Fabric: Lock-free events 3/n: EventEmitter::DispatchMutex is not recursive mutex anymore

Summary: The mutex is a "leaf" mutex, so the code cannot reenter that, so there is no reason to be a recursive one.

Reviewed By: sahrens

Differential Revision: D13642592

fbshipit-source-id: 0fb64d3405c5d3408251dc983c186f6747bc6ee2

ReactCommon/fabric/events/EventEmitter.cpp

@@ -31,8 +31,8 @@ static std::string normalizeEventType(const std::string &type) {
   return prefixedType;
 }
 
-std::recursive_mutex &EventEmitter::DispatchMutex() {
-  static std::recursive_mutex mutex;
+std::mutex &EventEmitter::DispatchMutex() {
+  static std::mutex mutex;
   return mutex;
 }
 

ReactCommon/fabric/events/EventEmitter.h

@@ -34,7 +34,7 @@ class EventEmitter {
   using Tag = int32_t;
 
  public:
-  static std::recursive_mutex &DispatchMutex();
+  static std::mutex &DispatchMutex();
 
   static ValueFactory defaultPayloadFactory();
 

ReactCommon/fabric/events/EventQueue.cpp

@@ -40,7 +40,7 @@ void EventQueue::onBeat(jsi::Runtime &runtime) const {
   }
 
   {
-    std::lock_guard<std::recursive_mutex> lock(EventEmitter::DispatchMutex());
+    std::lock_guard<std::mutex> lock(EventEmitter::DispatchMutex());
 
     for (const auto &event : queue) {
       if (event.eventTarget) {

ReactCommon/fabric/uimanager/ShadowTree.cpp

@@ -155,7 +155,7 @@ void ShadowTree::emitLayoutEvents(
 
 void ShadowTree::toggleEventEmitters(
     const ShadowViewMutationList &mutations) const {
-  std::lock_guard<std::recursive_mutex> lock(EventEmitter::DispatchMutex());
+  std::lock_guard<std::mutex> lock(EventEmitter::DispatchMutex());
 
   for (const auto &mutation : mutations) {
     if (mutation.type == ShadowViewMutation::Create) {