Discovering services

[Havoc Pennington]

Carlos Garcia Campos wrote:
> 
> where should I add the test stuff? bus/test.c? I still don't know how
> the tests work. 

I think bus/dispatch.c has most of the tests for the bus, in particular 
those that test OOM handling. You should be able to roughly just copy 
one of the other tests in there. It's a little bit tricky since it's all 
in one process, you have to avoid blocking when the other process hasn't 
sent something yet, or it hangs. Just do DBUS_VERBOSE=1 and look at what 
happens if your test doesn't work.

>>> Is it possible to deactivate services or something like that?
>> This is a pretty major can of worms. In general services should 
>> "self-deactivate" I would say - e.g. after a timeout, or when nobody is 
>> using them.
> 
> Exactly, when nobody is using them, but how can a service know when it's
> not going to be used anymore? Maybe a generic interface, with ref/unref
> methods that services could implement would be a solution.

Some reasonable approaches are:
  - time out and exit after being unused for a while
  - require clients to register/unregister (and track if any
    clients disconnect without unregistering, to avoid leaks)

Distributed reference counting has lots of problems so we've tried to 
avoid that. Eventually we might want some kind of generic 
register/unregister mechanism, but it's not clear to me what that would 
be like, so right now everyone is rolling their own suitable for their 
needs.

Havoc