refactor: deno_runtime crate (#8640)

This commit moves Deno JS runtime, ops, permissions and
inspector implementation to new "deno_runtime" crate located
in "runtime/" directory.

Details in "runtime/README.md".

Co-authored-by: Ryan Dahl <ry@tinyclouds.org>

1 files changed, 193 insertions, 0 deletions

diff --git a/runtime/ops/timers.rs b/runtime/ops/timers.rs
new file mode 100644
index 000000000..8037fd698
--- /dev/null
+++ b/runtime/ops/timers.rs
@@ -0,0 +1,193 @@
+// Copyright 2018-2020 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 super::dispatch_minimal::minimal_op;
+use super::dispatch_minimal::MinimalOp;
+use crate::metrics::metrics_op;
+use crate::permissions::Permissions;
+use deno_core::error::type_error;
+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::serde_json;
+use deno_core::serde_json::json;
+use deno_core::serde_json::Value;
+use deno_core::BufVec;
+use deno_core::OpState;
+use deno_core::ZeroCopyBuf;
+use serde::Deserialize;
+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::delay_until(deadline.into());
+    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::<StartTime>(StartTime::now());
+  }
+  super::reg_json_sync(rt, "op_global_timer_stop", op_global_timer_stop);
+  super::reg_json_sync(rt, "op_global_timer_start", op_global_timer_start);
+  super::reg_json_async(rt, "op_global_timer", op_global_timer);
+  rt.register_op("op_now", metrics_op(minimal_op(op_now)));
+  super::reg_json_sync(rt, "op_sleep_sync", op_sleep_sync);
+}
+
+fn op_global_timer_stop(
+  state: &mut OpState,
+  _args: Value,
+  _zero_copy: &mut [ZeroCopyBuf],
+) -> Result<Value, AnyError> {
+  let global_timer = state.borrow_mut::<GlobalTimer>();
+  global_timer.cancel();
+  Ok(json!({}))
+}
+
+#[derive(Deserialize)]
+struct GlobalTimerArgs {
+  timeout: u64,
+}
+
+// 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.
+fn op_global_timer_start(
+  state: &mut OpState,
+  args: Value,
+  _zero_copy: &mut [ZeroCopyBuf],
+) -> Result<Value, AnyError> {
+  let args: GlobalTimerArgs = serde_json::from_value(args)?;
+  let val = args.timeout;
+
+  let deadline = Instant::now() + Duration::from_millis(val);
+  let global_timer = state.borrow_mut::<GlobalTimer>();
+  global_timer.new_timeout(deadline);
+  Ok(json!({}))
+}
+
+async fn op_global_timer(
+  state: Rc<RefCell<OpState>>,
+  _args: Value,
+  _zero_copy: BufVec,
+) -> Result<Value, 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(json!({}))
+}
+
+// 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.
+fn op_now(
+  state: Rc<RefCell<OpState>>,
+  // Arguments are discarded
+  _sync: bool,
+  _x: i32,
+  mut zero_copy: BufVec,
+) -> MinimalOp {
+  match zero_copy.len() {
+    0 => return MinimalOp::Sync(Err(type_error("no buffer specified"))),
+    1 => {}
+    _ => {
+      return MinimalOp::Sync(Err(type_error("Invalid number of arguments")))
+    }
+  }
+
+  let op_state = state.borrow();
+  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::<Permissions>().check_hrtime().is_err() {
+    subsec_nanos -= subsec_nanos % reduced_time_precision;
+  }
+
+  let result = (seconds * 1_000) as f64 + (subsec_nanos / 1_000_000.0);
+
+  (&mut zero_copy[0]).copy_from_slice(&result.to_be_bytes());
+
+  MinimalOp::Sync(Ok(0))
+}
+
+#[derive(Deserialize)]
+struct SleepArgs {
+  millis: u64,
+}
+
+fn op_sleep_sync(
+  state: &mut OpState,
+  args: Value,
+  _zero_copy: &mut [ZeroCopyBuf],
+) -> Result<Value, AnyError> {
+  super::check_unstable(state, "Deno.sleepSync");
+  let args: SleepArgs = serde_json::from_value(args)?;
+  sleep(Duration::from_millis(args.millis));
+  Ok(json!({}))
+}