Source/WebCore/dom/NodeRareData.h - WebKit - Git at Google

 /*
  * Copyright (C) 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Smith <catfish.man@gmail.com>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */

 #ifndef NodeRareData_h
 #define NodeRareData_h

 #include "ChildNodeList.h"
 #include "ClassNodeList.h"
 #include "DOMSettableTokenList.h"
 #include "HTMLCollection.h"
 #include "HTMLNames.h"
 #include "LiveNodeList.h"
 #include "MutationObserver.h"
 #include "MutationObserverRegistration.h"
 #include "Page.h"
 #include "QualifiedName.h"
 #include "TagNodeList.h"
 #if ENABLE(VIDEO_TRACK)
 #include "TextTrack.h"
 #endif
 #include <wtf/HashSet.h>
 #include <wtf/OwnPtr.h>
 #include <wtf/PassOwnPtr.h>
 #include <wtf/text/AtomicString.h>
 #include <wtf/text/StringHash.h>

 namespace WebCore {

 class LabelsNodeList;
 class RadioNodeList;
 class TreeScope;

 class NodeListsNodeData {
     WTF_MAKE_NONCOPYABLE(NodeListsNodeData); WTF_MAKE_FAST_ALLOCATED;
 public:
     void clearChildNodeListCache()
     {
         if (m_childNodeList)
             m_childNodeList->invalidateCache();
     }

     PassRefPtr<ChildNodeList> ensureChildNodeList(ContainerNode& node)
     {
         ASSERT(!m_emptyChildNodeList);
         if (m_childNodeList)
             return m_childNodeList;
         RefPtr<ChildNodeList> list = ChildNodeList::create(node);
         m_childNodeList = list.get();
         return list.release();
     }

     void removeChildNodeList(ChildNodeList* list)
     {
         ASSERT(m_childNodeList == list);
         if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
             return;
         m_childNodeList = nullptr;
     }

     PassRefPtr<EmptyNodeList> ensureEmptyChildNodeList(Node& node)
     {
         ASSERT(!m_childNodeList);
         if (m_emptyChildNodeList)
             return m_emptyChildNodeList;
         RefPtr<EmptyNodeList> list = EmptyNodeList::create(node);
         m_emptyChildNodeList = list.get();
         return list.release();
     }

     void removeEmptyChildNodeList(EmptyNodeList* list)
     {
         ASSERT(m_emptyChildNodeList == list);
         if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
             return;
         m_emptyChildNodeList = nullptr;
     }

     template <typename StringType>
     struct NodeListCacheMapEntryHash {
         static unsigned hash(const std::pair<unsigned char, StringType>& entry)
         {
             return DefaultHash<StringType>::Hash::hash(entry.second) + entry.first;
         }
         static bool equal(const std::pair<unsigned char, StringType>& a, const std::pair<unsigned char, StringType>& b) { return a == b; }
         static const bool safeToCompareToEmptyOrDeleted = DefaultHash<StringType>::Hash::safeToCompareToEmptyOrDeleted;
     };

     typedef HashMap<std::pair<unsigned char, AtomicString>, LiveNodeList*, NodeListCacheMapEntryHash<AtomicString>> NodeListAtomicNameCacheMap;
     typedef HashMap<std::pair<unsigned char, String>, LiveNodeList*, NodeListCacheMapEntryHash<String>> NodeListNameCacheMap;
     typedef HashMap<std::pair<unsigned char, AtomicString>, HTMLCollection*, NodeListCacheMapEntryHash<AtomicString>> CollectionCacheMap;
     typedef HashMap<QualifiedName, TagNodeList*> TagNodeListCacheNS;

     template<typename T, typename ContainerType>
     PassRefPtr<T> addCacheWithAtomicName(ContainerType& container, LiveNodeList::Type type, const AtomicString& name)
     {
         NodeListAtomicNameCacheMap::AddResult result = m_atomicNameCaches.add(namedNodeListKey(type, name), nullptr);
         if (!result.isNewEntry)
             return static_cast<T*>(result.iterator->value);

         RefPtr<T> list = T::create(container, type, name);
         result.iterator->value = list.get();
         return list.release();
     }

     template<typename T>
     PassRefPtr<T> addCacheWithName(ContainerNode& node, LiveNodeList::Type type, const String& name)
     {
         NodeListNameCacheMap::AddResult result = m_nameCaches.add(namedNodeListKey(type, name), nullptr);
         if (!result.isNewEntry)
             return static_cast<T*>(result.iterator->value);

