1 files changed, 240 insertions, 138 deletions
diff --git a/src/wasm.rs b/src/wasm.rs
index 986bbf6..f11b82a 100644
--- a/src/wasm.rs
+++ b/src/wasm.rs
@@ -1,138 +1,240 @@
-use std::ops::{Add, AddAssign, Sub, SubAssign};
-use std::time::Duration;
-
-#[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Hash)]
-pub struct Instant(Duration);
-
-impl Ord for Instant {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.partial_cmp(other)
-            .expect("an instant should never be NaN or Inf.")
-    }
-}
-impl Eq for Instant {}
-
-impl Instant {
-    #[inline]
-    pub fn now() -> Self {
-        Instant(duration_from_f64(now()))
-    }
-
-    #[inline]
-    pub fn duration_since(&self, earlier: Instant) -> Duration {
-        assert!(
-            earlier.0 <= self.0,
-            "`earlier` cannot be later than `self`."
-        );
-        self.0 - earlier.0
-    }
-
-    #[inline]
-    pub fn elapsed(&self) -> Duration {
-        Self::now().duration_since(*self)
-    }
-
-    /// Returns `Some(t)` where `t` is the time `self + duration` if `t` can be represented as
-    /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
-    /// otherwise.
-    #[inline]
-    pub fn checked_add(&self, duration: Duration) -> Option<Instant> {
-        self.0.checked_add(duration).map(Instant)
-    }
-
-    /// Returns `Some(t)` where `t` is the time `self - duration` if `t` can be represented as
-    /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
-    /// otherwise.
-    #[inline]
-    pub fn checked_sub(&self, duration: Duration) -> Option<Instant> {
-        self.0.checked_sub(duration).map(Instant)
-    }
-}
-
-impl Add<Duration> for Instant {
-    type Output = Self;
-
-    #[inline]
-    fn add(self, rhs: Duration) -> Self {
-        Instant(self.0 + rhs)
-    }
-}
-
-impl AddAssign<Duration> for Instant {
-    #[inline]
-    fn add_assign(&mut self, rhs: Duration) {
-        self.0 += rhs
-    }
-}
-
-impl Sub<Duration> for Instant {
-    type Output = Self;
-
-    #[inline]
-    fn sub(self, rhs: Duration) -> Self {
-        Instant(self.0 - rhs)
-    }
-}
-
-impl Sub<Instant> for Instant {
-    type Output = Duration;
-
-    #[inline]
-    fn sub(self, rhs: Instant) -> Duration {
-        self.duration_since(rhs)
-    }
-}
-
-impl SubAssign<Duration> for Instant {
-    #[inline]
-    fn sub_assign(&mut self, rhs: Duration) {
-        self.0 -= rhs
-    }
-}
-
-fn duration_from_f64(millis: f64) -> Duration {
-    Duration::from_millis(millis.trunc() as u64)
-        + Duration::from_nanos((millis.fract() * 1.0e6) as u64)
-}
-
-#[cfg(all(feature = "stdweb", not(feature = "wasm-bindgen")))]
-#[allow(unused_results)] // Needed because the js macro triggers it.
-pub fn now() -> f64 {
-    use stdweb::unstable::TryInto;
-
-    // https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
-    #[cfg(not(feature = "inaccurate"))]
-    let v = js! { return performance.now(); };
-    #[cfg(feature = "inaccurate")]
-    let v = js! { return Date.now(); };
-    v.try_into().unwrap()
-}
-
-#[cfg(feature = "wasm-bindgen")]
-pub fn now() -> f64 {
-    #[cfg(not(feature = "inaccurate"))]
-    let now = {
-        use wasm_bindgen_rs::prelude::*;
-        use wasm_bindgen_rs::JsCast;
-        js_sys::Reflect::get(&js_sys::global(), &JsValue::from_str("performance"))
-            .expect("failed to get performance from global object")
-            .unchecked_into::<web_sys::Performance>()
-            .now()
-    };
-    #[cfg(feature = "inaccurate")]
-    let now = js_sys::Date::now();
-    now
-}
-
-// The JS now function is in a module so it won't have to be renamed
-#[cfg(not(any(feature = "wasm-bindgen", feature = "stdweb")))]
-mod js {
-    extern "C" {
-        pub fn now() -> f64;
-    }
-}
-// Make the unsafe extern function "safe" so it can be called like the other 'now' functions
-#[cfg(not(any(feature = "wasm-bindgen", feature = "stdweb")))]
-pub fn now() -> f64 {
-    unsafe { js::now() }
-}
+use std::cmp::Ordering;
+use std::ops::{Add, AddAssign, Sub, SubAssign};
+use std::time::Duration;
+
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Hash)]
+pub struct Instant(Duration);
+
+impl Ord for Instant {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.partial_cmp(other)
+            .expect("an instant should never be NaN or Inf.")
