Schedule sibling invalidation sets for sibling insert/remove.

third_party/WebKit/Source/core/dom/ContainerNode.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 570 matching lines @@
         {
             EventDispatchForbiddenScope assertNoEventDispatch;
             ScriptForbiddenScope forbidScript;
 
             while (Node* child = m_firstChild) {
                 removeBetween(0, child->nextSibling(), *child);
                 notifyNodeRemoved(*child);
             }
         }
 
-        ChildrenChange change = {AllChildrenRemoved, nullptr, nullptr, ChildrenChangeSourceAPI};
+        ChildrenChange change = {AllChildrenRemoved, nullptr, nullptr, nullptr, ChildrenChangeSourceAPI};
         childrenChanged(change);
     }
 
     if (action == DispatchSubtreeModifiedEvent)
         dispatchSubtreeModifiedEvent();
 }
 
 Node* ContainerNode::appendChild(Node* newChild, ExceptionState& exceptionState)
 {
 
@@ skipping 607 matching lines @@
             if (element->shouldCallRecalcStyle(change))
                 element->recalcStyle(change, lastTextNode);
             else if (element->supportsStyleSharing())
                 styleResolver.addToStyleSharingList(*element);
             if (element->layoutObject())
                 lastTextNode = nullptr;
         }
     }
 }
 
-void ContainerNode::checkForSiblingStyleChanges(SiblingCheckType changeType, Node* nodeBeforeChange, Node* nodeAfterChange)
+void ContainerNode::checkForSiblingStyleChanges(SiblingCheckType changeType, Node* changedNode, Node* nodeBeforeChange, Node* nodeAfterChange)
 {
     if (!inActiveDocument() || document().hasPendingForcedStyleRecalc() || getStyleChangeType() >= SubtreeStyleChange)
         return;
 
     // Forward positional selectors include nth-child, nth-of-type, first-of-type and only-of-type.
     // The indirect adjacent selector is the ~ selector.
     // Backward positional selectors include nth-last-child, nth-last-of-type, last-of-type and only-of-type.
     // We have to invalidate everything following the insertion point in the forward and indirect adjacent case,
     // and everything before the insertion point in the backward case.
     // |afterChange| is 0 in the parser callback case, so we won't do any work for the forward case if we don't have to.
     // For performance reasons we just mark the parent node as changed, since we don't want to make childrenChanged O(n^2) by crawling all our kids
     // here. recalcStyle will then force a walk of the children when it sees that this has happened.
-    if (((childrenAffectedByForwardPositionalRules() || childrenAffectedByIndirectAdjacentRules()) && nodeAfterChange)
+    if ((childrenAffectedByForwardPositionalRules() && nodeAfterChange)
         || (childrenAffectedByBackwardPositionalRules() && nodeBeforeChange)) {
         setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::SiblingSelector));

[esprehn, 2016/06/29 04:52:08]

We need to figure out how to kill all of these SubtreeStyleChanges in here.

[rune, 2016/06/29 07:44:21]

crbug.com/624277

         return;
     }
 
     // :first-child. In the parser callback case, we don't have to check anything, since we were right the first time.
     // In the DOM case, we only need to do something if |afterChange| is not 0.
     // |afterChange| is 0 in the parser case, so it works out that we'll skip this block.
     if (childrenAffectedByFirstChildRules() && nodeAfterChange) {
         DCHECK_NE(changeType, FinishedParsingChildren);
         // Find our new first child element.
         Element* firstChildElement = ElementTraversal::firstChild(*this);
 
         // Find the first element after the change.
         Element* elementAfterChange = nodeAfterChange->isElementNode() ? toElement(nodeAfterChange) : ElementTraversal::nextSibling(*nodeAfterChange);
 
         // This is the element insertion as first child element case.
         if (changeType == SiblingElementInserted && elementAfterChange && firstChildElement != elementAfterChange
             && (!nodeBeforeChange || !nodeBeforeChange->isElementNode()) && elementAfterChange->affectedByFirstChildRules()) {
             elementAfterChange->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::SiblingSelector));

[esprehn, 2016/06/29 04:52:08]

ex. we should use invalidation sets for the :first-child etc. cases here too.

