refactor: move timers to deno_timers op crate (#10179)

Move timers out of runtime/ and into a standalone op crate.

Cargo.lock

@@ -674,6 +674,7 @@ dependencies = [
  "deno_crypto",
  "deno_fetch",
  "deno_file",
+ "deno_timers",
  "deno_url",
  "deno_web",
  "deno_webgpu",
@@ -710,6 +711,14 @@ dependencies = [
  "winres",
 ]
 
+[[package]]
+name = "deno_timers"
+version = "0.1.0"
+dependencies = [
+ "deno_core",
+ "tokio",
+]
+
 [[package]]
 name = "deno_url"
 version = "0.3.0"

Cargo.toml

@@ -10,6 +10,7 @@ members = [
   "test_util",
   "op_crates/crypto",
   "op_crates/fetch",
+  "op_crates/timers",
   "op_crates/url",
   "op_crates/web",
   "op_crates/webgpu",

op_crates/timers/01_timers.js

@@ -2,9 +2,27 @@
 "use strict";
 
 ((window) => {
-  const assert = window.__bootstrap.util.assert;
   const core = window.Deno.core;
 
+  // Shamelessly cribbed from op_crates/fetch/11_streams.js
+  class AssertionError extends Error {
+    constructor(msg) {
+      super(msg);
+      this.name = "AssertionError";
+    }
+  }
+
+  /**
+   * @param {unknown} cond
+   * @param {string=} msg
+   * @returns {asserts cond}
+   */
+  function assert(cond, msg = "Assertion failed.") {
+    if (!cond) {
+      throw new AssertionError(msg);
+    }
+  }
+
   function opStopGlobalTimer() {
     core.opSync("op_global_timer_stop");
   }

op_crates/timers/Cargo.toml

@@ -0,0 +1,18 @@
+# Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+[package]
+name = "deno_timers"
+version = "0.1.0"
+edition = "2018"
+description = "Timers API implementation for Deno"
+authors = ["the Deno authors"]
+license = "MIT"
+readme = "README.md"
+repository = "https://github.com/denoland/deno"
+
+[lib]
+path = "lib.rs"
+
+[dependencies]
+deno_core = { version = "0.84.0", path = "../../core" }
+tokio = { version = "1.4.0", features = ["full"] }

op_crates/timers/README.md

@@ -0,0 +1,5 @@
+# deno_timers
+
+This crate implements the timers API.
+
+Spec: https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#timers

