[PATCH 4/4] Add a MessageWaiting interface to track message waiting indications.

[Denis Kenzior]

Hi Andrew,

> > For setting mailbox numbers, a working EF-MBDN is required since the only
> > alternative would be to store them on the filesystem.
>
> mw_set_indicator does the right thing, I missed this fact.  But when a
> mailbox number is set or received from network all clients get a
> PropertyChanged and the new number can be retrieved from the interface
> but only when the store succeeded, previously it would be available
> regardless of MBDN on the card and the writing to card was secondary.
> The number is kind of important if you want to hear the messages.

So you're right that even if we get an enhanced voice mail notification message 
the Mailbox number won't be signaled unless we have the SIM provisioned with 
EF-MBI & EF-MBDN.

The problem is, if we don't have the SIM files available, then the next time 
oFono is restarted this information is lost anyway until the next MWI 
notification arrives.  So you're back to not being able to dial the mailbox.

This is also an issue with the indications themselves.  If we don't have EF-
MWIS provisioned, the information is lost when oFono is restarted.  So we're 
now inconsistent between MBDN/MWIS, so maybe we shouldn't update them either 
in this case.

One solution is to always store this info on the filesystem and backup to SIM.

The other solution is to preserve current behavior, but to also expose the 
enhanced notifications in a separate interface (as discussed previously) and 
include any Mailbox numbers there.

Thoughts?

Regards,
-Denis