| /* |
| * 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. |
| */ |
| |
| #include "config.h" |
| #include "core/css/SelectorFilter.h" |
| |
| #include "core/css/CSSSelector.h" |
| #include "core/dom/Element.h" |
| |
| namespace WebCore { |
| |
| // Salt to separate otherwise identical string hashes so a class-selector like .article won't match <article> elements. |
| enum { TagNameSalt = 13, IdAttributeSalt = 17, ClassAttributeSalt = 19 }; |
| |
| static inline void collectElementIdentifierHashes(const Element* element, Vector<unsigned, 4>& identifierHashes) |
| { |
| identifierHashes.append(element->localName().impl()->existingHash() * TagNameSalt); |
| if (element->hasID()) |
| identifierHashes.append(element->idForStyleResolution().impl()->existingHash() * IdAttributeSalt); |
| if (element->isStyledElement() && element->hasClass()) { |
| const SpaceSplitString& classNames = element->classNames(); |
| size_t count = classNames.size(); |
| for (size_t i = 0; i < count; ++i) |
| identifierHashes.append(classNames[i].impl()->existingHash() * ClassAttributeSalt); |
| } |
| } |
| |
| void SelectorFilter::pushParentStackFrame(Element* parent) |
| { |
| ASSERT(m_ancestorIdentifierFilter); |
| ASSERT(m_parentStack.isEmpty() || m_parentStack.last().element == parent->parentOrShadowHostElement()); |
| ASSERT(!m_parentStack.isEmpty() || !parent->parentOrShadowHostElement()); |
| m_parentStack.append(ParentStackFrame(parent)); |
| ParentStackFrame& parentFrame = m_parentStack.last(); |
| // Mix tags, class names and ids into some sort of weird bouillabaisse. |
| // The filter is used for fast rejection of child and descendant selectors. |
| collectElementIdentifierHashes(parent, parentFrame.identifierHashes); |
| size_t count = parentFrame.identifierHashes.size(); |
| for (size_t i = 0; i < count; ++i) |
| m_ancestorIdentifierFilter->add(parentFrame.identifierHashes[i]); |
| } |
| |
| void SelectorFilter::popParentStackFrame() |
| { |
| ASSERT(!m_parentStack.isEmpty()); |
| ASSERT(m_ancestorIdentifierFilter); |
| const ParentStackFrame& parentFrame = m_parentStack.last(); |
| size_t count = parentFrame.identifierHashes.size(); |
| for (size_t i = 0; i < count; ++i) |
| m_ancestorIdentifierFilter->remove(parentFrame.identifierHashes[i]); |
| m_parentStack.removeLast(); |
| if (m_parentStack.isEmpty()) { |
| ASSERT(m_ancestorIdentifierFilter->likelyEmpty()); |
| m_ancestorIdentifierFilter.clear(); |
| } |
| } |
| |
| void SelectorFilter::setupParentStack(Element* parent) |
| { |
| ASSERT(m_parentStack.isEmpty() == !m_ancestorIdentifierFilter); |
| // Kill whatever we stored before. |
| m_parentStack.shrink(0); |
| m_ancestorIdentifierFilter = adoptPtr(new BloomFilter<bloomFilterKeyBits>); |
| // Fast version if parent is a root element: |
| if (!parent->parentOrShadowHostNode()) { |
| pushParentStackFrame(parent); |
| return; |
| } |
| // Otherwise climb up the tree. |
| Vector<Element*, 30> ancestors; |
| for (Element* ancestor = parent; ancestor; ancestor = ancestor->parentOrShadowHostElement()) |
| ancestors.append(ancestor); |
| for (size_t n = ancestors.size(); n; --n) |
| pushParentStackFrame(ancestors[n - 1]); |
| } |
| |
| void SelectorFilter::pushParent(Element* parent) |
| { |
| ASSERT(m_ancestorIdentifierFilter); |
| // We may get invoked for some random elements in some wacky cases during style resolve. |
| // Pause maintaining the stack in this case. |
| if (m_parentStack.last().element != parent->parentOrShadowHostElement()) |
| return; |
| pushParentStackFrame(parent); |
| } |
| |
| static inline void collectDescendantSelectorIdentifierHashes(const CSSSelector* selector, unsigned*& hash) |
| { |
| switch (selector->m_match) { |
| case CSSSelector::Id: |
| if (!selector->value().isEmpty()) |
| (*hash++) = selector->value().impl()->existingHash() * IdAttributeSalt; |
| break; |
| case CSSSelector::Class: |
| if (!selector->value().isEmpty()) |
| (*hash++) = selector->value().impl()->existingHash() * ClassAttributeSalt; |
| break; |
| case CSSSelector::Tag: |
| if (selector->tagQName().localName() != starAtom) |
| (*hash++) = selector->tagQName().localName().impl()->existingHash() * TagNameSalt; |
| break; |
| default: |
| break; |
| } |
| } |
| |
| void SelectorFilter::collectIdentifierHashes(const CSSSelector* selector, unsigned* identifierHashes, unsigned maximumIdentifierCount) |
| { |
| unsigned* hash = identifierHashes; |
| unsigned* end = identifierHashes + maximumIdentifierCount; |
| CSSSelector::Relation relation = selector->relation(); |
| bool relationIsAffectedByPseudoContent = selector->relationIsAffectedByPseudoContent(); |
| |
| // Skip the topmost selector. It is handled quickly by the rule hashes. |
| bool skipOverSubselectors = true; |
| for (selector = selector->tagHistory(); selector; selector = selector->tagHistory()) { |
| // Only collect identifiers that match ancestors. |
| switch (relation) { |
| case CSSSelector::SubSelector: |
| if (!skipOverSubselectors) |
| collectDescendantSelectorIdentifierHashes(selector, hash); |
| break; |
| case CSSSelector::DirectAdjacent: |
| case CSSSelector::IndirectAdjacent: |
| case CSSSelector::ShadowPseudo: |
| case CSSSelector::ChildTree: |
| case CSSSelector::DescendantTree: |
| skipOverSubselectors = true; |
| break; |
| case CSSSelector::Descendant: |
| case CSSSelector::Child: |
| if (relationIsAffectedByPseudoContent) { |
| skipOverSubselectors = true; |
| break; |
| } |
| skipOverSubselectors = false; |
| collectDescendantSelectorIdentifierHashes(selector, hash); |
| break; |
| } |
| if (hash == end) |
| return; |
| relation = selector->relation(); |
| relationIsAffectedByPseudoContent = selector->relationIsAffectedByPseudoContent(); |
| } |
| *hash = 0; |
| } |
| |
| } |