op_crates/timers/lib.rs

@@ -0,0 +1,165 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+//! This module helps deno implement timers.
+//!
+//! As an optimization, we want to avoid an expensive calls into rust for every
+//! setTimeout in JavaScript. Thus in //js/timers.ts a data structure is
+//! implemented that calls into Rust for only the smallest timeout.  Thus we
+//! only need to be able to start, cancel and await a single timer (or Delay, as Tokio
+//! calls it) for an entire Isolate. This is what is implemented here.
+
+use deno_core::error::AnyError;
+use deno_core::futures;
+use deno_core::futures::channel::oneshot;
+use deno_core::futures::FutureExt;
+use deno_core::futures::TryFutureExt;
+use deno_core::OpState;
+use deno_core::ZeroCopyBuf;
+use std::cell::RefCell;
+use std::future::Future;
+use std::pin::Pin;
+use std::rc::Rc;
+use std::thread::sleep;
+use std::time::Duration;
+use std::time::Instant;
+
+pub trait TimersPermission {
+  fn allow_hrtime(&mut self) -> bool;
+  fn check_unstable(&self, state: &OpState, api_name: &'static str);
+}
+
+pub fn init(rt: &mut deno_core::JsRuntime) {
+  rt.execute(
+    "deno:op_crates/timers/01_timers.js",
+    include_str!("01_timers.js"),
+  )
+  .unwrap();
+}
+
+pub type StartTime = Instant;
+
+type TimerFuture = Pin<Box<dyn Future<Output = Result<(), ()>>>>;
+
+#[derive(Default)]
+pub struct GlobalTimer {
+  tx: Option<oneshot::Sender<()>>,
+  pub future: Option<TimerFuture>,
+}
+
+impl GlobalTimer {
+  pub fn cancel(&mut self) {
+    if let Some(tx) = self.tx.take() {
+      tx.send(()).ok();
+    }
+  }
+
+  pub fn new_timeout(&mut self, deadline: Instant) {
+    if self.tx.is_some() {
+      self.cancel();
+    }
+    assert!(self.tx.is_none());
+    self.future.take();
+
+    let (tx, rx) = oneshot::channel();
+    self.tx = Some(tx);
+
+    let delay = tokio::time::sleep_until(deadline.into()).boxed_local();
+    let rx = rx
+      .map_err(|err| panic!("Unexpected error in receiving channel {:?}", err));
+
+    let fut = futures::future::select(delay, rx)
+      .then(|_| futures::future::ok(()))
+      .boxed_local();
+    self.future = Some(fut);
+  }
+}
+
+#[allow(clippy::unnecessary_wraps)]
+pub fn op_global_timer_stop(
+  state: &mut OpState,
+  _args: (),
+  _zero_copy: Option<ZeroCopyBuf>,
+) -> Result<(), AnyError> {
+  let global_timer = state.borrow_mut::<GlobalTimer>();
+  global_timer.cancel();
+  Ok(())
+}
+
+// Set up a timer that will be later awaited by JS promise.
+// It's a separate op, because canceling a timeout immediately
+// after setting it caused a race condition (because Tokio timeout)
+// might have been registered after next event loop tick.
+//
+// See https://github.com/denoland/deno/issues/7599 for more
+// details.
+#[allow(clippy::unnecessary_wraps)]
+pub fn op_global_timer_start(
+  state: &mut OpState,
+  timeout: u64,
+  _zero_copy: Option<ZeroCopyBuf>,
+) -> Result<(), AnyError> {
+  let deadline = Instant::now() + Duration::from_millis(timeout);
+  let global_timer = state.borrow_mut::<GlobalTimer>();
+  global_timer.new_timeout(deadline);
+  Ok(())
+}
+
+pub async fn op_global_timer(
+  state: Rc<RefCell<OpState>>,
+  _args: (),
+  _zero_copy: Option<ZeroCopyBuf>,
+) -> Result<(), AnyError> {
+  let maybe_timer_fut = {
+    let mut s = state.borrow_mut();
+    let global_timer = s.borrow_mut::<GlobalTimer>();
+    global_timer.future.take()
+  };
+  if let Some(timer_fut) = maybe_timer_fut {
+    let _ = timer_fut.await;
+  }
+  Ok(())
+}
+
+// Returns a milliseconds and nanoseconds subsec
+// since the start time of the deno runtime.
+// If the High precision flag is not set, the
+// nanoseconds are rounded on 2ms.
+#[allow(clippy::unnecessary_wraps)]
+pub fn op_now<TP>(
+  state: &mut OpState,
+  _argument: (),
+  _zero_copy: Option<ZeroCopyBuf>,
+) -> Result<f64, AnyError>
+where
+  TP: TimersPermission + 'static,
+{
+  let start_time = state.borrow::<StartTime>();
+  let seconds = start_time.elapsed().as_secs();
+  let mut subsec_nanos = start_time.elapsed().subsec_nanos() as f64;
+  let reduced_time_precision = 2_000_000.0; // 2ms in nanoseconds
+
+  // 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() {
+    subsec_nanos -= subsec_nanos % reduced_time_precision;
+  }
+
+  let result = (seconds * 1_000) as f64 + (subsec_nanos / 1_000_000.0);
+
+  Ok(result)
+}
+
+#[allow(clippy::unnecessary_wraps)]
+pub fn op_sleep_sync<TP>(
+  state: &mut OpState,
+  millis: u64,
+  _zero_copy: Option<ZeroCopyBuf>,
+) -> Result<(), AnyError>
+where
+  TP: TimersPermission + 'static,
+{
+  state.borrow::<TP>().check_unstable(state, "Deno.sleepSync");
+  sleep(Duration::from_millis(millis));
+  Ok(())
+}

runtime/Cargo.toml

@@ -18,32 +18,34 @@ name = "hello_runtime"
 path = "examples/hello_runtime.rs"
 
 [build-dependencies]
-deno_core = { path = "../core", version = "0.84.0" }
 deno_console = { path = "../op_crates/console", version = "0.3.0" }
+deno_core = { path = "../core", version = "0.84.0" }
 deno_crypto = { path = "../op_crates/crypto", version = "0.17.0" }
 deno_fetch = { path = "../op_crates/fetch", version = "0.25.0" }
 deno_file = { path = "../op_crates/file", version = "0.2.0" }
-deno_web = { path = "../op_crates/web", version = "0.33.0" }
+deno_timers = { path = "../op_crates/timers", version = "0.1.0" }
 deno_url = { path = "../op_crates/url", version = "0.3.0" }
+deno_web = { path = "../op_crates/web", version = "0.33.0" }
+deno_webgpu = { path = "../op_crates/webgpu", version = "0.4.0" }
 deno_webidl = { path = "../op_crates/webidl", version = "0.3.0" }
 deno_websocket = { path = "../op_crates/websocket", version = "0.8.0" }
-deno_webgpu = { path = "../op_crates/webgpu", version = "0.4.0" }
 
