Added reference tracking

ldap3_mapper_new/base.py

 from copy import deepcopy
 
 class SessionState:
-	def __init__(self, objects=None, deleted_objects=None):
+	def __init__(self, objects=None, deleted_objects=None, references=None):
 		self.objects = objects or {}
 		self.deleted_objects = deleted_objects or {}
+		self.references = references or {} # {(attr_name, value): {srcobj, ...}, ...}
 
 	def copy(self):
-		return SessionState(objects=deepcopy(self.objects), deleted_objects=deepcopy(self.deleted_objects))
+		return SessionState(deepcopy(self.objects), deepcopy(self.deleted_objects), deepcopy(self.references))
+
+	def ref(self, obj, attr, values):
+		for value in values:
+			if key not in self.references:
+				self.references[key] = {self.obj}
+			else:
+				self.references[key].add(self.obj)
+
+	def unref(self, obj, attr, values):
+		for value in values:
+			self.references.get((name, value), set()).discard(obj)
 
 class ObjectState:
 	def __init__(self, session=None, attributes=None, dn=None):
@@ -31,6 +43,8 @@ class AddOperation:
 	def apply_session(self, session_state):
 		assert self.dn not in session_state.objects
 		session_state.objects[self.dn] = self.obj
+		for name, values in self.attributes.items():
+			session_state.ref(self.obj, name, values)
 
 	def apply_ldap(self, conn):
 		success = conn.add(self.dn, self.object_classes, self.attributes)
@@ -41,6 +55,7 @@ class DeleteOperation:
 	def __init__(self, obj):
 		self.dn = obj.state.dn
 		self.obj = obj
+		self.attributes = deepcopy(obj.state.attributes)
 
 	def apply_object(self, obj_state):
 		obj_state.dn = None
@@ -49,6 +64,8 @@ class DeleteOperation:
 		assert self.dn in session_state.objects
 		del session_state.objects[self.dn]
 		session_state.deleted_objects[self.dn] = self.obj
+		for name, values in self.attributes.items():
+			session_state.unref(self.obj, name, values)
 
 	def apply_ldap(self, conn):
 		success = conn.delete(self.dn)
@@ -58,6 +75,7 @@ class DeleteOperation:
 class ModifyOperation:
 	def __init__(self, obj, changes):
 		self.obj = obj
+		self.attributes = deepcopy(obj.state.attributes)
 		self.changes = deepcopy(changes)
 
 	def apply_object(self, obj_state):
@@ -72,7 +90,15 @@ class ModifyOperation:
 						obj_state.attributes[attr].remove(value)
 
 	def apply_session(self, session_state):
-		pass
+		for attr, changes in self.changes.items():
+			for action, values in changes:
+				if action == MODIFY_REPLACE:
+					session_state.unref(self.obj, attr, self.attributes.get(attr, [])
+					session_state.ref(self.obj, attr, values)
+				elif action == MODIFY_ADD:
+					session_state.ref(self.obj, attr, values)
+				elif action == MODIFY_DELETE:
+					session_state.unref(self.obj, attr, values)
 
 	def apply_ldap(self, conn):
 		success = conn.modify(self.obj.state.dn, self.changes)
@@ -141,9 +167,12 @@ class Session:
 			return None
 		assert len(conn.response) == 1
 		assert conn.response[0]['dn'] == dn
-		self.state.objects[dn] = Object(self, conn.response[0])
-		self.committed_state.objects[dn] = self.state.objects[dn]
-		return self.state.objects[dn]
+		obj = Object(self, conn.response[0])
+		self.state.objects[dn] = obj
+		self.committed_state.objects[dn] = obj
+		for attr, values in obj.state.attributes.items():
+			self.state.ref(obj, attr, values)
+		return obj
 
 	def search(self, search_base, search_filter):
 		conn = self.get_connection()
@@ -156,9 +185,12 @@ class Session:
 			elif dn in self.state.deleted_objects:
 				continue
 			else:
-				self.state.objects[dn] = Object(self, response)
-				self.committed_state.objects[dn] = self.state.objects[dn]
-				res.append(self.state.objects[dn])
+				obj = Object(self, response)
+				self.state.objects[dn] = obj
+				self.committed_state.objects[dn] = obj
+				for attr, values in obj.state.attributes.items():
+					self.state.ref(obj, attr, values)
+				res.append(obj)
 		return res
 
 class Object: