remove `builtins.buffer` code from storage code

this is no longer needed on python 3

scripts-dev/convert_server_keys.py

@@ -3,8 +3,6 @@ import json
 import sys
 import time
 
-import six
-
 import psycopg2
 import yaml
 from canonicaljson import encode_canonical_json
@@ -12,10 +10,7 @@ from signedjson.key import read_signing_keys
 from signedjson.sign import sign_json
 from unpaddedbase64 import encode_base64
 
-if six.PY2:
-    db_type = six.moves.builtins.buffer
-else:
-    db_type = memoryview
+db_binary_type = memoryview
 
 
 def select_v1_keys(connection):
@@ -72,7 +67,7 @@ def rows_v2(server, json):
     valid_until = json["valid_until_ts"]
     key_json = encode_canonical_json(json)
     for key_id in json["verify_keys"]:
-        yield (server, key_id, "-", valid_until, valid_until, db_type(key_json))
+        yield (server, key_id, "-", valid_until, valid_until, db_binary_type(key_json))
 
 
 def main():

synapse/storage/_base.py

@@ -19,9 +19,6 @@ import random
 from abc import ABCMeta
 from typing import Any, Optional
 
-from six import PY2
-from six.moves import builtins
-
 from canonicaljson import json
 
 from synapse.storage.database import LoggingTransaction  # noqa: F401
@@ -103,11 +100,6 @@ def db_to_json(db_content):
     if isinstance(db_content, memoryview):
         db_content = db_content.tobytes()
 
-    # psycopg2 on Python 2 returns buffer objects, which we need to cast to
-    # bytes to decode
-    if PY2 and isinstance(db_content, builtins.buffer):
-        db_content = bytes(db_content)
-
     # Decode it to a Unicode string before feeding it to json.loads, so we
     # consistenty get a Unicode-containing object out.
     if isinstance(db_content, (bytes, bytearray)):

synapse/storage/data_stores/main/keys.py

@@ -17,8 +17,6 @@
 import itertools
 import logging
 
-import six
-
 from signedjson.key import decode_verify_key_bytes
 
 from synapse.storage._base import SQLBaseStore
@@ -28,12 +26,8 @@ from synapse.util.iterutils import batch_iter
 
 logger = logging.getLogger(__name__)
 
-# py2 sqlite has buffer hardcoded as only binary type, so we must use it,
-# despite being deprecated and removed in favor of memoryview
-if six.PY2:
-    db_binary_type = six.moves.builtins.buffer
-else:
-    db_binary_type = memoryview
+
+db_binary_type = memoryview
 
 
 class KeyStore(SQLBaseStore):

synapse/storage/data_stores/main/transactions.py

@@ -16,8 +16,6 @@
 import logging
 from collections import namedtuple
 
-import six
-
 from canonicaljson import encode_canonical_json
 
 from twisted.internet import defer
@@ -27,12 +25,7 @@ from synapse.storage._base import SQLBaseStore, db_to_json
 from synapse.storage.database import Database
 from synapse.util.caches.expiringcache import ExpiringCache
 
-# py2 sqlite has buffer hardcoded as only binary type, so we must use it,
-# despite being deprecated and removed in favor of memoryview
-if six.PY2:
-    db_binary_type = six.moves.builtins.buffer
-else:
-    db_binary_type = memoryview
+db_binary_type = memoryview
 
 logger = logging.getLogger(__name__)