simplify the chexor function

Replace all that map(operator) nonsense.

It changes the error raised on invalid hashes, but we don't handle that
anywhere, and it shouldn't ever happen in real life.

Change-Id: Ib8cb549fac05e0b2725b4ea295326ac0c5e1f035

swift/common/db.py

@@ -19,7 +19,6 @@ from __future__ import with_statement
 from contextlib import contextmanager
 import hashlib
 import logging
-import operator
 import os
 from uuid import uuid4
 import sys
@@ -112,11 +111,8 @@ def chexor(old, name, timestamp):
     """
     if name is None:
         raise Exception('name is None!')
-    old = old.decode('hex')
-    new = hashlib.md5(('%s-%s' % (name, timestamp)).encode('utf_8')).digest()
-    response = ''.join(
-        map(chr, map(operator.xor, map(ord, old), map(ord, new))))
-    return response.encode('hex')
+    new = hashlib.md5(('%s-%s' % (name, timestamp)).encode('utf8')).hexdigest()
+    return '%032x' % (int(old, 16) ^ int(new, 16))
 
 
 def get_db_connection(path, timeout=30, okay_to_create=False):

test/unit/common/test_db.py

@@ -71,7 +71,7 @@ class TestChexor(unittest.TestCase):
             '4f2ea31ac14d4273fe32ba08062b21de')
 
     def test_invalid_old_hash(self):
-        self.assertRaises(TypeError, chexor, 'oldhash', 'name',
+        self.assertRaises(ValueError, chexor, 'oldhash', 'name',
                           normalize_timestamp(1))
 
     def test_no_name(self):