81 lines
2.9 KiB
C++
81 lines
2.9 KiB
C++
/*
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* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
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* (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
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* Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
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* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
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* Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
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* Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
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* Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
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* Copyright (c) 2011, Code Aurora Forum. All rights reserved.
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* Copyright (C) Research In Motion Limited 2011. All rights reserved.
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* Copyright (C) 2012 Google 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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#pragma once
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#include "Element.h"
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#include <memory>
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#include <wtf/BloomFilter.h>
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#include <wtf/Vector.h>
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namespace WebCore {
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class CSSSelector;
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class SelectorFilter {
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public:
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void pushParent(Element* parent);
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void pushParentInitializingIfNeeded(Element& parent);
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void popParent();
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void popParentsUntil(Element* parent);
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bool parentStackIsEmpty() const { return m_parentStack.isEmpty(); }
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bool parentStackIsConsistent(const ContainerNode* parentNode) const;
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using Hashes = std::array<unsigned, 4>;
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bool fastRejectSelector(const Hashes&) const;
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static Hashes collectHashes(const CSSSelector&);
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private:
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void initializeParentStack(Element& parent);
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struct ParentStackFrame {
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ParentStackFrame() : element(0) { }
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ParentStackFrame(Element* element) : element(element) { }
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Element* element;
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Vector<unsigned, 4> identifierHashes;
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};
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Vector<ParentStackFrame> m_parentStack;
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// With 100 unique strings in the filter, 2^12 slot table has false positive rate of ~0.2%.
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static const unsigned bloomFilterKeyBits = 12;
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CountingBloomFilter<bloomFilterKeyBits> m_ancestorIdentifierFilter;
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};
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inline bool SelectorFilter::fastRejectSelector(const Hashes& hashes) const
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{
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for (auto& hash : hashes) {
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if (!hash)
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return false;
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if (!m_ancestorIdentifierFilter.mayContain(hash))
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return true;
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}
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return false;
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}
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} // namespace WebCore
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