         RefPtr<T> list = T::create(node, name);
         result.iterator->value = list.get();
         return list.release();
     }

     PassRefPtr<TagNodeList> addCacheWithQualifiedName(ContainerNode& node, const AtomicString& namespaceURI, const AtomicString& localName)
     {
         QualifiedName name(nullAtom, localName, namespaceURI);
         TagNodeListCacheNS::AddResult result = m_tagNodeListCacheNS.add(name, nullptr);
         if (!result.isNewEntry)
             return result.iterator->value;

         RefPtr<TagNodeList> list = TagNodeList::create(node, namespaceURI, localName);
         result.iterator->value = list.get();
         return list.release();
     }

     template<typename T, typename ContainerType>
     PassRefPtr<T> addCachedCollection(ContainerType& container, CollectionType collectionType, const AtomicString& name)
     {
         CollectionCacheMap::AddResult result = m_cachedCollections.add(namedCollectionKey(collectionType, name), nullptr);
         if (!result.isNewEntry)
             return static_cast<T*>(result.iterator->value);

         RefPtr<T> list = T::create(container, collectionType, name);
         result.iterator->value = list.get();
         return list.release();
     }

     template<typename T, typename ContainerType>
     PassRefPtr<T> addCachedCollection(ContainerType& container, CollectionType collectionType)
     {
         CollectionCacheMap::AddResult result = m_cachedCollections.add(namedCollectionKey(collectionType, starAtom), nullptr);
         if (!result.isNewEntry)
             return static_cast<T*>(result.iterator->value);

         RefPtr<T> list = T::create(container, collectionType);
         result.iterator->value = list.get();
         return list.release();
     }

     template<typename T>
     T* cachedCollection(CollectionType collectionType)
     {
         return static_cast<T*>(m_cachedCollections.get(namedCollectionKey(collectionType, starAtom)));
     }

     void removeCacheWithAtomicName(LiveNodeList* list, const AtomicString& name = starAtom)
     {
         ASSERT(list == m_atomicNameCaches.get(namedNodeListKey(list->type(), name)));
         if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
             return;
         m_atomicNameCaches.remove(namedNodeListKey(list->type(), name));
     }

     void removeCacheWithName(LiveNodeList* list, const String& name)
     {
         ASSERT(list == m_nameCaches.get(namedNodeListKey(list->type(), name)));
         if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
             return;
         m_nameCaches.remove(namedNodeListKey(list->type(), name));
     }

     void removeCacheWithQualifiedName(LiveNodeList* list, const AtomicString& namespaceURI, const AtomicString& localName)
     {
         QualifiedName name(nullAtom, localName, namespaceURI);
         ASSERT(list == m_tagNodeListCacheNS.get(name));
         if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
             return;
         m_tagNodeListCacheNS.remove(name);
     }

     void removeCachedCollection(HTMLCollection* collection, const AtomicString& name = starAtom)
     {
         ASSERT(collection == m_cachedCollections.get(namedCollectionKey(collection->type(), name)));
         if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(collection->ownerNode()))
             return;
         m_cachedCollections.remove(namedCollectionKey(collection->type(), name));
     }

     static PassOwnPtr<NodeListsNodeData> create()
     {
         return adoptPtr(new NodeListsNodeData);
     }

     void invalidateCaches(const QualifiedName* attrName = 0);
     bool isEmpty() const
     {
         return m_atomicNameCaches.isEmpty() && m_nameCaches.isEmpty() && m_cachedCollections.isEmpty() && m_tagNodeListCacheNS.isEmpty();
     }

     void adoptTreeScope()
     {
         invalidateCaches();
     }

     void adoptDocument(Document* oldDocument, Document* newDocument)
     {
         invalidateCaches();

         if (oldDocument != newDocument) {
             for (auto it = m_atomicNameCaches.begin(), end = m_atomicNameCaches.end(); it != end; ++it) {
                 LiveNodeList& list = *it->value;
                 oldDocument->unregisterNodeList(list);
                 newDocument->registerNodeList(list);
             }

             for (auto it = m_nameCaches.begin(), end = m_nameCaches.end(); it != end; ++it) {
                 LiveNodeList& list = *it->value;
                 oldDocument->unregisterNodeList(list);
                 newDocument->registerNodeList(list);
             }

