Bug 1700251 - Move the code to set the LayersId on the event into InputHandlingResult::Finish(). r=tnikkel

This allows that code (and in the future, other code that needs
to run for every input type) to be in just one place.

Depends on D109460

Differential Revision: https://phabricator.services.mozilla.com/D109461

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -1462,7 +1462,7 @@ static bool HasNonLockModifier(Modifiers aModifiers) {
 
 APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
   APZThreadUtils::AssertOnControllerThread();
-  InputHandlingState state;
+  InputHandlingState state{aEvent};
 
   // Use a RAII class for updating the focus sequence number of this event
   AutoFocusSequenceNumberSetter focusSetter(mFocusState, aEvent);
@@ -1489,7 +1489,6 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
       }
 
       state.mHit = GetTargetAPZC(mouseInput.mOrigin);
-      aEvent.mLayersId = state.mHit.mLayersId;
       bool hitScrollbar = (bool)state.mHit.mScrollbarNode;
 
       // When the mouse is outside the window we still want to handle dragging
@@ -1567,11 +1566,10 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
       // Do this before early return for Fission hit testing.
       ScrollWheelInput& wheelInput = aEvent.AsScrollWheelInput();
       state.mHit = GetTargetAPZC(wheelInput.mOrigin);
-      aEvent.mLayersId = state.mHit.mLayersId;
 
       wheelInput.mHandledByAPZ = WillHandleInput(wheelInput);
       if (!wheelInput.mHandledByAPZ) {
-        return state.mResult;
+        return state.Finish();
       }
 
       mOvershootDetector.Update(wheelInput);
@@ -1592,7 +1590,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
                                                  state.mHit.mTargetApzc);
           }
           state.mResult.SetStatusAsConsumeNoDefault();
-          return state.mResult;
+          return state.Finish();
         }
 
         MOZ_ASSERT(wheelInput.mAPZAction == APZWheelAction::Scroll);
@@ -1611,7 +1609,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
             UntransformBy(transformToGecko, wheelInput.mOrigin);
 
         if (!untransformedOrigin) {
-          return state.mResult;
+          return state.Finish();
         }
 
         state.mResult = mInputQueue->ReceiveInputEvent(
@@ -1629,11 +1627,10 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
       // Do this before early return for Fission hit testing.
       PanGestureInput& panInput = aEvent.AsPanGestureInput();
       state.mHit = GetTargetAPZC(panInput.mPanStartPoint);
-      aEvent.mLayersId = state.mHit.mLayersId;
 
       panInput.mHandledByAPZ = WillHandleInput(panInput);
       if (!panInput.mHandledByAPZ) {
-        return state.mResult;
+        return state.Finish();
       }
 
       // If/when we enable support for pan inputs off-main-thread, we'll need
@@ -1667,7 +1664,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
                               panInput.mPanStartPoint);
 
         if (!untransformedStartPoint || !untransformedDisplacement) {
-          return state.mResult;
+          return state.Finish();
         }
 
         state.mResult = mInputQueue->ReceiveInputEvent(
@@ -1688,11 +1685,10 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
       if (HasNonLockModifier(pinchInput.modifiers)) {
         APZCTM_LOG("Discarding pinch input due to modifiers 0x%x\n",
                    pinchInput.modifiers);
-        return state.mResult;
+        return state.Finish();
       }
 
       state.mHit = GetTargetAPZC(pinchInput.mFocusPoint);
-      aEvent.mLayersId = state.mHit.mLayersId;
 
       // We always handle pinch gestures as pinch zooms.
       pinchInput.mHandledByAPZ = true;
@@ -1713,7 +1709,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
             UntransformBy(outTransform, pinchInput.mFocusPoint);
 
         if (!untransformedFocusPoint) {
-          return state.mResult;
+          return state.Finish();
         }
 
         state.mResult = mInputQueue->ReceiveInputEvent(
@@ -1728,7 +1724,6 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
     case TAPGESTURE_INPUT: {  // note: no one currently sends these
       TapGestureInput& tapInput = aEvent.AsTapGestureInput();
       state.mHit = GetTargetAPZC(tapInput.mPoint);
-      aEvent.mLayersId = state.mHit.mLayersId;
 
       if (state.mHit.mTargetApzc) {
         MOZ_ASSERT(state.mHit.mHitResult != CompositorHitTestInvisibleToHit);
@@ -1740,7 +1735,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
             UntransformBy(outTransform, tapInput.mPoint);
 
         if (!untransformedPoint) {
-          return state.mResult;
+          return state.Finish();
         }
 
         state.mResult = mInputQueue->ReceiveInputEvent(
@@ -1758,7 +1753,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
       if (!StaticPrefs::apz_keyboard_enabled_AtStartup() ||
           StaticPrefs::accessibility_browsewithcaret()) {
         APZ_KEY_LOG("Skipping key input from invalid prefs\n");
-        return state.mResult;
+        return state.Finish();
       }
 
