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
30
31
32
33
34
35
36

extern crate std;

use core::{future::Future, pin::Pin, task::{Context, Poll}};
use std::time::{Duration, SystemTime};

pub struct Timer {
    length: Duration,
    start: SystemTime,
}

impl Future for Timer {
    type Output = ();

    fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
        if self.start.elapsed().unwrap_or_else(|_| self.length) >= self.length {
            Poll::Ready(())
        }
        else {
            Poll::Pending
        }
    }
}

pub async fn wait(duration: Duration) {
    Timer {
        length: duration,
        start: SystemTime::now(),
    }.await
}

pub async fn wait_ms(ms: u64) {
    Timer {
        length: Duration::from_millis(ms),
        start: SystemTime::now(),
    }.await
}