1 files changed, 65 insertions, 0 deletions
diff --git a/library/std/src/sys/wasi/time.rs b/library/std/src/sys/wasi/time.rs
new file mode 100644
index 000000000..3d326e491
--- /dev/null
+++ b/library/std/src/sys/wasi/time.rs
@@ -0,0 +1,65 @@
+#![deny(unsafe_op_in_unsafe_fn)]
+
+use crate::time::Duration;
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+pub struct Instant(Duration);
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+pub struct SystemTime(Duration);
+
+pub const UNIX_EPOCH: SystemTime = SystemTime(Duration::from_secs(0));
+
+fn current_time(clock: wasi::Clockid) -> Duration {
+    let ts = unsafe {
+        wasi::clock_time_get(
+            clock, 1, // precision... seems ignored though?
+        )
+        .unwrap()
+    };
+    Duration::new((ts / 1_000_000_000) as u64, (ts % 1_000_000_000) as u32)
+}
+
+impl Instant {
+    pub fn now() -> Instant {
+        Instant(current_time(wasi::CLOCKID_MONOTONIC))
+    }
+
+    pub fn checked_sub_instant(&self, other: &Instant) -> Option<Duration> {
+        self.0.checked_sub(other.0)
+    }
+
+    pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
+        Some(Instant(self.0.checked_add(*other)?))
+    }
+
+    pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
+        Some(Instant(self.0.checked_sub(*other)?))
+    }
+}
+
+impl SystemTime {
+    pub fn now() -> SystemTime {
+        SystemTime(current_time(wasi::CLOCKID_REALTIME))
+    }
+
+    pub fn from_wasi_timestamp(ts: wasi::Timestamp) -> SystemTime {
+        SystemTime(Duration::from_nanos(ts))
+    }
+
+    pub fn to_wasi_timestamp_or_panic(&self) -> wasi::Timestamp {
+        self.0.as_nanos().try_into().expect("time does not fit in WASI timestamp")
+    }
+
+    pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
+        self.0.checked_sub(other.0).ok_or_else(|| other.0 - self.0)
+    }
+
+    pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
+        Some(SystemTime(self.0.checked_add(*other)?))
+    }
+
+    pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
+        Some(SystemTime(self.0.checked_sub(*other)?))
+    }
+}