/*
* Copyright (c) 2007-2009 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:  This is disk space notifier for Metadata server.*
*/

#ifndef __MDSDISKSPACENOTIFIER_H__
#define __MDSDISKSPACENOTIFIER_H__

// INCLUDE FILES
#include <e32base.h>
#include <f32file.h>

/**
* MMdSDiskSpaceNotifierObserver
* Observer interface for a disk space notifier.
*/
class MMdSDiskSpaceNotifierObserver
	{
	public :
		enum TDiskSpaceDirection
			{
			/** Disk space is larger than threshold level */
			EMore,

			/** Disk space is smaller than threshold level */
			ELess
			};

		/**
		 * Called to notify the observer that disk space has crossed the specified threshold value.
		 *
		 * @param aCrossDirection threshold cross direction
		 */
		virtual void HandleDiskSpaceNotificationL(TDiskSpaceDirection aDiskSpaceDirection) = 0;

		/**
		 * Called to if disk space notifier has an error situation.
		 *
		 * @param aError error code
		 */
		virtual void HandleDiskSpaceError(TInt aError) = 0;
	};

/**
* CMSDiskSpaceNotifierAO.
* A disk space notifier class
*/
class CMdSDiskSpaceNotifierAO : public CActive
    {
    public:
    	enum TDiskSpaceNotifierState
    		{
    		ENormal,
    		EIterate
    		};

    public : // Constructors and destructors
	    /**
	     * Constructs a disk space notifier implementation.
	     *
	     * @param aThreshold minimum free disk space threshold level in bytes
	     * @param aFilename filename which defines monitored drive's number
	     * @return  metadata server implementation
	     */
        static CMdSDiskSpaceNotifierAO* NewL(
        	MMdSDiskSpaceNotifierObserver& aObserver, 
        	TInt64 aThreshold, const TDesC& aFilename);

	    /**
	     * Constructs a disk space notifier implementation and leaves it
	     * in the cleanup stack.
	     *
	     * @param aThreshold minimum free disk space threshold level in bytes
	     * @param aFilename filename which defines monitored drive's number
	     * @return  metadata server implementation
	     */
        static CMdSDiskSpaceNotifierAO* NewLC(        
        	MMdSDiskSpaceNotifierObserver& aObserver, 
        	TInt64 aThreshold, const TDesC& aFilename);

	    /**
	    * Destructor.
	    */
        virtual ~CMdSDiskSpaceNotifierAO();

        TBool DiskFull() const;

    protected: // Functions from base classes
        /**
         * From CActive
         * Callback function.
         * Invoked to handle responses from the server.
         */
        void RunL();

        /**
         * From CActive
         * Handles errors that occur during notifying the observer.
         */
        TInt RunError(TInt aError);

        /**
         * From CActive
         * Cancels any outstanding operation.
         */
        void DoCancel();

    private: // Constructors and destructors

        /**
         * constructor
         */
        CMdSDiskSpaceNotifierAO(
        	MMdSDiskSpaceNotifierObserver& aObserver,
        	TInt64 aThreshold, TDriveNumber aDrive);

        /**
         * 2nd phase constructor
	     * @param aThreshold minimum free disk space threshold level in bytes
	     * @param aDrive monitored drive's number
         */
        void ConstructL();

    private: // New methods

		void StartNotifier();

		static TDriveNumber GetDriveNumberL( const TDesC& aFilename );

    private: // Data

        MMdSDiskSpaceNotifierObserver& iObserver;
        
        RFs iFileServerSession;
        
        const TInt64 iThreshold;
        
        const TDriveNumber iDrive;
        
        TDiskSpaceNotifierState iState;
        
        TInt iIterationCount;
        
        TBool iDiskFull;
    };

#endif // __CMDSSERVER_H__

// End of File