[Kolab-devel] Re: Non-unique UIDs

[Bo Thorsen]

On Tuesday 28 September 2004 11:55, Bernhard Reiter wrote:
> On Friday 24 September 2004 11:24, Bo Thorsen wrote:
> > On Friday 24 September 2004 11:09, Reinhold Kainhofer wrote:
> > > > Currently, KOrganizer has a very basic assumption that an event
> > > > must have a unique UID.
> > >
> > > Yes, UIDs have to be *globally* unique, i.e. across all computers
> > > and users.
> > >
> > > > Now consider this scenario:
> > > >
> > > > 1) Secretary and Boss both agree on a meeting invitation and get
> > > > the event stored in the calendar folders.
> > > >
> > > > 2) Boss gives access to his calendar folder to the secretary.
> > > >
> > > > 3) Secretary now has two folders that contain an event with
> > > > identical UIDs.
> > >
> > > But both events describe the same meeting.
> >
> > Yes, but they are not the same - when you are invited to some event,
> > you don't get reliable information on what the other people have
> > answered. So the two events could easily have different attendee
> > responses set.
> >
> > > > We might be able to do 2), by changing the way we store an event.
> > > > So when the user accepts an invitation, we make a new event with
> > > > a new UID and keep the scheduling UID for reference. But I think
> > > > this is more easily described than done.
> > >
> > > Yes, that will be quite hard to ipmlement. Imagine that the
> > > secretary wants to send out an invitation for her bosses event. The
> > > uid needs to be adjusted again before sending. And if she accepts,
> > > well, again, etc.
> >
> > So you think demanding the user to switch off their own calendar
> > first is the only way to go?
> >
> > I would be inclined to agree.
>
> I also tend in that direction, but thinking about a twist:
> When displaying the overview, it seems easier to me to just
> display one even twice, but when making changes (1) going into the
> editor or accepting an update, the right folder could get the only one
> that is active?

And this won't work, because as I already said, libkcal *can not* handle 
two events with the same UID. And basic assumptions are always an amazing 
amount of work to change.

> When in doubt I believe that disabling the other folders is fine,
> but we need a way to copy event from one event folder to another
> somehow, so there must be some automatic support for switching those
> folder on an off as far as I can see.

If you copy an event to a folder that already has an event with the same 
UID, you will get the conflict resolution. You have to. There is no way 
to distinguish between conflicts and this use.

Bo.

-- 

     Bo Thorsen                 |   Praestevejen 4
     Senior Software Engineer   |   5290 Marslev
     Klarälvdalens Datakonsult  |   Denmark
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