On Tue, 2013-08-06 at 15:21 +0200, David Henningsson wrote: > On 08/06/2013 02:54 PM, Tanu Kaskinen wrote: > > On Tue, 2013-08-06 at 14:42 +0200, David Henningsson wrote: > >> On 08/06/2013 02:30 PM, Tanu Kaskinen wrote: > >>> On Tue, 2013-08-06 at 13:26 +0200, David Henningsson wrote: > >>>> On 08/05/2013 01:37 PM, Tanu Kaskinen wrote: > >>>>> On Wed, 2013-07-17 at 12:26 +0200, David Henningsson wrote: > >>>>>> On 07/17/2013 11:22 AM, Tanu Kaskinen wrote: > >>>>>>> On Wed, 2013-07-17 at 09:27 +0200, David Henningsson wrote: > >>>>>>>> On 07/16/2013 03:20 PM, Tanu Kaskinen wrote: > >>>>>>>>> What operations do you mean? Moving or removing a default connection is > >>>>>>>>> not supported as such, but if the client tries that anyway, we can > >>>>>>>>> implicitly convert the connection to an explicit one and disable default > >>>>>>>>> connections, or we can require the client to do these operations > >>>>>>>>> explicitly, but I think the latter would be too inconvenient for the > >>>>>>>>> client. > >>>>>>>> > >>>>>>>> Ok, I think I didn't read the proposal well enough. Having done that, I > >>>>>>>> understand that you're suggesting a global switch "default connections > >>>>>>>> on/off" only. Or is it a per-node switch? > >>>>>>> > >>>>>>> It is a per-node switch. > >>>>>>> > >>>>>>>> I have another idea that might be worth considering: how about that the > >>>>>>>> "explicit" layer can both enable and disable connections? So that there > >>>>>>>> could be a default connection between A and B, but there is also some > >>>>>>>> sort of explicit override that disables it. This would be more flexible > >>>>>>>> than a more global on/off switch. > >>>>>>> > >>>>>>> I'm not sure what you mean. Do you perhaps mean that the default > >>>>>>> connection on/off switch should be per-node (which it already is in my > >>>>>>> proposal), or that it should be per-connection (so that if there are > >>>>>>> multiple default from node A, it's possible to disable only a subset of > >>>>>>> those)? > >>>>>>> > >>>>>>> I didn't make make it possible to disable individual default > >>>>>>> connections, because I had a feeling that it would have very messy > >>>>>>> semantics. If default connection from A to B is disabled, what is the > >>>>>>> routing code supposed to do when conditions change and the default > >>>>>>> routing is re-evaluated? Can it ever reactivate the connection between A > >>>>>>> and B again? Is the per-connection disabling handled as a blacklist of > >>>>>>> connections that must never be automatically activated? > >>>>>> > >>>>>> If the A -> B route is explicitly_disabled, that overrides any default > >>>>>> connections the routing system tries to make. > >>>>> > >>>>> What is the use case for explicitly disabled connections? I'll assume > >>>>> here that your idea was to allow moving a default connection elsewhere > >>>>> (making the connection explicit in the process) without disabling all > >>>>> default connections for the node. > >>>>> > >>>>> When the user moves a default connection, the routing system obviously > >>>>> shouldn't immediately create another default connection elsewhere to > >>>>> replace the disabled connection. > >>>>> > >>>>> On the other hand, if the routing system doesn't create replacement > >>>>> connections, then that results in weird behaviour. Let's say that > >>>>> there's a default connection A -> B, and the user moves the connection > >>>>> to A -> C. Then B disappears. The routing changes its opinion of the > >>>>> best available routing for A, which might be D. So removing node B > >>>>> resulted in audio suddenly appearing in node D, even though nothing was > >>>>> playing to B. > >>>>> > >>>> > >>>> Assume your example of a default connection A -> B which the user > >>>> changes into A -> C, by adding an explicit A -> C connection. Without > >>>> some sort of explicitly_disabled blacklist that would then include A -> > >>>> B, the routing system would be free to route A to *both* B and C. > >>> > >>> My solution is that the application disables the default routing > >>> altogether for A, if it doesn't want to have the default connection A -> > >>> B. It seems to me that this causes fewer surprises than the blacklisting > >>> approach. > >>> > >>>> Whether this is implemented as a bool flag or as a separate blacklist is > >>>> an implementation detail, but a bool flag just seemed simpler and faster > >>>> to me, than having to look in several lists to figure out whether a > >>>> connection exists or not. > >>> > >>> You don't need to look in several lists to figure out whether a > >>> connection exists or not. If we have connection objects, which I think > >>> we both want to have, it's enough to get the list all connections and > >>> see whether a particular connection is included in that list. > >>> > >> > >> Okay, so let me see if I understand this right. You propose that you can > >> add explicit connections between two specified nodes, but blacklisting > >> default connections have to be done on a node wide level (rather than > >> per connection). > >> > >> That sounds interesting, as it would be more resilient towards nodes > >> appearing and disappearing later on. > >> I think that blacklisting would have to be two booleans per node though, > >> one for outgoing connections and one for incoming. And a connection > >> cannot exist if it is blocked on *either* side, rather than both sides. > >> Does that make sense? > > > > My plan has so far been to only disable outgoing default connections, > > but if there's need for it, I don't see any problem with adding another > > bool for disabling incoming default connections. Do you have a use case? > > > > Well, what's outgoing for playback is incoming for recording, so I think > this would be the corresponding use case: assume a user changes from B > -> A to C -> A, and that later on, a new source D appears. Then you > would want to disable A on the incoming side to avoid a new D -> A > connection? Ok, I misunderstood what you meant by incoming and outgoing. Since a node can't be both an input and output node, it can never have both incoming and outgoing connections in the audio flow direction sense. I thought that by "incoming" you meant connections that are initiated by other nodes, and by "outgoing" I thought you meant connections that are initiated by the node itself. That is, "incoming" and "outgoing" wouldn't have anything to do with audio flow direction. In your example, are B, C and D sources, and is A a capture stream? And B -> A was a default connection initiated by A? If so, I would do the move from B -> A to C -> A so that default connections are disabled for A, and an explicit connection is added from C to A. D probably won't initiate any default connections (sources and sinks usually don't do that), but if it does initiate a default connection to A, I think it's more likely that it should be allowed (this would be pretty unusual routing rule, though, and you didn't explain why the D -> A connection would be created, so it's hard to say anything with great confidence). -- Tanu
