Enumerate the return value of dispatchEvent so it is clear.

third_party/WebKit/Source/core/input/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 349 matching lines @@
     // is most significant. The enumeration is ordered with smaller specified
     // numbers first. Examples of merged results are:
     // (HandledApplication, HandledSystem) -> HandledSystem
     // (NotHandled, HandledApplication) -> HandledApplication
     static_assert(static_cast<int>(WebInputEventResult::NotHandled) == 0, "WebInputEventResult not ordered");
     static_assert(static_cast<int>(WebInputEventResult::HandledSuppressed) < static_cast<int>(WebInputEventResult::HandledApplication), "WebInputEventResult not ordered");
     static_assert(static_cast<int>(WebInputEventResult::HandledApplication) < static_cast<int>(WebInputEventResult::HandledSystem), "WebInputEventResult not ordered");
     return static_cast<WebInputEventResult>(max(static_cast<int>(resultA), static_cast<int>(resultB)));
 }
 
-WebInputEventResult EventHandler::eventToEventResult(
-    PassRefPtrWillBeRawPtr<Event> event, bool result)
+WebInputEventResult EventHandler::toWebInputEventResultWithStrictAsserts(
+    DispatchEventResult result)
 {
-    if (event->defaultPrevented())
+    switch (result) {
+    case DispatchEventResult::NotCanceled:
+        return WebInputEventResult::NotHandled;
+    case DispatchEventResult::CanceledByEventHandler:
         return WebInputEventResult::HandledApplication;
-    if (event->defaultHandled())
+    case DispatchEventResult::CanceledByDefaultEventHandler:
+        ASSERT_NOT_REACHED();
         return WebInputEventResult::HandledSystem;
+    case DispatchEventResult::CanceledBeforeDispatch:
+        ASSERT_NOT_REACHED();
+        return WebInputEventResult::HandledSuppressed;
+    }
+}
 
-    // TODO(dtapuska): There are cases in the code where dispatchEvent
-    // returns false (indicated handled) but event is not marked
-    // as default handled or default prevented. crbug.com/560355
-    if (!result)
+WebInputEventResult EventHandler::toWebInputEventResult(
+    DispatchEventResult result)
+{
+    switch (result) {
+    case DispatchEventResult::NotCanceled:
+        return WebInputEventResult::NotHandled;
+    case DispatchEventResult::CanceledByEventHandler:
+        return WebInputEventResult::HandledApplication;
+    case DispatchEventResult::CanceledByDefaultEventHandler:
+        return WebInputEventResult::HandledSystem;
+    case DispatchEventResult::CanceledBeforeDispatch:
         return WebInputEventResult::HandledSuppressed;
-    return WebInputEventResult::NotHandled;
+    }
 }
 
 void EventHandler::nodeWillBeRemoved(Node& nodeToBeRemoved)
 {
     if (nodeToBeRemoved.containsIncludingShadowDOM(m_clickNode.get())) {
         // We don't dispatch click events if the mousedown node is removed
         // before a mouseup event. It is compatible with IE and Firefox.
         m_clickNode = nullptr;
     }
 }
@@ skipping 947 matching lines @@
         // Both m_clickNode and mev.innerNode() don't need to be updated
         // because commonAncestor() will exit early if their documents are different.
         m_clickNode->updateDistribution();
         if (Node* clickTargetNode = mev.innerNode()->commonAncestor(
             *m_clickNode, parentForClickEvent)) {
 
             // Dispatch mouseup directly w/o calling updateMouseEventTargetNode
             // because the mouseup dispatch above has already updated it
             // correctly. Moreover, clickTargetNode is different from
             // mev.innerNode at drag-release.
-            if (clickTargetNode->dispatchMouseEvent(mouseEvent,
-                EventTypeNames::click, m_clickCount)) {
-                clickEventResult = WebInputEventResult::HandledApplication;
-            }
+            clickEventResult = toWebInputEventResult(clickTargetNode->dispatchMouseEvent(mouseEvent,
+                EventTypeNames::click, m_clickCount));
         }
     }
 
     if (m_resizeScrollableArea) {
         m_resizeScrollableArea->setInResizeMode(false);
         m_resizeScrollableArea = nullptr;
     }
 
     if (eventResult == WebInputEventResult::NotHandled)
         eventResult = handleMouseReleaseEvent(mev);
@@ skipping 11 matching lines @@
     if (!view)
         return WebInputEventResult::NotHandled;
 
