Prevent redundant dispatches onto RuntimeExecutor queue in AsynchronousEventBeat::induce

Summary:
Changelog: [internal]

Prevent redundant calls to RuntimeExecutor by making sure no two calls to the executor are scheduled at the same time.

Reviewed By: mdvacca

Differential Revision: D27989412

fbshipit-source-id: 8f9b1591f7c9c2265fd4b05bf3dc5505ffc2568b

ReactAndroid/src/main/java/com/facebook/react/fabric/jni/AsyncEventBeatV2.cpp

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <jsi/jsi.h>
+#include <react/renderer/core/EventBeat.h>
+#include <react/renderer/uimanager/primitives.h>
+
+#include "AsyncEventBeatV2.h"
+
+namespace facebook::react {
+
+AsyncEventBeatV2::AsyncEventBeatV2(
+    EventBeat::SharedOwnerBox const &ownerBox,
+    EventBeatManager *eventBeatManager,
+    RuntimeExecutor runtimeExecutor,
+    jni::global_ref<jobject> javaUIManager)
+    : EventBeat(ownerBox),
+      eventBeatManager_(eventBeatManager),
+      runtimeExecutor_(runtimeExecutor),
+      javaUIManager_(javaUIManager) {
+  eventBeatManager->addObserver(*this);
+}
+
+AsyncEventBeatV2::~AsyncEventBeatV2() {
+  eventBeatManager_->removeObserver(*this);
+}
+
+void AsyncEventBeatV2::tick() const {
+  if (!isRequested_ || isBeatCallbackScheduled_) {
+    return;
+  }
+
+  isRequested_ = false;
+  isBeatCallbackScheduled_ = true;
+
+  runtimeExecutor_([this, ownerBox = ownerBox_](jsi::Runtime &runtime) {
+    isBeatCallbackScheduled_ = false;
+    auto owner = ownerBox->owner.lock();
+    if (!owner) {
+      return;
+    }
+
+    if (beatCallback_) {
+      beatCallback_(runtime);
+    }
+  });
+}
+
+void AsyncEventBeatV2::induce() const {
+  tick();
+}
+
+void AsyncEventBeatV2::request() const {
+  bool alreadyRequested = isRequested_;
+  EventBeat::request();
+  if (!alreadyRequested) {
+    // Notifies java side that an event will be dispatched (e.g. LayoutEvent)
+    static auto onRequestEventBeat =
+        jni::findClassStatic("com/facebook/react/fabric/FabricUIManager")
+            ->getMethod<void()>("onRequestEventBeat");
+    onRequestEventBeat(javaUIManager_);
+  }
+}
+
+} // namespace facebook::react

ReactAndroid/src/main/java/com/facebook/react/fabric/jni/AsyncEventBeatV2.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <react/renderer/core/EventBeat.h>
+
+#include "EventBeatManager.h"
+
+namespace facebook::react {
+
+class AsyncEventBeatV2 final : public EventBeat,
+                               public EventBeatManagerObserver {
+ public:
+  AsyncEventBeatV2(
+      EventBeat::SharedOwnerBox const &ownerBox,
+      EventBeatManager *eventBeatManager,
+      RuntimeExecutor runtimeExecutor,
+      jni::global_ref<jobject> javaUIManager);
+
+  ~AsyncEventBeatV2() override;
+
+  void tick() const override;
+
+  void induce() const override;
+
+  void request() const override;
+
+ private:
+  EventBeatManager *eventBeatManager_;
+  RuntimeExecutor runtimeExecutor_;
+  jni::global_ref<jobject> javaUIManager_;
+  mutable std::atomic<bool> isBeatCallbackScheduled_{false};
+};
+
+} // namespace facebook::react

ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp

@@ -7,6 +7,7 @@
 
 #include "Binding.h"
 #include "AsyncEventBeat.h"
+#include "AsyncEventBeatV2.h"
 #include "EventEmitterWrapper.h"
 #include "ReactNativeConfigHolder.h"
 #include "StateWrapperImpl.h"
@@ -488,21 +489,40 @@ void Binding::installFabricUIManager(
       std::make_shared<JMessageQueueThread>(jsMessageQueueThread);
   auto runtimeExecutor = runtimeExecutorHolder->cthis()->get();
 
+  auto enableV2AsynchronousEventBeat =
+      config->getBool("react_fabric:enable_asynchronous_event_beat_v2_android");
+
   // TODO: T31905686 Create synchronous Event Beat
   jni::global_ref<jobject> localJavaUIManager = javaUIManager_;
   EventBeat::Factory synchronousBeatFactory =
-      [eventBeatManager, runtimeExecutor, localJavaUIManager](
-          EventBeat::SharedOwnerBox const &ownerBox) {
-        return std::make_unique<AsyncEventBeat>(
-            ownerBox, eventBeatManager, runtimeExecutor, localJavaUIManager);
-      };
+      [eventBeatManager,
+       runtimeExecutor,
+       localJavaUIManager,
+       enableV2AsynchronousEventBeat](EventBeat::SharedOwnerBox const &ownerBox)
+      -> std::unique_ptr<EventBeat> {
+    if (enableV2AsynchronousEventBeat) {
+      return std::make_unique<AsyncEventBeatV2>(
+          ownerBox, eventBeatManager, runtimeExecutor, localJavaUIManager);
+    } else {
+      return std::make_unique<AsyncEventBeat>(
+          ownerBox, eventBeatManager, runtimeExecutor, localJavaUIManager);
+    }
+  };
 
   EventBeat::Factory asynchronousBeatFactory =
-      [eventBeatManager, runtimeExecutor, localJavaUIManager](
-          EventBeat::SharedOwnerBox const &ownerBox) {
-        return std::make_unique<AsyncEventBeat>(
-            ownerBox, eventBeatManager, runtimeExecutor, localJavaUIManager);
-      };
+      [eventBeatManager,
+       runtimeExecutor,
+       localJavaUIManager,
+       enableV2AsynchronousEventBeat](EventBeat::SharedOwnerBox const &ownerBox)
+      -> std::unique_ptr<EventBeat> {
+    if (enableV2AsynchronousEventBeat) {
+      return std::make_unique<AsyncEventBeatV2>(
+          ownerBox, eventBeatManager, runtimeExecutor, localJavaUIManager);
+    } else {
+      return std::make_unique<AsyncEventBeat>(
+          ownerBox, eventBeatManager, runtimeExecutor, localJavaUIManager);
+    }
+  };
 
   contextContainer->insert("ReactNativeConfig", config);
   contextContainer->insert("FabricUIManager", javaUIManager_);