Implement optimized event batching on Android

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlags.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<b66656cc0c4c1556986bcb765b1a4717>>
+ * @generated SignedSource<<cd8b6b6fdb11377c119f6bb979560b0e>>
  */
 
 /**
@@ -280,6 +280,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun useOptimisedViewPreallocationOnAndroid(): Boolean = accessor.useOptimisedViewPreallocationOnAndroid()
 
+  /**
+   * Uses an optimized mechanism for event batching on Android that does not need to wait for a Choreographer frame callback.
+   */
+  @JvmStatic
+  public fun useOptimizedEventBatchingOnAndroid(): Boolean = accessor.useOptimizedEventBatchingOnAndroid()
+
   /**
    * When enabled, cloning shadow nodes within react native will update the reference held by the current JS fiber tree.
    */

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxAccessor.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<ffc9e4785820aa65fad28f79d27a85d2>>
+ * @generated SignedSource<<47dbdb6ffcd04bb7b2d2d01c4c1e7ace>>
  */
 
 /**
@@ -62,6 +62,7 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useNewReactImageViewBackgroundDrawingCache: Boolean? = null
   private var useOptimisedViewPreallocationOnAndroidCache: Boolean? = null
+  private var useOptimizedEventBatchingOnAndroidCache: Boolean? = null
   private var useRuntimeShadowNodeReferenceUpdateCache: Boolean? = null
   private var useRuntimeShadowNodeReferenceUpdateOnLayoutCache: Boolean? = null
   private var useStateAlignmentMechanismCache: Boolean? = null
@@ -445,6 +446,15 @@ public class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAccesso
     return cached
   }
 
+  override fun useOptimizedEventBatchingOnAndroid(): Boolean {
+    var cached = useOptimizedEventBatchingOnAndroidCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.useOptimizedEventBatchingOnAndroid()
+      useOptimizedEventBatchingOnAndroidCache = cached
+    }
+    return cached
+  }
+
   override fun useRuntimeShadowNodeReferenceUpdate(): Boolean {
     var cached = useRuntimeShadowNodeReferenceUpdateCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxInterop.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<580db8acae42a65aeb678d2d6ef4630c>>
+ * @generated SignedSource<<93ce8e0026e125192af1ad86730941c0>>
  */
 
 /**
@@ -112,6 +112,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun useOptimisedViewPreallocationOnAndroid(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun useOptimizedEventBatchingOnAndroid(): Boolean
+
   @DoNotStrip @JvmStatic public external fun useRuntimeShadowNodeReferenceUpdate(): Boolean
 
   @DoNotStrip @JvmStatic public external fun useRuntimeShadowNodeReferenceUpdateOnLayout(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsDefaults.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<00aae631e9d9b146fae9be838e04e165>>
+ * @generated SignedSource<<be36697a6f863c364f858112767399f8>>
  */
 
 /**
@@ -107,6 +107,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun useOptimisedViewPreallocationOnAndroid(): Boolean = false
 
+  override fun useOptimizedEventBatchingOnAndroid(): Boolean = false
+
   override fun useRuntimeShadowNodeReferenceUpdate(): Boolean = false
 
   override fun useRuntimeShadowNodeReferenceUpdateOnLayout(): Boolean = false

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsLocalAccessor.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<ead344838f30d7e3f1205d7bbabbc803>>
+ * @generated SignedSource<<7727737ae31a239d6b68397fafadbfea>>
  */
 
 /**
@@ -66,6 +66,7 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useNewReactImageViewBackgroundDrawingCache: Boolean? = null
   private var useOptimisedViewPreallocationOnAndroidCache: Boolean? = null
+  private var useOptimizedEventBatchingOnAndroidCache: Boolean? = null
   private var useRuntimeShadowNodeReferenceUpdateCache: Boolean? = null
   private var useRuntimeShadowNodeReferenceUpdateOnLayoutCache: Boolean? = null
   private var useStateAlignmentMechanismCache: Boolean? = null
@@ -491,6 +492,16 @@ public class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun useOptimizedEventBatchingOnAndroid(): Boolean {
+    var cached = useOptimizedEventBatchingOnAndroidCache
+    if (cached == null) {
+      cached = currentProvider.useOptimizedEventBatchingOnAndroid()
+      accessedFeatureFlags.add("useOptimizedEventBatchingOnAndroid")
+      useOptimizedEventBatchingOnAndroidCache = cached
+    }
+    return cached
+  }
+
   override fun useRuntimeShadowNodeReferenceUpdate(): Boolean {
     var cached = useRuntimeShadowNodeReferenceUpdateCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsProvider.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<2c8c28515aa6929b975ef7193c8bf72e>>
+ * @generated SignedSource<<d9975558a8a9981b4f43e7c5d4473231>>
  */
 
 /**
@@ -107,6 +107,8 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun useOptimisedViewPreallocationOnAndroid(): Boolean
 
