On Mon, 01 Mar 2010 11:27:07 -0500, Ben Gamari <bgamari@gmail.com> wrote:
> > 2. get the list of new mails which need to be indexed
> >    (current notmuch does recursive file traversal, for git-based store
> >    it will be something like system("git diff-tree --name-status ...")
> >
> Is this really necessary? Another option (which I believe has been
> mentioned here in the past) is to simply pass notmuch new a list of
> message "paths" to add (although I'm not sure if many mail delivery
> programs give you that sort of information). 

This could also be possible, but now, you say "notmuch new" and notmuch
itself figure out what to index. If passing notmuch a list on files to
index will be the only supported way, it might be hard for new users to
start with notmuch. A nice thing on notmuch is that it can be used
almost without any configuration.

> How do you propose that the backends keep track of what mail has been
> indexed?

For example by using Xapian metadata:
notmuch->xapian_db->set_metadata ("git-head", sha1);

> > Now, if we have this, it would be very easy to add support for
> > Maildir-based mail-store. The implementation of the first two methods
> > would be the same as what is currently in notmuch and the third method
> > would rename files in mailstore if certain tags (such as unread) are
> > added or removed. In case of rename, notmuch database would be
> > immediately updated to reflect the change.
> > 
> The interface here seems a little vague. How would the backend notify
> notmuch that the filename has changed?

notmuch new

The idea is that tags changed by notmuch are stored immediately (and
database is updated accordingly), whereas when the mail store is changed
by an external tool, you must explicitly ask notmuch to notice that.

> > So to summarize, I think there should be an abstract layer for
> > handling different types of mail-store. I can see at least three
> > possible implementations of this abstract interface: 1) immutable
> > mail-store (as currently implemented in notmuch) 2) Maildir-based
> > mail-store for limited synchronization with other Maildir tools and 
> > 3) git-based mail-store for full synchronization.
> 
> Don't forget mbox. It seems like it would be pretty trivial to
> implement (although I'm not sure what performance would look like).

I personally do not use mboxes, so I'm not interested in them.

> > I've already started working on this, but I'm still in the state where I
> > mainly study how notmuch works in order not to break its current
> > functionality.
> 
> With all of this infrastructure, it seems like it wouldn't be too
> difficult to support messages from multiple backends in a single index.
> Not sure if people would be interested enough to warrant the added
> complexity though.

I'm currently not interested in such a functionality, but we can add it
later if there is a need.


Bye
Michal