kapiti 0.0.3

The Kapiti DNS Server
Documentation 
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use core::pin::Pin;
use core::task::{Context, Poll};
use std::time::Duration;

use async_io::Timer;
use futures_lite::Future;
use pin_project_lite::pin_project;

pub fn timeout<T, F>(future: F, timeout: &Duration) -> Timeout<F>
where
    F: Future<Output = T>,
{
    Timeout {
        future,
        timer: Timer::after(timeout.clone()),
    }
}

pin_project! {
    /// Future for the [`or()`] function and the [`FutureExt::or()`] method.
    #[derive(Debug)]
    #[must_use = "futures do nothing unless you `.await` or poll them"]
    pub struct Timeout<F> {
        #[pin]
        future: F,
        #[pin]
        timer: Timer,
    }
}

impl<T, F> Future for Timeout<F>
where
    F: Future<Output = T>,
{
    type Output = Option<T>;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        let this = self.project();

        if let Poll::Ready(t) = this.future.poll(cx) {
            return Poll::Ready(Some(t));
        }
        if let Poll::Ready(_t) = this.timer.poll(cx) {
            return Poll::Ready(None);
        }
        Poll::Pending
    }
}