PageCache.h revision 2daae5fd11344eaa88a0d92b0f6d65f8d2255c00 
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 "HistoryItem.h"
30#include "Timer.h"
31#include <wtf/Forward.h>
32#include <wtf/HashSet.h>
33#include <wtf/Noncopyable.h>
34
35namespace WebCore {
36
37    class CachedPage;
38    class Frame;
39    class HistoryItem;
40    class Page;
41
42    class PageCache {
43        WTF_MAKE_NONCOPYABLE(PageCache); WTF_MAKE_FAST_ALLOCATED;
44    public:
45        friend PageCache* pageCache();
46
47        static bool canCache(Page*);
48
49        void setCapacity(int); // number of pages to cache
50        int capacity() { return m_capacity; }
51
52        void add(PassRefPtr<HistoryItem>, Page*); // Prunes if capacity() is exceeded.
53        void remove(HistoryItem*);
54        CachedPage* get(HistoryItem* item);
55
56        void releaseAutoreleasedPagesNow();
57
58        int pageCount() const { return m_size; }
59        int frameCount() const;
60        int autoreleasedPageCount() const;
61
62        void markPagesForVistedLinkStyleRecalc();
63
64    private:
65        typedef HashSet<RefPtr<CachedPage> > CachedPageSet;
66
67        PageCache(); // Use pageCache() instead.
68        ~PageCache(); // Not implemented to make sure nobody accidentally calls delete -- WebCore does not delete singletons.
69
70        static bool canCachePageContainingThisFrame(Frame*);
71
72        void addToLRUList(HistoryItem*); // Adds to the head of the list.
73        void removeFromLRUList(HistoryItem*);
74
75        void prune();
76
77        void autorelease(PassRefPtr<CachedPage>);
78        void releaseAutoreleasedPagesNowOrReschedule(Timer<PageCache>*);
79
80        int m_capacity;
81        int m_size;
82
83        // LRU List
84        HistoryItem* m_head;
85        HistoryItem* m_tail;
86
87        Timer<PageCache> m_autoreleaseTimer;
88        CachedPageSet m_autoreleaseSet;
89     };
90
91    // Function to obtain the global page cache.
92    PageCache* pageCache();
93
94} // namespace WebCore
95
96#endif // PageCache_h
97