tasc 0.2.0

A minimnal, asynchronous threadpool
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

use alloc::sync::Arc;
use core::{future::Future, task::Context};

/// Provides an abstraction on a signal that is used for the blocking API.
/// The signal is also used when a type is dropped, because asynchronous drops
/// are unstable.
pub trait Signal: Send + Unpin {
    /// Awaits the signal to trigger.
    fn wait(&self);

    /// Crates a waker from `[Self]`.
    fn waker(self: Arc<Self>) -> core::task::Waker;
}

/// Blocks asynchronous code based on a signal.
pub fn block_on_signal<F: Future>(signal: impl Signal, mut future: F) -> F::Output {
    let mut future = unsafe { core::pin::Pin::new_unchecked(&mut future) };

    let signal = Arc::new(signal);
    let waker = Signal::waker(signal.clone());

    let mut cx = Context::from_waker(&waker);
    loop {
        match future.as_mut().poll(&mut cx) {
            core::task::Poll::Ready(value) => break value,
            core::task::Poll::Pending => Signal::wait(&*signal),
        }
    }
}