Import the improved queryset_transform.py file from Towel

matthiask · matthiask · commit 87efc58393ce · 2013-11-26T14:34:28.000+01:00
diff --git a/feincms/utils/queryset_transform.py b/feincms/utils/queryset_transform.py
@@ -10,7 +10,7 @@
 This allows you to build optimisations like "fetch all tags for these 10 rows"
 while still benefiting from Django's lazy QuerySet evaluation.
 
-For example:
+For example::
 
     def lookup_tags(item_qs):
         item_pks = [item.pk for item in item_qs]
@@ -33,7 +33,7 @@ def lookup_tags(item_qs):
     for item in qs:
         print item, item.fetched_tags
 
-Prints:
+Prints::
 
     Winter comes to Ogglesbrook [<sledging>, <snow>, <winter>, <skating>]
     Summer now [<skating>, <sunny>]
@@ -94,9 +94,9 @@ def _clone(self, klass=None, setup=False, **kw):
         c._transform_fns = self._transform_fns[:]
         return c
 
-    def transform(self, fn):
+    def transform(self, *fn):
         c = self._clone()
-        c._transform_fns.append(fn)
+        c._transform_fns.extend(fn)
         return c
 
     def iterator(self):
@@ -109,6 +109,16 @@ def iterator(self):
         return result_iter
 
 
-class TransformManager(models.Manager):
-    def get_query_set(self):
-        return TransformQuerySet(self.model, using=self._db)
+if hasattr(models.Manager, 'from_queryset'):
+    TransformManager = models.Manager.from_queryset(TransformQuerySet)
+
+else:
+    class TransformManager(models.Manager):
+        def get_queryset(self):
+            return TransformQuerySet(self.model, using=self._db)
+
+        def get_query_set(self):
+            return TransformQuerySet(self.model, using=self._db)
+
+        def transform(self, *fn):
+            return self.get_query_set().transform(*fn)
