Proposing new external dependency for Empathy: libfolks

[Travis Reitter <travis reitter collabora co uk>]

I'd like to propose a new external dependency for Empathy: libfolks
[1][2].

Libfolks is a library to aggregate contacts from various sources (eg,
Telepathy accounts, e-d-s address books). I'm re-basing Empathy upon it
to provide metacontacts (People objects), which is one of our
most-requested missing features.  

New Dependencies
=====================

empathy depends on:
  libfolks

libfolks depends on:
  telepathy-glib Vala bindings [3] (should be in telepathy-glib 0.11.6)
for building

telepathy-glib Vala bindings depend on:
  gobject-introspection
  vala > 0.8.1 (first release to include fix for bgo #618660 [4])

Roadmap
=====================

For this Empathy/Gnome cycle, libfolks will only wrap Telepathy contacts
and allow merging and unmerging. Metacontacts will expose the
straightforward combination of subcontact attributes (eg, up to one
avatar, the most-available presence). Actions upon metacontacts will be
available through their Telepathy subcontacts. Empathy will provide UI
for itself to handle messaging, file transfers, merging contacts, etc.
with metacontacts in the contact list.

I plan to make a first release of libfolks soon, at which point I will
request a module on gnome.org for future development.

In future releases, we plan to support:

  * additional back-ends (beyond Telepathy)
  * writable back-ends, for storing custom avatars, alias, phone
    numbers, etc.

We want to provide metacontacts for the entire desktop, so it will be
possible to initiate collaborative editing sessions, games, etc. by
selecting people from an aggregated list. This should open a lot of nice
features for Gnome, and there's always a lot of excitement when anyone
mentions people as first-class objects on the desktop!

API/ABI stability
=====================

Libfolks is currently API/ABI unstable and under heavy development. The
general goal is for it to be relatively stable in 2-3 months from now.

References
=====================
[1] http://git.collabora.co.uk/?p=user/treitter/folks.git;a=summary
[2] http://telepathy.freedesktop.org/wiki/Folks
[3] https://bugs.freedesktop.org/show_bug.cgi?id=27792
[4] https://bugzilla.gnome.org/show_bug.cgi?id=618660