     RefPtrWillBeRawPtr<DragEvent> me = DragEvent::create(eventType,
         true, true, m_frame->document()->domWindow(),
         0, event.globalPosition().x(), event.globalPosition().y(), event.position().x(), event.position().y(),
         event.movementDelta().x(), event.movementDelta().y(),
         event.modifiers(),
         0, MouseEvent::platformModifiersToButtons(event.modifiers()), nullptr, event.timestamp(), dataTransfer, event.syntheticEventType());
 
-    bool dispatchResult = dragTarget->dispatchEvent(me.get());
-    return eventToEventResult(me, dispatchResult);
+    return toWebInputEventResult(dragTarget->dispatchEvent(me.get()));
 }
 
 static bool targetIsFrame(Node* target, LocalFrame*& frame)
 {
     if (!isHTMLFrameElementBase(target))
         return false;
 
     // Cross-process drag and drop is not yet supported.
     if (toHTMLFrameElementBase(target)->contentFrame() && !toHTMLFrameElementBase(target)->contentFrame()->isLocalFrame())
         return false;
@@ skipping 216 matching lines @@
         m_nodeUnderMouse, mouseEvent, m_frame->document()->domWindow());
 }
 
 WebInputEventResult EventHandler::dispatchMouseEvent(const AtomicString& eventType, Node* targetNode, int clickCount, const PlatformMouseEvent& mouseEvent)
 {
     updateMouseEventTargetNode(targetNode, mouseEvent);
     if (!m_nodeUnderMouse)
         return WebInputEventResult::NotHandled;
 
     RefPtrWillBeRawPtr<MouseEvent> event = MouseEvent::create(eventType, m_nodeUnderMouse->document().domWindow(), mouseEvent, clickCount, nullptr);
-    bool dispatchResult = m_nodeUnderMouse->dispatchEvent(event);
-    return eventToEventResult(event, dispatchResult);
+    return toWebInputEventResult(m_nodeUnderMouse->dispatchEvent(event));
 }
 
 // TODO(mustaq): Make PE drive ME dispatch & bookkeeping in EventHandler.
 WebInputEventResult EventHandler::updatePointerTargetAndDispatchEvents(const AtomicString& mouseEventType, Node* targetNode, int clickCount, const PlatformMouseEvent& mouseEvent)
 {
     ASSERT(mouseEventType == EventTypeNames::mousedown
         || mouseEventType == EventTypeNames::mousemove
         || mouseEventType == EventTypeNames::mouseup);
 
     updateMouseEventTargetNode(targetNode, mouseEvent);
     if (!m_nodeUnderMouse)
         return WebInputEventResult::NotHandled;
 
-    WebInputEventResult result = m_pointerEventManager.sendMousePointerEvent(
+    return m_pointerEventManager.sendMousePointerEvent(
         m_nodeUnderMouse, mouseEventType, clickCount, mouseEvent, nullptr,
         m_frame->document()->domWindow());
-
-    return result;
 }
 
 WebInputEventResult EventHandler::handleMouseFocus(const MouseEventWithHitTestResults& targetedEvent, InputDeviceCapabilities* sourceCapabilities)
 {
     // If clicking on a frame scrollbar, do not mess up with content focus.
     if (targetedEvent.hitTestResult().scrollbar() && m_frame->contentLayoutObject()) {
         if (targetedEvent.hitTestResult().scrollbar()->scrollableArea() == m_frame->contentLayoutObject()->scrollableArea())
             return WebInputEventResult::NotHandled;
     }
 
@@ skipping 147 matching lines @@
             if (Widget* widget = toLayoutPart(target)->widget()) {
                 WebInputEventResult result = passWheelEventToWidget(event, *widget);
                 if (result != WebInputEventResult::NotHandled) {
                     setFrameWasScrolledByUser();
                     return result;
                 }
             }
         }
 
         RefPtrWillBeRawPtr<Event> domEvent = WheelEvent::create(event, node->document().domWindow());
-        if (!node->dispatchEvent(domEvent)) {
+        DispatchEventResult domEventResult = node->dispatchEvent(domEvent);
+        if (domEventResult != DispatchEventResult::NotCanceled) {
             setFrameWasScrolledByUser();
-            return eventToEventResult(domEvent, false);
+            return toWebInputEventResult(domEventResult);
         }
     }
 
     // We do another check on the frame view because the event handler can run
     // JS which results in the frame getting destroyed.
     view = m_frame->view();
     if (!view)
         return WebInputEventResult::NotHandled;
 
