/*

* 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:  This is the header for the Diagnostics Logs Event Eraser.

*

*/

#ifndef DIAGLOGEVENTERASER_H

#define DIAGLOGEVENTERASER_H

// Include Files

#include <e32base.h>                    // CActive

#include <f32file.h>                    // RFs

// Forward Declarations

class MDiagLogEventEraserObserver;

class CActiveSchedulerWait;

class CLogClient;

class CLogViewEvent;

class CLogFilter;

/**

* Diagnostics Plugin Log Event Eraser

*

* This class is used to remove log events generated by diagnostics plugins.

* Events could be anything that is logged by the system log, such as call or

* data use records.

*

* @lib euser.lib

* @lib logcli.lib 

* @lib efsrv.lib

* @lib flogger.lib

*/

NONSHARABLE_CLASS( CDiagLogEventEraser ) : public CActive

    {

public: // New functions

    /**

    * Symbian OS two-phase constructor.

    *

    * @param aObserver A reference to the observer for this event eraser.

    * @param aFilter The filter to be used for log erasure.  Clients may pass

    *                NULL for no filtering.  Ownership is transferred.

    * @return An pointer to the new instance of CDiagLogEventEraser.

    */

    IMPORT_C static CDiagLogEventEraser* NewL(

        MDiagLogEventEraserObserver& aObserver,

        CLogFilter* aFilter = NULL );

    /**

    * Destructor.

    */

    IMPORT_C virtual ~CDiagLogEventEraser();

    /**

    * This gets the filter used for the log erasure.  Clients which want to

    * filter the logs to be erased must call this function and set the

    * appropriate filter before calling StartAsyncEraseLogsL or EraseLogsL.

    *

    * @return The filter to apply to the logs to check for erasure.

    */

    IMPORT_C CLogFilter& Filter();

    /**

    * This gets the log client used for the log erasure.

    *

    * @return The log client used for log erasure.

    */

    IMPORT_C CLogClient& LogClient();

    /**

    * This starts an asynchronous log erase operation.  The completion of this

    * request is notified by MDiagLogEventEraserObserver::CompleteEventEraseL.

    */

    IMPORT_C void StartAsyncEraseLogsL();

    /**

    * This performs a synchronous log erase operation.  The function will

    * leave if there is any error in log erasure.

    */

    IMPORT_C void EraseLogsL();

private: // New functions

    /**

    * C++ default constructor.

    *

    * @param aObserver A reference to the observer for this event eraser.

    * @param aFilter The filter to be used for log erasure.  If NULL is

    *                passed, a new filter will be created during the second

    *                phase of construction.  Ownership is transferred.

    */

    CDiagLogEventEraser( MDiagLogEventEraserObserver& aObserver,

                         CLogFilter* aFilter );

    /**

    * Symbian OS default constructor.

    */

    void ConstructL();

    /**

    * Handles the completion of log erasing and performs different operations

    * depending on whether the erasing was asynchronous or not.

    */

    void HandleCompletionL( TInt aError );

private: // From base class CActive

    /**

    * Handle active object completion event.

    */

    virtual void RunL();

    /**

    * Handle active object cancel event.

    */

    virtual void DoCancel();

private: // Data

    /** The state of the log erasing operation. */

    enum TDiagLogEventEraserState

        {

        EStateInitial = 0,

        EStateApplyingFilter,

        EStateReadingEntries,

        EStateDeletingEntry,

        EStateComplete

        };

    /** The observer for this instance of the log event eraser. */

    MDiagLogEventEraserObserver& iObserver;

    /** The active scheduler, used for synchronous log erasure.  Own. */

    CActiveSchedulerWait* iWaitScheduler;

    /** The Log client.  Own. */

    CLogClient* iLogClient;

    /** The Log view.  Own. */

    CLogViewEvent* iLogView;

    /** The Log filter.  Own. */

    CLogFilter* iLogFilter;

    /** A file server session used to delete the logs. */

    RFs iFsSession;

    /** The internal state of the log event eraser. */

    TDiagLogEventEraserState iState;

    /** Indicates if the log event eraser is running a synchronous delete. */

    TBool iIsDeletingSynchronous;

    /** The return code for syncronous operation. */

    TInt iError;

    };

#endif // DIAGLOGEVENTERASER_H

// End of File