src: add a threadsafe variant of SetImmediate()

Add a variant of `SetImmediate()` that can be called from any thread.
This allows removing the `AsyncRequest` abstraction and replaces it
with a more generic mechanism.

PR-URL: https://github.com/nodejs/node/pull/31386
Refs: https://github.com/openjs-foundation/summit/pull/240
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/src/env-inl.h b/src/env-inl.h
index cf6de689c4..ae4c02b6b2 100644
--- a/src/env-inl.h
+++ b/src/env-inl.h
@@ -748,6 +748,7 @@ Environment::NativeImmediateQueue::Shift() {
     if (!head_)
       tail_ = nullptr;  // The queue is now empty.
   }
+  size_--;
   return ret;
 }
 
@@ -755,6 +756,7 @@ void Environment::NativeImmediateQueue::Push(
     std::unique_ptr<Environment::NativeImmediateCallback> cb) {
   NativeImmediateCallback* prev_tail = tail_;
 
+  size_++;
   tail_ = cb.get();
   if (prev_tail != nullptr)
     prev_tail->set_next(std::move(cb));
@@ -774,6 +776,10 @@ void Environment::NativeImmediateQueue::ConcatMove(
   other.size_ = 0;
 }
 
+size_t Environment::NativeImmediateQueue::size() const {
+  return size_.load();
+}
+
 template <typename Fn>
 void Environment::CreateImmediate(Fn&& cb, bool ref) {
   auto callback = std::make_unique<NativeImmediateCallbackImpl<Fn>>(
@@ -795,6 +801,17 @@ void Environment::SetUnrefImmediate(Fn&& cb) {
   CreateImmediate(std::move(cb), false);
 }
 
+template <typename Fn>
+void Environment::SetImmediateThreadsafe(Fn&& cb) {
+  auto callback = std::make_unique<NativeImmediateCallbackImpl<Fn>>(
+      std::move(cb), false);
+  {
+    Mutex::ScopedLock lock(native_immediates_threadsafe_mutex_);
+    native_immediates_threadsafe_.Push(std::move(callback));
+  }
+  uv_async_send(&task_queues_async_);
+}
+
 Environment::NativeImmediateCallback::NativeImmediateCallback(bool refed)
   : refed_(refed) {}
 
@@ -1164,7 +1181,7 @@ void Environment::RemoveCleanupHook(void (*fn)(void*), void* arg) {
 inline void Environment::RegisterFinalizationGroupForCleanup(
     v8::Local<v8::FinalizationGroup> group) {
   cleanup_finalization_groups_.emplace_back(isolate(), group);
-  uv_async_send(&cleanup_finalization_groups_async_);
+  uv_async_send(&task_queues_async_);
 }
 
 size_t CleanupHookCallback::Hash::operator()(