use std::fmt;
use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
use std::time::{Duration, Instant};
use super::{delay_until, Delay};
use pin_project_lite::pin_project;
pub fn timeout<T>(duration: Duration, future: T) -> Timeout<T>
where
T: Future,
{
timeout_at(Instant::now() + duration, future)
}
pub fn timeout_at<T>(deadline: Instant, future: T) -> Timeout<T>
where
T: Future,
{
let delay = delay_until(deadline);
Timeout {
value: future,
delay,
}
}
pin_project! {
pub struct Timeout<T> {
#[pin]
value: T,
#[pin]
delay: Delay,
}
}
impl<T> Timeout<T> {
pub fn into_inner(self) -> T {
self.value
}
pub fn get_ref(&self) -> &T {
&self.value
}
pub fn get_mut(&mut self) -> &mut T {
&mut self.value
}
}
#[derive(Debug)]
pub struct Elapsed(());
impl std::error::Error for Elapsed {}
impl fmt::Display for Elapsed {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
"deadline has elapsed".fmt(fmt)
}
}
impl From<Elapsed> for std::io::Error {
fn from(_err: Elapsed) -> std::io::Error {
std::io::ErrorKind::TimedOut.into()
}
}
impl<T> Future for Timeout<T>
where
T: Future,
{
type Output = Result<T::Output, Elapsed>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let this = self.project();
if let Poll::Ready(v) = this.value.poll(cx) {
return Poll::Ready(Ok(v));
}
match this.delay.poll(cx) {
Poll::Ready(()) => Poll::Ready(Err(Elapsed(()))),
Poll::Pending => Poll::Pending,
}
}
}