[RFC] database: get and set mapping of dovecot compatible maildir keywords

[Michal Sojka]

Hi David,

On Sat, Sep 27 2014, David Bremner wrote:
> A future modification of notmuch_message_tags_to_maildir_flags and
> notmuch_message_maildir_flags_to_tags could allow 26 more tags to be
> synced via maildir.
> ---
>
> I'm not sure if this is worth pursuing or not, but I thought I'd toss
> it out there.  On IRC the other day the topic of syncing IMAP keywords
> to notmuch tags came up again, in particular the dovecot variant that
> maps 26 user defined keywords to characters a-z on the end of the
> maildir info.  One roadblock I saw at the time was the need for
> configuration of mapping of letters to tags.  This patch is the result
> of my realizing that at least that part is not hard (unlike the rabbit
> hole we seemed to get into for e.g. log configuration).
>
> Some downsides of this approach are fairly obvious
>
>     - only 26 tags. It turns out I don't have that many non-nmbug tags
>       that I really care about. YMMV, of course.
>
>     - nonstandard. this won't roundtrip via offlineimap (unless
>       offlineimap is modified).  Directly syncing the maildir or using
>       some dovecot specific syncer would work.
>
> Some upsides are:
>
>     - Provides an IMAP bridge solution; compatible with dovecot; my
>       impression is this is the most common imap solution among
>       notmuch users.  
>     - relatively simple implementation, just need to
>       update the maildir name synching routines. Of course no
>       implementation is as simple as possible
>
>  lib/database.cc | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++

I'd prefer having the mapping stored in the config file rather than in
the database. This would allow me to synchronize the configuration
between multiple computers. Would there be some benefit of having the
mapping (also) in the database?

-Michal