Rewrite dbus_helpers to not make a dbus connection on import. #2773

sugar/datastore/dbus_helpers.py

@@ -28,55 +28,63 @@ DS_DBUS_SERVICE = "org.laptop.sugar.DataStore"
 DS_DBUS_INTERFACE = "org.laptop.sugar.DataStore"
 DS_DBUS_PATH = "/org/laptop/sugar/DataStore"
 
-_bus = dbus.SessionBus()
-_data_store = dbus.Interface(_bus.get_object(DS_DBUS_SERVICE, DS_DBUS_PATH),
-                             DS_DBUS_INTERFACE)
+_data_store = None
+
+def _get_data_store():
+    global _data_store
+
+    if not _data_store:
+        _bus = dbus.SessionBus()
+        _data_store = dbus.Interface(_bus.get_object(DS_DBUS_SERVICE,
+                                                     DS_DBUS_PATH),
+                                     DS_DBUS_INTERFACE)
+    return _data_store
 
 def create(properties, filename):
-    object_id = _data_store.create(dbus.Dictionary(properties), filename)
+    object_id = _get_data_store().create(dbus.Dictionary(properties), filename)
     logging.debug('dbus_helpers.create: ' + object_id)
     return object_id
 
 def update(uid, properties, filename, reply_handler=None, error_handler=None, timeout=-1):
     logging.debug('dbus_helpers.update: %s, %s, %s' % (uid, filename, properties))
     if reply_handler and error_handler:
-        _data_store.update(uid, dbus.Dictionary(properties), filename,
+        _get_data_store().update(uid, dbus.Dictionary(properties), filename,
                 reply_handler=reply_handler,
                 error_handler=error_handler,
                 timeout=timeout)
     else:
-        _data_store.update(uid, dbus.Dictionary(properties), filename)
+        _get_data_store().update(uid, dbus.Dictionary(properties), filename)
 
 def delete(uid):
     logging.debug('dbus_helpers.delete: %r' % uid)
-    _data_store.delete(uid)
+    _get_data_store().delete(uid)
         
 def get_properties(uid):
     logging.debug('dbus_helpers.get_properties: %s' % uid)
-    return _data_store.get_properties(uid)
+    return _get_data_store().get_properties(uid)
 
 def get_filename(uid):
-    filename = _data_store.get_filename(uid)
+    filename = _get_data_store().get_filename(uid)
     logging.debug('dbus_helpers.get_filename: %s, %s' % (uid, filename))
     return filename
 
 def find(query, reply_handler, error_handler):
     logging.debug('dbus_helpers.find: %r' % query)
     if reply_handler and error_handler:
-        return _data_store.find(query, reply_handler=reply_handler,
+        return _get_data_store().find(query, reply_handler=reply_handler,
                 error_handler=error_handler)
     else:
-        return _data_store.find(query)
+        return _get_data_store().find(query)
 
 def mount(uri, options):
-    return _data_store.mount(uri, options)
+    return _get_data_store().mount(uri, options)
 
 def unmount(mount_point_id):
-    _data_store.unmount(mount_point_id)
+    _get_data_store().unmount(mount_point_id)
 
 def mounts():
-    return _data_store.mounts()
+    return _get_data_store().mounts()
 
 def get_unique_values(key):
-    return _data_store.get_uniquevaluesfor(key, dbus.Dictionary({}, signature='ss'))
+    return _get_data_store().get_uniquevaluesfor(key, dbus.Dictionary({}, signature='ss'))