       KeyboardInput& keyInput = aEvent.AsKeyboardInput();
@@ -1775,14 +1770,14 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
         if (mFocusState.CanIgnoreKeyboardShortcutMisses()) {
           focusSetter.MarkAsNonFocusChanging();
         }
-        return state.mResult;
+        return state.Finish();
       }
 
       // Check if this shortcut needs to be dispatched to content. Anything
       // matching this is assumed to be able to change focus.
       if (shortcut->mDispatchToContent) {
         APZ_KEY_LOG("Skipping key input with dispatch-to-content shortcut\n");
-        return state.mResult;
+        return state.Finish();
       }
 
       // We know we have an action to execute on whatever is the current focus
@@ -1811,7 +1806,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
       // to content.
       if (!targetGuid) {
         APZ_KEY_LOG("Skipping key input with no current focus target\n");
-        return state.mResult;
+        return state.Finish();
       }
 
       RefPtr<AsyncPanZoomController> targetApzc =
@@ -1819,7 +1814,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
 
       if (!targetApzc) {
         APZ_KEY_LOG("Skipping key input with focus target but no APZC\n");
-        return state.mResult;
+        return state.Finish();
       }
 
       // Attach the keyboard scroll action to the input event for processing
@@ -1843,7 +1838,7 @@ APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) {
       break;
     }
   }
-  return state.mResult;
+  return state.Finish();
 }
 
 static TouchBehaviorFlags ConvertToTouchBehavior(
@@ -1918,6 +1913,17 @@ APZCTreeManager::HitTestResult APZCTreeManager::GetTouchInputBlockAPZC(
   return hit;
 }
 
+APZEventResult APZCTreeManager::InputHandlingState::Finish() const {
+  // The validity check here handles both the case where mHit was
+  // never populated (because this event did not trigger a hit-test),
+  // and the case where it was populated with an invalid LayersId
+  // (which can happen e.g. for multi-touch events).
+  if (mHit.mLayersId.IsValid()) {
+    mEvent.mLayersId = mHit.mLayersId;
+  }
+  return mResult;
+}
+
 void APZCTreeManager::ProcessTouchInput(InputHandlingState& aState,
                                         MultiTouchInput& aInput) {
   aInput.mHandledByAPZ = true;
@@ -1947,11 +1953,6 @@ void APZCTreeManager::ProcessTouchInput(InputHandlingState& aState,
     aState.mHit = GetTouchInputBlockAPZC(aInput, &touchBehaviors);
     // Repopulate mTouchBlockHitResult with the fields we care about.
     mTouchBlockHitResult = aState.mHit.CopyWithoutScrollbarNode();
-    if (aState.mHit.mLayersId.IsValid()) {
-      // Check for validity because we won't get a layers id for multi-touch
-      // events.
-      aInput.mLayersId = aState.mHit.mLayersId;
-    }
     hitScrollbarNode = std::move(aState.mHit.mScrollbarNode);
 
     // Check if this event starts a scrollbar touch-drag. The conditions

gfx/layers/apz/src/APZCTreeManager.h

@@ -684,6 +684,9 @@ class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
    * A helper structure for use by ReceiveInputEvent() and its helpers.
    */
   struct InputHandlingState {
+    // A reference to the event being handled.
+    InputData& mEvent;
+
     // The value that will be returned by ReceiveInputEvent().
     APZEventResult mResult;
 
@@ -691,6 +694,10 @@ class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
     // reused the result of a previous hit-test in the input block,
     // this is populated with the result of the hit test.
     HitTestResult mHit;
+
+    // Called at the end of ReceiveInputEvent() to perform any final
+    // computations, and then return mResult.
+    APZEventResult Finish() const;
   };
 
   void ProcessTouchInput(InputHandlingState& aState, MultiTouchInput& aInput);