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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" {
#[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() };
}
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