We should not call pa_core_ref() anywhere in the code. Doing so
will prevent proper daemon shutdown as the only call (in daemon/main.c)
to pa_core_unref() should always call free_core() and perform a normal
shutdown (i.e. unload all modules gracefully).
This adds a PA_VOLUME_IS_VALID() macro for checking if a given
pa_volume_t is valid. This makes changes to the volume ranges simpler
(just change PA_VOLUME_MAX, for example, without needing to modify any
other code).
Using the subscription events caused an assertion crash sometimes when a sink
was removed and a new sink was created (i.e. card profile change) and a stream
was moved from the removed sink to the new sink. The stream dbus object's
subscription callback got a change event before the core dbus object's
subscription callback got the sink remove/creation events. The stream's
subscription callback then queried the core for the object path of the new
sink, and since the core was not yet aware of the new sink, an assertion was
hit in pa_dbusiface_device_get_path().
Now that the core uses synchronous hooks to keep the sink and source lists up
to date, this particular problem can't occur anymore.
* Make the dbus object constructors take a pa_dbusiface_core pointer
as an argument. Remove the path_prefix argument.
* Expose the core object path as a constant in protocol-dbus.h.
* Move the core interface name constant from iface-core.h to
protocol-dbus.h.
