This makes the contact ID its own newtype instead of being a plain
u32. The change purposefully does not yet try and reap any benefits
from this yet, instead aiming for a boring change that's easy to
review. Only exception is the ToSql/FromSql as not doing that yet
would also have created churn in the database code and it is easier to
go straight for the right solution here.
The state bob needs to maintain during a secure-join process when
exchanging messages used to be stored on the context. This means if
the process was killed this state was lost and the securejoin process
would fail. Moving this state into the database should help this.
This still only allows a single securejoin process at a time, this may
be relaxed in the future. For now any previous securejoin process
that was running is killed if a new one is started (this was already
the case).
This can remove some of the complexity around BobState handling: since
the state is in the database we can already make state interactions
transactional and correct. We no longer need the mutex around the
state handling. This means the BobStateHandle construct that was
handling the interactions between always having a valid state and
handling the mutex is no longer needed, resulting in some nice
simplifications.
Part of #2777.
- doc fixes
- make BobStateHandle safer by moving the state out of the handle.
- handle more match cases explicit in BobState returns
- fewer mutable variables
