1/*
2 * Copyright (C) 2013 Google, Inc.
3 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
4 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public License
17 * along with this library; see the file COPYING.LIB.  If not, write to
18 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21
22#ifndef SharedStyleFinder_h
23#define SharedStyleFinder_h
24
25#include "core/css/resolver/ElementResolveContext.h"
26#include "core/dom/Element.h"
27
28namespace blink {
29
30class Element;
31class RenderStyle;
32class RuleFeatureSet;
33class RuleSet;
34class SpaceSplitString;
35class StyleResolver;
36
37class SharedStyleFinder {
38    STACK_ALLOCATED();
39public:
40    // RuleSets are passed non-const as the act of matching against them can cause them
41    // to be compacted. :(
42    SharedStyleFinder(const ElementResolveContext& context,
43        const RuleFeatureSet& features, RuleSet* siblingRuleSet,
44        RuleSet* uncommonAttributeRuleSet, StyleResolver& styleResolver)
45        : m_elementAffectedByClassRules(false)
46        , m_features(features)
47        , m_siblingRuleSet(siblingRuleSet)
48        , m_uncommonAttributeRuleSet(uncommonAttributeRuleSet)
49        , m_styleResolver(styleResolver)
50        , m_context(context)
51    { }
52
53    RenderStyle* findSharedStyle();
54
55private:
56    Element* findElementForStyleSharing() const;
57
58    // Only used when we're collecting stats on styles.
59    bool documentContainsValidCandidate() const;
60
61    bool classNamesAffectedByRules(const SpaceSplitString&) const;
62
63    bool canShareStyleWithElement(Element& candidate) const;
64    bool canShareStyleWithControl(Element& candidate) const;
65    bool sharingCandidateHasIdenticalStyleAffectingAttributes(Element& candidate) const;
66    bool sharingCandidateCanShareHostStyles(Element& candidate) const;
67    bool sharingCandidateDistributedToSameInsertionPoint(Element& candidate) const;
68    bool matchesRuleSet(RuleSet*);
69
70    Element& element() const { return *m_context.element(); }
71    Document& document() const { return element().document(); }
72
73    bool m_elementAffectedByClassRules;
74    const RuleFeatureSet& m_features;
75    RawPtrWillBeMember<RuleSet> m_siblingRuleSet;
76    RawPtrWillBeMember<RuleSet> m_uncommonAttributeRuleSet;
77    StyleResolver& m_styleResolver;
78    const ElementResolveContext& m_context;
79};
80
81} // namespace blink
82
83#endif // SharedStyleFinder_h
84