1mod clock;
 2mod executor;
 3mod test_scheduler;
 4#[cfg(test)]
 5mod tests;
 6
 7pub use clock::*;
 8pub use executor::*;
 9pub use test_scheduler::*;
10
11use async_task::Runnable;
12use futures::{FutureExt as _, channel::oneshot, future::LocalBoxFuture};
13use std::{
14    future::Future,
15    pin::Pin,
16    sync::Arc,
17    task::{Context, Poll},
18    time::Duration,
19};
20
21pub trait Scheduler: Send + Sync {
22    // todo!("consider not taking sessions")
23    fn block(
24        &self,
25        session_id: Option<SessionId>,
26        future: LocalBoxFuture<()>,
27        timeout: Option<Duration>,
28    );
29    fn schedule_foreground(&self, session_id: SessionId, runnable: Runnable);
30    fn schedule_background(&self, runnable: Runnable);
31    fn timer(&self, timeout: Duration) -> Timer;
32    fn clock(&self) -> Arc<dyn Clock>;
33    fn as_test(&self) -> &TestScheduler {
34        panic!("this is not a test scheduler")
35    }
36}
37
38#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
39pub struct SessionId(u16);
40
41impl SessionId {
42    pub fn new(id: u16) -> Self {
43        SessionId(id)
44    }
45}
46
47pub struct Timer(oneshot::Receiver<()>);
48
49impl Timer {
50    pub fn new(rx: oneshot::Receiver<()>) -> Self {
51        Timer(rx)
52    }
53}
54
55impl Future for Timer {
56    type Output = ();
57
58    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<()> {
59        match self.0.poll_unpin(cx) {
60            Poll::Ready(_) => Poll::Ready(()),
61            Poll::Pending => Poll::Pending,
62        }
63    }
64}