Refactor EventEmitters to take optional surfaceId, migrate TouchEvent

Summary:
Refactor EventEmitters to take an optional SurfaceId that Fabric will use, and non-Fabric will not.

Migrating touches is a good proof-of-concept for how this could be used generally, and as it turns out, TouchEvent's API is more flexible than most other event APIs (because it uses a dictionary to pass data around, so we can just stuff SurfaceId into it - not efficient, but flexible).

All new APIs are backwards-compatible and designed to work with old-style events, with Fabric and non-Fabric. Native Views that migrate to the new API will be backwards-compatible and get an efficiency boost in Fabric.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D26025135

fbshipit-source-id: 5b418951e9d0a3882f2d67398f2aaadac8a3a556

ReactAndroid/src/main/java/com/facebook/react/fabric/events/FabricEventEmitter.java

@@ -9,6 +9,7 @@
 
 import static com.facebook.react.uimanager.events.TouchesHelper.CHANGED_TOUCHES_KEY;
 import static com.facebook.react.uimanager.events.TouchesHelper.TARGET_KEY;
+import static com.facebook.react.uimanager.events.TouchesHelper.TARGET_SURFACE_KEY;
 import static com.facebook.react.uimanager.events.TouchesHelper.TOP_TOUCH_CANCEL_KEY;
 import static com.facebook.react.uimanager.events.TouchesHelper.TOP_TOUCH_END_KEY;
 import static com.facebook.react.uimanager.events.TouchesHelper.TOUCHES_KEY;
@@ -76,14 +77,15 @@ public void receiveTouches(
       touch.putArray(TOUCHES_KEY, copyWritableArray(touches));
       WritableMap nativeEvent = touch;
       int rootNodeID = 0;
-      int target = nativeEvent.getInt(TARGET_KEY);
-      if (target < 1) {
+      int targetSurfaceId = nativeEvent.getInt(TARGET_SURFACE_KEY);
+      int targetReactTag = nativeEvent.getInt(TARGET_KEY);
+      if (targetReactTag < 1) {
         FLog.e(TAG, "A view is reporting that a touch occurred on tag zero.");
       } else {
-        rootNodeID = target;
+        rootNodeID = targetReactTag;
       }
 
-      receiveEvent(rootNodeID, eventTopLevelType, touch);
+      receiveEvent(targetSurfaceId, rootNodeID, eventTopLevelType, touch);
     }
   }
 

ReactAndroid/src/main/java/com/facebook/react/uimanager/JSTouchDispatcher.java

@@ -50,6 +50,17 @@ public void onChildStartedNativeGesture(
     mTargetTag = -1;
   }
 
+  private int getSurfaceId() {
+    if (mRootViewGroup instanceof ReactRoot) {
+      return ((ReactRoot) mRootViewGroup).getRootViewTag();
+    }
+    if (mRootViewGroup != null && mRootViewGroup.getContext() instanceof ThemedReactContext) {
+      ThemedReactContext context = (ThemedReactContext) mRootViewGroup.getContext();
+      return context.getSurfaceId();
+    }
+    return -1;
+  }
+
   /**
    * Main catalyst view is responsible for collecting and sending touch events to JS. This method
    * reacts for an incoming android native touch events ({@link MotionEvent}) and calls into {@link
@@ -70,9 +81,11 @@ public void handleTouchEvent(MotionEvent ev, EventDispatcher eventDispatcher) {
       // this gesture
       mChildIsHandlingNativeGesture = false;
       mGestureStartTime = ev.getEventTime();
+
       mTargetTag = findTargetTagAndSetCoordinates(ev);
       eventDispatcher.dispatchEvent(
           TouchEvent.obtain(
+              getSurfaceId(),
               mTargetTag,
               TouchEventType.START,
               ev,
@@ -97,6 +110,7 @@ public void handleTouchEvent(MotionEvent ev, EventDispatcher eventDispatcher) {
       findTargetTagAndSetCoordinates(ev);
       eventDispatcher.dispatchEvent(
           TouchEvent.obtain(
+              getSurfaceId(),
               mTargetTag,
               TouchEventType.END,
               ev,
@@ -111,6 +125,7 @@ public void handleTouchEvent(MotionEvent ev, EventDispatcher eventDispatcher) {
       findTargetTagAndSetCoordinates(ev);
       eventDispatcher.dispatchEvent(
           TouchEvent.obtain(
+              getSurfaceId(),
               mTargetTag,
               TouchEventType.MOVE,
               ev,
@@ -122,6 +137,7 @@ public void handleTouchEvent(MotionEvent ev, EventDispatcher eventDispatcher) {
       // New pointer goes down, this can only happen after ACTION_DOWN is sent for the first pointer
       eventDispatcher.dispatchEvent(
           TouchEvent.obtain(
+              getSurfaceId(),
               mTargetTag,
               TouchEventType.START,
               ev,
@@ -133,6 +149,7 @@ public void handleTouchEvent(MotionEvent ev, EventDispatcher eventDispatcher) {
       // Exactly onw of the pointers goes up
       eventDispatcher.dispatchEvent(
           TouchEvent.obtain(
+              getSurfaceId(),
               mTargetTag,
               TouchEventType.END,
               ev,
@@ -181,6 +198,7 @@ private void dispatchCancelEvent(MotionEvent androidEvent, EventDispatcher event
     Assertions.assertNotNull(eventDispatcher)
         .dispatchEvent(
             TouchEvent.obtain(
+                getSurfaceId(),
                 mTargetTag,
                 TouchEventType.CANCEL,
                 androidEvent,