+    }
+}
+impl Eq for Instant {}
+
+impl Instant {
+    #[inline]
+    pub fn now() -> Self {
+        Instant(duration_from_f64(now()))
+    }
+
+    #[inline]
+    pub fn duration_since(&self, earlier: Instant) -> Duration {
+        assert!(
+            earlier.0 <= self.0,
+            "`earlier` cannot be later than `self`."
+        );
+        self.0 - earlier.0
+    }
+
+    #[inline]
+    pub fn elapsed(&self) -> Duration {
+        Self::now().duration_since(*self)
+    }
+
+    /// Returns `Some(t)` where `t` is the time `self + duration` if `t` can be represented as
+    /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
+    /// otherwise.
+    #[inline]
+    pub fn checked_add(&self, duration: Duration) -> Option<Instant> {
+        self.0.checked_add(duration).map(Instant)
+    }
+
+    /// Returns `Some(t)` where `t` is the time `self - duration` if `t` can be represented as
+    /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
+    /// otherwise.
+    #[inline]
+    pub fn checked_sub(&self, duration: Duration) -> Option<Instant> {
+        self.0.checked_sub(duration).map(Instant)
+    }
+
+    /// Returns the amount of time elapsed from another instant to this one, or None if that
+    /// instant is later than this one.
+    #[inline]
+    pub fn checked_duration_since(&self, earlier: Instant) -> Option<Duration> {
+        if earlier.0 > self.0 {
+            None
+        } else {
+            Some(self.0 - earlier.0)
+        }
+    }
+
+    /// Returns the amount of time elapsed from another instant to this one, or zero duration if
+    /// that instant is later than this one.
+    #[inline]
+    pub fn saturating_duration_since(&self, earlier: Instant) -> Duration {
+        self.checked_duration_since(earlier).unwrap_or_default()
+    }
+}
+
+impl Add<Duration> for Instant {
+    type Output = Self;
+
+    #[inline]
+    fn add(self, rhs: Duration) -> Self {
+        Instant(self.0 + rhs)
+    }
+}
+
+impl AddAssign<Duration> for Instant {
+    #[inline]
+    fn add_assign(&mut self, rhs: Duration) {
+        self.0 += rhs
+    }
+}
+
+impl Sub<Duration> for Instant {
+    type Output = Self;
+
+    #[inline]
+    fn sub(self, rhs: Duration) -> Self {
+        Instant(self.0 - rhs)
+    }
+}
+
+impl Sub<Instant> for Instant {
+    type Output = Duration;
+
+    #[inline]
+    fn sub(self, rhs: Instant) -> Duration {
+        self.duration_since(rhs)
+    }
+}
+
+impl SubAssign<Duration> for Instant {
+    #[inline]
+    fn sub_assign(&mut self, rhs: Duration) {
+        self.0 -= rhs
+    }
+}
+
+fn duration_from_f64(millis: f64) -> Duration {
+    Duration::from_millis(millis.trunc() as u64)
+        + Duration::from_nanos((millis.fract() * 1.0e6) as u64)
+}
+
+#[cfg(all(feature = "stdweb", not(feature = "wasm-bindgen")))]
+#[allow(unused_results)] // Needed because the js macro triggers it.
