Just prepare the output on the port and signal ready. When the graph
completes we will be signaled again to recycle the buffer and
prepare more output if we can.
Improve the bookkeeping a little when activating nodes.
Fix race with moving nodes between drivers.
When we have a client driver node, it will have prepared the io
areas for us before sending the ready signal. We then need to run
the converters before signaling ready.
It is assumed that the output io area is ready when the ready
callback is called so that the next elements in the graph can be
triggered immediately. When the graph finishes, the node that
triggered the ready (the driver) is scheduled to recycle and complete
the graph.
Simplify the scheduling by using simple lists and removing the
subgraphs etc..
Make the driver node trigger all nodes it manages and when they
complete, trigger the driver node to finish the graph.
Remove the mix states, we can get rid of them when:
The format is the same for all mixer ports. Set the existing
format on new mixer ports. When the first format is set, the port
becomes READY. When all mixer ports are cleared the port goes back
to CONFIGURE.
Only output ports allocate and manage buffers, input ports share
the buffers of the peer output port on the link.
Pass the complete spa_node_info to update node information. Remove
the redundant max/min port info.
Update the remote node based on port and node update events.
Make struct spa_node_events for events emited from the main thread
and keep the spa_node_callbacks for the data thread callbacks.
The add_listener method installs the events and it's possible to
install multiple handles. Adding a listener first emits the info
and port_info events when installed, similar to how the PipeWire
proxy bind works.
This removes the need for the spa_pending_queue and makes it easier
to implement the _sync versions.
Add some helpers to make it easier for plugins to emit all the info
to new listeners.
Use the listeners for devices as well.
Add a new struct spa_param_info that lists the available params on
a node/port and if they are readable/writable/updated. We can use
this to replace and improve the PARAM_List and also to notify
property change and updates.
Update elements and code to deal with this new param stuff. Add
port and node info to most elements and signal changes.
Use async enum_params in -inspect and use the param info to know
which ones to enumerate.
Use the port info to know what parameters to update in the
remote-node.
