100 lines
3.1 KiB
C++
100 lines
3.1 KiB
C++
/*
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* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
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* (C) 1999 Antti Koivisto (koivisto@kde.org)
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* (C) 2001 Dirk Mueller (mueller@kde.org)
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* Copyright (C) 2004-2017 Apple Inc. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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*/
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#pragma once
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#include "CollectionIndexCache.h"
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#include "NodeList.h"
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#include <wtf/IsoMalloc.h>
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#include <wtf/Ref.h>
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namespace WebCore {
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class ContainerNode;
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class EmptyNodeList final : public NodeList {
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WTF_MAKE_ISO_ALLOCATED(EmptyNodeList);
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public:
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static Ref<EmptyNodeList> create(Node& owner)
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{
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return adoptRef(*new EmptyNodeList(owner));
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}
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virtual ~EmptyNodeList();
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Node& ownerNode() { return m_owner; }
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private:
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explicit EmptyNodeList(Node& owner) : m_owner(owner) { }
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unsigned length() const override { return 0; }
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Node* item(unsigned) const override { return nullptr; }
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size_t memoryCost() const override { return 0; }
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bool isEmptyNodeList() const override { return true; }
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Ref<Node> m_owner;
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};
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class ChildNodeList final : public NodeList {
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WTF_MAKE_ISO_ALLOCATED(ChildNodeList);
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public:
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static Ref<ChildNodeList> create(ContainerNode& parent)
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{
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return adoptRef(*new ChildNodeList(parent));
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}
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virtual ~ChildNodeList();
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ContainerNode& ownerNode() { return m_parent; }
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void invalidateCache();
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// For CollectionIndexCache
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Node* collectionBegin() const;
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Node* collectionLast() const;
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void collectionTraverseForward(Node*&, unsigned count, unsigned& traversedCount) const;
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void collectionTraverseBackward(Node*&, unsigned count) const;
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bool collectionCanTraverseBackward() const { return true; }
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void willValidateIndexCache() const { }
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private:
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explicit ChildNodeList(ContainerNode& parent);
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unsigned length() const override;
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Node* item(unsigned index) const override;
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size_t memoryCost() const override
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{
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// memoryCost() may be invoked concurrently from a GC thread, and we need to be careful
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// about what data we access here and how. Accessing m_indexCache is safe because
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// because it doesn't involve any pointer chasing.
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return m_indexCache.memoryCost();
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}
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bool isChildNodeList() const override { return true; }
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Ref<ContainerNode> m_parent;
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mutable CollectionIndexCache<ChildNodeList, Node*> m_indexCache;
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};
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} // namespace WebCore
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