawn_local_obj(Box::pin(pending()).into()).unwrap();
+
+        let cnt = cnt.clone();
+        spawn
+            .spawn_local_obj(
+                Box::pin(lazy(move |_| {
+                    cnt.set(cnt.get() + 1);
+                }))
+                .into(),
+            )
+            .unwrap();
+
+        spawn.spawn_local_obj(Box::pin(pending()).into()).unwrap();
+    }
+
+    for i in 0..ITER {
+        assert_eq!(cnt.get(), i);
+        assert!(pool.try_run_one());
+        assert_eq!(cnt.get(), i + 1);
+    }
+    assert!(!pool.try_run_one());
+}
+
+#[test]
+fn try_run_one_returns_on_no_progress() {
+    const ITER: usize = 10;
+
+    let cnt = Rc::new(Cell::new(0));
+
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+
+    let waker: Rc<Cell<Option<Waker>>> = Rc::new(Cell::new(None));
+    {
+        let cnt = cnt.clone();
+        let waker = waker.clone();
+        spawn
+            .spawn_local_obj(
+                Box::pin(poll_fn(move |ctx| {
+                    cnt.set(cnt.get() + 1);
+                    waker.set(Some(ctx.waker().clone()));
+                    if cnt.get() == ITER {
+                        Poll::Ready(())
+                    } else {
+                        Poll::Pending
+                    }
+                }))
+                .into(),
+            )
+            .unwrap();
+    }
+
+    for i in 0..ITER - 1 {
+        assert_eq!(cnt.get(), i);
+        assert!(!pool.try_run_one());
+        assert_eq!(cnt.get(), i + 1);
+        let w = waker.take();
+        assert!(w.is_some());
+        w.unwrap().wake();
+    }
+    assert!(pool.try_run_one());
+    assert_eq!(cnt.get(), ITER);
+}
+
+#[test]
+fn try_run_one_runs_sub_futures() {
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+    let cnt = Rc::new(Cell::new(0));
+
+    let inner_spawner = spawn.clone();
+    let cnt1 = cnt.clone();
+    spawn
+        .spawn_local_obj(
+            Box::pin(poll_fn(move |_| {
+                cnt1.set(cnt1.get() + 1);
+
+                let cnt2 = cnt1.clone();
+                inner_spawner
+                    .spawn_local_obj(Box::pin(lazy(move |_| cnt2.set(cnt2.get() + 1))).into())
+                    .unwrap();
+
+                Poll::Pending
+            }))
+            .into(),
+        )
+        .unwrap();
+
+    pool.try_run_one();
+    assert_eq!(cnt.get(), 2);
+}
+
+#[test]
+fn run_until_stalled_returns_if_empty() {
+    let mut pool = LocalPool::new();
+    pool.run_until_stalled();
+    pool.run_until_stalled();
+}
+
+#[test]
+fn run_until_stalled_returns_multiple_times() {
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+    let cnt = Rc::new(Cell::new(0));
+
+    let cnt1 = cnt.clone();
+    spawn.spawn_local_obj(Box::pin(lazy(move |_| cnt1.set(cnt1.get() + 1))).into()).unwrap();
+    pool.run_until_stalled();
+    assert_eq!(cnt.get(), 1);
+
+    let cnt2 = cnt.clone();
+    spawn.spawn_local_obj(Box::pin(lazy(move |_| cnt2.set(cnt2.get() + 1))).into()).unwrap();
+    pool.run_until_stalled();
+    assert_eq!(cnt.get(), 2);
+}
+
+#[test]
+fn run_until_stalled_runs_spawned_sub_futures() {
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+    let cnt = Rc::new(Cell::new(0));
+
+    let inner_spawner = spawn.clone();
+    let cnt1 = cnt.clone();
+    spawn
+        .spawn_local_obj(
+            Box::pin(poll_fn(move |_| {
+                cnt1.set(cnt1.get() + 1);
+
+                let cnt2 = cnt1.clone();
+                inner_spawner
+                    .spawn_local_obj(Box::pin(lazy(move |_| cnt2.set(cnt2.get() + 1))).into())
+                    .unwrap();
+
+                Poll::Pending
+            }))
+            .into(),
+        )
+        .unwrap();
+
+    pool.run_until_stalled();
+    assert_eq!(cnt.get(), 2);
+}
+
+#[test]
+fn run_until_stalled_executes_all_ready() {
+    const ITER: usize = if cfg!(miri) { 50 } else { 200 };
+    const PER_ITER: usize = 3;
+
+    let cnt = Rc::new(Cell::new(0));
+
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+
+    for i in 0..ITER {
+        for _ in 0..PER_ITER {
+            spawn.spawn_local_obj(Box::pin(pending()).into()).unwrap();
+
+            let cnt = cnt.clone();
+            spawn
+                .spawn_local_obj(
+                    Box::pin(lazy(move |_| {
+                        cnt.set(cnt.get() + 1);
+                    }))
+                    .into(),
+                )
+                .unwrap();
+
+            // also add some pending tasks to test if they are ignored
+            spawn.spawn_local_obj(Box::pin(pending()).into()).unwrap();
+        }
+        assert_eq!(cnt.get(), i * PER_ITER);
+        pool.run_until_stalled();
