Monkey-patch ZODB.Connection.tpc_finish.

This is required since r2534, but was omitted from repository (patch was
posted on zodb-dev, awaiting review).

git-svn-id: https://svn.erp5.org/repos/neo/trunk@2658 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/client/__init__.py

+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+
+# NEO requires ZODB to allow TID to be returned as late as tpc_finish.
+# At the moment, no ZODB release include this patch.
+# Later, this must be replaced by some detection mechanism.
+needs_patch = True
+
+if needs_patch:
+    from ZODB import Connection
+
+    def tpc_finish(self, transaction):
+        """Indicate confirmation that the transaction is done."""
+
+        def callback(tid):
+            if self._mvcc_storage:
+                # Inter-connection invalidation is not needed when the
+                # storage provides MVCC.
+                return
+            d = dict.fromkeys(self._modified)
+            self._db.invalidate(tid, d, self)
+#       It's important that the storage calls the passed function
+#       while it still has its lock.  We don't want another thread
+#       to be able to read any updated data until we've had a chance
+#       to send an invalidation message to all of the other
+#       connections!
+        serial = self._storage.tpc_finish(transaction, callback)
+        if serial is not None:
+            assert isinstance(serial, str), repr(serial)
+            for oid_iterator in (self._modified, self._creating.iterkeys()):
+                for oid in oid_iterator:
+                    obj = self._cache.get(oid, None)
+                    # Ignore missing objects and don't update ghosts.
+                    if obj is not None and obj._p_changed:
+                        obj._p_changed = 0
+                        obj._p_serial = serial
+        self._tpc_cleanup()
+
+    Connection.tpc_finish = tpc_finish
+