2 files changed, 45 insertions, 20 deletions

diff --git a/src/mailman/database/base.py b/src/mailman/database/base.py
index 34f644afa..55dee2068 100644
--- a/src/mailman/database/base.py
+++ b/src/mailman/database/base.py
@@ -15,7 +15,7 @@
 # You should have received a copy of the GNU General Public License along with
 # GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
@@ -32,7 +32,7 @@ from lazr.config import as_boolean
 from pkg_resources import resource_listdir, resource_string
 from storm.cache import GenerationalCache
 from storm.locals import create_database, Store
-from zope.interface import implements
+from zope.interface import implementer
 
 from mailman.config import config
 from mailman.interfaces.database import IDatabase
@@ -45,6 +45,7 @@ NL = '\n'
 
 
 
+@implementer(IDatabase)
 class StormBaseDatabase:
     """The database base class for use with the Storm ORM.
 
@@ -55,8 +56,6 @@ class StormBaseDatabase:
     # classes.
     TAG = ''
 
-    implements(IDatabase)
-
     def __init__(self):
         self.url = None
         self.store = None
@@ -194,7 +193,7 @@ class StormBaseDatabase:
 
         :param store: The Storm store to load the schema into.
         :type store: storm.locals.Store`
-        :param version: The schema version identifier of the form 
+        :param version: The schema version identifier of the form
             YYYYMMDDHHMMSS.
         :type version: string
         :param filename: The file name containing the schema to load.  Pass
diff --git a/src/mailman/database/transaction.py b/src/mailman/database/transaction.py
index 47e58d3e2..295f3d567 100644
--- a/src/mailman/database/transaction.py
+++ b/src/mailman/database/transaction.py
@@ -17,19 +17,36 @@
 
 """Transactional support."""
 
-from __future__ import absolute_import, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
 __metaclass__ = type
 __all__ = [
-    'txn',
+    'dbconnection',
+    'transaction',
+    'transactional',
     ]
 
 
+from contextlib import contextmanager
+
 from mailman.config import config
 
 
 
-class txn(object):
+@contextmanager
+def transaction():
+    """Context manager for ensuring the transaction is complete."""
+    try:
+        yield
+    except:
+        config.db.abort()
+        raise
+    else:
+        config.db.commit()
+
+
+
+def transactional(function):
     """Decorator for transactional support.
 
     When the function this decorator wraps exits cleanly, the current
@@ -38,16 +55,25 @@ class txn(object):
 
     Either way, the current transaction is completed.
     """
-    def __init__(self, function):
-        self._function = function
+    def wrapper(*args, **kws):
+        try:
+            rtn = function(*args, **kws)
+            config.db.commit()
+            return rtn
+        except:
+            config.db.abort()
+            raise
+    return wrapper
 
-    def __get__(self, obj, type=None):
-        def wrapper(*args, **kws):
-            try:
-                rtn = self._function(obj, *args, **kws)
-                config.db.commit()
-                return rtn
-            except:
-                config.db.abort()
-                raise
-        return wrapper
+
+
+def dbconnection(function):
+    """Decorator for getting at the database connection.
+
+    Use this to avoid having to access the global `config.db.store`
+    attribute.  This calls the function with `store` as the first argument.
+    """
+    def wrapper(*args, **kws):
+        # args[0] is self.
+        return function(args[0], config.db.store, *args[1:], **kws)
+    return wrapper