/*

* Copyright (c) 2007 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:  

 *

*/

#ifndef C_CCHSWIUSBHANDLER_H

#define C_CCHSWIUSBHANDLER_H

// INCLUDES

#include <e32std.h>

#include <e32base.h>

#include <f32file.h>

// FORWARD DECLARATION

class MCHSwiMassModeObserver;

/*

 * Inherited CActive, performs a asynchronous checks for mass storage mode

 *

 * @since 3.1

 */

class CCHSwiUsbHandler : public CActive

    {

public:

	/**

	 * Two-phased constructor.

     * @param aPlugin Owning plugin.

     * @param aFs File session. 

	 */

    static CCHSwiUsbHandler* NewL( MCHSwiMassModeObserver* aMassModeObserver,

    		RFs& aFs );

	/**

	 * Destructor.

	 */

    virtual ~CCHSwiUsbHandler();

    /**

     * Performs synchronous drive scan. Checks whether Mass Drive is available.

     * If it available: observer's Mass Mode flag is set to EFalse.

     * If it is not available: Mass Mode flag is set to ETrue.

     * In case of error, the check is postponed to be done again in RunL and Mass 

     * Mode flag is set to ETrue.

     */

    void SynchronousDriveScan();

    /**

     * Performs postponed drive scan. Checks whether Mass Drive is available.

     * If it available: observer's Mass Mode flag is set to EFalse.

     * If it is not available: Mass Mode flag is set to ETrue.

     * In case of error, the check is postponed to be done again in RunL and Mass 

     * Mode flag is set to ETrue.

     */

    void PostponedDriveScan();

protected:

	/**

	 * Handles timer events to start drive scan.

	 */

    void RunL();

    /**

     * RunL error handling.

     * @param aError Error.

     */

    TInt RunError( TInt aError );

    /**

     * Cancels notifications.

     */

    void DoCancel();

private:

    /**

     * no copy constructor

     */

    CCHSwiUsbHandler( const CCHSwiUsbHandler& );

    /**

     * no assignment

     */    

    CCHSwiUsbHandler& operator=( const CCHSwiUsbHandler& );

    /**

     * C++ default constructor

     */

    CCHSwiUsbHandler( MCHSwiMassModeObserver* aMassModeObserver, RFs& aFs );

    /**

     * Symbian default constructor.

     */

    void ConstructL();

    /**

     * Scans drives to check mass storage mode.

     */

    TInt ScanDrives( TInt& aDriveFlags );

    /**

     * Handles drive access errors by launching new postponed scan.

     */

    void HandleDriveError();

    /**

     * Scans drives and updates Mass Mode flag in the observer. 

     * @param aFlagsValid indicates whether current iDriveFlags are valid 

     * (they become invalid in case of an error).

     */

    TInt ScanDrivesAndUpdateFlag( TBool aFlagsValid );

    /**

     * Updates mass mode flag in observer.

     */

    TInt UpdateMassModeFlag();

private:

	/**

	 * Error from last drive scan.

	 */

	TInt iLastDriveScanError;

	/**

	 * Observer.

	 */

	MCHSwiMassModeObserver* iMassModeObserver;

	/**

	 * File session. Not owned.

	 */

    RFs iFs;

    /**

     * Drive flags obtained in last drive scan. Every bit indicates presence 

     * of given drive. This member is used for drive access optimalization -

     * if flags are valid (i.e. no error occured)

     */

    TInt iDriveFlags;

    /**

     * Timer for postponed drive scan.

     */

    RTimer iTimer;

    };

#endif // #ifndef C_CCHSWIUSBHANDLER_H