[packagekit] Implementing what-provides

[Richard Hughes]

On 9 October 2010 19:12, Fabio Erculiani <lxnay at sabayon.org> wrote:
> Maybe it's because there is no clear standard that defines expected
> input values?

Well, we've kinda envolved the different standards to actually get it
to work. For instance, Pango gives us a string describing the language
we need to install (as that's all it knows) and the printer installer
gives us all it knows. Really it's a compromise of what we can stick
in a package provide string.

> Same thing for PROVIDES_CODEC and PROVIDES_HARDWARE_DRIVER.

I don't think we actually have any docs for this, although if you're
volunteering to help I can certainly get you started.

For starters, this link describes what the yum backend adds to the
provide string and what it uses as an rpm provide:
http://gitorious.org/packagekit/packagekit/blobs/master/backends/yum/yumBackend.py#line776
which is more Fedora policy than any standard.

For actually what gets passed to PackageKit, see gpk-dbus-task.c --
for instance http://git.gnome.org/browse/gnome-packagekit/tree/src/gpk-dbus-task.c#n2596
shows you the crazy things we have to do to get the CUPS print ID
string to something that PackageKit expects.

We should put some examples on the wiki, and help welcome. We probably
need a more formal document, but the wiki would be a good start.

Richard.