Instead of letting the plugins specify a default storage to use, just look at
the supported ones and use the best one.
"MT is preferred over "ME" or "SM", as "MT=ME+SM"
There is no point in specifying a default 'mem1' memory storage, which is used
for reading/listing/deleting, as those are operations that need a specific
'mem1' set each time.
Also, there is no point in specifying separate default 'mem2' and 'mem3' memory
storages, specially because now we allow Sms.Store() to specify a storage.
So, we will now only have a 'default' memory storage, which is applicable for
both 'mem2' and 'mem3' (storing, sending from storage and deleting).
Different ports of the same modem may get handled by different drivers. We
therefore need to provide a list of drivers (new `Modem.Drivers' property with
signature 'as') instead of just one (removed `Modem.Driver' property with
signature 's').
$ sudo mmcli -m 0 | grep drivers
| drivers: 'qcserial, qmi_wwan'
Instead of the `_in_port()' variants, we'll provide more generic
`_full()' methods. These should be used either if we want to send commands
to a specific port, or if we want to use a specific user-provided GCancellable.
In addition to this user-provided GCancellable, we keep the internal modem-wide
one.
* mm_base_modem_peek_port_* () will return either a port object (no new
reference), or NULL if none available.
You would usually peek() a port if you're going to use it just in the current
method, as there is no way to that reference to get invalid (we're single
threaded).
* mm_base_modem_get_port_* () will return either NEW references to valid
port objects, or NULL if none available.
And, you would usually get() a port, whenever you want the port object to be
valid even out of the current method, for example when keeping it in the
context of an async operation.
Also, we need to consider that the primary AT port MAY BE NULL when you
peek() or get() it. This is due to the fact that we may be releasing ports
(due to device disconnection) in the middle of async operations.