Ken Murchison wrote:
Boris Lytochkin wrote:
Hello!
I need an advice in implementing per-mailbox \Seen flag (or 'shared'
\Seen flag in per-user basis).
For now I want to implement it this way:
1) add a new mailbox attribute, say 'sharedseen'
2) switch path for .seen file in imap/seen_*.c:seen_getpath() if
'sharedseen' flag is set on mailbox.
3) changes in replication module?
So, setting 'sharedseen' attribute to mailbox will cause using
per-mailbox seen-file.
What are weak points of this implementation?
Is there more correct way to make per-mailbox \Seen flag?
My quick thoughts would be the following:
- Add a 'sharedseen' mailbox attribute as you suggest (as a mailbox
annotation)
- When a mailbox is opened that has this annotation enabled, we open the
seen state database for the special 'anyone' user instead of the
authorized user. This would allow using the same API with minimal
changes. Perhaps we could come up with a better userid then 'anyone'
but its already reserved as special via ACL.
-----
- As an alternative to using a seen db for 'anyone' we could go back to
using a local seen db in the mailbox folder, but then we'd have to have
function pointers to swap between the functions for local access vs
per-user access.
- As another alternative, we could keep track of shared seen state in
cyrus.index, but that would require an upgrade to the index file format,
and more API changes.
I actually went digging into seen state and cyrus.index a little today
for another reason, and I realized that we wouldn't have to
expand/upgrade the index file to accomodate a shared seen state. The
existing field for system flags is just a bitmask, so we could easily
add a bit for shared \Seen. We could also implement the sharedseen
annotation as a mailbox flag in the index header, just like condstore.
Based on other changes that I'm thinking about, I'm starting to like
this idea better, even thought it *may* involve more code.
--
Kenneth Murchison
Systems Programmer
Project Cyrus Developer/Maintainer
Carnegie Mellon University
