Coverity issue 464935: Check of thread-shared field evades lock acquisition

[targos]

@nodejs/cpp-reviewers

The data guarded by this critical section may be read while in an inconsistent state or modified by multiple racing threads.

In node::​inspector::​MainThreadInterface::​DispatchMessages(): Checking the value of a thread-shared field outside of a locked region to determine if a locked operation involving that thread shared field has completed. (CWE-543)

node/src/inspector/main_thread_interface.cc

Lines 242 to 263 in a08129c

	void MainThreadInterface::DispatchMessages() {
	if (dispatching_messages_)
	return;
	dispatching_messages_ = true;
	bool had_messages = false;
	do {
	if (dispatching_message_queue_.empty()) {
	Mutex::ScopedLock scoped_lock(requests_lock_);
	requests_.swap(dispatching_message_queue_);
	}
	had_messages = !dispatching_message_queue_.empty();
	while (!dispatching_message_queue_.empty()) {
	MessageQueue::value_type task;
	std::swap(dispatching_message_queue_.front(), task);
	dispatching_message_queue_.pop_front();
	v8::SealHandleScope seal_handle_scope(agent_->env()->isolate());
	task->Call(this);
	}
	} while (had_messages);
	dispatching_messages_ = false;
	}