--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/history/PageCache.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2007 Apple Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef PageCache_h
+#define PageCache_h
+
+#include "HistoryItem.h"
+#include "Timer.h"
+#include <wtf/Forward.h>
+#include <wtf/HashSet.h>
+#include <wtf/Noncopyable.h>
+
+namespace WebCore {
+
+    class CachedPage;
+    class Frame;
+    class HistoryItem;
+    class Page;
+    
+    class PageCache : public Noncopyable {
+    public:
+        friend PageCache* pageCache();
+        
+        static bool canCache(Page*);
+
+        void setCapacity(int); // number of pages to cache
+        int capacity() { return m_capacity; }
+        
+        void add(PassRefPtr<HistoryItem>, Page*); // Prunes if capacity() is exceeded.
+        void remove(HistoryItem*);
+        CachedPage* get(HistoryItem* item);
+
+        void releaseAutoreleasedPagesNow();
+        
+        int pageCount() const { return m_size; }
+        int frameCount() const;
+        int autoreleasedPageCount() const;
+
+    private:
+        typedef HashSet<RefPtr<CachedPage> > CachedPageSet;
+
+        PageCache(); // Use pageCache() instead.
+        ~PageCache(); // Not implemented to make sure nobody accidentally calls delete -- WebCore does not delete singletons.
+        
+        static bool canCachePageContainingThisFrame(Frame*);
+
+        void addToLRUList(HistoryItem*); // Adds to the head of the list.
+        void removeFromLRUList(HistoryItem*);
+
+        void prune();
+
+        void autorelease(PassRefPtr<CachedPage>);
+        void releaseAutoreleasedPagesNowOrReschedule(Timer<PageCache>*);
+
+        int m_capacity;
+        int m_size;
+
+        // LRU List
+        HistoryItem* m_head;
+        HistoryItem* m_tail;
+        
+        Timer<PageCache> m_autoreleaseTimer;
+        CachedPageSet m_autoreleaseSet;
+     };
+
+    // Function to obtain the global page cache.
+    PageCache* pageCache();
+
+} // namespace WebCore
+
+#endif // PageCache_h