[Chandler-dev] Chandler IMAP server parcel

[Grant Baillie]

Hey, Andi

Thanks for looking at that code: Most of your comments are right on  
the money. IMAP has restrictions on what UIDs can be, though: see below.

On 7 Jul, 2006, at 11:00, Andi Vajda wrote:

> ...
>     validityUID = schema.One(
>         schema.Integer,
>         doc = 'The unique id number of this mailbox.',
>         initialValue = random.randint(1000000, 9999999),
>         )  #@# why not use a UUID ?
>            #@# from chandlerdb.util.c import UUID()
>            #@# initialValue = UUID()
>            #@# also, maybe this should be in __init__() so that all  
> mailboxes
>            #@# don't endup with the same UID
>            #@# (an initial value is not required, by the way)

In IMAP, a mailbox uid (a.k.a. "UIDVALIDITY value") has to be a non- 
zero 32-bit unsigned value. It's also supposed to be unique for the  
mailbox at that path (i.e. deleting & recreating the mailbox should  
give a new UID). So, a UUID (128 bits IIRC) won't work here: Most  
implementations use a timestamp (an increasing sequence of integers  
is also possible).

However, as you point out, an initialValue isn't really required,  
either, and doesn't have the right behaviour w.r.t. deletion and  
recreation. Also, a random int could theoretically collide. Maybe the  
best thing is to override __init__ to make validityUID a computed  
value (like a timestamp).

A similar comment applies to your comments about UUIDs for uidNext &  
UIDs: these also have to be 32-bit positive unsigned ints, and have  
the additionial requirement of increasing monotonically as messages  
are added to the mailbox.

--Grant