There are two variants one with storage and identify support and the
other without storage.
It implements the following commands:
* INSERT id
* REMOVE id
* SCAN id
* ERROR error-code
* LIST (returns saved print)
The INSERT/REMOVE/LIST commands are only available in the storage
driver. The SCAN command emulates presenting a finger.
These commands can be send ahead of time, and will be queued and
processed when appropriate. i.e. for INSERT/REMOVE that is immediately
when possible, for SCAN/ERROR processing is delayed.
The LIST command is always processed immediately.
Note that only a single command can be send per socket connection and
the command must be send in a single message. The socket will be closed
after the command has been processed.
Co-authored-by: Bastien Nocera <hadess@hadess.net>
Co-authored-by: Marco Trevisan (Treviño) <mail@3v1n0.net>
Use the virtual image device as base for now, while the new setup allows
to create easily fake device drivers without including the driver in
libfprint itself and test all the fpi_device functionalities.
