WebCore/PageCache.h

   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
  35 namespace WebCore {
  36
  37     class CachedPage;
  38     class HistoryItem;
  39
  40     class PageCache : Noncopyable {
  41     public:
  42         friend PageCache* pageCache();
  43
  44         void setCapacity(int); // number of pages to cache
  45         int capacity() { return m_capacity; }
  46
  47         void add(PassRefPtr<HistoryItem>, PassRefPtr<CachedPage>); // Prunes if capacity() is exceeded.
  48         void remove(HistoryItem*);
  49         CachedPage* get(HistoryItem* item) { return item ? item->m_cachedPage.get() : 0; }
  50
  51         void releaseAutoreleasedPagesNow();
  52
  53     private:
  54         typedef HashSet<RefPtr<CachedPage> > CachedPageSet;
  55
  56         PageCache(); // Use pageCache() instead.
  57         ~PageCache(); // Not implemented to make sure nobody accidentally calls delete -- WebCore does not delete singletons.
  58
  59         void addToLRUList(HistoryItem*); // Adds to the head of the list.
  60         void removeFromLRUList(HistoryItem*);
  61
  62         void prune();
  63
  64         void autorelease(PassRefPtr<CachedPage>);
  65         void releaseAutoreleasedPagesNowOrReschedule(Timer<PageCache>*);
  66
  67         int m_capacity;
  68         int m_size;
  69
  70         // LRU List
  71         HistoryItem* m_head;
  72         HistoryItem* m_tail;
  73
  74         Timer<PageCache> m_autoreleaseTimer;
  75         CachedPageSet m_autoreleaseSet;
  76      };
  77
  78     // Function to obtain the global page cache.
  79     PageCache* pageCache();
  80
  81 } // namespace WebCore
  82
  83 #endif // PageCache_h