[Python-checkins] r72223 - in python/trunk: Lib/pickle.py Lib/test/pickletester.py Misc/NEWS Modules/cPickle.c

Sat May 2 23:13:24 CEST 2009

Author: antoine.pitrou
Date: Sat May 2 23:13:23 2009
New Revision: 72223
Log:
Isue #5084: unpickling now interns the attribute names of pickled objects,
saving memory and avoiding growth in size of subsequent pickles. Proposal
and original patch by Jake McGuire.
Modified:
 python/trunk/Lib/pickle.py
 python/trunk/Lib/test/pickletester.py
 python/trunk/Misc/NEWS
 python/trunk/Modules/cPickle.c
Modified: python/trunk/Lib/pickle.py
==============================================================================

--- python/trunk/Lib/pickle.py	(original)
+++ python/trunk/Lib/pickle.py	Sat May 2 23:13:23 2009
@@ -1221,7 +1221,15 @@
 state, slotstate = state
 if state:
 try:
- inst.__dict__.update(state)
+ d = inst.__dict__
+ try:
+ for k, v in state.iteritems():
+ d[intern(k)] = v
+ # keys in state don't have to be strings
+ # don't blow up, but don't go out of our way
+ except TypeError:
+ d.update(state)
+
 except RuntimeError:
 # XXX In restricted execution, the instance's __dict__
 # is not accessible. Use the old way of unpickling
Modified: python/trunk/Lib/test/pickletester.py
==============================================================================
--- python/trunk/Lib/test/pickletester.py	(original)
+++ python/trunk/Lib/test/pickletester.py	Sat May 2 23:13:23 2009
@@ -938,6 +938,20 @@
 "Failed protocol %d: %r != %r"
 % (proto, obj, loaded))
 
+ def test_attribute_name_interning(self):
+ # Test that attribute names of pickled objects are interned when
+ # unpickling.
+ for proto in protocols:
+ x = C()
+ x.foo = 42
+ x.bar = "hello"
+ s = self.dumps(x, proto)
+ y = self.loads(s)
+ x_keys = sorted(x.__dict__)
+ y_keys = sorted(y.__dict__)
+ for x_key, y_key in zip(x_keys, y_keys):
+ self.assertIs(x_key, y_key)
+
 
 # Test classes for reduce_ex
 
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Sat May 2 23:13:23 2009
@@ -261,6 +261,10 @@
 Library
 -------
 
+- Issue #5084: unpickling now interns the attribute names of pickled objects,
+ saving memory and avoiding growth in size of subsequent pickles. Proposal
+ and original patch by Jake McGuire.
+
 - Issue #3002: ``shutil.copyfile()`` and ``shutil.copytree()`` now raise an
 error when a named pipe is encountered, rather than blocking infinitely.
 
Modified: python/trunk/Modules/cPickle.c
==============================================================================
--- python/trunk/Modules/cPickle.c	(original)
+++ python/trunk/Modules/cPickle.c	Sat May 2 23:13:23 2009
@@ -4473,8 +4473,16 @@
 
 		i = 0;
 		while (PyDict_Next(state, &i, &d_key, &d_value)) {
-			if (PyObject_SetItem(dict, d_key, d_value) < 0)
+			/* normally the keys for instance attributes are
+			 interned. we should try to do that here. */
+			Py_INCREF(d_key);
+			if (PyString_CheckExact(d_key))
+				PyString_InternInPlace(&d_key);
+			if (PyObject_SetItem(dict, d_key, d_value) < 0) {
+				Py_DECREF(d_key);
 				goto finally;
+			}
+			Py_DECREF(d_key);
 		}
 		Py_DECREF(dict);
 	}
