zynq-rs/libasync/src/task.rs

51 lines
1.3 KiB
Rust
Raw Normal View History

//! Asynchronous tasks
use core::{
future::Future,
pin::Pin,
task::{Context, Poll},
};
use super::executor;
/// Drives the future `f` to completion
///
/// This also makes any previously `spawn`-ed future make progress
pub fn block_on<T>(f: impl Future<Output = T>) -> T {
executor::current().block_on(f)
}
/// Spawns a task onto the executor
///
/// The spawned task will not make any progress until `block_on` is called.
///
/// The future `f` must never terminate. The program will *abort* if `f` (the async code) returns.
/// The right signature here would be `f: impl Future<Output = !>` but that requires nightly
pub fn spawn<T>(f: impl Future<Output = T> + 'static) {
executor::current().spawn(f)
}
/// Use `r#yield.await` to suspend the execution of a task
pub async fn r#yield() {
struct Yield {
yielded: bool,
}
impl Future for Yield {
type Output = ();
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
if self.yielded {
Poll::Ready(())
} else {
self.yielded = true;
// wake ourselves
cx.waker().wake_by_ref();
//asm::sev();
Poll::Pending
}
}
}
Yield { yielded: false }.await
}