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/BlackHoleEventDispatcher.java

@@ -49,6 +49,9 @@ public void removeBatchEventDispatchedListener(BatchEventDispatchedListener list
   @Override
   public void registerEventEmitter(int uiManagerType, RCTEventEmitter eventEmitter) {}
 
+  @Override
+  public void registerEventEmitter(int uiManagerType, RCTModernEventEmitter eventEmitter) {}
+
   @Override
   public void unregisterEventEmitter(int uiManagerType) {}
 

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/EventDispatcher.java

@@ -26,8 +26,11 @@ public interface EventDispatcher {
 
   void removeBatchEventDispatchedListener(BatchEventDispatchedListener listener);
 
+  @Deprecated
   void registerEventEmitter(@UIManagerType int uiManagerType, RCTEventEmitter eventEmitter);
 
+  void registerEventEmitter(@UIManagerType int uiManagerType, RCTModernEventEmitter eventEmitter);
+
   void unregisterEventEmitter(@UIManagerType int uiManagerType);
 
   void onCatalystInstanceDestroyed();

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/EventDispatcherImpl.java

@@ -263,6 +263,11 @@ public void registerEventEmitter(@UIManagerType int uiManagerType, RCTEventEmitt
     mReactEventEmitter.register(uiManagerType, eventEmitter);
   }
 
+  public void registerEventEmitter(
+      @UIManagerType int uiManagerType, RCTModernEventEmitter eventEmitter) {
+    mReactEventEmitter.register(uiManagerType, eventEmitter);
+  }
+
   public void unregisterEventEmitter(@UIManagerType int uiManagerType) {
     mReactEventEmitter.unregister(uiManagerType);
   }
@@ -361,7 +366,7 @@ public void run() {
               }
               Systrace.endAsyncFlow(
                   Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, event.getEventName(), event.getUniqueID());
-              event.dispatch(mReactEventEmitter);
+              event.dispatchV2(mReactEventEmitter);
               event.dispose();
             }
             clearEventsToDispatch();

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/RCTEventEmitter.java

@@ -13,6 +13,7 @@
 import com.facebook.react.bridge.WritableArray;
 import com.facebook.react.bridge.WritableMap;
 
+/** Deprecated in favor of RCTModernEventEmitter, which extends this interface. */
 @DoNotStrip
 @Deprecated
 public interface RCTEventEmitter extends JavaScriptModule {

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/ReactEventEmitter.java

@@ -9,9 +9,7 @@
 
 import static com.facebook.react.uimanager.events.TouchesHelper.TARGET_KEY;
 
-import android.util.SparseArray;
 import androidx.annotation.Nullable;
-import com.facebook.common.logging.FLog;
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactNoCrashSoftException;
@@ -21,58 +19,78 @@
 import com.facebook.react.uimanager.common.UIManagerType;
 import com.facebook.react.uimanager.common.ViewUtil;
 
-public class ReactEventEmitter implements RCTEventEmitter {
+public class ReactEventEmitter implements RCTModernEventEmitter {
 
   private static final String TAG = "ReactEventEmitter";
 
-  private final SparseArray<RCTEventEmitter> mEventEmitters = new SparseArray<>();
+  @Nullable
+  private RCTModernEventEmitter mFabricEventEmitter =
+      null; /* Corresponds to a Fabric EventEmitter */
+
+  @Nullable
+  private RCTEventEmitter mRCTEventEmitter = null; /* Corresponds to a Non-Fabric EventEmitter */
 
   private final ReactApplicationContext mReactContext;
 
   public ReactEventEmitter(ReactApplicationContext reactContext) {
     mReactContext = reactContext;
   }
 
