Re: [gfvs] cdda backend

[Alexander Larsson <alexl redhat com>]

So, I thought some more about the content type guessing. The current
code allows you to read files from all sorts of backends, and enumerate
the various places you can read from (volume monitor), if you add to
this a content type and a way to get at the lowlevel identifiers for the
volumes (so that you can optionally map them to other libraries and get
more details) this is quite powerful for many apps.

However, I'm not sure its the right place the actual content type
guessing API. Lets take a step back and consider the whole desktop. Any
time you mount something you want to guess the content on that so that
you can spawn the default operation. Another user of the content type
would be the f-spot photo import dialog, which would default to only
show "photo" type devices and mounts. However, at this points its not
ideal to have to start sniffing all the mounts before bringing up the
dialog, as that is kinda slow.

So, it seems to me, that the ideal approach is to sniff content types
each time something is mounted, and to remember that for further
(cross-process) use. And a good place to put the sniffing would be where
the "open default content action" guessing happens. 

I'm not sure where/how to store this though, as its a per-session thing
really (some mounts are session local, and session settings might affect
the results), and hal is system wide.