[packagekit] WhatProvides

[Richard Hughes]

Guys,

I was talking to hadess earlier today about code installation. Bastien
is writing a script to take the gstreamer codec information and encode
it in the rpm. This would look something like
gstreamer0.10(decoder-audio/mpeg)(layer=(int)1)()(64bit)

In this way yum could install something like gstreamer-codecs-bad just
from an application codec string. This would rock as an application use
case and would also allow us to do some cool things.

This is similar to what DavidZ proposed before, only lower down the
stack. WhatProvides would be system level and backend specific. We can
be clever with the client tools in the existing framework.

This can be used for:

* Getting the packages that provide a modalias
* Installing codecs
* Installing general things, e.g. smtpdaemon
* <other ideas welcome>

Now, I think to be properly abstract, I envisage a method like:

WhatProvides(PkProvidesEnum provide_type, const char *data)

where PkProvidesEnum would be ALL, MODALIAS, CODEC, GENERAL or other
things that we think up.

The backend would be responsible for actually working out what
package_s_ provide the data, and the client tools for helping the user.

I guess we could standardize the format for MODALIAS and CODEC although
i don't think that's particularly important as we don't enforce the
names of packages either.

Comments?

Richard.