diff options
Diffstat (limited to 'rtic-channel/src/waker_registration.rs')
| -rw-r--r-- | rtic-channel/src/waker_registration.rs | 64 |
1 files changed, 0 insertions, 64 deletions
diff --git a/rtic-channel/src/waker_registration.rs b/rtic-channel/src/waker_registration.rs deleted file mode 100644 index c30df7f..0000000 --- a/rtic-channel/src/waker_registration.rs +++ /dev/null @@ -1,64 +0,0 @@ -use core::cell::UnsafeCell; -use core::task::Waker; - -/// A critical section based waker handler. -pub struct CriticalSectionWakerRegistration { - waker: UnsafeCell<Option<Waker>>, -} - -unsafe impl Send for CriticalSectionWakerRegistration {} -unsafe impl Sync for CriticalSectionWakerRegistration {} - -impl CriticalSectionWakerRegistration { - /// Create a new waker registration. - pub const fn new() -> Self { - Self { - waker: UnsafeCell::new(None), - } - } - - /// Register a waker. - /// This will overwrite the previous waker if there was one. - pub fn register(&self, new_waker: &Waker) { - critical_section::with(|_| { - // SAFETY: This access is protected by the critical section. - let self_waker = unsafe { &mut *self.waker.get() }; - - // From embassy - // https://github.com/embassy-rs/embassy/blob/b99533607ceed225dd12ae73aaa9a0d969a7365e/embassy-sync/src/waitqueue/waker.rs#L59-L61 - match self_waker { - // Optimization: If both the old and new Wakers wake the same task, we can simply - // keep the old waker, skipping the clone. (In most executor implementations, - // cloning a waker is somewhat expensive, comparable to cloning an Arc). - Some(ref w2) if (w2.will_wake(new_waker)) => {} - _ => { - // clone the new waker and store it - if let Some(old_waker) = core::mem::replace(self_waker, Some(new_waker.clone())) - { - // We had a waker registered for another task. Wake it, so the other task can - // reregister itself if it's still interested. - // - // If two tasks are waiting on the same thing concurrently, this will cause them - // to wake each other in a loop fighting over this WakerRegistration. This wastes - // CPU but things will still work. - // - // If the user wants to have two tasks waiting on the same thing they should use - // a more appropriate primitive that can store multiple wakers. - old_waker.wake() - } - } - } - }); - } - - /// Wake the waker. - pub fn wake(&self) { - critical_section::with(|_| { - // SAFETY: This access is protected by the critical section. - let self_waker = unsafe { &mut *self.waker.get() }; - if let Some(waker) = self_waker.take() { - waker.wake() - } - }); - } -} |
