/*!

    \class CHsBURActiveCallback

    \ingroup group_hsdomainmodel

    \brief B&R active callback.

    Home screen active callback in backup/restore.

*/

/*!

    Constructor.

    \a observer Backup restore observer

*/

/*!

    Destructor.

*/

/*!

    This method informs the active backup data client that all 

    snapshots have been supplied. If the client has not

    received a snapshot then it should perform a base backup.

    Inform that all data has been backed up or restored.

*/

/*!

    This method receives all or part of a snapshot of data to allow 

    calculation of an incremental backup.  The snapshot is one that

    was previously supplied by the data owner.  The snapshot data 

    should be read from the location supplied. The snapshot data may

    be larger than the location supplied in which case the routine 

    will be called repeatedly until all data has been supplied.

    Snapshot data will also be supplied as part of a restore operation

    @param aDrive the drive being backed up

    @param aBuffer a pointer to the base of the location from whence 

           data can be copied.

    @param aLastSection ETrue if this is the last section of snapshot 

           data, else EFalse.

    Not supported.

*/

/*!

    This method returns the expected size of backup data that will be

    supplied. If an incremental backup is underway then this method

    then this method will not be called until after 

    ReceiveSnapshotDataL(). The size data will be used for the purpose

    of tracking progess during a backup. If it is inaccurate then the

    user may see irregular progress but the actual backup data will 

    not be affected so it is acceptable to return an estimated value.

    @param aDrive the drive being backed up.

    @return the size of the data that will be returned

	Make a guess about data size.

*/

/*!

    This method returns a snapshot of data to accompany a backup. The 

    snapshot is expected to contain details on files / data being 

    backed up. The format of the snapshot is only meaningful to the

    data owner. The snapshot will be supplied if the data owner is 

    asked for an incremental backup and for a restore operation. The 

    snapshot data should be copied to the location supplied.

    The snapshot data may be larger than the location supplied in 

    which case the routine will be called repeatedly until all data

    has been retrieved.

    @param aDrive the drive being backed up

    @param aBuffer a pointer to the base of the location where data 

           can be copied.

    @param aFinished on return ETrue if all data has been returned 

           for this drive, else EFalse.

    Not supported.

*/

/*!

    This method prepares the implementor to return backup data. It 

    will be followed by a sequence of calls to request the actual 

    data.

    @param aDrive the drive being backed up.

    Initialize for backup.

*/

/*!

    This method requests a section of backup data.  

    InitialiseGetBackupDataL() will have been called previously to

    specify the drive concerned.  The data returned may be base or

    incremental depending on the type of backup and the capability of

    the data owner.

    @param aBuffer a pointer to the base of the location where data 

           can be copied.

    @param aFinished on return ETrue if all data has been returned 

          for this drive, else EFalse.

*/

/*!

    This method prepares the implementor to receive base restore data

    for a drive. It will be followed by a sequence of calls to supply

    the actual data.

    @param aDrive the drive being restored.

	Initialize restore.

*/

/*!

    This method receives a section of base restore data.

    InitialiseRestoreBaseDataL() will have been called previously to 

    specify the drive concerned.

    @param aBuffer a pointer to the base of the location whence data

           can be read.

    @param aFinished ETrue if all data has been returned for this 

           drive, else EFalse.

    Run state machine for restore. Receive stream from BUR engine and turn it

    to file(s).

*/

/*!

    This method prepares the implementor to receive incremental 

    restore data for a drive. It will be followed by a sequence 

    of calls to supply the actual data.  If multiple increments

    are supplied then this methid will be called before each increment

    @param aDrive the drive being restored.

    Not supported.

*/

/*!

    This method receives a section of increment restore data.

    InitialiseRestoreIncrementDataL() will have been called 

    previously to specify the drive concerned.

    @param aBuffer a pointer to the base of the location whence data 

           can be read.

    @param aFinished ETrue if all data has been returned for this 

           increment, else EFalse.

    Not supported.

*/

/*!

    This method is called when all data to be restored has been 

    supplied.

    @param aDrive the drive being restored.

    Called when restore is complete - sets data back to initial state.

*/

/*!

    This method is called if copying of data is terminated prematurely 

    to allow the implementor to tidy up.  The same method applies to 

    all types of data and to backup and restore.

    Tidy up when operation is over.

*/

/*!

    Gets a 32-bit checksum for its private data.

    This routine is for test purposes.  It must be implemented but an

    invariant checksum value can be provided.  Some tests may cause 

    checksum values to be compared.

    @param aDrive the drive containing data being checksummed

    @return the 32-bit checksum

*/

/*!

    C++ constructor.

*/

/*!

    2nd phase constructor.

*/