--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/soc/logic/common.py	Wed Oct 01 14:23:28 2008 +0000
@@ -0,0 +1,49 @@
+#!/usr/bin/python2.5
+#
+# Copyright 2008 the Melange authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Common helper functions.
+"""
+
+__authors__ = [
+  '"Pawel Solyga" <pawel.solyga@gmail.com>',
+  ]
+
+
+import re
+
+
+LINKNAME_PATTERN = r'''(?x)
+    ^
+    [0-9a-z]   # start with ASCII digit or lowercase
+    (
+     [0-9a-z]  # additional ASCII digit or lowercase
+     |         # -OR-
+     _[0-9a-z] # underscore and ASCII digit or lowercase
+    )*         # zero or more of OR group
+    $
+'''
+
+LINKNAME_REGEX = re.compile(LINKNAME_PATTERN)
+
+def isLinkNameFormatValid(link_name):
+  """Returns True if link_name is in a valid format.
+
+  Args:
+    link_name: link name used in URLs for identification
+  """
+  if LINKNAME_REGEX.match(link_name):
+    return True
+  return False
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