1use core::cell::Cell;
2use core::task::Waker;
3
4use crate::blocking_mutex::raw::{CriticalSectionRawMutex, RawMutex};
5use crate::blocking_mutex::Mutex;
6
7/// Utility struct to register and wake a waker.
8pub struct GenericAtomicWaker<M: RawMutex> {
9 waker: Mutex<M, Cell<Option<Waker>>>,
10}
11
12impl<M: RawMutex> GenericAtomicWaker<M> {
13 /// Create a new `AtomicWaker`.
14 pub const fn new(mutex: M) -> Self {
15 Self {
16 waker: Mutex::const_new(mutex, Cell::new(None)),
17 }
18 }
19
20 /// Register a waker. Overwrites the previous waker, if any.
21 pub fn register(&self, w: &Waker) {
22 self.waker.lock(|cell| {
23 cell.set(match cell.replace(None) {
24 Some(w2) if (w2.will_wake(w)) => Some(w2),
25 _ => Some(w.clone()),
26 })
27 })
28 }
29
30 /// Wake the registered waker, if any.
31 pub fn wake(&self) {
32 self.waker.lock(|cell| {
33 if let Some(w) = cell.replace(None) {
34 w.wake_by_ref();
35 cell.set(Some(w));
36 }
37 })
38 }
39}
40
41/// Utility struct to register and wake a waker.
42pub struct AtomicWaker {
43 waker: GenericAtomicWaker<CriticalSectionRawMutex>,
44}
45
46impl AtomicWaker {
47 /// Create a new `AtomicWaker`.
48 pub const fn new() -> Self {
49 Self {
50 waker: GenericAtomicWaker::new(mutex:CriticalSectionRawMutex::new()),
51 }
52 }
53
54 /// Register a waker. Overwrites the previous waker, if any.
55 pub fn register(&self, w: &Waker) {
56 self.waker.register(w);
57 }
58
59 /// Wake the registered waker, if any.
60 pub fn wake(&self) {
61 self.waker.wake();
62 }
63}
64