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