rart_rs/futures/
trigger.rs

1use heapless::Deque;
2use core::task::Waker;
3use core::future::Future;
4use core::pin::Pin;
5use core::task::{Context, Poll};
6use core::sync::atomic::{AtomicUsize, Ordering};
7use crate::common::arc::Arc;
8use crate::common::ArcMutex;
9use crate::common::blocking_mutex::BlockingMutex;
10use crate::common::result::RARTError;
11use crate::Expect;
12
13pub struct Trigger<const TN: usize> {
14    wait_wakers: ArcMutex<Deque<Waker, TN>>,
15    is_triggered: AtomicUsize,
16}
17
18struct Waiter<const TN: usize> {
19    trigger: &'static Trigger<TN>,
20}
21
22impl<const TN: usize> Trigger<TN> {
23    pub fn new() -> Self {
24        Self {
25            wait_wakers: Arc::new(BlockingMutex::new(Deque::new())),
26            is_triggered: AtomicUsize::new(0),
27        }
28    }
29
30    pub fn trigger(&'static self) -> Result<(), RARTError> {
31        let mut wait_wakers = self.wait_wakers.lock()?;
32
33        if self.is_triggered.compare_exchange(0, wait_wakers.len(),
34                                              Ordering::AcqRel,
35                                              Ordering::Relaxed).is_ok() {
36            for waker in wait_wakers.iter() {
37                waker.wake_by_ref();
38            }
39            wait_wakers.clear();
40        }
41
42        Ok(())
43    }
44
45    pub async fn wait(&'static self) {
46        Waiter { trigger: &self }.await
47    }
48}
49
50impl<const TN: usize> Future for Waiter<TN> {
51    type Output = ();
52
53    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
54        if self.trigger.is_triggered.load(Ordering::Acquire) == 0 {
55            let mut wait_wakers = self.trigger.wait_wakers.lock().rart_expect("Cannot lock wait_wakers at trigger poll");
56            wait_wakers.push_back(cx.waker().clone()).rart_expect("Cannot push back the wait waker");
57            Poll::Pending
58        } else {
59            self.trigger.is_triggered.fetch_sub(1, Ordering::AcqRel);
60            Poll::Ready(())
61        }
62    }
63}
rart_rs/futures/trigger.rs

rart_rs/futures/
trigger.rs
