Add attributeTracker debugging-helper module.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@1562 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/attributeTracker.py

+#
+# Copyright (C) 2006-2010  Nexedi SA
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+from neo.locking import LockUser
+
+"""
+  Usage example:
+
+    from neo import attributeTracker
+
+    class Foo(object):
+
+        ...
+
+        def assertBar(self, expected_value):
+            if self.bar_attr != expected_value:
+                attributeTracker.whoSet(self, 'bar_attr')
+
+    attributeTracker.track(Foo)
+"""
+
+MODIFICATION_CONTAINER_ID = '_attribute_tracker_dict'
+
+def tracker_setattr(self, attr, value, setattr):
+    modification_container = getattr(self, MODIFICATION_CONTAINER_ID, None)
+    if modification_container is None:
+        modification_container = {}
+        setattr(self, MODIFICATION_CONTAINER_ID, modification_container)
+    modification_container[attr] = LockUser()
+    setattr(self, attr, value)
+
+def track(klass):
+    original_setattr = klass.__setattr__
+    def klass_tracker_setattr(self, attr, value):
+        tracker_setattr(self, attr, value, original_setattr)
+    klass.__setattr__ = klass_tracker_setattr
+
+def whoSet(instance, attr):
+    result = getattr(instance, MODIFICATION_CONTAINER_ID, None)
+    if result is not None:
+        result = result.get(attr)
+    if result is not None:
+        result = result.formatStack()
+    return result
+