Initialize signal handler, so we can remove getattr

common/lib/xmodule/xmodule/modulestore/__init__.py

@@ -154,17 +154,6 @@ class ActiveBulkThread(threading.local):
         self.records = defaultdict(bulk_ops_record_type)
 
 
-class NullSignalHandler(object):
-    """
-    A null handler that does nothing
-    """
-    def send(self, *args, **kwargs):
-        """
-        No-op
-        """
-        pass
-
-
 class BulkOperationsMixin(object):
     """
     This implements the :meth:`bulk_operations` modulestore semantics which handles nested invocations
@@ -180,23 +169,8 @@ class BulkOperationsMixin(object):
     def __init__(self, *args, **kwargs):
         super(BulkOperationsMixin, self).__init__(*args, **kwargs)
         self._active_bulk_ops = ActiveBulkThread(self._bulk_ops_record_type)
-        self._signal_handler = None
+        self.signal_handler = None
 
-    @property
-    def signal_handler(self):
-        """
-        Return a signal handler, defaults to a null handler that does nothing.
-        """
-        if not self._signal_handler:
-            self._signal_handler = NullSignalHandler()
-        return self._signal_handler
-
-    @signal_handler.setter
-    def signal_handler(self, value):
-        """
-        Set the signal handler
-        """
-        self._signal_handler = value
 
     @contextmanager
     def bulk_operations(self, course_id, emit_signals=True):
@@ -324,7 +298,7 @@ class BulkOperationsMixin(object):
         """
         Sends out the signal that items have been published from within this course.
         """
-        if bulk_ops_record.has_publish_item:
+        if self.signal_handler and bulk_ops_record.has_publish_item:
             self.signal_handler.send("course_published", course_key=course_id)
             bulk_ops_record.has_publish_item = False
 
@@ -332,7 +306,7 @@ class BulkOperationsMixin(object):
         """
         Sends out the signal that library have been updated.
         """
-        if bulk_ops_record.has_library_updated_item:
+        if self.signal_handler and bulk_ops_record.has_library_updated_item:
             self.signal_handler.send("library_updated", library_key=library_id)
             bulk_ops_record.has_library_updated_item = False
 
@@ -1364,11 +1338,12 @@ class ModuleStoreWriteBase(ModuleStoreReadBase, ModuleStoreWrite):
         Arguments:
             course_key - course_key to which the signal applies
         """
-        bulk_record = self._get_bulk_ops_record(course_key) if isinstance(self, BulkOperationsMixin) else None
-        if bulk_record and bulk_record.active:
-            bulk_record.has_publish_item = True
-        else:
-            self.signal_handler.send("course_published", course_key=course_key)
+        if self.signal_handler:
+            bulk_record = self._get_bulk_ops_record(course_key) if isinstance(self, BulkOperationsMixin) else None
+            if bulk_record and bulk_record.active:
+                bulk_record.has_publish_item = True
+            else:
+                self.signal_handler.send("course_published", course_key=course_key)
 
     def _flag_library_updated_event(self, library_key):
         """
@@ -1379,17 +1354,19 @@ class ModuleStoreWriteBase(ModuleStoreReadBase, ModuleStoreWrite):
         Arguments:
             library_key - library_key to which the signal applies
         """
-        bulk_record = self._get_bulk_ops_record(library_key) if isinstance(self, BulkOperationsMixin) else None
-        if bulk_record and bulk_record.active:
-            bulk_record.has_library_updated_item = True
-        else:
-            self.signal_handler.send("library_updated", library_key=library_key)
+        if self.signal_handler:
+            bulk_record = self._get_bulk_ops_record(library_key) if isinstance(self, BulkOperationsMixin) else None
+            if bulk_record and bulk_record.active:
+                bulk_record.has_library_updated_item = True
+            else:
+                self.signal_handler.send("library_updated", library_key=library_key)
 
     def _emit_course_deleted_signal(self, course_key):
         """
         Helper method used to emit the course_deleted signal.
         """
-        self.signal_handler.send("course_deleted", course_key=course_key)
+        if self.signal_handler:
+            self.signal_handler.send("course_deleted", course_key=course_key)
 
 
 def only_xmodules(identifier, entry_points):