library/std/src/sys/wasi/time.rs

   1 #![deny(unsafe_op_in_unsafe_fn)]
   2
   3 use crate::time::Duration;
   4
   5 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
   6 pub struct Instant(Duration);
   7
   8 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
   9 pub struct SystemTime(Duration);
  10
  11 pub const UNIX_EPOCH: SystemTime = SystemTime(Duration::from_secs(0));
  12
  13 fn current_time(clock: u32) -> Duration {
  14     let ts = unsafe {
  15         wasi::clock_time_get(
  16             clock, 1, // precision... seems ignored though?
  17         )
  18         .unwrap()
  19     };
  20     Duration::new((ts / 1_000_000_000) as u64, (ts % 1_000_000_000) as u32)
  21 }
  22
  23 impl Instant {
  24     pub fn now() -> Instant {
  25         Instant(current_time(wasi::CLOCKID_MONOTONIC))
  26     }
  27
  28     pub const fn zero() -> Instant {
  29         Instant(Duration::from_secs(0))
  30     }
  31
  32     pub fn actually_monotonic() -> bool {
  33         true
  34     }
  35
  36     pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
  37         self.0.checked_sub(other.0)
  38     }
  39
  40     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
  41         Some(Instant(self.0.checked_add(*other)?))
  42     }
  43
  44     pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
  45         Some(Instant(self.0.checked_sub(*other)?))
  46     }
  47 }
  48
  49 impl SystemTime {
  50     pub fn now() -> SystemTime {
  51         SystemTime(current_time(wasi::CLOCKID_REALTIME))
  52     }
  53
  54     pub fn from_wasi_timestamp(ts: wasi::Timestamp) -> SystemTime {
  55         SystemTime(Duration::from_nanos(ts))
  56     }
  57
  58     pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
  59         self.0.checked_sub(other.0).ok_or_else(|| other.0 - self.0)
  60     }
  61
  62     pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
  63         Some(SystemTime(self.0.checked_add(*other)?))
  64     }
  65
  66     pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
  67         Some(SystemTime(self.0.checked_sub(*other)?))
  68     }
  69 }