             for (auto it = m_tagNodeListCacheNS.begin(), end = m_tagNodeListCacheNS.end(); it != end; ++it) {
                 LiveNodeList& list = *it->value;
                 ASSERT(!list.isRootedAtDocument());
                 oldDocument->unregisterNodeList(list);
                 newDocument->registerNodeList(list);
             }

             for (auto it = m_cachedCollections.begin(), end = m_cachedCollections.end(); it != end; ++it) {
                 HTMLCollection& collection = *it->value;
                 oldDocument->unregisterCollection(collection);
                 newDocument->registerCollection(collection);
             }
         }
     }

 private:
     NodeListsNodeData()
         : m_childNodeList(nullptr)
         , m_emptyChildNodeList(nullptr)
     { }

     std::pair<unsigned char, AtomicString> namedCollectionKey(CollectionType type, const AtomicString& name)
     {
         return std::pair<unsigned char, AtomicString>(type, name);
     }

     std::pair<unsigned char, String> namedNodeListKey(LiveNodeList::Type type, const String& name)
     {
         return std::pair<unsigned char, String>(type, name);
     }

     bool deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node&);

     // These two are currently mutually exclusive and could be unioned. Not very important as this class is large anyway.
     ChildNodeList* m_childNodeList;
     EmptyNodeList* m_emptyChildNodeList;

     NodeListAtomicNameCacheMap m_atomicNameCaches;
     NodeListNameCacheMap m_nameCaches;
     TagNodeListCacheNS m_tagNodeListCacheNS;
     CollectionCacheMap m_cachedCollections;
 };

 class NodeMutationObserverData {
     WTF_MAKE_NONCOPYABLE(NodeMutationObserverData); WTF_MAKE_FAST_ALLOCATED;
 public:
     Vector<OwnPtr<MutationObserverRegistration>> registry;
     HashSet<MutationObserverRegistration*> transientRegistry;

     static PassOwnPtr<NodeMutationObserverData> create() { return adoptPtr(new NodeMutationObserverData); }

 private:
     NodeMutationObserverData() { }
 };

 class NodeRareData : public NodeRareDataBase {
     WTF_MAKE_NONCOPYABLE(NodeRareData); WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassOwnPtr<NodeRareData> create(RenderObject* renderer) { return adoptPtr(new NodeRareData(renderer)); }

     void clearNodeLists() { m_nodeLists.clear(); }
     NodeListsNodeData* nodeLists() const { return m_nodeLists.get(); }
     NodeListsNodeData& ensureNodeLists()
     {
         if (!m_nodeLists)
             m_nodeLists = NodeListsNodeData::create();
         return *m_nodeLists;
     }

     NodeMutationObserverData* mutationObserverData() { return m_mutationObserverData.get(); }
     NodeMutationObserverData& ensureMutationObserverData()
     {
         if (!m_mutationObserverData)
             m_mutationObserverData = NodeMutationObserverData::create();
         return *m_mutationObserverData;
     }

     unsigned connectedSubframeCount() const { return m_connectedFrameCount; }
     void incrementConnectedSubframeCount(unsigned amount)
     {
         m_connectedFrameCount += amount;
     }
     void decrementConnectedSubframeCount(unsigned amount)
     {
         ASSERT(m_connectedFrameCount);
         ASSERT(amount <= m_connectedFrameCount);
         m_connectedFrameCount -= amount;
     }

 protected:
     NodeRareData(RenderObject* renderer)
         : NodeRareDataBase(renderer)
         , m_connectedFrameCount(0)
     { }

 private:
     unsigned m_connectedFrameCount : 10; // Must fit Page::maxNumberOfFrames.

     OwnPtr<NodeListsNodeData> m_nodeLists;
     OwnPtr<NodeMutationObserverData> m_mutationObserverData;
 };

 inline bool NodeListsNodeData::deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node& ownerNode)
 {
     ASSERT(ownerNode.nodeLists() == this);
     if ((m_childNodeList ? 1 : 0) + (m_emptyChildNodeList ? 1 : 0) + m_atomicNameCaches.size() + m_nameCaches.size()
         + m_tagNodeListCacheNS.size() + m_cachedCollections.size() != 1)
         return false;
     ownerNode.clearNodeLists();
     return true;
 }

 // Ensure the 10 bits reserved for the m_connectedFrameCount cannot overflow
 COMPILE_ASSERT(Page::maxNumberOfFrames < 1024, Frame_limit_should_fit_in_rare_data_count);

