[Tracker] tracker & nautilus integration += metatags

[yelo_3 <yelo_3 yahoo it>]

I think that nautilus integration can be improved a lot, so I'm trying
to write a new extension that lets users view file metadata in the
"list view" of nautilus.
This is done filling files with attributes.
I started the project with the idea of showing media tags (artist,
album, ecc.) and so I had a look at totem's code. But now I realized
that maybe racker (or better to say XESAM) could be used for this aim.
So, does tracker have an interface of this type,

 extract_metatags(const char* uri)

which saves in a list the couples (MetaTag name, MetaTag value) so
they can be stored in nautilus file representations, and shown in the
detailed list view?

Thank you very much for your help. I hope that this extension will be
ready soon. I have the "skeleton" ready, only the tag extract part is
missing.