Move the volume code into a separate file with the reference C implementations.
Add a function to retrieve the volume function and one to install a new one.
Make the coding style match the rest of pulseaudio more.
Remove some liboil functions, they seem unoptimized and likely slower than our
handrolled versions here.
According to POSIX getgrnam_r() returns the error code as return value,
and not in errno. Honour that.
Pointed out and inspired by a patch from Ted Percival.
- We now implement a logic where the sink maintains two distinct
volumes: the 'reference' volume which is shown to the users, and the
'real' volume, which is configured to the hardware. The latter is
configured to the max of all streams. Volume changes on sinks are
propagated back to the streams proportional to the reference volume
change. Volume changes on sink inputs are forwarded to the sink by
'pushing' the volume if necessary.
This renames the old 'virtual_volume' to 'real_volume'. The
'reference_volume' is now the one exposed to users.
By this logic the sink volume visible to the user, will always be the
"upper" boundary for everything that is played. Saved/restored stream
volumes are measured relative to this boundary, the factor here is
always < 1.0.
- introduce accuracy for sink volumes, similar to the accuracy we
already have for source volumes.
- other cleanups.
- drop the 'virtual_' prefix from s->virtual_volume since we don't
distuingish between reference and real volumes for sources
- introduce an accuracy for source volumes: if the hardware can control
the volume "close enough" don't necessarily adjust the rest in
software unless it is beyond a certain threshold. This should save a
little bit of CPU at the expensive of a bit of accuracy in volume
handling.
- other minor cleanups
This of course makes the name 'fixed' a bit of a misnomer. However the
definitions are now like this:
fixed latency: the latency may change during runtime, but is solely
controlled by the backend, the client has no influence.
dynamic latency: the latency may change during runtime, influenced by
the requests of the clients.
i.e. fixed vs. dynamic is from the perspective of the client.
Previously we might have dropped messages from IO trheads to the main
thread. This tuend out to be problematic since this cause SHM release
messages to be lost. More visibly however this could cause playback
freezing when moving streams between sinks and removing the old sink
right away.
This adds pa_assert_io_context() and pa_assert_ctl_context() in addition
to a few related macros. When called they will fail when the current execution
context is not IO resp. not control context. (aka 'thread' context vs.
'main' context)