+        assert_eq!(cnt.get(), (i + 1) * PER_ITER);
+    }
+}
+
+#[test]
+#[should_panic]
+fn nesting_run() {
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+
+    spawn
+        .spawn_obj(
+            Box::pin(lazy(|_| {
+                let mut pool = LocalPool::new();
+                pool.run();
+            }))
+            .into(),
+        )
+        .unwrap();
+
+    pool.run();
+}
+
+#[test]
+#[should_panic]
+fn nesting_run_run_until_stalled() {
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+
+    spawn
+        .spawn_obj(
+            Box::pin(lazy(|_| {
+                let mut pool = LocalPool::new();
+                pool.run_until_stalled();
+            }))
+            .into(),
+        )
+        .unwrap();
+
+    pool.run();
+}
+
+#[test]
+fn tasks_are_scheduled_fairly() {
+    let state = Rc::new(RefCell::new([0, 0]));
+
+    struct Spin {
+        state: Rc<RefCell<[i32; 2]>>,
+        idx: usize,
+    }
+
+    impl Future for Spin {
+        type Output = ();
+
+        fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
+            let mut state = self.state.borrow_mut();
+
+            if self.idx == 0 {
+                let diff = state[0] - state[1];
+
+                assert!(diff.abs() <= 1);
+
+                if state[0] >= 50 {
+                    return Poll::Ready(());
+                }
+            }
+
+            state[self.idx] += 1;
+
+            if state[self.idx] >= 100 {
+                return Poll::Ready(());
+            }
+
+            cx.waker().wake_by_ref();
+            Poll::Pending
+        }
+    }
+
+    let mut pool = LocalPool::new();
+    let spawn = pool.spawner();
+
+    spawn.spawn_local_obj(Box::pin(Spin { state: state.clone(), idx: 0 }).into()).unwrap();
+
+    spawn.spawn_local_obj(Box::pin(Spin { state, idx: 1 }).into()).unwrap();
+
+    pool.run();
+}
+
+// Tests that the use of park/unpark in user-code has no
+// effect on the expected behavior of the executor.
+#[test]
+fn park_unpark_independence() {
+    let mut done = false;
+
+    let future = future::poll_fn(move |cx| {
+        if done {
+            return Poll::Ready(());
+        }
+        done = true;
+        cx.waker().clone().wake(); // (*)
+                                   // some user-code that temporarily parks the thread
+        let test = thread::current();
+        let latch = Arc::new(AtomicBool::new(false));
+        let signal = latch.clone();
+        thread::spawn(move || {
+            thread::sleep(Duration::from_millis(10));
+            signal.store(true, Ordering::SeqCst);
+            test.unpark()
+        });
+        while !latch.load(Ordering::Relaxed) {
+            thread::park();
+        }
+        Poll::Pending // Expect to be called again due to (*).
+    });
+
+    futures::executor::block_on(future)
+}
+
+struct SelfWaking {
+    wakeups_remaining: Rc<RefCell<usize>>,
+}
+
+impl Future for SelfWaking {
+    type Output = ();
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        if *self.wakeups_remaining.borrow() != 0 {
+            *self.wakeups_remaining.borrow_mut() -= 1;
+            cx.waker().wake_by_ref();
+        }
+
+        Poll::Pending
+    }
+}
+
+/// Regression test for https://github.com/rust-lang/futures-rs/pull/2593
+///
+/// The issue was that self-waking futures could cause `run_until_stalled`
+/// to exit early, even when progress could still be made.
+#[test]
+fn self_waking_run_until_stalled() {
+    let wakeups_remaining = Rc::new(RefCell::new(10));
+
+    let mut pool = LocalPool::new();
+    let spawner = pool.spawner();
+    for _ in 0..3 {
+        let wakeups_remaining = Rc::clone(&wakeups_remaining);
+        spawner.spawn_local(SelfWaking { wakeups_remaining }).unwrap();
+    }
+
+    // This should keep polling until there are no more wakeups.
+    pool.run_until_stalled();
+
+    assert_eq!(*wakeups_remaining.borrow(), 0);
+}
+
+/// Regression test for https://github.com/rust-lang/futures-rs/pull/2593
+///
+/// The issue was that self-waking futures could cause `try_run_one`
+/// to exit early, even when progress could still be made.
+#[test]
+fn self_waking_try_run_one() {
+    let wakeups_remaining = Rc::new(RefCell::new(10));
+
+    let mut pool = LocalPool::new();
+    let spawner = pool.spawner();
+    for _ in 0..3 {
+        let wakeups_remaining = Rc::clone(&wakeups_remaining);
+        spawner.spawn_local(SelfWaking { wakeups_remaining }).unwrap();
+    }
+
+    spawner.spawn(future::ready(())).unwrap();
+
+    // The `ready` future should complete.
+    assert!(pool.try_run_one());
+
+    // The self-waking futures are each polled once.
+    assert_eq!(*wakeups_remaining.borrow(), 7);
+}