This commit adds basic support for devices implementing HSP Headset
Unit, HSP Audio Gateway, HFP Handsfree Unit, HFP Audio Gateway to the
BlueZ 5 bluetooth audio devices driver module (module-bluez5-device).
There are several intertwined changes that I couldn't separate into
nicer commits. This is mostly just refactoring, but this also fixes
a bug: the old code set the device valid in parse_device_properties()
even if the device's adapter was invalid (had NULL address).
To improve the clarity of the code, I split the device_info_valid
variable into two booleans: properties_received and valid.
I added function device_update_valid() that checks all conditions that
affect the device validity. The function can then be called from any
place where something changes that potentially affects the device
validity. However, currently the only validity-affecting thing that
can change is the device adapter, so device_update_valid() is only
called from set_device_adapter().
I added the aforementioned set_device_adapter() function so that
whenever the adapter is set, the device validity gets updated
automatically.
The new properties_received variable allowed me to remove the
is_property_update function parameters.
This is a cosmetic change. There are a couple of places where we check
whether the adapter object is valid, and while checking whether the
address property is set works just fine, I find it nicer to have a
dedicated flag for the object validity. This improves maintainability
too, because if there will ever be more adapter properties that affect
the adapter validity, the places that check if the adapter is valid
don't need to be updated.
bluetoothd always send the GetManagedObjects() reply messages with the
objects array argument following an in-depth order starting from the
root. That means parents will always be known at the time their children
objects are parsed, if clients parse the objects in the same order they
appear in the array, as we do in PulseAudio.
This commit tries to protect PulseAudio in the case bluetoothd changes
that behavior for some reason. It hasn't been tested, since this
situation never occurs.
Create the pa_bluetooth_transport structure to store information about
the bluetooth transport and utility functions to manipulate this
structure. The acquire() and release() operations are function pointers
in the pa_bluetooth_transport structure to make possible for different
transport backends to provide different implementations of these
operations. Thre is also a userdata field for the transport backend
provide data for the acquire/release functions.
This commit also creates a new function
pa_bluetooth_device_any_transport_connected() to check if there is any
audio connection between the host and a remote device.
pa_bluetooth_discovery is the struct that holds information about known
Bluetooth audio devices and other information about the Bluetooth stack.
This commit also creates bluez5-util.[ch], which will hold a lot of
utility functions to help with the BlueZ 5 support.