+  @DoNotStrip public fun useOptimizedEventBatchingOnAndroid(): Boolean
+
   @DoNotStrip public fun useRuntimeShadowNodeReferenceUpdate(): Boolean
 
   @DoNotStrip public fun useRuntimeShadowNodeReferenceUpdateOnLayout(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/FabricEventDispatcher.java

@@ -7,6 +7,7 @@
 
 package com.facebook.react.uimanager.events;
 
+import android.os.Handler;
 import android.view.Choreographer;
 import com.facebook.infer.annotation.Nullsafe;
 import com.facebook.react.bridge.LifecycleEventListener;
@@ -15,6 +16,7 @@
 import com.facebook.react.bridge.ReactSoftExceptionLogger;
 import com.facebook.react.bridge.UIManager;
 import com.facebook.react.bridge.UiThreadUtil;
+import com.facebook.react.internal.featureflags.ReactNativeFeatureFlags;
 import com.facebook.react.modules.core.ReactChoreographer;
 import com.facebook.react.uimanager.UIManagerHelper;
 import com.facebook.react.uimanager.common.UIManagerType;
@@ -27,6 +29,8 @@
  */
 @Nullsafe(Nullsafe.Mode.LOCAL)
 public class FabricEventDispatcher implements EventDispatcher, LifecycleEventListener {
+  private static final Handler uiThreadHandler = UiThreadUtil.getUiThreadHandler();
+
   private final ReactEventEmitter mReactEventEmitter;
   private final ReactApplicationContext mReactContext;
   private final CopyOnWriteArrayList<EventDispatcherListener> mListeners =
@@ -36,6 +40,25 @@ public class FabricEventDispatcher implements EventDispatcher, LifecycleEventLis
   private final FabricEventDispatcher.ScheduleDispatchFrameCallback mCurrentFrameCallback =
       new FabricEventDispatcher.ScheduleDispatchFrameCallback();
 
+  private boolean mIsDispatchScheduled = false;
+  private final Runnable mDispatchEventsRunnable =
+      new Runnable() {
+        @Override
+        public void run() {
+          mIsDispatchScheduled = false;
+
+          Systrace.beginSection(
+              Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, "BatchEventDispatchedListeners");
+          try {
+            for (BatchEventDispatchedListener listener : mPostEventDispatchListeners) {
+              listener.onBatchEventDispatched();
+            }
+          } finally {
+            Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
+          }
+        }
+      };
+
   public FabricEventDispatcher(ReactApplicationContext reactContext) {
     mReactContext = reactContext;
     mReactContext.addLifecycleEventListener(this);
@@ -54,7 +77,7 @@ public void dispatchEvent(Event event) {
     }
 
     event.dispose();
-    maybePostFrameCallbackFromNonUI();
+    scheduleDispatchOfBatchedEvents();
   }
 
   private void dispatchSynchronous(Event event) {
@@ -85,19 +108,17 @@ private void dispatchSynchronous(Event event) {
   }
 
   public void dispatchAllEvents() {
-    maybePostFrameCallbackFromNonUI();
+    scheduleDispatchOfBatchedEvents();
   }
 
-  private void maybePostFrameCallbackFromNonUI() {
-    if (mReactEventEmitter != null) {
-      // If the host activity is paused, the frame callback may not be currently
-      // posted. Ensure that it is so that this event gets delivered promptly.
-      mCurrentFrameCallback.maybePostFromNonUI();
+  private void scheduleDispatchOfBatchedEvents() {
+    if (ReactNativeFeatureFlags.useOptimizedEventBatchingOnAndroid()) {
+      if (!mIsDispatchScheduled) {
+        mIsDispatchScheduled = true;
+        uiThreadHandler.postAtFrontOfQueue(mDispatchEventsRunnable);
+      }
     } else {
-      // No JS application has started yet, or resumed. This can happen when a ReactRootView is
-      // added to view hierarchy, but ReactContext creation has not completed yet. In this case, any
-      // touch event dispatch will hit this codepath, and we simply queue them so that they
-      // are dispatched once ReactContext creation completes and JS app is running.
+      mCurrentFrameCallback.maybeScheduleDispatchOfBatchedEvents();
     }
   }
 
@@ -121,32 +142,37 @@ public void removeBatchEventDispatchedListener(BatchEventDispatchedListener list
 
   @Override
   public void onHostResume() {
-    maybePostFrameCallbackFromNonUI();
+    scheduleDispatchOfBatchedEvents();
   }
 
   @Override
   public void onHostPause() {
-    stopFrameCallback();
+    cancelDispatchOfBatchedEvents();
   }
 
   @Override
   public void onHostDestroy() {
-    stopFrameCallback();
+    cancelDispatchOfBatchedEvents();
   }
 
   public void onCatalystInstanceDestroyed() {
     UiThreadUtil.runOnUiThread(
         new Runnable() {
           @Override
           public void run() {
-            stopFrameCallback();
+            cancelDispatchOfBatchedEvents();
           }
         });
   }
 
