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/resolver/MatchResult.h"
27
28#include "core/platform/Timer.h"
29#include "wtf/Forward.h"
30#include "wtf/HashMap.h"
31#include "wtf/Noncopyable.h"
32
33namespace WebCore {
34
35class RenderStyle;
36class StyleResolverState;
37
38struct CachedMatchedProperties {
39    Vector<MatchedProperties> matchedProperties;
40    MatchRanges ranges;
41    RefPtr<RenderStyle> renderStyle;
42    RefPtr<RenderStyle> parentRenderStyle;
43};
44
45class MatchedPropertiesCache {
46    WTF_MAKE_NONCOPYABLE(MatchedPropertiesCache);
47public:
48    MatchedPropertiesCache();
49
50    const CachedMatchedProperties* find(unsigned hash, const StyleResolverState&, const MatchResult&);
51    void add(const RenderStyle*, const RenderStyle* parentStyle, unsigned hash, const MatchResult&);
52
53    void clear();
54
55    static bool isCacheable(const Element*, const RenderStyle*, const RenderStyle* parentStyle);
56
57private:
58    // Every N additions to the matched declaration cache trigger a sweep where entries holding
59    // the last reference to a style declaration are garbage collected.
60    void sweep(Timer<MatchedPropertiesCache>*);
61
62    unsigned m_additionsSinceLastSweep;
63
64    typedef HashMap<unsigned, CachedMatchedProperties> Cache;
65    Cache m_cache;
66
67    Timer<MatchedPropertiesCache> m_sweepTimer;
68};
69
70}
71
72#endif
73