--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/contrib/formtools/utils.py	Wed Jun 02 18:57:35 2010 +0200
@@ -0,0 +1,39 @@
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
+from django.conf import settings
+from django.utils.hashcompat import md5_constructor
+from django.forms import BooleanField
+
+def security_hash(request, form, *args):
+    """
+    Calculates a security hash for the given Form instance.
+
+    This creates a list of the form field names/values in a deterministic
+    order, pickles the result with the SECRET_KEY setting, then takes an md5
+    hash of that.
+    """
+
+    data = []
+    for bf in form:
+        # Get the value from the form data. If the form allows empty or hasn't
+        # changed then don't call clean() to avoid trigger validation errors.
+        if form.empty_permitted and not form.has_changed():
+            value = bf.data or ''
+        else:
+            value = bf.field.clean(bf.data) or ''
+        if isinstance(value, basestring):
+            value = value.strip()
+        data.append((bf.name, value))
+        
+    data.extend(args)
+    data.append(settings.SECRET_KEY)
+
+    # Use HIGHEST_PROTOCOL because it's the most efficient. It requires
+    # Python 2.3, but Django requires 2.4 anyway, so that's OK.
+    pickled = pickle.dumps(data, pickle.HIGHEST_PROTOCOL)
+
+    return md5_constructor(pickled).hexdigest()
+