use std::prelude::v1::*;
use std::convert::TryInto;
use std::fmt::Debug;
use std::ops::Add;
use std::sync::atomic::AtomicU64;
use std::sync::atomic::Ordering;
use std::sync::Arc;
use std::time::Duration;
use crate::nanos::Nanos;
pub trait Reference:
Sized + Add<Nanos, Output = Self> + PartialEq + Eq + Ord + Copy + Clone + Send + Sync + Debug
{
fn duration_since(&self, earlier: Self) -> Nanos;
fn saturating_sub(&self, duration: Nanos) -> Self;
}
pub trait Clock: Clone {
type Instant: Reference;
fn now(&self) -> Self::Instant;
}
impl Reference for Duration {
fn duration_since(&self, earlier: Self) -> Nanos {
self.checked_sub(earlier)
.unwrap_or_else(|| Duration::new(0, 0))
.into()
}
fn saturating_sub(&self, duration: Nanos) -> Self {
self.checked_sub(duration.into()).unwrap_or(*self)
}
}
impl Add<Nanos> for Duration {
type Output = Self;
fn add(self, other: Nanos) -> Self {
let other: Duration = other.into();
self + other
}
}
#[derive(Debug, Clone, Default)]
pub struct FakeRelativeClock {
now: Arc<AtomicU64>,
}
impl FakeRelativeClock {
pub fn advance(&self, by: Duration) {
let by: u64 = by
.as_nanos()
.try_into()
.expect("Can not represent times past ~584 years");
let mut prev = self.now.load(Ordering::Acquire);
let mut next = prev + by;
while let Err(next_prev) =
self.now
.compare_exchange_weak(prev, next, Ordering::Release, Ordering::Relaxed)
{
prev = next_prev;
next = prev + by;
}
}
}
impl PartialEq for FakeRelativeClock {
fn eq(&self, other: &Self) -> bool {
self.now.load(Ordering::Relaxed) == other.now.load(Ordering::Relaxed)
}
}
impl Clock for FakeRelativeClock {
type Instant = Nanos;
fn now(&self) -> Self::Instant {
self.now.load(Ordering::Relaxed).into()
}
}
#[cfg(feature = "std")]
mod with_std;
#[cfg(feature = "std")]
pub use with_std::*;
#[cfg(all(feature = "std", feature = "quanta"))]
mod quanta;
#[cfg(all(feature = "std", feature = "quanta"))]
pub use self::quanta::*;
mod default;
pub use default::*;
#[cfg(all(feature = "std", test))]
mod test {
use super::*;
use crate::nanos::Nanos;
use std::iter::repeat;
use std::sync::Arc;
use std::thread;
use std::time::Duration;
#[test]
fn fake_clock_parallel_advances() {
let clock = Arc::new(FakeRelativeClock::default());
let threads = repeat(())
.take(10)
.map(move |_| {
let clock = Arc::clone(&clock);
thread::spawn(move || {
for _ in 0..1000000 {
let now = clock.now();
clock.advance(Duration::from_nanos(1));
assert!(clock.now() > now);
}
})
})
.collect::<Vec<_>>();
for t in threads {
t.join().unwrap();
}
}
#[test]
fn duration_addition_coverage() {
let d = Duration::from_secs(1);
let one_ns = Nanos::new(1);
assert!(d + one_ns > d);
}
}