Adjust for the fact that Python 2.5 doesn't have collections.MutableSet.

[invirt/packages/python-afs.git] / afs / pts.py

diff --git a/afs/pts.py b/afs/pts.py
index 9c44f3a..f99bc8f 100644 (file)
--- a/afs/pts.py
+++ b/afs/pts.py
@@ -1,7 +1,12 @@
 import collections
 from afs import _pts
 
-class PTRelationSet(collections.MutableSet):
+try:
+    SetMixin = collections.MutableSet
+except AttributeError:
+    SetMixin = object
+
+class PTRelationSet(SetMixin):
     """Collection class for the groups/members of a PTEntry.
 
     This class, which acts like a set, is actually a view of the
@@ -45,7 +50,8 @@ class PTRelationSet(collections.MutableSet):
         Args:
             elt: The element to add.
         """
-        self._set.add(self._ent._pts.getEntry(elt))
+        if hasattr(self, '_set'):
+            self._set.add(self._ent._pts.getEntry(elt))
 
     def _discard(self, elt):
         """Remove a PTEntry to this instance's internal representation.
@@ -57,7 +63,8 @@ class PTRelationSet(collections.MutableSet):
         Args:
             elt: The element to discard.
         """
-        self._set.discard(self._ent._pts.getEntry(elt))
+        if hasattr(self, '_set'):
+            self._set.discard(self._ent._pts.getEntry(elt))
 
     def __len__(self):
         """Count the members/groups in this set.
@@ -165,6 +172,16 @@ class PTRelationSet(collections.MutableSet):
 
         self._discard(elt)
 
+    def remove(self, elt):
+        """Remove an entity from a group; it must already be a member.
+
+        If the entity is not a member, raise a KeyError.
+        """
+        if elt not in self:
+            raise KeyError(elt)
+
+        self.discard(elt)
+
 
 class PTEntry(object):
     """An entry in the AFS protection database.