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Monorepo for Tangled
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use tokio::time::Instant;
#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]pub struct UnixMicros(u64);
impl UnixMicros { pub const fn new(value: u64) -> Self { Self(value) }
pub const fn raw(self) -> u64 { self.0 }}
pub type SleepFuture = Pin<Box<dyn Future<Output = ()> + Send + 'static>>;
pub trait Clock: Send + Sync + 'static { fn now_unix_micros(&self) -> UnixMicros; fn now_instant(&self) -> Instant; fn sleep(&self, duration: Duration) -> SleepFuture; fn sleep_until(&self, deadline: Instant) -> SleepFuture;}
#[derive(Clone, Copy, Debug)]pub struct SystemClock { base_unix: UnixMicros, base_instant: Instant,}
impl SystemClock { pub fn new() -> Self { let raw = SystemTime::now() .duration_since(UNIX_EPOCH) .expect("system clock before unix epoch") .as_micros(); Self { base_unix: UnixMicros::new(u64::try_from(raw).unwrap_or(u64::MAX)), base_instant: Instant::now(), } }}
impl Default for SystemClock { fn default() -> Self { Self::new() }}
impl Clock for SystemClock { fn now_unix_micros(&self) -> UnixMicros { let elapsed = self .now_instant() .saturating_duration_since(self.base_instant); let micros = u64::try_from(elapsed.as_micros()).unwrap_or(u64::MAX); UnixMicros::new(self.base_unix.raw().saturating_add(micros)) }
fn now_instant(&self) -> Instant { Instant::now() }
fn sleep(&self, duration: Duration) -> SleepFuture { Box::pin(tokio::time::sleep(duration)) }
fn sleep_until(&self, deadline: Instant) -> SleepFuture { Box::pin(tokio::time::sleep_until(deadline)) }}
#[derive(Clone, Debug)]pub struct SimClock { base_unix: UnixMicros, base_instant: Instant,}
impl SimClock { pub fn at(base_unix: UnixMicros) -> Self { Self { base_unix, base_instant: Instant::now(), } }}
impl Clock for SimClock { fn now_unix_micros(&self) -> UnixMicros { let elapsed = self .now_instant() .saturating_duration_since(self.base_instant); let micros = u64::try_from(elapsed.as_micros()).unwrap_or(u64::MAX); UnixMicros::new(self.base_unix.raw().saturating_add(micros)) }
fn now_instant(&self) -> Instant { Instant::now() }
fn sleep(&self, duration: Duration) -> SleepFuture { Box::pin(tokio::time::sleep(duration)) }
fn sleep_until(&self, deadline: Instant) -> SleepFuture { Box::pin(tokio::time::sleep_until(deadline)) }}
#[cfg(test)]mod tests { use super::*; use std::sync::Arc; use std::sync::atomic::{AtomicU64, Ordering};
struct ManualClock { base: Instant, unix_micros: AtomicU64, }
impl ManualClock { fn new(unix_micros: u64) -> Self { Self { base: Instant::now(), unix_micros: AtomicU64::new(unix_micros), } }
fn advance(&self, micros: u64) { self.unix_micros.fetch_add(micros, Ordering::SeqCst); } }
impl Clock for ManualClock { fn now_unix_micros(&self) -> UnixMicros { UnixMicros::new(self.unix_micros.load(Ordering::SeqCst)) }
fn now_instant(&self) -> Instant { self.base + Duration::from_micros(self.unix_micros.load(Ordering::SeqCst)) }
fn sleep(&self, _: Duration) -> SleepFuture { Box::pin(std::future::ready(())) }
fn sleep_until(&self, _: Instant) -> SleepFuture { Box::pin(std::future::ready(())) } }
#[tokio::test] async fn external_clock_works_behind_dyn_arc() { let clock: Arc<dyn Clock> = Arc::new(ManualClock::new(42)); assert_eq!(clock.now_unix_micros().raw(), 42); let before = clock.now_instant(); clock.sleep(Duration::from_secs(60)).await; assert_eq!( clock.now_instant(), before, "manual clock's sleep must not advance virtual time on its own", ); }
#[tokio::test] async fn manual_clock_advance_moves_both_unix_and_instant() { let clock = Arc::new(ManualClock::new(1_000)); let dyn_clock: Arc<dyn Clock> = clock.clone(); let unix_before = dyn_clock.now_unix_micros().raw(); let instant_before = dyn_clock.now_instant(); clock.advance(500); assert_eq!(dyn_clock.now_unix_micros().raw(), unix_before + 500); assert_eq!( dyn_clock.now_instant(), instant_before + Duration::from_micros(500), ); }
#[tokio::test(start_paused = true)] async fn sim_clock_anchors_unix_at_explicit_base_under_paused_time() { let base = UnixMicros::new(1_700_000_000_000_000); let clock = SimClock::at(base); assert_eq!( clock.now_unix_micros(), base, "sim clock unix axis must reflect the explicit base, not wall clock", ); let bump = Duration::from_secs(10); tokio::time::advance(bump).await; assert_eq!( clock.now_unix_micros().raw(), base.raw() + u64::try_from(bump.as_micros()).unwrap(), "sim clock unix axis must follow tokio virtual advance", ); }
#[tokio::test(start_paused = true)] async fn sim_clock_two_constructions_with_same_base_align() { let base = UnixMicros::new(2_000_000_000_000_000); let a = SimClock::at(base); let b = SimClock::at(base); assert_eq!(a.now_unix_micros(), b.now_unix_micros()); tokio::time::advance(Duration::from_secs(5)).await; assert_eq!( a.now_unix_micros(), b.now_unix_micros(), "two sim clocks anchored at the same base must agree on virtual time", ); }
#[tokio::test(start_paused = true)] async fn system_clock_axes_advance_together_under_paused_time() { let clock = SystemClock::new(); let unix_before = clock.now_unix_micros().raw(); let instant_before = clock.now_instant(); let bump = Duration::from_secs(60); tokio::time::advance(bump).await; let unix_after = clock.now_unix_micros().raw(); let instant_after = clock.now_instant(); assert_eq!( instant_after.saturating_duration_since(instant_before), bump, "instant axis must reflect virtual advance", ); assert_eq!( unix_after - unix_before, u64::try_from(bump.as_micros()).unwrap(), "unix axis must follow the same virtual advance, not wall clock", ); }}