[Telepathy] fd.o#20772: Just what is stream directionality?

[Simon McVittie]

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On Fri, 20 Mar 2009 at 14:06:11 +0000, Simon McVittie wrote:
> To keep things simple for clients, I'm inclined to declare that from now on,
> CMs MUST emit StreamDirectionChanged at least once per StreamAdded, to fill
> in the missing information.
> 
> Perhaps a better ordering would be to emit SDC *before* the corresponding SA,
> to signal "you are about to receive StreamAdded for the stream whose ID is 42:
> when you do, its direction will be..."; this means that when dealing with
> 0.17.22-compliant connection managers, there will not be a "limbo" period in
> which we can only guess the direction.
> 
> Which direction to assume when dealing with pre-0.17.22 CMs is an open
> question. Having incoming (remotely created) streams send media immediately
> would be a privacy violation, but having us expect to receive media
> immediately is fine.
> 
> I'm inclined to say that when dealing with pre-0.17.22 CMs, the client
> SHOULD assume that the stream is Receive and Pending_Local_Send; if the client
> is the one that created the stream, then it will learn the real directionality
> soon (from the return of RequestStreams).

I've proposed some spec wording in the StreamAdded, StreamDirectionChanged
and StreamRemoved documentation:

http://git.collabora.co.uk/?p=user/smcv/telepathy-spec-smcv.git;a=shortlog;h=refs/heads/streaming-errata

http://people.freedesktop.org/~smcv/telepathy-spec-streaming_errata/spec.html#org.freedesktop.Telepathy.Channel.Type.StreamedMedia

For further discussion, see:

http://bugs.freedesktop.org/show_bug.cgi?id=20772

Regards,
    Simon
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