// 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
*/

//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//!!
//!! WARNING!! DO NOT edit this file !! '\sfat' component is obsolete and is not being used. '\sfat32'replaces it
//!!
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


#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,
        EActivePage,
        };

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(TFatDriveInterface& 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(TFatDriveInterface& 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);
    
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

    TFatDriveInterface& 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 TFatDriveInterface directly

    TDynamicDirCachePage*   iActivePage;    ///< a unique page in cache, used to read new page before make it MRU or have it replaced
    
    // 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
    };

#include"sl_dir_cache.inl"

#endif //SL_DIR_CACHE_H