// Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// f32\sfat32\inc\sl_dir_cache.h

// 

//

/**

 @file

 @internalTechnology

*/

#ifndef SL_DIR_CACHE_H

#define SL_DIR_CACHE_H

#include "sf_memory_man.h"

#include "sf_memory_client.h"

#include "sl_cache.h"

#include <e32hashtab.h>

//---------------------------------------------------------------------------------------------------------------------------------

class 	CDynamicDirCache;

/**

The dynamic directory cache page class

*/

class TDynamicDirCachePage

    {

public:

	enum TPageType

		{

		EUnknown,

		ELocked,

		EUnlocked,

		};

public:

	~TDynamicDirCachePage();

	static TDynamicDirCachePage* NewL(CDynamicDirCache* aOwnerCache, TInt64 aStartMedPos, TUint8* aStartRamAddr);

	inline void	SetLocked(TBool);

	inline TBool	IsLocked() const;

	inline TUint8*	StartPtr()	const;

	inline void 	SetStartPtr(TUint8* aPtr);

	inline void	SetValid(TBool aIsValid);

	inline TBool	IsValid()	const;

	inline void	SetPageType(TPageType aType);

	inline TPageType PageType();

	inline TUint32	PageSizeInBytes() const;

    inline TUint32	PageSizeInSegs() const;

    inline void	SetPos(TInt64 aPos);

    inline void	ResetPos();

	inline TInt64	StartPos()	const;

	inline TUint8*	PtrInPage(TInt64 aPos) const;

	inline TBool	PosCachedInPage(TInt64 aPos) const;

	inline void	Deque();

private:

	// declared to disable copying and assignment

	TDynamicDirCachePage& operator=(const TDynamicDirCachePage&);

	TDynamicDirCachePage(const TDynamicDirCachePage&);

	// private constructor, as this class is not supposed to be created on stack

	TDynamicDirCachePage(CDynamicDirCache* aOwnerCache, TInt64 aStartMedPos, TUint8* aStartRamAddr);

public:

	TDblQueLink			iLink;			///< the embedded link object, see TCachePageList

    TInt64  			iStartMedPos;	///< the starting media address that this page caches

    TUint8*				iStartRamAddr;	///< the starting ram address that thsi page lives

    CDynamicDirCache* 	iOwnerCache;	///< pointer to the cache that owns this page

    TBool				iValid 	:1;		///< flag to indicate the validity of the page content

	TBool				iLocked :1;		///< flag to indicate if the page is locked or not

	TPageType			iType;			///< page type, see TPageType

    };

/**

The lookup table entry class

@see	CDynamicDirCache

*/

class TLookupEntry

	{

	public:

		TLookupEntry(): iPos(0), iRange(0), iPage(NULL) {};

		TLookupEntry(TInt64 aPos, TUint32 aRange, TDynamicDirCachePage* aPage): iPos(aPos), iRange(aRange), iPage(aPage) {};

	public:

		TInt64 					iPos;

		TUint32					iRange;

		TDynamicDirCachePage* 	iPage;

	};

//---------------------------------------------------------------------------------------------------------------------------------

typedef TDblQue<TDynamicDirCachePage> TCachePageList;

/**

Dynamic directory cache.

For now it is directly derived from MWTCacheInterface.

Provides caching FAT directory data.

*/

class CDynamicDirCache : public CBase, public MWTCacheInterface

    {

public:

	~CDynamicDirCache();

	static CDynamicDirCache* NewL(TDriveInterface& aDrive, TUint32 aMinPageNum, TUint32 aMaxPageNum, TUint32 aPageSizeLog2, const TDesC& aClientName);

	//-- overloads from the base class

	void    ReadL (TInt64 aPos, TInt aLength, TDes8& aDes);

	void    WriteL(TInt64 aPos, const TDesC8& aDes);

	void    InvalidateCache(void);

    void    InvalidateCachePage(TUint64 aPos);

	TUint32 PosCached(const TInt64& aPosToSearch, TInt64& aCachedPosStart);

