Questions about the Backend Interface

[Derek Atkins]

Dave Peticolas <dave@krondo.com> writes:

> We must be careful here. Presumably the Backend is going to receive
> information that the engine needs to be updated by some out-of-band
> mechanism like a signal. Right now, the Backend must not mess with
> the engine outside of the normal flow of control. Everything outside
> the engine has been written under the assumption that the engine
> cannot change outside of the current thread of control. Relaxing
> that assumption would require a significant amount of work.
> 
> I think it would be much easier if the Backend informed the engine
> that it needs to be synchronized with the external source, and then
> the GUI event loop would poll the engine and, if needed, tell it to
> synchronize with the external source.

This works well for Transactions.  I could just have the server
send a list of all the 'changed' transactions.  The backend can just
save that transaction list and signal that there is update work to be
done.  Then it can request the updated list of transactions from the
server.

I suppose I could do the same thing with accounts.  However I'm going
to have to change how I think about it.  In particular, I need to
change how I cope with account parenting.  Currently I'm only
transfering complete AccountGroups..  If I'm going to transfer a
single account at a time, I'm going to need a way to signal that the
parent changed.  Unfortunately an AccountGroup doesn't have a GUID, so
I really need to grab account->parent->parent->guid to figure out who
my parent is (and assume that I'm a top-level account is
account->parent->parent is NULL).

> dave

-derek

-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
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