33 lines
1.1 KiB
Rust
33 lines
1.1 KiB
Rust
use core::task::Waker;
|
|
|
|
/// Utility struct to register and wake a waker.
|
|
#[derive(Debug)]
|
|
pub struct WakerRegistration {
|
|
waker: Option<Waker>,
|
|
}
|
|
|
|
impl WakerRegistration {
|
|
pub const fn new() -> Self {
|
|
Self { waker: None }
|
|
}
|
|
|
|
/// Register a waker. Overwrites the previous waker, if any.
|
|
pub fn register(&mut self, w: &Waker) {
|
|
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(w)) => {}
|
|
// In all other cases
|
|
// - we have no waker registered
|
|
// - we have a waker registered but it's for a different task.
|
|
// then clone the new waker and store it
|
|
_ => self.waker = Some(w.clone()),
|
|
}
|
|
}
|
|
|
|
/// Wake the registered waker, if any.
|
|
pub fn wake(&mut self) {
|
|
self.waker.take().map(|w| w.wake());
|
|
}
|
|
} |