 } // namespace WebCore

 #endif // NodeRareData_h
	/*
	* Copyright (C) 2008, 2010 Apple Inc. All rights reserved.
	* Copyright (C) 2008 David Smith <catfish.man@gmail.com>
	*
	* 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.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public License
	* along with this library; see the file COPYING.LIB. If not, write to
	* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*
	*/

	#ifndef NodeRareData_h
	#define NodeRareData_h

	#include "ChildNodeList.h"
	#include "ClassNodeList.h"
	#include "DOMSettableTokenList.h"
	#include "HTMLCollection.h"
	#include "HTMLNames.h"
	#include "LiveNodeList.h"
	#include "MutationObserver.h"
	#include "MutationObserverRegistration.h"
	#include "Page.h"
	#include "QualifiedName.h"
	#include "TagNodeList.h"
	#if ENABLE(VIDEO_TRACK)
	#include "TextTrack.h"
	#endif
	#include <wtf/HashSet.h>
	#include <wtf/OwnPtr.h>
	#include <wtf/PassOwnPtr.h>
	#include <wtf/text/AtomicString.h>
	#include <wtf/text/StringHash.h>

	namespace WebCore {

	class LabelsNodeList;
	class RadioNodeList;
	class TreeScope;

	class NodeListsNodeData {
	WTF_MAKE_NONCOPYABLE(NodeListsNodeData); WTF_MAKE_FAST_ALLOCATED;
	public:
	void clearChildNodeListCache()
	{
	if (m_childNodeList)
	m_childNodeList->invalidateCache();
	}

	PassRefPtr<ChildNodeList> ensureChildNodeList(ContainerNode& node)
	{
	ASSERT(!m_emptyChildNodeList);
	if (m_childNodeList)
	return m_childNodeList;
	RefPtr<ChildNodeList> list = ChildNodeList::create(node);
	m_childNodeList = list.get();
	return list.release();
	}

	void removeChildNodeList(ChildNodeList* list)
	{
	ASSERT(m_childNodeList == list);
	if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
	return;
	m_childNodeList = nullptr;
	}

	PassRefPtr<EmptyNodeList> ensureEmptyChildNodeList(Node& node)
	{
	ASSERT(!m_childNodeList);
	if (m_emptyChildNodeList)
	return m_emptyChildNodeList;
	RefPtr<EmptyNodeList> list = EmptyNodeList::create(node);
	m_emptyChildNodeList = list.get();
	return list.release();
	}

	void removeEmptyChildNodeList(EmptyNodeList* list)
	{
	ASSERT(m_emptyChildNodeList == list);
	if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
	return;
	m_emptyChildNodeList = nullptr;
	}

	template <typename StringType>
	struct NodeListCacheMapEntryHash {
	static unsigned hash(const std::pair<unsigned char, StringType>& entry)
	{
	return DefaultHash<StringType>::Hash::hash(entry.second) + entry.first;
	}
	static bool equal(const std::pair<unsigned char, StringType>& a, const std::pair<unsigned char, StringType>& b) { return a == b; }
	static const bool safeToCompareToEmptyOrDeleted = DefaultHash<StringType>::Hash::safeToCompareToEmptyOrDeleted;
	};

	typedef HashMap<std::pair<unsigned char, AtomicString>, LiveNodeList*, NodeListCacheMapEntryHash<AtomicString>> NodeListAtomicNameCacheMap;
	typedef HashMap<std::pair<unsigned char, String>, LiveNodeList*, NodeListCacheMapEntryHash<String>> NodeListNameCacheMap;
	typedef HashMap<std::pair<unsigned char, AtomicString>, HTMLCollection*, NodeListCacheMapEntryHash<AtomicString>> CollectionCacheMap;
	typedef HashMap<QualifiedName, TagNodeList*> TagNodeListCacheNS;

	template<typename T, typename ContainerType>
	PassRefPtr<T> addCacheWithAtomicName(ContainerType& container, LiveNodeList::Type type, const AtomicString& name)
	{
	NodeListAtomicNameCacheMap::AddResult result = m_atomicNameCaches.add(namedNodeListKey(type, name), nullptr);
	if (!result.isNewEntry)
	return static_cast<T*>(result.iterator->value);

	RefPtr<T> list = T::create(container, type, name);
	result.iterator->value = list.get();
	return list.release();
	}

	template<typename T>
	PassRefPtr<T> addCacheWithName(ContainerNode& node, LiveNodeList::Type type, const String& name)
	{
	NodeListNameCacheMap::AddResult result = m_nameCaches.add(namedNodeListKey(type, name), nullptr);
	if (!result.isNewEntry)
	return static_cast<T*>(result.iterator->value);