+pub fn now() -> f64 {
+    use stdweb::unstable::TryInto;
+
+    // https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
+    #[cfg(not(feature = "inaccurate"))]
+    let v = js! { return performance.now(); };
+    #[cfg(feature = "inaccurate")]
+    let v = js! { return Date.now(); };
+    v.try_into().unwrap()
+}
+
+#[cfg(feature = "wasm-bindgen")]
+pub fn now() -> f64 {
+    #[cfg(not(feature = "inaccurate"))]
+    let now = {
+        use wasm_bindgen_rs::prelude::*;
+        use wasm_bindgen_rs::JsCast;
+        js_sys::Reflect::get(&js_sys::global(), &JsValue::from_str("performance"))
+            .expect("failed to get performance from global object")
+            .unchecked_into::<web_sys::Performance>()
+            .now()
+    };
+    #[cfg(feature = "inaccurate")]
+    let now = js_sys::Date::now();
+    now
+}
+
+// The JS now function is in a module so it won't have to be renamed
+#[cfg(not(any(feature = "wasm-bindgen", feature = "stdweb")))]
+mod js {
+    extern "C" {
+        #[cfg(not(target_os = "emscripten"))]
+        pub fn now() -> f64;
+        #[cfg(target_os = "emscripten")]
+        pub fn _emscripten_get_now() -> f64;
+    }
+}
+// Make the unsafe extern function "safe" so it can be called like the other 'now' functions
+#[cfg(not(any(feature = "wasm-bindgen", feature = "stdweb")))]
+pub fn now() -> f64 {
+    #[cfg(not(target_os = "emscripten"))]
+    return unsafe { js::now() };
+    #[cfg(target_os = "emscripten")]
+    return unsafe { js::_emscripten_get_now() };
+}
+
+/// Returns the number of millisecods elapsed since January 1, 1970 00:00:00 UTC.
+#[cfg(any(feature = "wasm-bindgen", feature = "stdweb"))]
+fn get_time() -> f64 {
+    #[cfg(feature = "wasm-bindgen")]
+    return js_sys::Date::now();
+    #[cfg(all(feature = "stdweb", not(feature = "wasm-bindgen")))]
+    {
+        let v = js! { return Date.now(); };
+        return v.try_into().unwrap();
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
+pub struct SystemTime(f64);
+
+impl SystemTime {
+    pub const UNIX_EPOCH: SystemTime = SystemTime(0.0);
+
+    pub fn now() -> SystemTime {
+        cfg_if::cfg_if! {
+            if #[cfg(any(feature = "wasm-bindgen", feature = "stdweb"))] {
+                SystemTime(get_time())
+            } else {
+                SystemTime(now())
+            }
+        }
+    }
+
+    pub fn duration_since(&self, earlier: SystemTime) -> Result<Duration, ()> {
+        let dur_ms = self.0 - earlier.0;
+        if dur_ms < 0.0 {
+            return Err(());
+        }
+        Ok(Duration::from_millis(dur_ms as u64))
+    }
+
+    pub fn elapsed(&self) -> Result<Duration, ()> {
+        self.duration_since(SystemTime::now())
+    }
+
+    pub fn checked_add(&self, duration: Duration) -> Option<SystemTime> {
+        Some(*self + duration)
+    }
+
+    pub fn checked_sub(&self, duration: Duration) -> Option<SystemTime> {
+        Some(*self - duration)
+    }
+}
+
+impl Add<Duration> for SystemTime {
+    type Output = SystemTime;
+
+    fn add(self, other: Duration) -> SystemTime {
+        SystemTime(self.0 + other.as_millis() as f64)
+    }
+}
+
+impl Sub<Duration> for SystemTime {
+    type Output = SystemTime;
+
+    fn sub(self, other: Duration) -> SystemTime {
+        SystemTime(self.0 - other.as_millis() as f64)
+    }
+}
+
+impl AddAssign<Duration> for SystemTime {
+    fn add_assign(&mut self, rhs: Duration) {
+        *self = *self + rhs;
+    }
+}
+
+impl SubAssign<Duration> for SystemTime {
+    fn sub_assign(&mut self, rhs: Duration) {
+        *self = *self - rhs;
+    }
+}