Add basic emitting of click event (#36616)

Summary:
Pull Request resolved: #36616

Changelog: [iOS][Internal] - Add basic emitting of click event

This diff adds the basic implementation of click event emitting, particularlly focused on ensuring clicks are only fired if the pointer interaction ends within the same tree "branch" of elements as which it started.

Reviewed By: yungsters

Differential Revision: D44148427

fbshipit-source-id: 9e91c32fe0e1ca8a5c50e72cd819625294e070f4

packages/react-native/React/Fabric/RCTSurfacePointerHandler.mm

@@ -24,6 +24,26 @@ typedef NS_ENUM(NSInteger, RCTPointerEventType) {
   RCTPointerEventTypeCancel,
 };
 
+static BOOL AllTouchesAreCancelledOrEnded(NSSet<UITouch *> *touches)
+{
+  for (UITouch *touch in touches) {
+    if (touch.phase == UITouchPhaseBegan || touch.phase == UITouchPhaseMoved || touch.phase == UITouchPhaseStationary) {
+      return NO;
+    }
+  }
+  return YES;
+}
+
+static BOOL AnyTouchesChanged(NSSet<UITouch *> *touches)
+{
+  for (UITouch *touch in touches) {
+    if (touch.phase == UITouchPhaseBegan || touch.phase == UITouchPhaseMoved) {
+      return YES;
+    }
+  }
+  return NO;
+}
+
 struct ActivePointer {
   /*
    * Pointer ID
@@ -349,7 +369,9 @@ static void UpdateActivePointerWithUITouch(
     UIEvent *uiEvent,
     UIView *rootComponentView)
 {
-  activePointer.componentView = FindClosestFabricManagedTouchableView(uiTouch.view);
+  CGPoint location = [uiTouch locationInView:rootComponentView];
+  UIView *hitTestedView = [rootComponentView hitTest:location withEvent:nil];
+  activePointer.componentView = FindClosestFabricManagedTouchableView(hitTestedView);
 
   activePointer.clientPoint = [uiTouch locationInView:rootComponentView];
   activePointer.screenPoint = [rootComponentView convertPoint:activePointer.clientPoint
@@ -396,6 +418,22 @@ static BOOL IsAnyViewInPathListeningToEvent(NSOrderedSet<RCTReactTaggedView *> *
   return NO;
 }
 
+/**
+ * Given an ActivePointer determine if it is still within the same event target tree as
+ * the one which initiated the pointer gesture.
+ */
+static BOOL IsPointerWithinInitialTree(ActivePointer activePointer)
+{
+  NSOrderedSet<RCTReactTaggedView *> *initialViewSet =
+      GetTouchableViewsInPathToRoot(activePointer.initialComponentView);
+  for (RCTReactTaggedView *canidateTaggedView in initialViewSet) {
+    if (canidateTaggedView.tag == activePointer.componentView.tag) {
+      return YES;
+    }
+  }
+  return NO;
+}
+
 /**
  * Surprisingly, `__unsafe_unretained id` pointers are not regular pointers
  * and `std::hash<>` cannot hash them.
@@ -526,6 +564,8 @@ - (void)_registerTouches:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
       activePointer.shouldLeaveWhenReleased = YES;
     }
 
+    activePointer.initialComponentView = FindClosestFabricManagedTouchableView(touch.view);
+
     UpdateActivePointerWithUITouch(activePointer, touch, event, _rootComponentView);
 
     _activePointers.emplace(touch, activePointer);
@@ -618,6 +658,11 @@ - (void)_dispatchActivePointers:(std::vector<ActivePointer>)activePointers event
         }
         case RCTPointerEventTypeEnd: {
           eventEmitter->onPointerUp(pointerEvent);
+
+          if (pointerEvent.isPrimary && pointerEvent.button == 0 && IsPointerWithinInitialTree(activePointer)) {
+            eventEmitter->onClick(pointerEvent);
+          }
+
           if (activePointer.shouldLeaveWhenReleased) {
             [self handleIncomingPointerEvent:pointerEvent onView:nil];
           }
@@ -641,6 +686,12 @@ - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
 
   [self _registerTouches:touches withEvent:event];
   [self _dispatchActivePointers:[self _activePointersFromTouches:touches] eventType:RCTPointerEventTypeStart];
+
+  if (self.state == UIGestureRecognizerStatePossible) {
+    self.state = UIGestureRecognizerStateBegan;
+  } else if (self.state == UIGestureRecognizerStateBegan) {
+    self.state = UIGestureRecognizerStateChanged;
+  }
 }
 
 - (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
@@ -649,6 +700,8 @@ - (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
 
   [self _updateTouches:touches withEvent:event];
   [self _dispatchActivePointers:[self _activePointersFromTouches:touches] eventType:RCTPointerEventTypeMove];
+
+  self.state = UIGestureRecognizerStateChanged;
 }
 
 - (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
@@ -658,6 +711,12 @@ - (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
   [self _updateTouches:touches withEvent:event];
   [self _dispatchActivePointers:[self _activePointersFromTouches:touches] eventType:RCTPointerEventTypeEnd];
   [self _unregisterTouches:touches];
+
+  if (AllTouchesAreCancelledOrEnded(event.allTouches)) {
+    self.state = UIGestureRecognizerStateEnded;
+  } else if (AnyTouchesChanged(event.allTouches)) {
+    self.state = UIGestureRecognizerStateChanged;
+  }
 }
 
 - (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
@@ -667,6 +726,12 @@ - (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
   [self _updateTouches:touches withEvent:event];
   [self _dispatchActivePointers:[self _activePointersFromTouches:touches] eventType:RCTPointerEventTypeCancel];
   [self _unregisterTouches:touches];
+
+  if (AllTouchesAreCancelledOrEnded(event.allTouches)) {
+    self.state = UIGestureRecognizerStateCancelled;
+  } else if (AnyTouchesChanged(event.allTouches)) {
+    self.state = UIGestureRecognizerStateChanged;
+  }
 }
 
 - (void)reset