	RefPtr<T> list = T::create(node, name);
	result.iterator->value = list.get();
	return list.release();
	}

	PassRefPtr<TagNodeList> addCacheWithQualifiedName(ContainerNode& node, const AtomicString& namespaceURI, const AtomicString& localName)
	{
	QualifiedName name(nullAtom, localName, namespaceURI);
	TagNodeListCacheNS::AddResult result = m_tagNodeListCacheNS.add(name, nullptr);
	if (!result.isNewEntry)
	return result.iterator->value;

	RefPtr<TagNodeList> list = TagNodeList::create(node, namespaceURI, localName);
	result.iterator->value = list.get();
	return list.release();
	}

	template<typename T, typename ContainerType>
	PassRefPtr<T> addCachedCollection(ContainerType& container, CollectionType collectionType, const AtomicString& name)
	{
	CollectionCacheMap::AddResult result = m_cachedCollections.add(namedCollectionKey(collectionType, name), nullptr);
	if (!result.isNewEntry)
	return static_cast<T*>(result.iterator->value);

	RefPtr<T> list = T::create(container, collectionType, name);
	result.iterator->value = list.get();
	return list.release();
	}

	template<typename T, typename ContainerType>
	PassRefPtr<T> addCachedCollection(ContainerType& container, CollectionType collectionType)
	{
	CollectionCacheMap::AddResult result = m_cachedCollections.add(namedCollectionKey(collectionType, starAtom), nullptr);
	if (!result.isNewEntry)
	return static_cast<T*>(result.iterator->value);

	RefPtr<T> list = T::create(container, collectionType);
	result.iterator->value = list.get();
	return list.release();
	}

	template<typename T>
	T* cachedCollection(CollectionType collectionType)
	{
	return static_cast<T*>(m_cachedCollections.get(namedCollectionKey(collectionType, starAtom)));
	}

	void removeCacheWithAtomicName(LiveNodeList* list, const AtomicString& name = starAtom)
	{
	ASSERT(list == m_atomicNameCaches.get(namedNodeListKey(list->type(), name)));
	if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
	return;
	m_atomicNameCaches.remove(namedNodeListKey(list->type(), name));
	}

	void removeCacheWithName(LiveNodeList* list, const String& name)
	{
	ASSERT(list == m_nameCaches.get(namedNodeListKey(list->type(), name)));
	if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
	return;
	m_nameCaches.remove(namedNodeListKey(list->type(), name));
	}

	void removeCacheWithQualifiedName(LiveNodeList* list, const AtomicString& namespaceURI, const AtomicString& localName)
	{
	QualifiedName name(nullAtom, localName, namespaceURI);
	ASSERT(list == m_tagNodeListCacheNS.get(name));
	if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(list->ownerNode()))
	return;
	m_tagNodeListCacheNS.remove(name);
	}

	void removeCachedCollection(HTMLCollection* collection, const AtomicString& name = starAtom)
	{
	ASSERT(collection == m_cachedCollections.get(namedCollectionKey(collection->type(), name)));
	if (deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(collection->ownerNode()))
	return;
	m_cachedCollections.remove(namedCollectionKey(collection->type(), name));
	}

	static PassOwnPtr<NodeListsNodeData> create()
	{
	return adoptPtr(new NodeListsNodeData);
	}

	void invalidateCaches(const QualifiedName* attrName = 0);
	bool isEmpty() const
	{
	return m_atomicNameCaches.isEmpty() && m_nameCaches.isEmpty() && m_cachedCollections.isEmpty() && m_tagNodeListCacheNS.isEmpty();
	}

	void adoptTreeScope()
	{
	invalidateCaches();
	}

	void adoptDocument(Document* oldDocument, Document* newDocument)
	{
	invalidateCaches();

	if (oldDocument != newDocument) {
	for (auto it = m_atomicNameCaches.begin(), end = m_atomicNameCaches.end(); it != end; ++it) {
	LiveNodeList& list = *it->value;
	oldDocument->unregisterNodeList(list);
	newDocument->registerNodeList(list);
	}

	for (auto it = m_nameCaches.begin(), end = m_nameCaches.end(); it != end; ++it) {
	LiveNodeList& list = *it->value;
	oldDocument->unregisterNodeList(list);
	newDocument->registerNodeList(list);
	}

