Merge "Return 413 status on over-quota in the native API."

1 files changed, 13 insertions, 0 deletions

diff --git a/nova/utils.py b/nova/utils.py
index 86cbdce1d..9cfb6d06d 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -1238,6 +1238,19 @@ def sys_platform_translate(arch):
     return arch
 
 
+def walk_class_hierarchy(clazz, encountered=None):
+    """Walk class hierarchy, yielding most derived classes first"""
+    if not encountered:
+        encountered = []
+    for subclass in clazz.__subclasses__():
+        if subclass not in encountered:
+            encountered.append(subclass)
+            # drill down to leaves first
+            for subsubclass in walk_class_hierarchy(subclass, encountered):
+                yield subsubclass
+            yield subclass
+
+
 class UndoManager(object):
     """Provides a mechanism to facilitate rolling back a series of actions
     when an exception is raised.