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use crossbeam_channel::{bounded, Receiver, Sender};
pub struct JobHandle {
job_alive: Receiver<Never>,
_job_canceled: Sender<Never>,
}
pub struct JobToken {
_job_alive: Sender<Never>,
job_canceled: Receiver<Never>,
}
impl JobHandle {
pub fn new_pair() -> (JobHandle, JobToken) {
let (sender_alive, receiver_alive) = bounded(0);
let (sender_canceled, receiver_canceled) = bounded(0);
let token = JobToken {
_job_alive: sender_alive,
job_canceled: receiver_canceled,
};
let handle = JobHandle {
job_alive: receiver_alive,
_job_canceled: sender_canceled,
};
(handle, token)
}
pub fn has_completed(&self) -> bool {
is_closed(&self.job_alive)
}
pub fn cancel(self) {}
}
impl JobToken {
pub fn is_canceled(&self) -> bool {
is_closed(&self.job_canceled)
}
}
// We don't actually send messages through the channels,
// and instead just check if the channel is closed,
// so we use uninhabited enum as a message type
enum Never {}
/// Nonblocking
fn is_closed(chan: &Receiver<Never>) -> bool {
select! {
recv(chan, msg) => match msg {
None => true,
Some(never) => match never {}
}
default => false,
}
}
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