/*

* Copyright (c) 2005-2006 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:  Header for CIRDiskSpaceWatcher

*

*/

#ifndef CIRDISKSPACEWATCHER_H

#define CIRDISKSPACEWATCHER_H

#include <e32base.h>

#include <f32file.h>

#include "irdiskspacewatcherobserver.h"

class CIRDiskSpaceSession;

// Default drive. Used to save for example settings and cache files.

const TDriveNumber KVRDefaultDrive = EDriveC;

/**

 *  CIRDiskSpaceWatcher. Watcher of disk space on defined disks.

 *

 *  Observes a disk and notifies the observer if the supplied critical disk 

 *  space limit is reached. 

 */

NONSHARABLE_CLASS( CIRDiskSpaceWatcher ): public CBase, public MIRDiskSpaceWatcherObserver

    {

public:  // Methods

    /**

     * Static constructor.     

     * 

     * @param aCriticalLevel, critical disk space level

     * @param aDiskSpaceWatcherObserver observer of disk space status     

     */

    static CIRDiskSpaceWatcher* NewL( const TInt64& aCriticalLevel, 

        MIRDiskSpaceWatcherObserver& aDiskSpaceWatcherObserver );

    /**

     * Destructor.

     */

    virtual ~CIRDiskSpaceWatcher();

    /**

     * IsBelowCriticalLevel Returns whether or disk defined by parameter 

     * contains less than the critical level free disk space.

     * Please note that StartObservingDriveL must have been called 

     * before calling this. Otherwise method will return EFalse whetever

     * disk space is below critical level or not.

     *  

     * @param aDriveNumber drive which space is checked

     * @return ETrue if there is less free disk space than the critical 

     * level, otherwise EFalse.

     */

    TBool IsBelowCriticalLevel( const TDriveNumber& aDriveNumber ) const;

    /**

     * Starts observing space of drive which is given as parameter

     *

     * @param aDriveNumber drive which will be observed

     */

    void StartObservingDriveL( const TDriveNumber& aDriveNumber );            

    /**

     * Stops observing space of drive which is given as parameter.

     * Please note that if drive is observed by some other object 

     * it will be observed until all objects have asked 

     * VRDiskSpaceWatcher to stop observing that drive.

     *

     * @param aDriveNumber drive which observing will be stopped. 

     */

    void StopObservingDrive( const TDriveNumber& aDriveNumber );    

    // From base class MIRDiskSpaceWatcherObserver

    /** 

     * From MIRDiskSpaceWatcherObserver

     *

     * @see MIRDiskSpaceWatcherObserver::NotifyLowDiskSpaceL()

     */

    void NotifyLowDiskSpaceL();

protected:  

private: 

    /**

     * C++ default constructor.

     * 

     * @param aCriticalLevel, critical disk space level

     * @param aDiskSpaceWatcherObserver observer of disk space status

     */

    CIRDiskSpaceWatcher( const TInt64& aCriticalLevel, 

        MIRDiskSpaceWatcherObserver& aDiskSpaceWatcherObserver );

    /**

     * By default Symbian 2nd phase constructor is private.

     */

    void ConstructL();

private:    // Data

    /** 

     * Handle to the file system. 

     */

    RFs iFs;

    /** 

     * Critical disk space level. 

     */

    const TInt64 iCriticalLevel;

	/** 

	 * The observer to be notified when critical disk space limit is reached.

	 */

    MIRDiskSpaceWatcherObserver& iObserver;

    /** 

     * Contains active objects which do the actual disk space checking 

     */

    RPointerArray<CIRDiskSpaceSession> iDiskSpaceSessions;

    };

#endif      // IRDISKSPACEWATCHER_H