Merge "Make boot_time::timeout() timeout immediately when passing zero duration" am: 8bc0e5c6

    }

    fn set(&self, duration: Duration) {

        assert_ne!(duration, Duration::from_millis(0));

        let timer = libc::itimerspec {

            it_interval: libc::timespec { tv_sec: 0, tv_nsec: 0 },

            it_value: libc::timespec {

    // Ideally, all timeouts in a runtime would share a timerfd. That will be much more

    // straightforwards to implement when moving this functionality into `tokio`.

    // According to timerfd_settime(), setting zero duration will disarm the timer, so

    // we return immediate timeout here.

    // Can't use is_zero() for now because sc-mainline-prod's Rust version is below 1.53.

    if duration == Duration::from_millis(0) {

        return Err(Elapsed(()));

    }

    // The failure conditions for this are rare (see `man 2 timerfd_create`) and the caller would

    // not be able to do much in response to them. When integrated into tokio, this would be called

    // during runtime setup.

        assert!(drift < Duration::from_millis(5));

    }

}

#[tokio::test]

async fn timeout_duration_zero() {

    let start = BootTime::now();

    assert!(timeout(Duration::from_millis(0), pending::<()>()).await.is_err());

    let taken = start.elapsed();

    assert!(taken < Duration::from_millis(5));

}