	TUint32 CacheSizeInBytes()  const;

	TInt    Control(TUint32 aFunction, TUint32 aParam1, TAny* aParam2);

	void 	SetCacheBasePos(TInt64 aBasePos);

	void 	MakePageMRU(TInt64 aPos);

	TUint32	PageSizeInBytesLog2() const;

	TUint32 PageSizeInSegs() const;

    // Debugging functions

	void Dump();

	void Info() const;

protected:

	CDynamicDirCache(TDriveInterface& aDrive, TUint32 aMinSizeInBytes, TUint32 aMaxSizeInBytes, TUint32 aPageSizeInBytesLog2);

	void ConstructL(const TDesC& aClientName);

	void ReadDataFromSinglePageL(TInt64 aPos, TInt aLength, TDes8& aDes);

	void WriteDataOntoSinglePageL(TInt64 aPos, const TUint8* aData, TUint32 aDataLen);

	TDynamicDirCachePage* FindPageByPos(TInt64 aPos);

	TDynamicDirCachePage* UpdateActivePageL(TInt64 aPos);

	TDynamicDirCachePage* AllocateAndLockNewPageL(TInt64 aStartMedPos);

	TUint8* LockPage(TDynamicDirCachePage* aPage);

	TInt 	UnlockPage(TDynamicDirCachePage* aPage);

	TInt 	DecommitPage(TDynamicDirCachePage* aPage);

	inline TInt64  CalcPageStartPos(TInt64 aPos) const;

	void CheckThresholds();

	inline TBool CacheIsFull() const;

	inline TUint32 MaxCacheSizeInPages() const;

	TInt DeQueue(TDynamicDirCachePage* aPage);

	TInt AddFirstOntoQueue(TDynamicDirCachePage* aPage, TDynamicDirCachePage::TPageType aType);

	TInt LookupTblRemove(TInt64 aPagePos);

	TInt LookupTblAdd(TDynamicDirCachePage* aPage);

	TDynamicDirCachePage* LookupTblFind(TInt64 aPos);

	TInt ResetPagePos(TDynamicDirCachePage* aPage);

	void MakePageLastLocked(TDynamicDirCachePage* aPage);

	void DoMakePageMRU(TInt64 aPos);

	void DoInvalidateCache(void);

private:

	TUint32				iPageSizeLog2;		///< log2 value of cache pages size in bytes

	TUint32				iMinCacheSizeInBytes;	///< minimum cache data size

	TUint32				iMaxCacheSizeInBytes;	///< maximum cache data size

	TUint32				iMinSizeInPages;	///< minimum cache page number

	TUint32				iMaxSizeInPages;	///< maximum cache page number

	TUint32             iPageSizeInBytes;	///< cache page size in bytes

	TInt64              iCacheBasePos; 		///< cache pages base position, used to align them at cluster size

	TDriveInterface&    iDrive;        		///< reference to the driver for media access

	TUint32             iCacheDisabled : 1; ///< if not 0 the cache is disabled totally and all reads and writes go via TDriveInterface directly

	// data structures for LRU page list	

	TCachePageList 	iLockedQ;				///< the locked queue that manages all locked pages, limited by minimum page number

	TCachePageList 	iUnlockedQ;				///< the unlocked queue that manages all locked pages, limited by maximum page number - minimum page number

	TUint32			iLockedQCount;

	TUint32			iUnlockedQCount;

	// data structures for look up table

	THashFunction32<TLookupEntry> 	iHashFunction;

	TIdentityRelation<TLookupEntry>	iIdentityFunction;

	RHashSet<TLookupEntry> 			iLookupTable;	///< a lookup table that used to speed up page look up

	CCacheMemoryClient*	iCacheMemoryClient;	///< interface to cache memory manager

	TUint32 iPermanentlyAllocatedPageCount;	///< count of pages in locked queue that are never unlocked

    };

#include"sl_dir_cache.inl"

#endif //SL_DIR_CACHE_H