 [target.'cfg(windows)'.build-dependencies]
 winres = "0.1.11"
 winapi = "0.3.9"
 
 [dependencies]
-deno_core = { path = "../core", version = "0.84.0" }
 deno_console = { path = "../op_crates/console", version = "0.3.0" }
+deno_core = { path = "../core", version = "0.84.0" }
 deno_crypto = { path = "../op_crates/crypto", version = "0.17.0" }
 deno_fetch = { path = "../op_crates/fetch", version = "0.25.0" }
 deno_file = { path = "../op_crates/file", version = "0.2.0" }
-deno_web = { path = "../op_crates/web", version = "0.33.0" }
+deno_timers = { path = "../op_crates/timers", version = "0.1.0" }
 deno_url = { path = "../op_crates/url", version = "0.3.0" }
+deno_web = { path = "../op_crates/web", version = "0.33.0" }
+deno_webgpu = { path = "../op_crates/webgpu", version = "0.4.0" }
 deno_webidl = { path = "../op_crates/webidl", version = "0.3.0" }
 deno_websocket = { path = "../op_crates/websocket", version = "0.8.0" }
-deno_webgpu = { path = "../op_crates/webgpu", version = "0.4.0" }
 
 atty = "0.2.14"
 bytes = "1"

runtime/build.rs

@@ -13,8 +13,10 @@ fn create_snapshot(
   snapshot_path: &Path,
   files: Vec<PathBuf>,
 ) {
+  // Initialization order matters.
   deno_webidl::init(&mut js_runtime);
   deno_console::init(&mut js_runtime);
+  deno_timers::init(&mut js_runtime);
   deno_url::init(&mut js_runtime);
   deno_web::init(&mut js_runtime);
   deno_file::init(&mut js_runtime);

runtime/ops/timers.rs

@@ -1,161 +1,28 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
-
-//! This module helps deno implement timers.
-//!
-//! As an optimization, we want to avoid an expensive calls into rust for every
-//! setTimeout in JavaScript. Thus in //js/timers.ts a data structure is
-//! implemented that calls into Rust for only the smallest timeout.  Thus we
-//! only need to be able to start, cancel and await a single timer (or Delay, as Tokio
-//! calls it) for an entire Isolate. This is what is implemented here.
-
 use crate::permissions::Permissions;
-use deno_core::error::AnyError;
-use deno_core::futures;
-use deno_core::futures::channel::oneshot;
-use deno_core::futures::FutureExt;
-use deno_core::futures::TryFutureExt;
-use deno_core::OpState;
-use deno_core::ZeroCopyBuf;
-use std::cell::RefCell;
-use std::future::Future;
-use std::pin::Pin;
-use std::rc::Rc;
-use std::thread::sleep;
-use std::time::Duration;
-use std::time::Instant;
-
-pub type StartTime = Instant;
-
-type TimerFuture = Pin<Box<dyn Future<Output = Result<(), ()>>>>;
-
-#[derive(Default)]
-pub struct GlobalTimer {
-  tx: Option<oneshot::Sender<()>>,
-  pub future: Option<TimerFuture>,
-}
-
-impl GlobalTimer {
-  pub fn cancel(&mut self) {
-    if let Some(tx) = self.tx.take() {
-      tx.send(()).ok();
-    }
-  }
-
-  pub fn new_timeout(&mut self, deadline: Instant) {
-    if self.tx.is_some() {
-      self.cancel();
-    }
-    assert!(self.tx.is_none());
-    self.future.take();
-
-    let (tx, rx) = oneshot::channel();
-    self.tx = Some(tx);
-
-    let delay = tokio::time::sleep_until(deadline.into()).boxed_local();
-    let rx = rx
-      .map_err(|err| panic!("Unexpected error in receiving channel {:?}", err));
-
-    let fut = futures::future::select(delay, rx)
-      .then(|_| futures::future::ok(()))
-      .boxed_local();
-    self.future = Some(fut);
-  }
-}
 