	for (auto it = m_tagNodeListCacheNS.begin(), end = m_tagNodeListCacheNS.end(); it != end; ++it) {
	LiveNodeList& list = *it->value;
	ASSERT(!list.isRootedAtDocument());
	oldDocument->unregisterNodeList(list);
	newDocument->registerNodeList(list);
	}

	for (auto it = m_cachedCollections.begin(), end = m_cachedCollections.end(); it != end; ++it) {
	HTMLCollection& collection = *it->value;
	oldDocument->unregisterCollection(collection);
	newDocument->registerCollection(collection);
	}
	}
	}

	private:
	NodeListsNodeData()
	: m_childNodeList(nullptr)
	, m_emptyChildNodeList(nullptr)
	{ }

	std::pair<unsigned char, AtomicString> namedCollectionKey(CollectionType type, const AtomicString& name)
	{
	return std::pair<unsigned char, AtomicString>(type, name);
	}

	std::pair<unsigned char, String> namedNodeListKey(LiveNodeList::Type type, const String& name)
	{
	return std::pair<unsigned char, String>(type, name);
	}

	bool deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node&);

	// These two are currently mutually exclusive and could be unioned. Not very important as this class is large anyway.
	ChildNodeList* m_childNodeList;
	EmptyNodeList* m_emptyChildNodeList;

	NodeListAtomicNameCacheMap m_atomicNameCaches;
	NodeListNameCacheMap m_nameCaches;
	TagNodeListCacheNS m_tagNodeListCacheNS;
	CollectionCacheMap m_cachedCollections;
	};

	class NodeMutationObserverData {
	WTF_MAKE_NONCOPYABLE(NodeMutationObserverData); WTF_MAKE_FAST_ALLOCATED;
	public:
	Vector<OwnPtr<MutationObserverRegistration>> registry;
	HashSet<MutationObserverRegistration*> transientRegistry;

	static PassOwnPtr<NodeMutationObserverData> create() { return adoptPtr(new NodeMutationObserverData); }

	private:
	NodeMutationObserverData() { }
	};

	class NodeRareData : public NodeRareDataBase {
	WTF_MAKE_NONCOPYABLE(NodeRareData); WTF_MAKE_FAST_ALLOCATED;
	public:
	static PassOwnPtr<NodeRareData> create(RenderObject* renderer) { return adoptPtr(new NodeRareData(renderer)); }

	void clearNodeLists() { m_nodeLists.clear(); }
	NodeListsNodeData* nodeLists() const { return m_nodeLists.get(); }
	NodeListsNodeData& ensureNodeLists()
	{
	if (!m_nodeLists)
	m_nodeLists = NodeListsNodeData::create();
	return *m_nodeLists;
	}

	NodeMutationObserverData* mutationObserverData() { return m_mutationObserverData.get(); }
	NodeMutationObserverData& ensureMutationObserverData()
	{
	if (!m_mutationObserverData)
	m_mutationObserverData = NodeMutationObserverData::create();
	return *m_mutationObserverData;
	}

	unsigned connectedSubframeCount() const { return m_connectedFrameCount; }
	void incrementConnectedSubframeCount(unsigned amount)
	{
	m_connectedFrameCount += amount;
	}
	void decrementConnectedSubframeCount(unsigned amount)
	{
	ASSERT(m_connectedFrameCount);
	ASSERT(amount <= m_connectedFrameCount);
	m_connectedFrameCount -= amount;
	}

	protected:
	NodeRareData(RenderObject* renderer)
	: NodeRareDataBase(renderer)
	, m_connectedFrameCount(0)
	{ }

	private:
	unsigned m_connectedFrameCount : 10; // Must fit Page::maxNumberOfFrames.

	OwnPtr<NodeListsNodeData> m_nodeLists;
	OwnPtr<NodeMutationObserverData> m_mutationObserverData;
	};

	inline bool NodeListsNodeData::deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node& ownerNode)
	{
	ASSERT(ownerNode.nodeLists() == this);
	if ((m_childNodeList ? 1 : 0) + (m_emptyChildNodeList ? 1 : 0) + m_atomicNameCaches.size() + m_nameCaches.size()
	+ m_tagNodeListCacheNS.size() + m_cachedCollections.size() != 1)
	return false;
	ownerNode.clearNodeLists();
	return true;
	}

	// Ensure the 10 bits reserved for the m_connectedFrameCount cannot overflow
	COMPILE_ASSERT(Page::maxNumberOfFrames < 1024, Frame_limit_should_fit_in_rare_data_count);

	} // namespace WebCore

	#endif // NodeRareData_h