SIS file recognition

Symbian OS provides a standard ECOM plugin data recogniser to recognise SIS files.

The recogniser parses the file's header and checks its UIDs. If the UIDs identify the file as a v9.x SIS file, the recogniser's confidence is set to CApaDataRecognizerType::EProbable. If the file additionally has a .sis file extension, then the confidence is increased to CApaDataRecognizerType::ECertain.

The recogniser is capable of recognising the x-epoc/x-sisx-app MIME type (this is the value returned by its implementation of SupportedDataTypeL()). So, an application that handles SIS files, for instance a software installer, must specify this MIME type in its registration resource file's datatype_list section.