From: Raymond Hettinger <python@rcn.com>
Date: Sat, 3 Apr 2010 03:14:28 +0000 (+0000)
Subject: Improve clear() method.  Keeps key/value refcnts >= 1 until final dict.clear() so... 
X-Git-Tag: v2.7b1~113
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6b96ecb0ab8d06b7c11d1b82baebc47452a7b13e;p=python

Improve clear() method.  Keeps key/value refcnts >= 1 until final dict.clear() so that decrefs to zero won't trigger arbitrary code .  Also runs a bit faster.
---

diff --git a/Lib/collections.py b/Lib/collections.py
index 1f1f51072b..79f6696bb8 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -107,8 +107,14 @@ class OrderedDict(dict, MutableMapping):
 
     def clear(self):
         'od.clear() -> None.  Remove all items from od.'
-        for k in dict.keys(self):
-            del self[k]
+        try:
+            for node in self.__map.itervalues():
+                del node[:]
+            self.__root[:] = [self.__root, self.__root, None]
+            self.__map.clear()
+        except AttributeError:
+            pass
+        dict.clear(self)
 
     setdefault = MutableMapping.setdefault
     update = MutableMapping.update