Make shell responsible for activity ID generation

Enables tracking of activity launch throughout the whole process, so that
the shell can be aware of the activity ID from the moment the activity
is started by the shell, until the activity becomes active.  Previously,
the activity itself generated its own ID and told the shell what it was.

shell/view/Shell.py

@@ -68,6 +68,8 @@ class Shell(gobject.GObject):
         self._frame = Frame(self)
         self._frame.show_and_hide(3)
 
+        self._pservice = PresenceService.get_instance()
+
         #self.start_activity('org.laptop.JournalActivity')
 
     def _handle_camera_key(self):
@@ -190,13 +192,11 @@ class Shell(gobject.GObject):
         return self._model
 
     def join_activity(self, bundle_id, activity_id):
-        pservice = PresenceService.get_instance()
-
         activity = self.get_activity(activity_id)
         if activity:
             activity.present()
         else:
-            activity_ps = pservice.get_activity(activity_id)
+            activity_ps = self._pservice.get_activity(activity_id)
 
             if activity_ps:
                 # Get the service name for this activity, if
@@ -218,10 +218,51 @@ class Shell(gobject.GObject):
             else:
                 logging.error('Cannot start activity.')
 
+    def _find_unique_activity_id(self):
+        # create a new unique activity ID
+        i = 0
+        act_id = None
+        while i < 10:
+            act_id = sugar.util.unique_id()
+            i += 1
+
+            # check through existing activities
+            found = False
+            for xid, act_host in self._hosts.items():
+                if act_host.get_id() == act_id:
+                    found = True
+                    break
+            if found:
+                act_id = None
+                continue
+
+            # check through network activities
+            activities = self._pservice.get_activities()
+            for act in activities:
+                if act_id == act.get_id():
+                    found = True
+                    break
+            if found:
+                act_id = None
+                continue
+
+        return act_id
+
     def start_activity(self, activity_type):
         logging.debug('Shell.start_activity')
-        activity = ActivityFactory.create(activity_type)
-        activity.start()
+        act_id = self._find_unique_activity_id()
+        if not act_id:
+            logging.error("Couldn't find available activity ID.")
+            return None
+
+        try:
+            logging.debug("Shell.start_activity will start %s:%s" % (activity_type, act_id))
+            activity = ActivityFactory.create(activity_type)
+        except dbus.DBusException, e:
+            logging.debug("Couldn't start activity '%s':\n  %s" % (activity_type, e))
+            return None
+
+        activity.start(act_id)
         return activity
 
     def set_zoom_level(self, level):

shell/view/clipboardicon.py

@@ -4,6 +4,7 @@ from sugar.graphics.menuicon import MenuIcon
 from view.clipboardmenu import ClipboardMenu
 from sugar.activity import ActivityFactory
 from sugar.clipboard import clipboardservice
+from sugar import util
 
 class ClipboardIcon(MenuIcon):
 
@@ -53,7 +54,7 @@ class ClipboardIcon(MenuIcon):
                 
                 if activity_id:
                     activity = ActivityFactory.create(activity_id)
-                    activity.start()
+                    activity.start(util.unique_id())
                     activity.execute("open_document", [self._object_id])
                 
     def _popup_action_cb(self, popup, action):