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atomic_waker.rs
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atomic_waker.rs
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use core::cell::Cell;
use core::task::Waker;
use crate::blocking_mutex::raw::CriticalSectionRawMutex;
use crate::blocking_mutex::Mutex;
/// Utility struct to register and wake a waker.
pub struct AtomicWaker {
waker: Mutex<CriticalSectionRawMutex, Cell<Option<Waker>>>,
}
impl AtomicWaker {
/// Create a new `AtomicWaker`.
pub const fn new() -> Self {
Self {
waker: Mutex::const_new(CriticalSectionRawMutex::new(), Cell::new(None)),
}
}
/// Register a waker. Overwrites the previous waker, if any.
pub fn register(&self, w: &Waker) {
critical_section::with(|cs| {
let cell = self.waker.borrow(cs);
cell.set(match cell.replace(None) {
Some(w2) if (w2.will_wake(w)) => Some(w2),
_ => Some(w.clone()),
})
})
}
/// Wake the registered waker, if any.
pub fn wake(&self) {
critical_section::with(|cs| {
let cell = self.waker.borrow(cs);
if let Some(w) = cell.replace(None) {
w.wake_by_ref();
cell.set(Some(w));
}
})
}
}