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