/*
 * Copyright 2007 Stephen Liu
 * For license terms, see the file COPYING along with this library.
 */

#ifndef __spcache_hpp__
#define __spcache_hpp__

#include <time.h>

class SP_CacheHandler {
public:
	virtual ~SP_CacheHandler();

	virtual int compare( const void * item1, const void * item2 ) = 0;
	virtual void destroy( void * item ) = 0;
	virtual void onHit( const void * item, void * resultHolder ) = 0;
};

class SP_CacheStatistics {
public:
	virtual ~SP_CacheStatistics();

	virtual int getHits() const = 0;
	virtual int getAccesses() const = 0;
	virtual int getSize() const = 0;
};

class SP_Cache {
public:
	virtual ~SP_Cache();

	/**
	 * @param expTime : expiration time. If it's 0, the item never expires
	 *  (although it may be deleted from the cache to make place for other
	 *  items). If it's non-zero (either Unix time or offset in seconds from
	 *  current time), it is guaranteed that clients will not be able to
	 *  retrieve this item after the expiration time arrives (measured by
	 *  server time). 
	 *
	 * @return 0 : insert ok, 1 : update ok
	 */
	virtual int put( void * item, time_t expTime = 0 ) = 0;

	// @return 0 : no such key, 1 : found it
	virtual int get( const void * key, void * resultHolder ) = 0;

	// @return 0 : no such key, 1 : erase it
	virtual int erase( const void * key ) = 0;

	// @return NULL : no such key, NOT NULL : remove and return the item
	virtual void * remove( const void * key, time_t * expTime = 0 ) = 0;

	// caller need to delete the return object
	virtual SP_CacheStatistics * getStatistics() = 0;

	//===========================================================

	enum { eFIFO, eLRU };

	static SP_Cache * newInstance( int algo, int maxItems,
			SP_CacheHandler * handler, int threadSafe = 1 );
};

#endif