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 Frame;

    39     class HistoryItem;

    40     class Page;

    41     

    42     class PageCache : public Noncopyable {

    43     public:

    44         friend PageCache* pageCache();

    45         

    46         static bool canCache(Page*);

    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         void releaseAutoreleasedPagesNow();

    56         

    57         int pageCount() const { return m_size; }

    58         int frameCount() const;

    59         int autoreleasedPageCount() const;

    60 

    61     private:

    62         typedef HashSet<RefPtr<CachedPage> > CachedPageSet;

    63 

    64         PageCache(); // Use pageCache() instead.

    65         ~PageCache(); // Not implemented to make sure nobody accidentally calls delete -- WebCore does not delete singletons.

    66         

    67         static bool canCachePageContainingThisFrame(Frame*);

    68 

    69         void addToLRUList(HistoryItem*); // Adds to the head of the list.

    70         void removeFromLRUList(HistoryItem*);

    71 

    72         void prune();

    73 

    74         void autorelease(PassRefPtr<CachedPage>);

    75         void releaseAutoreleasedPagesNowOrReschedule(Timer<PageCache>*);

    76 

    77         int m_capacity;

    78         int m_size;

    79 

    80         // LRU List

    81         HistoryItem* m_head;

    82         HistoryItem* m_tail;

    83         

    84         Timer<PageCache> m_autoreleaseTimer;

    85         CachedPageSet m_autoreleaseSet;

    86      };

    87 

    88     // Function to obtain the global page cache.

    89     PageCache* pageCache();

    90 

    91 } // namespace WebCore

    92 

    93 #endif // PageCache_h