1
0
Fork 0
mirror of https://github.com/denoland/deno.git synced 2024-12-04 17:18:23 -05:00
denoland-deno/ext/web/timers.rs

85 lines
2.2 KiB
Rust
Raw Normal View History

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
//! This module helps deno implement timers and performance APIs.
use deno_core::op2;
use deno_core::OpState;
use std::time::Duration;
use std::time::Instant;
use std::time::SystemTime;
use std::time::UNIX_EPOCH;
pub trait TimersPermission {
fn allow_hrtime(&mut self) -> bool;
}
impl TimersPermission for deno_permissions::PermissionsContainer {
#[inline(always)]
fn allow_hrtime(&mut self) -> bool {
true
}
}
pub struct StartTime(Instant);
impl Default for StartTime {
fn default() -> Self {
Self(Instant::now())
}
}
impl std::ops::Deref for StartTime {
type Target = Instant;
fn deref(&self) -> &Self::Target {
&self.0
}
}
fn expose_time<TP>(state: &mut OpState, duration: Duration, out: &mut [u8])
where
TP: TimersPermission + 'static,
{
let seconds = duration.as_secs() as u32;
let mut subsec_nanos = duration.subsec_nanos();
// If the permission is not enabled
// Round the nano result on 2 milliseconds
// see: https://developer.mozilla.org/en-US/docs/Web/API/DOMHighResTimeStamp#Reduced_time_precision
if !state.borrow_mut::<TP>().allow_hrtime() {
2022-08-28 02:51:49 -04:00
let reduced_time_precision = 2_000_000; // 2ms in nanoseconds
subsec_nanos -= subsec_nanos % reduced_time_precision;
}
if out.len() >= 8 {
out[0..4].copy_from_slice(&seconds.to_ne_bytes());
out[4..8].copy_from_slice(&subsec_nanos.to_ne_bytes());
2022-08-28 02:51:49 -04:00
}
}
#[op2(fast)]
pub fn op_now<TP>(state: &mut OpState, #[buffer] buf: &mut [u8])
where
TP: TimersPermission + 'static,
{
let start_time = state.borrow::<StartTime>();
let elapsed = start_time.elapsed();
expose_time::<TP>(state, elapsed, buf);
}
#[op2(fast)]
pub fn op_time_origin<TP>(state: &mut OpState, #[buffer] buf: &mut [u8])
where
TP: TimersPermission + 'static,
{
// https://w3c.github.io/hr-time/#dfn-estimated-monotonic-time-of-the-unix-epoch
let wall_time = SystemTime::now();
let monotonic_time = state.borrow::<StartTime>().elapsed();
let epoch = wall_time.duration_since(UNIX_EPOCH).unwrap() - monotonic_time;
expose_time::<TP>(state, epoch, buf);
}
#[allow(clippy::unused_async)]
#[op2(async(lazy), fast)]
pub async fn op_defer() {}