/*
* 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.
*/
#ifndef SelectorFilter_h
#define SelectorFilter_h
#include "core/dom/Element.h"
#include "wtf/BloomFilter.h"
#include "wtf/Vector.h"
namespace WebCore {
class CSSSelector;
class SelectorFilter {
public:
void pushParentStackFrame(Element& parent);
void popParentStackFrame();
void setupParentStack(Element& parent);
void pushParent(Element& parent);
void popParent() { popParentStackFrame(); }
bool parentStackIsEmpty() const { return m_parentStack.isEmpty(); }
bool parentStackIsConsistent(const ContainerNode* parentNode) const { return !m_parentStack.isEmpty() && m_parentStack.last().element == parentNode; }
template <unsigned maximumIdentifierCount>
inline bool fastRejectSelector(const unsigned* identifierHashes) const;
static void collectIdentifierHashes(const CSSSelector&, unsigned* identifierHashes, unsigned maximumIdentifierCount);
private:
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;
OwnPtr<BloomFilter<bloomFilterKeyBits> > m_ancestorIdentifierFilter;
};
template <unsigned maximumIdentifierCount>
inline bool SelectorFilter::fastRejectSelector(const unsigned* identifierHashes) const
{
ASSERT(m_ancestorIdentifierFilter);
for (unsigned n = 0; n < maximumIdentifierCount && identifierHashes[n]; ++n) {
if (!m_ancestorIdentifierFilter->mayContain(identifierHashes[n]))
return true;
}
return false;
}
}
#endif