[Sugar-devel] [PATCH sugar] Friendstray: make sure the tray is right on the sharer side OLPC #10817

[Sascha Silbe]

Excerpts from Simon Schampijer's message of Fri Jun 24 11:57:56 +0200 2011:
> The code path that listens for the 'activity-added' signal is used to
> track the following use case: 'A' starts an activity
> (he gets the 'active-activity-changed' signal from the shell), he then
> at a later point shares the activity. In order to track joining/leaving
> buddies he needs to get the shared activity. On other machines if we
> receive the 'activity-added' signal we can ignore it, therefore the
> check if the current active activity is the shared one.

I understood neither the description nor the patch at first. Let's go
into detail a bit:


Sequence of events:

A					B
---------------------------------------------------------------------------
starts activity
shell:active-activity-changed fires
shares activity
neighborhood:activity-added fires?	neighborhood:activity-added fires
					joins activity
					shell:active-activity-changed fires


According to the HIG, the People side of the Frame shows the individuals
that the user is collaborating with in the currently active
activity. [1]

On the "sharer" side shell:active-activity-changed will fire before a
shared activity object exists. So we need to wait for the corresponding
neighborhood:activity-added signal in order to access the shared
activity object and connect to its buddy-added and buddy-received
signals.

On the "joiner" side the shared activity object is already available
when shell:active-activity-changed fires, so we can connect to the
signals right away. neighborhood:activity-added doesn't need to do
anything in this case.

When switching between different activities, the shared activity object
also already exists (if the activity is shared at all), so again
neighborhood:activity-added should be a no-op.


> +++ b/src/jarabe/frame/friendstray.py
> @@ -75,6 +75,10 @@ class FriendsTray(VTray):
>      def __neighborhood_activity_added_cb(self, neighborhood_model,
>                                           shared_activity):
>          logging.debug('FriendsTray.__neighborhood_activity_added_cb')
> +        active_activity = shell.get_model().get_active_activity()
> +        if active_activity.get_activity_id() != shared_activity.activity_id:
> +            return
> +

With the above understanding, shouldn't we reset self._shared_activity
to None in __active_activity_changed_cb() and add the following check
before yours?

        if self._shared_activity is not None:
            return


Sascha

[1] http://wiki.sugarlabs.org/go/Human_Interface_Guidelines/The_Laptop_Experience/The_Frame#People
-- 
http://sascha.silbe.org/
http://www.infra-silbe.de/
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