[rune, 2016/06/29 07:44:21]

Acknowledged.

         }
 
         // This is the first child element removal case.
         if (changeType == SiblingElementRemoved && firstChildElement == elementAfterChange && firstChildElement && firstChildElement->affectedByFirstChildRules())
             firstChildElement->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::SiblingSelector));
     }
 
     // :last-child. In the parser callback case, we don't have to check anything, since we were right the first time.
     // In the DOM case, we only need to do something if |afterChange| is not 0.
     if (childrenAffectedByLastChildRules() && nodeBeforeChange) {
         // Find our new last child element.
         Element* lastChildElement = ElementTraversal::lastChild(*this);
 
         // Find the last element before the change.
         Element* elementBeforeChange = nodeBeforeChange->isElementNode() ? toElement(nodeBeforeChange) : ElementTraversal::previousSibling(*nodeBeforeChange);
 
         // This is the element insertion as last child element case.
         if (changeType == SiblingElementInserted && elementBeforeChange && lastChildElement != elementBeforeChange
             && (!nodeAfterChange || !nodeAfterChange->isElementNode()) && elementBeforeChange->affectedByLastChildRules()) {
             elementBeforeChange->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::SiblingSelector));
         }
 
         // This is the last child element removal case. The parser callback case is similar to node removal as well in that we need to change the last child
         // to match now.
         if ((changeType == SiblingElementRemoved || changeType == FinishedParsingChildren) && lastChildElement == elementBeforeChange && lastChildElement && lastChildElement->affectedByLastChildRules())
             lastChildElement->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::SiblingSelector));
     }
 
-    // The + selector. We need to invalidate the first element following the change. It is the only possible element
-    // that could be affected by this DOM change.
-    if (childrenAffectedByDirectAdjacentRules() && nodeAfterChange) {
-        Element* elementAfterChange = nodeAfterChange->isElementNode() ? toElement(nodeAfterChange) : ElementTraversal::nextSibling(*nodeAfterChange);
-        for (unsigned i = document().styleEngine().maxDirectAdjacentSelectors(); i && elementAfterChange; --i, elementAfterChange = ElementTraversal::nextSibling(*elementAfterChange))
-            elementAfterChange->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::SiblingSelector));
-    }
+    // For ~ and + combinators, succeeding siblings may need style invalidation
+    // after an element is inserted or removed.
+
+    if (!nodeAfterChange)
+        return;
+    if (changeType != SiblingElementRemoved && changeType != SiblingElementInserted)
+        return;
+    if (!childrenAffectedByIndirectAdjacentRules() && !childrenAffectedByDirectAdjacentRules())
+        return;
+
+    Element* elementAfterChange = nodeAfterChange->isElementNode() ? toElement(nodeAfterChange) : ElementTraversal::nextSibling(*nodeAfterChange);
+    if (!elementAfterChange)
+        return;
+    Element* elementBeforeChange = nullptr;
+    if (nodeBeforeChange)
+        elementBeforeChange = nodeBeforeChange->isElementNode() ? toElement(nodeBeforeChange) : ElementTraversal::previousSibling(*nodeBeforeChange);
+
+    if (changeType == SiblingElementInserted)
+        document().styleEngine().scheduleInvalidationsForInsertedSibling(elementBeforeChange, *toElement(changedNode));
+    else
+        document().styleEngine().scheduleInvalidationsForRemovedSibling(elementBeforeChange, *toElement(changedNode), *elementAfterChange);
 }
 
 void ContainerNode::invalidateNodeListCachesInAncestors(const QualifiedName* attrName, Element* attributeOwnerElement)
 {
     if (hasRareData() && (!attrName || isAttributeNode())) {
         if (NodeListsNodeData* lists = rareData()->nodeLists()) {
             if (ChildNodeList* childNodeList = lists->childNodeList(*this))
                 childNodeList->invalidateCache();
         }
     }
@@ skipping 87 matching lines @@
         return true;
 
     if (node->isElementNode() && toElement(node)->shadow())
         return true;
 
     return false;
 }
 #endif
 
 } // namespace blink