On Sat, 28 Feb 2004, Volker Sauer wrote:
>Oha, now I understand why I couldn't create a Unix-Structure which maps 
>directly to the IMAP-Tree.
>But the question is then: what is the difference between ImapDir and 
>MailDir++?? I read the explenation on the website twice and after that, 

Maildir++ is a depot structure suggested by Courier-IMAP, and before Binc
IMAP came up with IMAPdir, it was the only IMAP->File system map for
nested folders in IMAP.

It's widely deployed, so Binc IMAP supports it. But IMAPdir is better.

>I thought, that ImapDir allows subfolders in a Unix-style-way, but as I 
>see, this is not the case. So what is it??

You may be mixing up a few things here ;-). It allows folders at any level
of nesting, and allows a folder to contain both messages and folders. It
also allows subfolders of INBOX as well as root level folders (siblings of
INBOX).

This maps onto the UNIX filesystem as each leaf node having one entry. 
Currently there is no map from a UNIX nested subfolder structure back to 
IMAP, because all mappings we've seen so far are too messy and don't seem 
to benefit anyone ;-).

>What is the difference between quota and maildirsize?

QUOTA is an IMAP protocol extension. maildirsize is a feature in Maildir++
for keeping track of the size of the Maildir, and it's therefore useful
for keeping track of the user's quota.

Binc IMAP needs a generic way to support QUOTA, where maildirsize has to
be supported for Binc IMAP to apply QUOTA with Maildir++.

>Or better: if imap-quota is the same as Unix-filesystem-quotas - what 
>does maildirsize mean?

It's not! :-). maildirsize is a file that contains the size of the mailbox
as an integer. It's an inaccurate, somewhat broken idea which assumes that
whomever accesses the Maildir mailboxes know how it works. It only counts
the size of the files, not the directory entries; hence the inaccuracy.

For most systems, it's all that's needed for keeping track of users'
quotas. Courier-IMAP inserts the size of files in the files' filenames'
unique part (exactly what DjB says _not_ to do) to speed up the
calculation of a Maildir's size, and this size is stored in the
maildirsize file. This file is updated on new arrivals, copying and
inserting messages into a mailbox.

maildirsize doesn't work on a system that only uses Courier-IMAP to access
the Maildirs, as the delivery agent (for many Binc'ers, qmail-local)  
doesn't know anything about maildirsize so it'll keep delivering mails to
that account.

So maildirsize isn't trivial to add support for; but QUOTA support in
general is something Binc IMAP can have handles for. In 1.3. :-)

Andy

--
Andreas Aardal Hanssen   | http://www.andreas.hanssen.name/gpg
Author of Binc IMAP      |  "It is better not to do something
http://www.bincimap.org/ |        than to do it poorly."


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