Fixed mouseenter/mouseleave event firing order.

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 3100 matching lines @@
     // mousemove events before the first layout should not lead to a premature layout()
     // happening, which could show a flash of white.
     // See also the similar code in EventHandler::hitTestResultAtPoint.
     if (!layoutView() || !view() || !view()->didFirstLayout())
         return MouseEventWithHitTestResults(event, HitTestResult(LayoutPoint()));
 
     HitTestResult result(documentPoint);
     layoutView()->hitTest(request, result);
 
     if (!request.readOnly())
-        updateHoverActiveState(request, result.innerElement(), &event);
+        updateHoverActiveState(request, result.innerElement());
 
     return MouseEventWithHitTestResults(event, result);
 }
 
 // DOM Section 1.1.1
 bool Document::childTypeAllowed(NodeType type) const
 {
     switch (type) {
     case ATTRIBUTE_NODE:
     case CDATA_SECTION_NODE:
@@ skipping 2100 matching lines @@
     for (LayoutObject* currObj1 = obj1; currObj1; currObj1 = currObj1->hoverAncestor()) {
         for (LayoutObject* currObj2 = obj2; currObj2; currObj2 = currObj2->hoverAncestor()) {
             if (currObj1 == currObj2)
                 return currObj1;
         }
     }
 
     return 0;
 }
 
-void Document::updateHoverActiveState(const HitTestRequest& request, Element* innerElement, const PlatformMouseEvent* event)
+void Document::updateHoverActiveState(const HitTestRequest& request, Element* innerElement)
 {
     ASSERT(!request.readOnly());
 
     if (request.active() && m_frame)
         m_frame->eventHandler().notifyElementActivated();
 
     Element* innerElementInDocument = innerElement;
     while (innerElementInDocument && innerElementInDocument->document() != this) {
-        innerElementInDocument->document().updateHoverActiveState(request, innerElementInDocument, event);
+        innerElementInDocument->document().updateHoverActiveState(request, innerElementInDocument);
         innerElementInDocument = innerElementInDocument->document().ownerElement();
     }
 
     Element* oldActiveElement = activeHoverElement();
     if (oldActiveElement && !request.active()) {
         // The oldActiveElement renderer is null, dropped on :active by setting display: none,
         // for instance. We still need to clear the ActiveChain as the mouse is released.
         for (Node* node = oldActiveElement; node; node = NodeRenderingTraversal::parent(*node)) {
             ASSERT(!node->isTextNode());
             node->setActive(false);
@@ skipping 53 matching lines @@
                     nodesToRemoveFromChain.append(node);
             }
 
         }
 
         // The old hover path only needs to be cleared up to (and not including) the common ancestor;
         for (LayoutObject* curr = oldHoverObj; curr && curr != ancestor; curr = curr->hoverAncestor()) {
             if (curr->node() && !curr->isText() && (!mustBeInActiveChain || curr->node()->inActiveChain()))
                 nodesToRemoveFromChain.append(curr->node());
         }
+
+        // FIXME: It seems the two loops above can push a single node twice into nodesToRemoveFromChain. There must be a better way.

[Mike West, 2015/03/31 11:45:33]

Nit: Blink is now writing these as "// TODO(mustaq)".

[mustaq, 2015/03/31 14:08:31]

Done.

     }
 
     // Now set the hover state for our new object up to the root.
     for (LayoutObject* curr = newHoverObj; curr; curr = curr->hoverAncestor()) {
         if (curr->node() && !curr->isText() && (!mustBeInActiveChain || curr->node()->inActiveChain()))
             nodesToAddToChain.append(curr->node());
     }
 
-    // mouseenter and mouseleave events do not bubble, so they are dispatched iff there is a capturing
-    // event handler on an ancestor or a normal event handler on the element itself. This special
-    // handling is necessary to avoid O(n^2) capturing event handler checks. We'll check the previously
-    // hovered node's ancestor tree for 'mouseleave' handlers here, then check the newly hovered node's
-    // ancestor tree for 'mouseenter' handlers after dispatching the 'mouseleave' events (as the handler
-    // for 'mouseleave' might set a capturing 'mouseenter' handler, odd as that might be).
-    bool ancestorHasCapturingMouseleaveListener = false;
-    if (event && newHoverNode != oldHoverNode.get()) {
-        for (Node* node = oldHoverNode.get(); node; node = node->parentOrShadowHostNode()) {
-            if (node->hasCapturingEventListeners(EventTypeNames::mouseleave)) {
-                ancestorHasCapturingMouseleaveListener = true;
-                break;
-            }
-        }
-    }
-
     size_t removeCount = nodesToRemoveFromChain.size();
     for (size_t i = 0; i < removeCount; ++i) {
         nodesToRemoveFromChain[i]->setHovered(false);
-        if (event && (ancestorHasCapturingMouseleaveListener || nodesToRemoveFromChain[i]->hasEventListeners(EventTypeNames::mouseleave)))
-            nodesToRemoveFromChain[i]->dispatchMouseEvent(*event, EventTypeNames::mouseleave, 0, newHoverNode);
-    }
-
-    bool ancestorHasCapturingMouseenterListener = false;
-    if (event && newHoverNode != oldHoverNode.get()) {
-        for (Node* node = newHoverNode; node; node = node->parentOrShadowHostNode()) {
-            if (node->hasCapturingEventListeners(EventTypeNames::mouseenter)) {
-                ancestorHasCapturingMouseenterListener = true;
-                break;
-            }
-        }
     }
 
     bool sawCommonAncestor = false;
     size_t addCount = nodesToAddToChain.size();
     for (size_t i = 0; i < addCount; ++i) {
         // Elements past the common ancestor do not change hover state, but might change active state.
         if (ancestorNode && nodesToAddToChain[i] == ancestorNode)
             sawCommonAncestor = true;
         if (allowActiveChanges)
             nodesToAddToChain[i]->setActive(true);
         if (!sawCommonAncestor) {
             nodesToAddToChain[i]->setHovered(true);
-            if (event && (ancestorHasCapturingMouseenterListener || nodesToAddToChain[i]->hasEventListeners(EventTypeNames::mouseenter)))
-                nodesToAddToChain[i]->dispatchMouseEvent(*event, EventTypeNames::mouseenter, 0, oldHoverNode.get());
         }
     }
 }
 
 bool Document::haveStylesheetsLoaded() const
 {
     return m_styleEngine->haveStylesheetsLoaded();
 }
 
 Locale& Document::getCachedLocale(const AtomicString& locale)
@@ skipping 368 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     WeakDocumentSet& set = liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif