/*

* Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "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:  Declaration of the DCF cache class

*

*/

#ifndef DCFCACHE_H

#define DCFCACHE_H

//  INCLUDES

#include <mode.h>

#include <symmetric.h>

#include <rijndael.h>

// enables async reading

#define ASYNC_READ

// FORWARD DECLARATIONS

class RFile;

class RDRMRightsClient;

class CDcfCommon;

// CLASS DECLARATION

/**

 *  Cache for reading decrypted or plain data from a DCF file

 *

 *  @lib OmaDrmAgent.dll

 *  @since Series 60 3.0

 */

class CDcfCache : public

#ifdef ASYNC_READ

    CActive

#else

    CBase

#endif

    {

public:

    // Constructors and destructor

    /**

     * Two-phased constructor.

     */

    static CDcfCache* NewL(

        RDRMRightsClient& aRightsClient,

        RFile& aFile,

        CDcfCommon& aDcf,

        TInt aPageSize = 2048,

        TInt aPageCount = 32 );

    /**

     * Destructor.

     */

    virtual ~CDcfCache();

public:

    // New functions

    /**

     * Read data from the file via the cache. Depending on the decryption

     * mode, the data is decrypted in the RightsServer or in the cache

     * @since Series 60 3.0

     * @param aPos Position from the start of the file where to read from

     * @param aDes Descriptor holding the read data

     * @param aLength Amount of data to read

     * @return KErrNone if the data is read successfully

     */

    TInt Read(

        TInt& aPos,

        TDes8& aDes,

        TInt aLength );

    /**

     * Set the decryption key to be used if decryption shall happen in the

     * cache itself.

     * @since Series 60 3.0

     * @param aKey AES128 decryption key

     * @return ?description

     */

    void SetKey(

        const TDesC8& aKey );

#ifdef ASYNC_READ

    TInt Read(

        TInt aPos,

        TDes8& aDes,

        TInt aLength,

        TRequestStatus& aStatus );

    void ReadCancel( TRequestStatus& aStatus );

#endif

protected:

    // New functions

    void CachedReadL(

        TInt& aPos,

        TDes8& aDes,

        TInt aLength );

    void UncachedReadL(

        TInt& aPos,

        TDes8& aDes,

        TInt aLength );

    /**

     * Check if a file position is in the give cache page

     * @since Series 60 3.0

     * @param aPage Page to check

     * @param aPosition Position to check

     * @return ETrue if the position is in the cache page

     */

    TBool InPage( TInt aPage, TInt aPosition );

    /**

     * Return the index of a free cache page

     * @since Series 60 3.0

     * @return Index of a free cache page

     */

    TInt GetFreePage();

    /**

     * Read a page of plain data for a given file position into the cache

     * @since Series 60 3.0

     * @param aPage Page to read

     * @param aPosition Position to read

     */

    void ReadPageL( TInt aPage, TInt aPosition );

    /**

     * Read a page of data for a given file position into the cache and

     * decrypt it

     * @since Series 60 3.0

     * @param aPage Page to read

     * @param aPosition Position to read

     */

    void ReadAndDecryptPageL( TInt aPage, TInt aPosition );

    /**

     * Copy data from a cache page into a descriptor

     * @since Series 60 3.0

     * @param aPage Page from which to read

     * @param aDes Decscriptor where the data is stored

     * @param aPosition Position in the file, updated with the new

     *                  position after the data has been read

     * @param aLength Amount of data to be read, updated with the actual

     *                amount that was read

     */

    void CopyOut( TInt aPage, TDes8& aDes, TInt& aPosition, TInt& aLength );

    /**

     * Decrypt a memory buffer using either the stored key or the

     * RightsServer.

     * @since Series 60 3.0

     * @param aIv AES CBC initialization vector

     * @param aPtr Data to be decrypted

     */

    void DecryptL( const TDesC8& aIv, TPtr8& aPtr );

#ifdef ASYNC_READ

    void ReadAsyncL();

#endif

protected:

    // Functions from base classes

#ifdef ASYNC_READ

    /**

     * From CActive

     * @since Series60 3.0

     */

    void RunL();

    /**

     * From CActive

     * @since Series60 3.0

     */

    void DoCancel();

    /**

     * From CActive

     */

    TInt RunError( TInt aError );

#endif

private:

    /**

     * C++ default constructor.

     */

    CDcfCache(

        RDRMRightsClient& aRightsClient,

        RFile& aFile,

        CDcfCommon& aDcf,

        TInt aPageSize,

        TInt aPageCount );

    /**

     * By default Symbian 2nd phase constructor is private.

     */

    void ConstructL();

protected:

    // Types and enumerations

    enum TDecryptionMode

        {

        EServerSide,

        EClientSide,

        };

#ifdef ASYNC_READ

    enum TReadMode

        {

        ENonPosRead,

        EPosRead,

        };

#endif

protected:

    // Data

    RFile& iFile;

    RDRMRightsClient& iRightsClient;

    CDcfCommon& iDcf;

    TInt iPageSize;

    TInt iPageCount;

    RPointerArray<TUint8> iPage;

    RArray<TInt> iPageUsageCount;

    RArray<TInt> iPagePosition;

    TEncryptionMethod iEncryptionMethod;

    TBuf8<KDCFKeySize> iKey;

    TDecryptionMode iDecryptionMode;

#ifdef ASYNC_READ

    TRequestStatus* iAsyncStatus;

    TInt iPos;

    TDes8* iDes;

    TInt iLength;

    TReadMode iOperation;

    TBool iAsyncReadingOngoing;

    TInt iError;

#endif

    };

#endif      // DCFCACHE_H

// End of File