+  public void register(@UIManagerType int uiManagerType, RCTModernEventEmitter eventEmitter) {
+    assert uiManagerType == UIManagerType.FABRIC;
+    mFabricEventEmitter = eventEmitter;
+  }
+
   public void register(@UIManagerType int uiManagerType, RCTEventEmitter eventEmitter) {
-    mEventEmitters.put(uiManagerType, eventEmitter);
+    assert uiManagerType == UIManagerType.DEFAULT;
+    mRCTEventEmitter = eventEmitter;
   }
 
   public void unregister(@UIManagerType int uiManagerType) {
-    mEventEmitters.remove(uiManagerType);
+    if (uiManagerType == UIManagerType.DEFAULT) {
+      mRCTEventEmitter = null;
+    } else {
+      mFabricEventEmitter = null;
+    }
   }
 
   @Override
   public void receiveEvent(int targetReactTag, String eventName, @Nullable WritableMap event) {
-    RCTEventEmitter eventEmitter = getEventEmitter(targetReactTag);
-    if (eventEmitter != null) {
-      eventEmitter.receiveEvent(targetReactTag, eventName, event);
-    }
+    receiveEvent(-1, targetReactTag, eventName, event);
   }
 
   @Override
   public void receiveTouches(
       String eventName, WritableArray touches, WritableArray changedIndices) {
-
     Assertions.assertCondition(touches.size() > 0);
 
     int reactTag = touches.getMap(0).getInt(TARGET_KEY);
-    RCTEventEmitter eventEmitter = getEventEmitter(reactTag);
-    if (eventEmitter != null) {
-      eventEmitter.receiveTouches(eventName, touches, changedIndices);
+    @UIManagerType int uiManagerType = ViewUtil.getUIManagerType(reactTag);
+    if (uiManagerType == UIManagerType.FABRIC && mFabricEventEmitter != null) {
+      mFabricEventEmitter.receiveTouches(eventName, touches, changedIndices);
+    } else if (uiManagerType == UIManagerType.DEFAULT && getEventEmitter(reactTag) != null) {
+      mRCTEventEmitter.receiveTouches(eventName, touches, changedIndices);
+    } else {
+      ReactSoftException.logSoftException(
+          TAG,
+          new ReactNoCrashSoftException(
+              "Cannot find EventEmitter for receivedTouches: ReactTag["
+                  + reactTag
+                  + "] UIManagerType["
+                  + uiManagerType
+                  + "] EventName["
+                  + eventName
+                  + "]"));
     }
   }
 
   @Nullable
   private RCTEventEmitter getEventEmitter(int reactTag) {
     int type = ViewUtil.getUIManagerType(reactTag);
-    RCTEventEmitter eventEmitter = mEventEmitters.get(type);
-    if (eventEmitter == null) {
-      // TODO T54145494: Refactor RN Event Emitter system to make sure reactTags are always managed
-      // by RN
-      FLog.e(
-          TAG, "Unable to find event emitter for reactTag: %d - uiManagerType: %d", reactTag, type);
+    assert type == UIManagerType.DEFAULT;
+    if (mRCTEventEmitter == null) {
       if (mReactContext.hasActiveCatalystInstance()) {
-        eventEmitter = mReactContext.getJSModule(RCTEventEmitter.class);
+        mRCTEventEmitter = mReactContext.getJSModule(RCTEventEmitter.class);
       } else {
         ReactSoftException.logSoftException(
             TAG,
@@ -84,6 +102,30 @@ private RCTEventEmitter getEventEmitter(int reactTag) {
                     + " - No active Catalyst instance!"));
       }
     }
-    return eventEmitter;
+    return mRCTEventEmitter;
+  }
+
+  @Override
+  public void receiveEvent(
+      int surfaceId, int targetReactTag, String eventName, @Nullable WritableMap event) {
+    @UIManagerType int uiManagerType = ViewUtil.getUIManagerType(targetReactTag);
+    if (uiManagerType == UIManagerType.FABRIC && mFabricEventEmitter != null) {
+      mFabricEventEmitter.receiveEvent(surfaceId, targetReactTag, eventName, event);
+    } else if (uiManagerType == UIManagerType.DEFAULT && getEventEmitter(targetReactTag) != null) {
+      mRCTEventEmitter.receiveEvent(targetReactTag, eventName, event);
+    } else {
+      ReactSoftException.logSoftException(
+          TAG,
+          new ReactNoCrashSoftException(
+              "Cannot find EventEmitter for receiveEvent: SurfaceId["
+                  + surfaceId
+                  + "] ReactTag["
+                  + targetReactTag
+                  + "] UIManagerType["
+                  + uiManagerType
+                  + "] EventName["
+                  + eventName
+                  + "]"));
+    }
   }
 }

