Adjust Pickler and UnPickler imports to use ZODB._compat python 2 and…

… 3 compatible versions.

Add conditional import for cStringIO also.

setup.py

@@ -28,7 +28,7 @@
         'Acquisition',
         'DateTime',
         'transaction',
-        'ZODB3',
+        'ZODB',
         'Zope2',
     ],
 )

src/Products/ZopeVersionControl/Version.py

@@ -15,17 +15,16 @@
 
 import tempfile
 import time
-from cStringIO import StringIO
-from cPickle import Pickler, Unpickler
 
 from Acquisition import Implicit, aq_parent, aq_inner, aq_base
 from App.class_init import default__class_init__ as InitializeClass
 from Persistence import Persistent
 from AccessControl import ClassSecurityInfo
 from BTrees.OOBTree import OOBTree
 from OFS.SimpleItem import SimpleItem
-
 from Utility import VersionControlError
+from ZODB._compat import BytesIO
+from ZODB._compat import Pickler, Unpickler
 from nonversioned import listNonVersionedObjects, removeNonVersionedData
 
 
@@ -54,7 +53,7 @@ def persistent_load(ref):
         placeholder.id = "ignored_subobject"
         return placeholder
 
-    stream = StringIO()
+    stream = BytesIO()
     p = Pickler(stream, 1)
     p.persistent_id = persistent_id
     p.dump(obj)

src/Products/ZopeVersionControl/tests/common.py

@@ -26,7 +26,6 @@ def common_setUp(self):
     # Install a hack to make SimpleItem version aware, so that the
     # tests work. In normal development, you would mix in the
     # VersionSupport class on an as-needed basis.
-    import cStringIO
     from AccessControl.SecurityManagement import newSecurityManager
     from OFS.Application import Application
     from OFS.DTMLDocument import addDTMLDocument
@@ -38,15 +37,22 @@ def common_setUp(self):
 
     from Products.ZopeVersionControl.ZopeRepository import addRepository
     from ZODB import DB
+    from ZODB._compat import PY3
     from ZODB.DemoStorage import DemoStorage
+
+    if PY3:
+        from io import cStringIO
+    else:
+        from cStringIO import cStringIO
+
     s = DemoStorage()
     self.connection = DB( s ).open()
     try:
         r = self.connection.root()
         a = Application()
         r['Application'] = a
         self.root = a
-        responseOut = self.responseOut = cStringIO.StringIO()
+        responseOut = self.responseOut = cStringIO()
         self.app = makerequest( self.root, stdout=responseOut )
         self.app.acl_users.userFolderAddUser('UnitTester', '123', (), ())
         manage_addFolder(self.app, 'folder1')