     // Wheel events which do not scroll are used to trigger zooming.
@@ skipping 109 matching lines @@
     if (scrollbar) {
         bool eventSwallowed = scrollbar->gestureEvent(gestureEvent);
         if (gestureEvent.type() == PlatformEvent::GestureTapDown && eventSwallowed)
             m_scrollbarHandlingScrollGesture = scrollbar;
         if (eventSwallowed)
             return WebInputEventResult::HandledSuppressed;
     }
 
     if (eventTarget) {
         RefPtrWillBeRawPtr<GestureEvent> gestureDomEvent = GestureEvent::create(eventTarget->document().domWindow(), gestureEvent);
-        // TODO(dtapuska): dispatchEvent is inverted for Gesture Events
-        // crbug.com/560357
-        if (gestureDomEvent.get() && eventTarget->dispatchEvent(gestureDomEvent))
-            return eventToEventResult(gestureDomEvent, false);
+        if (gestureDomEvent.get()) {
+            DispatchEventResult gestureDomEventResult = eventTarget->dispatchEvent(gestureDomEvent);
+            if (gestureDomEventResult != DispatchEventResult::NotCanceled)
+                return toWebInputEventResultWithStrictAsserts(gestureDomEventResult);
+        }
     }
 
     switch (gestureEvent.type()) {
     case PlatformEvent::GestureTap:
         return handleGestureTap(targetedEvent);
     case PlatformEvent::GestureShowPress:
         return handleGestureShowPress();
     case PlatformEvent::GestureLongPress:
         return handleGestureLongPress(targetedEvent);
     case PlatformEvent::GestureLongTap:
@@ skipping 55 matching lines @@
         }
         if (eventSwallowed)
             return WebInputEventResult::HandledSuppressed;
     }
 
     if (eventTarget) {
         if (handleScrollGestureOnResizer(eventTarget.get(), gestureEvent))
             return WebInputEventResult::HandledSuppressed;
 
         RefPtrWillBeRawPtr<GestureEvent> gestureDomEvent = GestureEvent::create(eventTarget->document().domWindow(), gestureEvent);
-        // TODO(dtapuska): dispatchEvent is inverted for Gesture Events
-        // crbug.com/560357
-        if (gestureDomEvent.get() && eventTarget->dispatchEvent(gestureDomEvent))
-            return eventToEventResult(gestureDomEvent, false);
+        if (gestureDomEvent.get()) {
+            DispatchEventResult gestureDomEventResult = eventTarget->dispatchEvent(gestureDomEvent);
+            if (gestureDomEventResult != DispatchEventResult::NotCanceled)
+                return toWebInputEventResultWithStrictAsserts(gestureDomEventResult);
+        }
     }
 
     switch (gestureEvent.type()) {
     case PlatformEvent::GestureScrollBegin:
         return handleGestureScrollBegin(gestureEvent);
     case PlatformEvent::GestureScrollUpdate:
         return handleGestureScrollUpdate(gestureEvent);
     case PlatformEvent::GestureScrollEnd:
         return handleGestureScrollEnd(gestureEvent);
     case PlatformEvent::GestureFlingStart:
@@ skipping 1051 matching lines @@
     // On Windows, WebKit explicitly calls handleAccessKey() instead of dispatching a keypress event for WM_SYSCHAR messages.
     // Other platforms currently match either Mac or Windows behavior, depending on whether they send combined KeyDown events.
     bool matchedAnAccessKey = false;
     if (initialKeyEvent.type() == PlatformEvent::KeyDown)
         matchedAnAccessKey = handleAccessKey(initialKeyEvent);
 
     // FIXME: it would be fair to let an input method handle KeyUp events before DOM dispatch.
     if (initialKeyEvent.type() == PlatformEvent::KeyUp || initialKeyEvent.type() == PlatformEvent::Char) {
         RefPtrWillBeRawPtr<KeyboardEvent> domEvent = KeyboardEvent::create(initialKeyEvent, m_frame->document()->domWindow());
 
-        bool dispatchResult = node->dispatchEvent(domEvent);
-        return eventToEventResult(domEvent, dispatchResult);
+        return toWebInputEventResult(node->dispatchEvent(domEvent));
     }
 
     PlatformKeyboardEvent keyDownEvent = initialKeyEvent;
     if (keyDownEvent.type() != PlatformEvent::RawKeyDown)
         keyDownEvent.disambiguateKeyDownEvent(PlatformEvent::RawKeyDown);
     RefPtrWillBeRawPtr<KeyboardEvent> keydown = KeyboardEvent::create(keyDownEvent, m_frame->document()->domWindow());
     if (matchedAnAccessKey)
         keydown->setDefaultPrevented(true);
     keydown->setTarget(node);
 
