Re: Custom IMAP flags

[Oswald B. <osw...@gm...>]

On Sun, Jun 29, 2014 at 02:09:15PM +0200, Vincent Bernat wrote:
> How could we support them in mbsync?
> 
> If I would like to support them with an ad hoc modification, I think
> this would be easy:
> 
hacking in support for a few fixed flags would be reasonably easy.

>  1. Would the above steps work correctly?
> 
you need to adjust the imap flag parser as well.

>  2. Do I really need to keep the sort order in maildir's Flags array?
>
it's a requirement of maildir.

> It would be easier to add flags from configuration file if I didn't
> have to.
> 
too bad. :P

so far, i thought of a fully dynamic system somewhat inspired by
http://wiki2.dovecot.org/MailboxFormat/Maildir (it might make sense to
store the mapping directly in .uidvalidity).
of course, the downside of such a system would be that it wouldn't be
supported by anything else. i have some vague ideas how to make it
useful with mutt, but that's about it.

a configuration file based system would be easier to implement and would
be indeed more useful in the cases where the MUA already has some
defined meaning for particular flags in maildir.
it would be somewhat higher-maintenance configuration-wise, but i guess
it's acceptable.

it's probably sufficient to support 32 flags total, so 27 custom ones.
the config could look like that:

  Keywords J:$Junk N:$NoJunk a:Green b:Red c:Blue

maybe it should be per-Channel, but i guess we can start with only a
global config.

simply build an array of letter-word pairs from the predefined flags and
the config. then sort it and complain about duplicates. change the
drivers and sync.c to use that instead of its own tables. done.
caveat: the journal replay must refuse to proceed when the mapping
changes (it uses numerical flag values. though it may be a good idea to
change that anyway).