From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Wed, 6 Dec 2006 21:37:25 +0000 (+0000)
Subject: moved _impl_dict to an external weakref so that TypeEngine objects can be pickled
X-Git-Tag: rel_0_3_2~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=21d4e2a96eb8f505e8d2c942204917477c4323d3;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

moved _impl_dict to an external weakref so that TypeEngine objects can be pickled
---

diff --git a/lib/sqlalchemy/types.py b/lib/sqlalchemy/types.py
index 08f2c98436..eddb5d306f 100644
--- a/lib/sqlalchemy/types.py
+++ b/lib/sqlalchemy/types.py
@@ -12,19 +12,20 @@ __all__ = [ 'TypeEngine', 'TypeDecorator', 'NullTypeEngine',
             ]
 
 from sqlalchemy import util, exceptions
-import inspect
+import inspect, weakref
 try:
     import cPickle as pickle
 except:
     import pickle
 
+_impl_cache = weakref.WeakKeyDictionary()
+
 class AbstractType(object):
     def _get_impl_dict(self):
         try:
-            return self._impl_dict
-        except AttributeError:
-            self._impl_dict = {}
-            return self._impl_dict
+            return _impl_cache[self]
+        except KeyError:
+            return _impl_cache.setdefault(self, {})
     impl_dict = property(_get_impl_dict)
 
     def copy_value(self, value):