plugin XEP-0384: Fully reworked to adjust to the reworked python-omemo:

- support for both (modern) OMEMO under the `urn:xmpp:omemo:2` namespace and (legacy) OMEMO under the `eu.siacs.conversations.axolotl` namespace
- maintains one identity across both versions of OMEMO
- migrates data from the old plugin
- includes more features for protocol stability
- uses SCE for modern OMEMO
- fully type-checked, linted and format-checked
- added type hints to various pieces of backend code used by the plugin
- added stubs for some Twisted APIs used by the plugin under stubs/ (use `export MYPYPATH=stubs/` before running mypy)
- core (xmpp): enabled `send` trigger and made it an asyncPoint

fix 375

sat/memory/encryption.py

@@ -19,10 +19,11 @@
 
 import copy
 from functools import partial
-from collections import namedtuple
+from typing import Optional
 from twisted.words.protocols.jabber import jid
 from twisted.internet import defer
 from twisted.python import failure
+from sat.core.core_types import EncryptionPlugin, EncryptionSession, MessageData
 from sat.core.i18n import D_, _
 from sat.core.constants import Const as C
 from sat.core import exceptions
@@ -34,12 +35,6 @@ from sat.memory import persistent
 
 log = getLogger(__name__)
 
-EncryptionPlugin = namedtuple("EncryptionPlugin", ("instance",
-                                                   "name",
-                                                   "namespace",
-                                                   "priority",
-                                                   "directed"))
-
 
 class EncryptionHandler:
     """Class to handle encryption sessions for a client"""
@@ -339,7 +334,7 @@ class EncryptionHandler:
 
         self.client.feedback(entity, msg)
 
-    def getSession(self, entity):
+    def getSession(self, entity: jid.JID) -> Optional[EncryptionSession]:
         """Get encryption session for this contact
 
         @param entity(jid.JID): get the session for this entity
@@ -476,13 +471,17 @@ class EncryptionHandler:
 
         return mess_data
 
-    def isEncryptionRequested(self, mess_data, namespace=None):
+    def isEncryptionRequested(
+        self,
+        mess_data: MessageData,
+        namespace: Optional[str] = None
+    ) -> bool:
         """Helper method to check if encryption is requested in an outgoind message
 
-        @param mess_data(dict): message data for outgoing message
-        @param namespace(str, None): if set, check if encryption is requested for the
-            algorithm specified
-        @return (bool): True if the encryption flag is present
+        @param mess_data: message data for outgoing message
+        @param namespace: if set, check if encryption is requested for the algorithm
+            specified
+        @return: True if the encryption flag is present
         """
         encryption = mess_data.get(C.MESS_KEY_ENCRYPTION)
         if encryption is None: