forked from mirrors/gecko-dev
65 lines
2.4 KiB
Rust
65 lines
2.4 KiB
Rust
#![cfg(feature = "async")]
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use core::{future, mem, pin, task};
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#[cfg(loom)]
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pub use loom::sync::{Arc, Mutex};
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#[cfg(not(loom))]
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pub use std::sync::{Arc, Mutex};
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mod helpers;
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use helpers::maybe_loom_model;
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#[test]
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fn multiple_receiver_polls_keeps_only_latest_waker() {
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#[derive(Default)]
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struct MockWaker {
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cloned: usize,
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dropped: usize,
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}
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fn clone_mock_waker(waker: *const ()) -> task::RawWaker {
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let mock_waker = unsafe { Arc::from_raw(waker as *const Mutex<MockWaker>) };
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mock_waker.lock().unwrap().cloned += 1;
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let new_waker =
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task::RawWaker::new(Arc::into_raw(mock_waker.clone()) as *const (), &VTABLE);
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mem::forget(mock_waker);
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new_waker
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}
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fn drop_mock_waker(waker: *const ()) {
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let mock_waker = unsafe { Arc::from_raw(waker as *const Mutex<MockWaker>) };
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mock_waker.lock().unwrap().dropped += 1;
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}
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const VTABLE: task::RawWakerVTable =
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task::RawWakerVTable::new(clone_mock_waker, |_| (), |_| (), drop_mock_waker);
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maybe_loom_model(|| {
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let mock_waker1 = Arc::new(Mutex::new(MockWaker::default()));
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let raw_waker1 =
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task::RawWaker::new(Arc::into_raw(mock_waker1.clone()) as *const (), &VTABLE);
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let waker1 = unsafe { task::Waker::from_raw(raw_waker1) };
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let mut context1 = task::Context::from_waker(&waker1);
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let (_sender, mut receiver) = oneshot::channel::<()>();
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let poll_result = future::Future::poll(pin::Pin::new(&mut receiver), &mut context1);
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assert_eq!(poll_result, task::Poll::Pending);
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assert_eq!(mock_waker1.lock().unwrap().cloned, 1);
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assert_eq!(mock_waker1.lock().unwrap().dropped, 0);
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let mock_waker2 = Arc::new(Mutex::new(MockWaker::default()));
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let raw_waker2 =
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task::RawWaker::new(Arc::into_raw(mock_waker2.clone()) as *const (), &VTABLE);
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let waker2 = unsafe { task::Waker::from_raw(raw_waker2) };
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let mut context2 = task::Context::from_waker(&waker2);
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let poll_result = future::Future::poll(pin::Pin::new(&mut receiver), &mut context2);
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assert_eq!(poll_result, task::Poll::Pending);
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assert_eq!(mock_waker2.lock().unwrap().cloned, 1);
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assert_eq!(mock_waker2.lock().unwrap().dropped, 0);
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assert_eq!(mock_waker1.lock().unwrap().cloned, 1);
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assert_eq!(mock_waker1.lock().unwrap().dropped, 1);
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});
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}
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