[Gimp-developer] Weird question: how to retrieve a saving plugin's mime type?

[Alessandro Francesconi <alessandrofrancesconi live it>]

Hello,
I'll try to be more precise than the title: I'm the developer of BIMP - Batch Image Manipulation Plugin for 
GIMP (http://www.alessandrofrancesconi.it/projects/bimp/) and I'm trying to implement a new feature.
 
This plugin provides an interface similar to the GIMP's PDB dialog: 
http://static.blogo.it/ossblog/Figure2pdb_3.jpg
The user can select one of the plugins from the list and use it on the batch process. Not all the procedures 
from the whole DB are provided (it's a "filtered" subset) and I'm try to include the possibility to select a 
"saving plugin", for example one of those named in the form "file-XXX-save", where XXX is a file format like 
JPG, BZ2, DDS and so on.
 
I already know how to get all the information about a given plugin with the function 
'gimp_procedural_db_proc_info()', but now a particular detail is missing: I need to know which mime type is 
handled by the plugin.
For example, giving the plugin 'file-openraster-save', the function must return 'opa'.
 
I didn't see any APIs about this, so I took the GIMP's source code and I opened the source of the application 
saving dialog: 'file-save-dialog.c'.
Here the developers use the following system to retrieve the mime type of a saving plugin, if I understand:
 
- they access to the saving procedure (e.g. "save_proc") as a datatype 'GimpPlugInProcedure'
- they access to its handled extension with save_proc->extensions_list->data  (but what datatype does it 
have?)
 
Reading the docs, I see a function called 'gimp_plug_in_procedure_find(GSList* list, const gchar* name)'... 
so apparently I can get the procedure object in this way... but what is the 'list' parameter? Where to 
retrieve it?
Also, how is 'GimpPlugInProcedure' datatype structured? A lot of things are missing from the GIMP-dev's 
reference and I'm groping in the dark  :(


Ale