 pub fn init(rt: &mut deno_core::JsRuntime) {
   {
     let op_state = rt.op_state();
     let mut state = op_state.borrow_mut();
-    state.put::<GlobalTimer>(GlobalTimer::default());
+    state.put(deno_timers::GlobalTimer::default());
-    state.put::<StartTime>(StartTime::now());
+    state.put(deno_timers::StartTime::now());
   }
-  super::reg_sync(rt, "op_global_timer_stop", op_global_timer_stop);
+  super::reg_sync(
-  super::reg_sync(rt, "op_global_timer_start", op_global_timer_start);
+    rt,
-  super::reg_async(rt, "op_global_timer", op_global_timer);
+    "op_global_timer_stop",
-  super::reg_sync(rt, "op_now", op_now);
+    deno_timers::op_global_timer_stop,
-  super::reg_sync(rt, "op_sleep_sync", op_sleep_sync);
+  );
-}
+  super::reg_sync(
-
+    rt,
-#[allow(clippy::unnecessary_wraps)]
+    "op_global_timer_start",
-fn op_global_timer_stop(
+    deno_timers::op_global_timer_start,
-  state: &mut OpState,
+  );
-  _args: (),
+  super::reg_async(rt, "op_global_timer", deno_timers::op_global_timer);
-  _zero_copy: Option<ZeroCopyBuf>,
+  super::reg_sync(rt, "op_now", deno_timers::op_now::<Permissions>);
-) -> Result<(), AnyError> {
+  super::reg_sync(
-  let global_timer = state.borrow_mut::<GlobalTimer>();
+    rt,
-  global_timer.cancel();
+    "op_sleep_sync",
-  Ok(())
+    deno_timers::op_sleep_sync::<Permissions>,
-}
+  );
-
-// Set up a timer that will be later awaited by JS promise.
-// It's a separate op, because canceling a timeout immediately
-// after setting it caused a race condition (because Tokio timeout)
-// might have been registered after next event loop tick.
-//
-// See https://github.com/denoland/deno/issues/7599 for more
-// details.
-#[allow(clippy::unnecessary_wraps)]
-fn op_global_timer_start(
-  state: &mut OpState,
-  timeout: u64,
-  _zero_copy: Option<ZeroCopyBuf>,
-) -> Result<(), AnyError> {
-  let deadline = Instant::now() + Duration::from_millis(timeout);
-  let global_timer = state.borrow_mut::<GlobalTimer>();
-  global_timer.new_timeout(deadline);
-  Ok(())
-}
-
-async fn op_global_timer(
-  state: Rc<RefCell<OpState>>,
-  _args: (),
-  _zero_copy: Option<ZeroCopyBuf>,
-) -> Result<(), AnyError> {
-  let maybe_timer_fut = {
-    let mut s = state.borrow_mut();
-    let global_timer = s.borrow_mut::<GlobalTimer>();
-    global_timer.future.take()
-  };
-  if let Some(timer_fut) = maybe_timer_fut {
-    let _ = timer_fut.await;
-  }
-  Ok(())
-}
-
-// Returns a milliseconds and nanoseconds subsec
-// since the start time of the deno runtime.
-// If the High precision flag is not set, the
-// nanoseconds are rounded on 2ms.
-#[allow(clippy::unnecessary_wraps)]
-fn op_now(
-  op_state: &mut OpState,
-  _argument: (),
-  _zero_copy: Option<ZeroCopyBuf>,
-) -> Result<f64, AnyError> {
-  let start_time = op_state.borrow::<StartTime>();
-  let seconds = start_time.elapsed().as_secs();
-  let mut subsec_nanos = start_time.elapsed().subsec_nanos() as f64;
-  let reduced_time_precision = 2_000_000.0; // 2ms in nanoseconds
-
-  // 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 op_state.borrow_mut::<Permissions>().hrtime.check().is_err() {
-    subsec_nanos -= subsec_nanos % reduced_time_precision;
-  }
-
-  let result = (seconds * 1_000) as f64 + (subsec_nanos / 1_000_000.0);
-
-  Ok(result)
-}
-
-#[allow(clippy::unnecessary_wraps)]
-fn op_sleep_sync(
-  state: &mut OpState,
-  millis: u64,
-  _zero_copy: Option<ZeroCopyBuf>,
-) -> Result<(), AnyError> {
-  super::check_unstable(state, "Deno.sleepSync");
-  sleep(Duration::from_millis(millis));
-  Ok(())
 }

runtime/permissions.rs

@@ -9,6 +9,7 @@ use deno_core::serde::Deserialize;
 use deno_core::serde::Serialize;
 use deno_core::url;
 use deno_core::ModuleSpecifier;
+use deno_core::OpState;
 use log::debug;
 use std::collections::HashSet;
 use std::fmt;
@@ -968,6 +969,16 @@ impl deno_fetch::FetchPermissions for Permissions {
   }
 }
 
+impl deno_timers::TimersPermission for Permissions {
+  fn allow_hrtime(&mut self) -> bool {
+    self.hrtime.check().is_ok()
+  }
+
+  fn check_unstable(&self, state: &OpState, api_name: &'static str) {
+    crate::ops::check_unstable(state, api_name);
+  }
+}
+
 impl deno_websocket::WebSocketPermissions for Permissions {
   fn check_net_url(&mut self, url: &url::Url) -> Result<(), AnyError> {
     self.net.check_url(url)