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/TouchEvent.java

@@ -31,6 +31,7 @@ public class TouchEvent extends Event<TouchEvent> {
   public static final long UNSET = Long.MIN_VALUE;
 
   public static TouchEvent obtain(
+      int surfaceId,
       int viewTag,
       TouchEventType touchEventType,
       MotionEvent motionEventToCopy,
@@ -43,6 +44,7 @@ public static TouchEvent obtain(
       event = new TouchEvent();
     }
     event.init(
+        surfaceId,
         viewTag,
         touchEventType,
         motionEventToCopy,
@@ -64,14 +66,15 @@ public static TouchEvent obtain(
   private TouchEvent() {}
 
   private void init(
+      int surfaceId,
       int viewTag,
       TouchEventType touchEventType,
       MotionEvent motionEventToCopy,
       long gestureStartTime,
       float viewX,
       float viewY,
       TouchEventCoalescingKeyHelper touchEventCoalescingKeyHelper) {
-    super.init(viewTag);
+    super.init(surfaceId, viewTag);
 
     SoftAssertions.assertCondition(
         gestureStartTime != UNSET, "Gesture start time must be initialized");
@@ -141,7 +144,11 @@ public short getCoalescingKey() {
   @Override
   public void dispatch(RCTEventEmitter rctEventEmitter) {
     TouchesHelper.sendTouchEvent(
-        rctEventEmitter, Assertions.assertNotNull(mTouchEventType), getViewTag(), this);
+        rctEventEmitter,
+        Assertions.assertNotNull(mTouchEventType),
+        getSurfaceId(),
+        getViewTag(),
+        this);
   }
 
   public MotionEvent getMotionEvent() {

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/TouchesHelper.java

@@ -16,6 +16,7 @@
 /** Class responsible for generating catalyst touch events based on android {@link MotionEvent}. */
 public class TouchesHelper {
 
+  public static final String TARGET_SURFACE_KEY = "targetSurface";
   public static final String TARGET_KEY = "target";
   public static final String CHANGED_TOUCHES_KEY = "changedTouches";
   public static final String TOUCHES_KEY = "touches";
@@ -34,7 +35,8 @@ public class TouchesHelper {
    * given {@param event} instance. This method use {@param reactTarget} parameter to set as a
    * target view id associated with current gesture.
    */
-  private static WritableArray createsPointersArray(int reactTarget, TouchEvent event) {
+  private static WritableArray createsPointersArray(
+      int surfaceId, int reactTarget, TouchEvent event) {
     WritableArray touches = Arguments.createArray();
     MotionEvent motionEvent = event.getMotionEvent();
 
@@ -60,6 +62,7 @@ private static WritableArray createsPointersArray(int reactTarget, TouchEvent ev
       float locationY = motionEvent.getY(index) - targetViewCoordinateY;
       touch.putDouble(LOCATION_X_KEY, PixelUtil.toDIPFromPixel(locationX));
       touch.putDouble(LOCATION_Y_KEY, PixelUtil.toDIPFromPixel(locationY));
+      touch.putInt(TARGET_SURFACE_KEY, surfaceId);
       touch.putInt(TARGET_KEY, reactTarget);
       touch.putDouble(TIMESTAMP_KEY, event.getTimestampMs());
       touch.putDouble(POINTER_IDENTIFIER_KEY, motionEvent.getPointerId(index));
@@ -81,10 +84,10 @@ private static WritableArray createsPointersArray(int reactTarget, TouchEvent ev
   public static void sendTouchEvent(
       RCTEventEmitter rctEventEmitter,
       TouchEventType type,
+      int surfaceId,
       int reactTarget,
       TouchEvent touchEvent) {
-
-    WritableArray pointers = createsPointersArray(reactTarget, touchEvent);
+    WritableArray pointers = createsPointersArray(surfaceId, reactTarget, touchEvent);
     MotionEvent motionEvent = touchEvent.getMotionEvent();
 
     // For START and END events send only index of the pointer that is associated with that event