1/*
2 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
3 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
4 * Copyright (C) 2013 Google 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
23#ifndef MatchedPropertiesCache_h
24#define MatchedPropertiesCache_h
25
26#include "core/css/StylePropertySet.h"
27#include "core/css/resolver/MatchResult.h"
28#include "platform/Timer.h"
29#include "platform/heap/Handle.h"
30#include "wtf/Forward.h"
31#include "wtf/HashMap.h"
32#include "wtf/Noncopyable.h"
33
34namespace blink {
35
36class RenderStyle;
37class StyleResolverState;
38
39class CachedMatchedProperties FINAL : public NoBaseWillBeGarbageCollectedFinalized<CachedMatchedProperties> {
40
41public:
42    WillBeHeapVector<MatchedProperties> matchedProperties;
43    MatchRanges ranges;
44    RefPtr<RenderStyle> renderStyle;
45    RefPtr<RenderStyle> parentRenderStyle;
46
47    void set(const RenderStyle*, const RenderStyle* parentStyle, const MatchResult&);
48    void clear();
49    void trace(Visitor* visitor) { visitor->trace(matchedProperties); }
50};
51
52// Specialize the HashTraits for CachedMatchedProperties to check for dead
53// entries in the MatchedPropertiesCache.
54#if ENABLE(OILPAN)
55struct CachedMatchedPropertiesHashTraits : HashTraits<Member<CachedMatchedProperties> > {
56    static const WTF::WeakHandlingFlag weakHandlingFlag = WTF::WeakHandlingInCollections;
57    static bool traceInCollection(Visitor*, Member<CachedMatchedProperties>&, WTF::ShouldWeakPointersBeMarkedStrongly);
58};
59#endif
60
61class MatchedPropertiesCache {
62    DISALLOW_ALLOCATION();
63    WTF_MAKE_NONCOPYABLE(MatchedPropertiesCache);
64public:
65    MatchedPropertiesCache();
66
67    const CachedMatchedProperties* find(unsigned hash, const StyleResolverState&, const MatchResult&);
68    void add(const RenderStyle*, const RenderStyle* parentStyle, unsigned hash, const MatchResult&);
69
70    void clear();
71    void clearViewportDependent();
72
73    static bool isCacheable(const Element*, const RenderStyle*, const RenderStyle* parentStyle);
74
75    void trace(Visitor*);
76
77private:
78#if ENABLE(OILPAN)
79    typedef HeapHashMap<unsigned, Member<CachedMatchedProperties>, DefaultHash<unsigned>::Hash, HashTraits<unsigned>, CachedMatchedPropertiesHashTraits > Cache;
80#else
81    // Every N additions to the matched declaration cache trigger a sweep where entries holding
82    // the last reference to a style declaration are garbage collected.
83    void sweep(Timer<MatchedPropertiesCache>*);
84
85    unsigned m_additionsSinceLastSweep;
86
87    typedef HashMap<unsigned, OwnPtr<CachedMatchedProperties> > Cache;
88    Timer<MatchedPropertiesCache> m_sweepTimer;
89#endif
90    Cache m_cache;
91};
92
93}
94
95#endif
96