some performance optimizations

src/c3nav/editor/models/changedobject.py

@@ -42,8 +42,7 @@ class ChangedObject(models.Model):
         unique_together = ('changeset', 'content_type', 'existing_object_pk')
         ordering = ['created', 'pk']
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, model_class=None, **kwargs):
-        model_class = kwargs.pop('model_class', None)
         super().__init__(*args, **kwargs)
         self._set_object = None
         self._m2m_added_cache = {name: set(values) for name, values in self.m2m_added.items()}

src/c3nav/editor/models/changeset.py

@@ -75,6 +75,14 @@ class ChangeSet(models.Model):
 
         self.direct_editing = False
 
+        self._wrapped_model_cache = {}
+
+    def __getstate__(self):
+        return {
+            **self.__dict__,
+            '_wrapped_model_cache': {}
+        }
+
     """
     Get Changesets for Request/Session/User
     """
@@ -138,13 +146,20 @@ class ChangeSet(models.Model):
         if self.direct_editing:
             model.EditorForm = ModelWrapper(self, model).EditorForm
             return model
-        return ModelWrapper(self, model)
+        return self._get_wrapped_model(model)
+
+    def _get_wrapped_model(self, model):
+        wrapped = self._wrapped_model_cache.get(model, None)
+        if wrapped is None:
+            wrapped = ModelWrapper(self, model)
+            self._wrapped_model_cache[model] = wrapped
+        return wrapped
 
     def wrap_instance(self, instance):
         assert isinstance(instance, models.Model)
         if self.direct_editing:
             return instance
-        return self.wrap_model(instance.__class__).create_wrapped_model_class()(self, instance)
+        return self.wrap_model(instance.__class__).wrapped_model_class(self, instance)
 
     def relevant_changed_objects(self) -> typing.Iterable[ChangedObject]:
         return self.changed_objects_set.exclude(existing_object_pk__isnull=True, deleted=True)

src/c3nav/editor/wrappers.py

@@ -42,7 +42,7 @@ class BaseWrapper:
                 return model
             model = model._obj
         assert issubclass(model, models.Model)
-        return ModelWrapper(self._changeset, model)
+        return self._changeset._get_wrapped_model(model)
 
     def _wrap_instance(self, instance):
         """
@@ -53,7 +53,7 @@ class BaseWrapper:
                 return instance
             instance = instance._obj
         assert isinstance(instance, models.Model)
-        return self._wrap_model(instance.__class__).create_wrapped_model_class()(self._changeset, instance)
+        return self._wrap_model(instance.__class__).wrapped_model_class(self._changeset, instance)
 
     def _wrap_manager(self, manager):
         """
@@ -133,12 +133,16 @@ class ModelWrapper(BaseWrapper):
         """
         return get_submodels(self._obj)
 
+    @cached_property
+    def wrapped_model_class(self) -> typing.Type['ModelInstanceWrapper']:
+        return self.create_wrapped_model_class()
+
     def create_wrapped_model_class(self) -> typing.Type['ModelInstanceWrapper']:
         """
         Return a ModelInstanceWrapper that has a proxy to this instance as its type / metaclass. #voodoo
         """
         # noinspection PyTypeChecker
-        return self.create_metaclass()(self._obj.__name__ + 'InstanceWrapper', (ModelInstanceWrapper,), {})
+        return self.metaclass(self._obj.__name__ + 'InstanceWrapper', (ModelInstanceWrapper,), {})
 
     def __call__(self, **kwargs):
         """
@@ -149,6 +153,10 @@ class ModelWrapper(BaseWrapper):
             setattr(instance, name, value)
         return instance
 
+    @cached_property
+    def metaclass(self):
+        return self.create_metaclass()
+
     def create_metaclass(self):
         """
         Create the proxy metaclass for craeate_wrapped_model_class().