/*

* Copyright (c) 2008 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 Base class for log busses.

*

*/

#ifndef HSPS_LOGBUS_H

#define HSPS_LOGBUS_H

// INCLUDES

#include <e32std.h>

#include <e32base.h>

// CLASS DECLARATION

/**

 * Base class for log busses. Not instanciable.

 * 

 * @lib hspsTools.lib

 * @since S60 5.0

 * @ingroup group_homescreenpluginservice_tools

 */

class ChspsLogBus : public CBase, TDes16Overflow, TDes8Overflow

    {

public:

    /**

     * Destructor.

     */

    IMPORT_C ~ChspsLogBus();

    /**

     * Log formattable 16bit string.

     * 

     * @since S60 5.0

     * @param aFmt  String to be logged. May contain format specifiers, but

     *              those must match with additional arguments given.

     *        ...   Data to be inserted to formatted string.

     */    

    IMPORT_C void LogText( TRefByValue<const TDesC16> aFmt, ... );

    /**

     * Log formattable 8bit string.

     * 

     * @since S60 5.0

     * @param aFmt  String to be logged. May contain format specifiers, but

     *              those must match with additional arguments given.

     *        ...   Data to be inserted to formatted string.

     */    

    IMPORT_C void LogText( TRefByValue<const TDesC8> aFmt, ... );    

protected:

    /**

     * This method must be overwritten in inherited class (implementation).

     * Implementation must log given string using logging channel of

     * it's choice.

     * 

     * @param aMessage Message to be logged.

     */    

    virtual void _LogText( const TDesC& aMessage ) = 0;

    /**

     * This method is used to query max. line length from inheriting object.

     * Default implementation returns 128.

     * This value is used to crop descriptors before _LogText is called.

     * 

     * @return  TInt    Max line length supported by this log bus.

     */    

    virtual TInt MaxLineLen() const;    

    /**

     * Constructor for performing 1st stage construction.

     */

    IMPORT_C ChspsLogBus();    

private: // Methods.

    /**

     * Create a heap descriptor using given arguments.

     * 

     * @param   aFmt    Descriptor

     * @param   aList   Variable length argument list.

     * @return  HBufC*  Pointer to created heap descriptor. OWNERSHIP TRANSFERRED

     *                  TO CALLER.

     */    

    HBufC* FormatMessage( TRefByValue<const TDesC16> aFmt, VA_LIST aList );

    /**

     * From TDes16Overflow.

     * 

     * Handles the overflow.

     * This function is called when the TDes16::AppendFormat() 

     * variant that takes an overflow handler argument, fails.    

     * 

     * @param aDes  The 16-bit modifiable descriptor whose overflow results in the 

     *              call to this overflow handler.

     * 

     */    

    void Overflow( TDes16& aDes );    

    /**

     * Create a heap descriptor using given arguments.

     * 

     * @param   aFmt    Descriptor

     * @param   aList   Variable length argument list.

     * @return  HBufC*  Pointer to created heap descriptor. OWNERSHIP TRANSFERRED

     *                  TO CALLER.

     */    

    HBufC* FormatMessage( TRefByValue<const TDesC8> aFmt, VA_LIST aList );

    /**

     * From TDes8Overflow.

     * 

     * Handles the overflow.

     * This function is called when the TDes16::AppendFormat() 

     * variant that takes an overflow handler argument, fails.    

     * 

     * @param aDes  The 16-bit modifiable descriptor whose overflow results in the 

     *              call to this overflow handler.

     * 

     */    

    void Overflow( TDes8& aDes );     

    /**

     * Crops text according to max line and then calls

     * inherited class' _LogText. 

     * 

     * @param   aText   Message to be logged.

     */

    void CropAndLogText( const TDesC& aText );

private: // Data.    

    /**

     * Internal flag to indicate possible overflow.

     */

    TBool iOverflow;

    };

#endif // HSPS_LOGBUS_H