sepolgen: convert cmp functions to key functions

In python3 it is needed to pass compare function as a key argument
instead of directly passing compare function to sort function

Signed-off-by: Robert Kuska <rkuska@redhat.com>

sepolgen/src/sepolgen/output.py

@@ -131,7 +131,7 @@ def sort_filter(module):
         rules = []
         rules.extend(node.avrules())
         rules.extend(node.interface_calls())
-        rules.sort(rule_cmp)
+        rules.sort(key=util.cmp_to_key(rule_cmp))
 
         cur = None
         sep_rules = []
@@ -155,7 +155,7 @@ def sort_filter(module):
 
         ras = []
         ras.extend(node.role_types())
-        ras.sort(role_type_cmp)
+        ras.sort(key=util.cmp_to_key(role_type_cmp))
         if len(ras):
             comment = refpolicy.Comment()
             comment.lines.append("============= ROLES ==============")

sepolgen/src/sepolgen/util.py

@@ -145,6 +145,29 @@ class Comparison():
     def __ne__(self, other):
         return self._compare(other, lambda a, b: a != b)
 
+if sys.version_info < (2,7):
+    # cmp_to_key function is missing in python2.6
+    def cmp_to_key(mycmp):
+        'Convert a cmp= function into a key= function'
+        class K:
+            def __init__(self, obj, *args):
+                self.obj = obj
+            def __lt__(self, other):
+                return mycmp(self.obj, other.obj) < 0
+            def __gt__(self, other):
+                return mycmp(self.obj, other.obj) > 0
+            def __eq__(self, other):
+                return mycmp(self.obj, other.obj) == 0
+            def __le__(self, other):
+                return mycmp(self.obj, other.obj) <= 0
+            def __ge__(self, other):
+                return mycmp(self.obj, other.obj) >= 0
+            def __ne__(self, other):
+                return mycmp(self.obj, other.obj) != 0
+        return K
+else:
+    from functools import cmp_to_key
+
 def cmp(first, second):
     return (first > second) - (second > first)