Refactor findTargetPathAndCoordinatesForTouch to improve perf of event delivery

Summary:
Refactor of TouchTargetHelper.findTargetPathAndCoordinatesForTouch to avoid unnecessary lookup of views during the dispatching of Hover Events

changelog: [internal] internal

Reviewed By: lunaleaps, mdvacca

Differential Revision: D32296003

fbshipit-source-id: 93834c37331ad5d75645a5665a1c8c3d965765fb

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

@@ -25,6 +25,7 @@ import com.facebook.react.uimanager.common.ViewUtil;
 import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * Class responsible for identifying which react view should handle a given {@link MotionEvent}. It
@@ -109,11 +110,12 @@ public class TouchTargetHelper {
    * @param eventY the Y screen coordinate of the touch location
    * @param viewGroup the container view to traverse
    * @param viewCoords an out parameter that will return the X,Y value in the target view
-   * @return If a target was found, returns a path through the view tree of all react tags that are
-   *     a container for the touch target, ordered from target to root (last element)
+   * @return If a target was found, returns a {@link Lis<ViewTarget>} containing the path through
+   *     the view tree of all react tags and views that are a container for the touch target,
+   *     ordered from target to root (last element)
    */
   @SuppressLint("ResourceType")
-  public static List<Integer> findTargetPathAndCoordinatesForTouch(
+  public static List<ViewTarget> findTargetPathAndCoordinatesForTouch(
       float eventX, float eventY, ViewGroup viewGroup, float[] viewCoords) {
     UiThreadUtil.assertOnUiThread();
 
@@ -121,7 +123,7 @@ public class TouchTargetHelper {
     viewCoords[0] = eventX;
     viewCoords[1] = eventY;
 
-    List<Integer> pathAccumulator = new ArrayList<>();
+    List<ViewTarget> pathAccumulator = new ArrayList<>();
     View targetView = findTouchTargetViewWithPointerEvents(viewCoords, viewGroup, pathAccumulator);
 
     if (targetView != null) {
@@ -140,7 +142,7 @@ public class TouchTargetHelper {
 
       int targetTag = getTouchTargetForView(reactTargetView, eventX, eventY);
       if (targetTag != reactTargetView.getId()) {
-        pathAccumulator.add(0, targetTag);
+        pathAccumulator.add(0, new ViewTarget(targetTag, (View) null));
       }
     }
 
@@ -178,7 +180,7 @@ public class TouchTargetHelper {
       float[] eventCoords,
       View view,
       EnumSet<TouchTargetReturnType> allowReturnTouchTargetTypes,
-      List<Integer> pathAccumulator) {
+      List<ViewTarget> pathAccumulator) {
     // We prefer returning a child, so we check for a child that can handle the touch first
     if (allowReturnTouchTargetTypes.contains(TouchTargetReturnType.CHILD)
         && view instanceof ViewGroup) {
@@ -303,7 +305,7 @@ public class TouchTargetHelper {
    * its descendants are the touch target.
    */
   private static @Nullable View findTouchTargetViewWithPointerEvents(
-      float eventCoords[], View view, @Nullable List<Integer> pathAccumulator) {
+      float eventCoords[], View view, @Nullable List<ViewTarget> pathAccumulator) {
     PointerEvents pointerEvents =
         view instanceof ReactPointerEventsView
             ? ((ReactPointerEventsView) view).getPointerEvents()
@@ -330,7 +332,7 @@ public class TouchTargetHelper {
           findTouchTargetView(
               eventCoords, view, EnumSet.of(TouchTargetReturnType.SELF), pathAccumulator);
       if (targetView != null && pathAccumulator != null) {
-        pathAccumulator.add(view.getId());
+        pathAccumulator.add(new ViewTarget(view.getId(), view));
       }
       return targetView;
 
@@ -341,7 +343,7 @@ public class TouchTargetHelper {
               eventCoords, view, EnumSet.of(TouchTargetReturnType.CHILD), pathAccumulator);
       if (targetView != null) {
         if (pathAccumulator != null) {
-          pathAccumulator.add(view.getId());
+          pathAccumulator.add(new ViewTarget(view.getId(), view));
         }
         return targetView;
       }
@@ -358,7 +360,7 @@ public class TouchTargetHelper {
         // make sure we exclude the View itself because of the PointerEvents.BOX_NONE
         if (reactTag != view.getId()) {
           if (pathAccumulator != null) {
-            pathAccumulator.add(view.getId());
+            pathAccumulator.add(new ViewTarget(view.getId(), view));
           }
           return view;
         }
@@ -372,7 +374,7 @@ public class TouchTargetHelper {
           && isTouchPointInView(eventCoords[0], eventCoords[1], view)
           && ((ReactCompoundViewGroup) view).interceptsTouchEvent(eventCoords[0], eventCoords[1])) {
         if (pathAccumulator != null) {
-          pathAccumulator.add(view.getId());
+          pathAccumulator.add(new ViewTarget(view.getId(), view));
         }
         return view;
       }
@@ -384,7 +386,7 @@ public class TouchTargetHelper {
               EnumSet.of(TouchTargetReturnType.SELF, TouchTargetReturnType.CHILD),
               pathAccumulator);
       if (result != null && pathAccumulator != null) {
-        pathAccumulator.add(view.getId());
+        pathAccumulator.add(new ViewTarget(view.getId(), view));
       }
       return result;
 
@@ -402,4 +404,47 @@ public class TouchTargetHelper {
     }
     return targetView.getId();
   }
+
+  public static class ViewTarget {
+    private final int mViewId;
+    private final @Nullable View mView;
+
+    private ViewTarget(int viewId, @Nullable View view) {
+      mViewId = viewId;
+      mView = view;
+    }
+
+    public int getViewId() {
+      return mViewId;
+    }
+
+    @Nullable
+    public View getView() {
+      return mView;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      // If the object is compared with itself then return true
+      if (o == this) {
+        return true;
+      }
+
+      // Check if o is an instance of ViewTarget. Note that "null instanceof ViewTarget" also
+      // returns false.
+      if (!(o instanceof ViewTarget)) {
+        return false;
+      }
+
+      ViewTarget other = (ViewTarget) o;
+      // We only need to compare view id, as we assume the same view id will always map to the same
+      // view. TargetView is not mutable so this should be safe.
+      return other.getViewId() == mViewId;
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hashCode(mViewId);
+    }
+  }
 }