1/*
2 * Copyright (C) 2007 Apple Inc.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef PageCache_h
27#define PageCache_h
28
29#include "Timer.h"
30#include <wtf/Forward.h>
31#include <wtf/HashSet.h>
32#include <wtf/Noncopyable.h>
33
34namespace WebCore {
35
36    class CachedPage;
37    class Frame;
38    class HistoryItem;
39    class Page;
40
41    class PageCache {
42        WTF_MAKE_NONCOPYABLE(PageCache); WTF_MAKE_FAST_ALLOCATED;
43    public:
44        friend PageCache* pageCache();
45
46        bool canCache(Page*) const;
47
48        void setCapacity(int); // number of pages to cache
49        int capacity() { return m_capacity; }
50
51        void add(PassRefPtr<HistoryItem>, Page*); // Prunes if capacity() is exceeded.
52        void remove(HistoryItem*);
53        CachedPage* get(HistoryItem* item);
54
55        int pageCount() const { return m_size; }
56        int frameCount() const;
57
58        void markPagesForVistedLinkStyleRecalc();
59
60        // Will mark all cached pages associated with the given page as needing style recalc.
61        void markPagesForFullStyleRecalc(Page*);
62
63#if ENABLE(VIDEO_TRACK)
64        void markPagesForCaptionPreferencesChanged();
65#endif
66
67#if USE(ACCELERATED_COMPOSITING)
68        bool shouldClearBackingStores() const { return m_shouldClearBackingStores; }
69        void setShouldClearBackingStores(bool flag) { m_shouldClearBackingStores = flag; }
70        void markPagesForDeviceScaleChanged(Page*);
71#endif
72
73    private:
74        PageCache(); // Use pageCache() instead.
75        ~PageCache(); // Not implemented to make sure nobody accidentally calls delete -- WebCore does not delete singletons.
76
77        static bool canCachePageContainingThisFrame(Frame*);
78
79        void addToLRUList(HistoryItem*); // Adds to the head of the list.
80        void removeFromLRUList(HistoryItem*);
81
82        void prune();
83
84        int m_capacity;
85        int m_size;
86
87        // LRU List
88        HistoryItem* m_head;
89        HistoryItem* m_tail;
90
91#if USE(ACCELERATED_COMPOSITING)
92        bool m_shouldClearBackingStores;
93#endif
94     };
95
96    // Function to obtain the global page cache.
97    PageCache* pageCache();
98
99} // namespace WebCore
100
101#endif // PageCache_h
102