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use crate::prelude::*;
use parking_lot::Mutex;
type Millis = u32;
type Micros = u64;
#[derive(Serialize,Deserialize,Error,Debug,Clone)]
#[error("Time is real")]
pub struct TimeIsReal;
#[derive(Deserialize,Debug,Clone,Default)]
#[serde(transparent)]
pub struct FakeTimeConfig(pub Option<FakeTimeSpec>);
#[derive(Deserialize,Serialize,Debug,Clone,Default)]
#[serde(into="Vec<Millis>", try_from="Vec<Millis>")]
pub struct FakeTimeSpec(pub Option<Millis>);
#[derive(Error,Debug)]
#[error("invalid fake time: must be list of 0 or 1 numbers (ms)")]
pub struct InvalidFakeTime;
impl TryFrom<Vec<Millis>> for FakeTimeSpec {
type Error = InvalidFakeTime;
#[throws(InvalidFakeTime)]
fn try_from(l: Vec<Millis>) -> FakeTimeSpec {
FakeTimeSpec(match &*l {
[] => None,
&[ms] => Some(ms),
_ => throw!(InvalidFakeTime),
})
}
}
impl Into<Vec<Millis>> for FakeTimeSpec {
fn into(self) -> Vec<Millis> {
self.0.into_iter().collect()
}
}
#[derive(Debug)]
pub struct GlobalClock {
fakeable: Option<Mutex<Option<FakeClock>>>,
}
#[derive(Debug)]
struct FakeClock {
start: Instant,
current: Micros,
}
impl FakeClock {
fn from_millis(ms: Millis) -> FakeClock { FakeClock {
start: Instant::now(),
current: (ms as Micros) * 1000,
} }
fn from_spec(FakeTimeSpec(fspec): FakeTimeSpec) -> Option<FakeClock> {
fspec.map(FakeClock::from_millis)
}
}
impl FakeTimeConfig {
pub fn make_global_clock(self) -> GlobalClock {
let fakeable = self.0.map(|fspec| FakeClock::from_spec(fspec).into());
GlobalClock { fakeable }
}
}
impl GlobalClock {
pub fn now(&self) -> Instant {
self.now_fake().unwrap_or_else(|| Instant::now())
}
#[throws(as Option)]
fn now_fake(&self) -> Instant {
let mut guard = self.fakeable.as_ref()?.lock();
let fake = guard.as_mut()?;
fake.current += 1;
fake.start + Duration::from_micros(fake.current)
}
#[throws(TimeIsReal)]
pub fn set_fake(&self, fspec: FakeTimeSpec, _: AuthorisationSuperuser) {
let mut guard = self.fakeable.as_ref().ok_or(TimeIsReal)?.lock();
*guard = FakeClock::from_spec(fspec)
}
pub fn is_fake(&self) -> bool {
self.fakeable.is_some()
}
}