-  private void stopFrameCallback() {
+  private void cancelDispatchOfBatchedEvents() {
     UiThreadUtil.assertOnUiThread();
-    mCurrentFrameCallback.stop();
+    if (ReactNativeFeatureFlags.useOptimizedEventBatchingOnAndroid()) {
+      mIsDispatchScheduled = false;
+      uiThreadHandler.removeCallbacks(mDispatchEventsRunnable);
+    } else {
+      mCurrentFrameCallback.stop();
+    }
   }
 
   public void registerEventEmitter(@UIManagerType int uiManagerType, RCTEventEmitter eventEmitter) {
@@ -163,17 +189,17 @@ public void unregisterEventEmitter(@UIManagerType int uiManagerType) {
   }
 
   private class ScheduleDispatchFrameCallback implements Choreographer.FrameCallback {
-    private volatile boolean mIsPosted = false;
+    private volatile boolean mIsDispatchScheduled = false;
     private boolean mShouldStop = false;
 
     @Override
     public void doFrame(long frameTimeNanos) {
       UiThreadUtil.assertOnUiThread();
 
       if (mShouldStop) {
-        mIsPosted = false;
+        mIsDispatchScheduled = false;
       } else {
-        post();
+        dispatchBatchedEvents();
       }
 
       Systrace.beginSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, "BatchEventDispatchedListeners");
@@ -190,32 +216,32 @@ public void stop() {
       mShouldStop = true;
     }
 
-    public void maybePost() {
-      if (!mIsPosted) {
-        mIsPosted = true;
-        post();
+    public void maybeDispatchBatchedEvents() {
+      if (!mIsDispatchScheduled) {
+        mIsDispatchScheduled = true;
+        dispatchBatchedEvents();
       }
     }
 
-    private void post() {
+    private void dispatchBatchedEvents() {
       ReactChoreographer.getInstance()
           .postFrameCallback(ReactChoreographer.CallbackType.TIMERS_EVENTS, mCurrentFrameCallback);
     }
 
-    public void maybePostFromNonUI() {
-      if (mIsPosted) {
+    public void maybeScheduleDispatchOfBatchedEvents() {
+      if (mIsDispatchScheduled) {
         return;
       }
 
       // We should only hit this slow path when we receive events while the host activity is paused.
       if (mReactContext.isOnUiQueueThread()) {
-        maybePost();
+        maybeDispatchBatchedEvents();
       } else {
         mReactContext.runOnUiQueueThread(
             new Runnable() {
               @Override
               public void run() {
-                maybePost();
+                maybeDispatchBatchedEvents();
               }
             });
       }

packages/react-native/ReactAndroid/src/main/jni/react/featureflags/JReactNativeFeatureFlagsCxxInterop.cpp

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<35f5003b77104e68e32741e4626e2ba6>>
+ * @generated SignedSource<<c01d216f03d56fed027117e78dc590ab>>
  */
 
 /**
@@ -291,6 +291,12 @@ class ReactNativeFeatureFlagsProviderHolder
     return method(javaProvider_);
   }
 
+  bool useOptimizedEventBatchingOnAndroid() override {
+    static const auto method =
+        getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("useOptimizedEventBatchingOnAndroid");
+    return method(javaProvider_);
+  }
+
   bool useRuntimeShadowNodeReferenceUpdate() override {
     static const auto method =
         getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("useRuntimeShadowNodeReferenceUpdate");
@@ -529,6 +535,11 @@ bool JReactNativeFeatureFlagsCxxInterop::useOptimisedViewPreallocationOnAndroid(
   return ReactNativeFeatureFlags::useOptimisedViewPreallocationOnAndroid();
 }
 
+bool JReactNativeFeatureFlagsCxxInterop::useOptimizedEventBatchingOnAndroid(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
+  return ReactNativeFeatureFlags::useOptimizedEventBatchingOnAndroid();
+}
+
 bool JReactNativeFeatureFlagsCxxInterop::useRuntimeShadowNodeReferenceUpdate(
     facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
   return ReactNativeFeatureFlags::useRuntimeShadowNodeReferenceUpdate();
@@ -692,6 +703,9 @@ void JReactNativeFeatureFlagsCxxInterop::registerNatives() {
       makeNativeMethod(
         "useOptimisedViewPreallocationOnAndroid",
         JReactNativeFeatureFlagsCxxInterop::useOptimisedViewPreallocationOnAndroid),
+      makeNativeMethod(
+        "useOptimizedEventBatchingOnAndroid",
+        JReactNativeFeatureFlagsCxxInterop::useOptimizedEventBatchingOnAndroid),
       makeNativeMethod(
         "useRuntimeShadowNodeReferenceUpdate",
         JReactNativeFeatureFlagsCxxInterop::useRuntimeShadowNodeReferenceUpdate),