Backup +Engine Overview

The Backup Engine contains the logic related to backing up and restoring +data, including base and incremental backup. It also contains the data transfer +mechanism.

Architecture

The following diagram shows the Backup +Engine and its associated components. The components provided by the Symbian +platform are in green. The components that a device creator must implement +are in blue. The architecture supports two methods of connecting to the host +PC: Media Transfer +Protocol (MTP) and OBEX.

+ Backup and Restore Architecture + +

Backup and restore using the MTP Backup and Restore Data Provider

The +Symbian platform includes a Backup and Restore Data Provider plug-in for data +backup and restore over MTP. The plug-in is loaded by the MTP Framework when +a host PC requests a backup or restore. The plug-in is a client of the Backup +Engine, which interacts with backup-aware client applications.

For +more information on the MTP Backup and Restore Data Provider, refer to Implementing Backup and Restore +over MTP.

Backup and restore using OBEX

The +Symbian platform includes a basic backup server which uses OBEX. Device creators +may replace this component with their own. The backup server is a client of +the Backup Engine and must handle PC requests for backup and restore.

APIs

The Backup Engine exports conn::CSBEClient and +its utility APIs for writing a backup server.

+ + + +API +Description + + + + +

conn::CSBEClient

Provides data to a host PC for backup and receives data from a host +PC for restore. It also encapsulates state information for backup and restore +operations. Device creators can call this interface class to write a backup +server with their transport protocols.

+ + +

conn::CSBGenericDataType

Is a generic parent class to be passed through a common interface. +It represents any type of data structure used by conn::CSBEClient. +For example, the derived class conn::CSBSecureId represents +the Security ID of a data owning process. Derived classes are defined in the epoc32/include/connect/sbtypes.h header +file.

+ + +

conn::CDataOwnerInfo

Encapsulates the data owner information.

+ + +

conn::RFileArray

conn::RRestoreFileFilterArray

conn::RSIDStatusArray

Are derived from conn::RExternalisableArray to +store different backup and restore data.

+ + + +

Note: conn::CActiveBackupClient and conn::MActiveBackupDataClient are +also Backup Engine APIs . They are used to write data owner applications for +active backup and restore. For further information see Active +Backup Client under the OS layer.

Typical uses

The Backup Engine can +be used to write a backup server to communicate with a host PC for data backup +and restore.