[Telepathy] Spec advice needed: ChannelDispatcher.DelegateChannels() and PresentChannel()

[Olli Salli]

On Wed, Apr 13, 2011 at 2:40 PM, Guillaume Desmottes
<guillaume.desmottes at collabora.co.uk> wrote:
> Le mercredi 13 avril 2011 à 13:43 +0300, Olli Salli a écrit :
>> On Wed, Apr 13, 2011 at 11:35 AM, Guillaume Desmottes
>> <guillaume.desmottes at collabora.co.uk> wrote:
>> > The other issue is about updating the Handler.HandledChannels property:
>> > """
>> > Humm I thought about a potential issue with DelegateChannels(). Handlers
>> > are supposed to announce the channels they are handling in
>> > Handler.HandledChannels
>> > [1].
>> >
>> > In practice clients don't have to care as TpBaseClient (or the tp-qt4
>> > equivalent) transparently does it for them. We'll have to make sure that
>> > TpBaseClient is informed when a channel is delegated as it'll have to
>> > remove the channel from the HandledChannels list.
>> > Maybe we should announce that on D-Bus? Another option would be to hook
>> > the tp-glib DelegateChannels API with TpBaseClient but that sounds
>> > pretty fragile a bit hacky to me.
>> >
>>
>> Isn't only the Handler that's currently handling the channel supposed
>> to call DelegateChannels on it? In this context, it'd make sense to me
>> to make the DelegateChannels high-level API *a part of* whatever
>> baseclass you derive from when being a Handler (AbstractClientHandler
>> in tp-qt4, and I guess just the generic TpBaseClient in tp-glib?).
>> Doing that, the API could sanity-check that the handler is in fact
>> handling the channel in question (from the current value of
>> HandledChannels) and update HandledChannels if the D-Bus call
>> succeeds.
>
>
> Indeed we could make it a TpBaseClient API even if that would be a bit
> weird (a TpChannelDispatcher API would seem more natural imho). That
> wouldn't help us if some does it behind our back (by using the D-Bus API
> directly) but I'm ready to be convinced we don't care much about such
> case.
>
>

You can already break HandledChannels by using the D-Bus API directly,
as it's per-unique-name (per-bus-connection), not per-Client object.
That is, if you implement a Handler using bare D-Bus API, your
HandledChannels property should be the same as for all other Handlers
on the same unique name, which it probably isn't.

-- 

Br,
Olli Salli