-    if (initialKeyEvent.type() == PlatformEvent::RawKeyDown) {
-        if (!node->dispatchEvent(keydown))
-            return eventToEventResult(keydown, false);
-        // If frame changed as a result of keydown dispatch, then return true to avoid sending a subsequent keypress message to the new frame.
-        bool changedFocusedFrame = m_frame->page() && m_frame != m_frame->page()->focusController().focusedOrMainFrame();
-        if (changedFocusedFrame)
-            return WebInputEventResult::HandledSystem;
-        return WebInputEventResult::NotHandled;
-    }
-
-    if (!node->dispatchEvent(keydown))
-        return eventToEventResult(keydown, false);
+    DispatchEventResult dispatchResult = node->dispatchEvent(keydown);
+    if (dispatchResult != DispatchEventResult::NotCanceled)
+        return toWebInputEventResult(dispatchResult);
     // If frame changed as a result of keydown dispatch, then return early to avoid sending a subsequent keypress message to the new frame.
     bool changedFocusedFrame = m_frame->page() && m_frame != m_frame->page()->focusController().focusedOrMainFrame();
     if (changedFocusedFrame)
         return WebInputEventResult::HandledSystem;
 
+    if (initialKeyEvent.type() == PlatformEvent::RawKeyDown)
+        return WebInputEventResult::NotHandled;
+
     // Focus may have changed during keydown handling, so refetch node.
     // But if we are dispatching a fake backward compatibility keypress, then we pretend that the keypress happened on the original node.
     node = eventTargetNodeForDocument(m_frame->document());
     if (!node)
         return WebInputEventResult::NotHandled;
 
     PlatformKeyboardEvent keyPressEvent = initialKeyEvent;
     keyPressEvent.disambiguateKeyDownEvent(PlatformEvent::Char);
     if (keyPressEvent.text().isEmpty())
         return WebInputEventResult::NotHandled;
     RefPtrWillBeRawPtr<KeyboardEvent> keypress = KeyboardEvent::create(keyPressEvent, m_frame->document()->domWindow());
     keypress->setTarget(node);
-    bool dispatchResult = node->dispatchEvent(keypress);
-    return eventToEventResult(keypress, dispatchResult);
+    return toWebInputEventResult(node->dispatchEvent(keypress));
 }
 
 static WebFocusType focusDirectionForKey(const AtomicString& keyIdentifier)
 {
     DEFINE_STATIC_LOCAL(AtomicString, Down, ("Down", AtomicString::ConstructFromLiteral));
     DEFINE_STATIC_LOCAL(AtomicString, Up, ("Up", AtomicString::ConstructFromLiteral));
     DEFINE_STATIC_LOCAL(AtomicString, Left, ("Left", AtomicString::ConstructFromLiteral));
     DEFINE_STATIC_LOCAL(AtomicString, Right, ("Right", AtomicString::ConstructFromLiteral));
 
     WebFocusType retVal = WebFocusTypeNone;
@@ skipping 553 matching lines @@
             continue;
 
         const AtomicString& eventName(touchEventNameForTouchPointState(static_cast<PlatformTouchPoint::State>(state)));
         for (const auto& eventTarget : changedTouches[state].m_targets) {
             EventTarget* touchEventTarget = eventTarget.get();
             RefPtrWillBeRawPtr<TouchEvent> touchEvent = TouchEvent::create(
                 touches.get(), touchesByTarget.get(touchEventTarget), changedTouches[state].m_touches.get(),
                 eventName, touchEventTarget->toNode()->document().domWindow(),
                 event.modifiers(), event.cancelable(), event.causesScrollingIfUncanceled(), event.timestamp());
 
-            bool dispatchResult = touchEventTarget->dispatchEvent(touchEvent.get());
-            eventResult = mergeEventResult(eventResult, eventToEventResult(touchEvent, dispatchResult));
+            eventResult = mergeEventResult(eventResult, toWebInputEventResult(touchEventTarget->dispatchEvent(touchEvent.get())));
         }
     }
 
     return eventResult;
 }
 
 WebInputEventResult EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
 {
     TRACE_EVENT0("blink", "EventHandler::handleTouchEvent");
 
@@ skipping 251 matching lines @@
 PlatformEvent::Modifiers EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return static_cast<PlatformEvent::Modifiers>(PlatformEvent::CtrlKey | PlatformEvent::AltKey);
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink