[sugar] Importing objects from journal

[Tomeu Vizoso]

This was discussed somewhat lightly a while ago. I expect the security
people to correct me where I'm wrong.

On Tue, 2007-09-25 at 13:48 +0200, Bert Freudenberg wrote:
> What's the policy on accessing objects in the journal?

There will be a D-Bus service (perhaps a new one, perhaps will be the
service corresponding to the Journal activity) that will offer a
retrieveObjectFromJournal method. This method will allow some preset
filters for filtering by Kind, Date, etc.

This method will open a modal dialog similar to the overlay in [1] and
will let the user choose one or several objects from a simplified
journal list view.

[1] http://wiki.laptop.org/go/Image:Activity_browse_handheld_navigation.jpg

Now would be a good moment to discuss if we should implement this for
FRS or later.

> I see Write uses sugar.graphics.objectchooser which simply queries  
> the datastore. Will that work once security is enabled?

The current implementation of sugar.graphics.objectchooser won't work,
but that interface could call in the future the service referred above
instead of calling directly the DataStore.

> Can I then store the retrieved object id in my activity instance and  
> keep that reference? Can I re-open that external object after  
> resuming my activity? Can I track changes to the object in this way?  
> How do I let the datastore know that my activity contains a reference  
> to another object, so that the other would not get discarded?
> 
> Or do I have to copy and keep that copy in "my" datastore entry,  
> which given the limited amount of NAND would be highly undesirable?

We have chosen to not support links to other objects in the journal.
This will waste space, but simplifies greatly things and we hope will
give a better experience.

This was decided expecting that differential storage and transparent
backup to the server will reduce the impact of storage waste and that
self contained objects will allow for easier sharing and management of
journal objects.

Tomeu