This was causing a memory corruption and crash because the
simple-endpoint-link was not calling finalize of the endpoint-link
and the GWeakRefs pointing to the endpoints were not uninitialized,
causing g_object_unref later to try to write to them (on free'ed memory)
* rework how global objects are stored in the core
* rework how users get notified about global objects
and proxies of remote global objects
The purpose of this change is to have a class that can manage
objects that are registered in the core or signalled through the
registry. This object can declare interest on certain types
of global objects and only keep & signal those objects that it is
interested in. Additionally, it can prepare proxy features and
asynchronously deliver an 'objects-changed' signal, which is
basically telling us that the list of objects has changed.
This is useful to simplify port proxies management in WpAudioStream.
Now the stream object can declare that it is interested in ports
that have "node.id" == X and the object manager will only maintain
a list of those. Additionally, it will emit the 'objects-changed'
signal when the list of ports is complete, so there is no reason to
do complex operations and core syncs in the WpAudioStream class
in order to figure out when the list of ports is ready.
As a side effect, this also reduces resource management. Now we
don't construct a WpProxy for every global that pipewire reports;
we only construct proxies when there is interest in them!
Another interesting side effect is that we can now register an
object manager at any point in time and get immediately notified
about remote globals that already exist. i.e. when you register
an object manager that is interested in nodes, it will be immediately
notified about all the existing nodes in the graph. This is useful
to avoid race conditions between connecting the signal and objects
beting created in pipewire
* Every client has a priority based on its role
* For playback, we allow only a single client to play at a time
* For capture, we allow all clients to capture simultaneously
* Every time the "selected" device changes (either because devices
are discovered/removed or because the user changed the selection),
the clients are re-linked to the new "selected" device.
* When a playback client quits and there are others waiting unlinked,
the highest priority one is linked automatically.
* This also properly fixes re-linking the correct client(s) to the
correct device(s) when wireplumber exits and restarts.
This changes the registration point to be the endpoint and not the
session manager, as it seems easier to implement (the implementation
will not need to keep a pointer to the session manager around)
* Make streams a GVariant array, for future-proofness
* Add API for controls (volume, mute, brightness, contrast, etc...)
* Remove API for profiles (it's not well-thought; may be re-added
in the future)
After discussing things at the AGL May 2019 F2F meeting
and reflecting on the initial design of WirePlumber,
it became clear that it needed a fresh start.
