/*
 * 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 "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 {
	WTF_MAKE_NONCOPYABLE(PageCache); WTF_MAKE_FAST_ALLOCATED;
public:
	friend PageCache* pageCache();

	bool canCache(Page*) const;

	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);

	int pageCount() const { return m_size; }
	int frameCount() const;

	void markPagesForVistedLinkStyleRecalc();

	// Will mark all cached pages associated with the given page as needing style recalc.
	void markPagesForFullStyleRecalc(Page*);

#if ENABLE(VIDEO_TRACK)
	void markPagesForCaptionPreferencesChanged();
#endif

private:
	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();

	int m_capacity;
	int m_size;

	// LRU List
	HistoryItem* m_head;
	HistoryItem* m_tail;
 };

// Function to obtain the global page cache.
PageCache* pageCache();

} // namespace WebCore

#endif // PageCache_h
