1 files changed, 44 insertions, 0 deletions
diff --git a/poky/meta/lib/oe/classutils.py b/poky/meta/lib/oe/classutils.py
new file mode 100644
index 000000000..45cd5249b
--- /dev/null
+++ b/poky/meta/lib/oe/classutils.py
@@ -0,0 +1,44 @@
+
+class ClassRegistryMeta(type):
+    """Give each ClassRegistry their own registry"""
+    def __init__(cls, name, bases, attrs):
+        cls.registry = {}
+        type.__init__(cls, name, bases, attrs)
+
+class ClassRegistry(type, metaclass=ClassRegistryMeta):
+    """Maintain a registry of classes, indexed by name.
+
+Note that this implementation requires that the names be unique, as it uses
+a dictionary to hold the classes by name.
+
+The name in the registry can be overridden via the 'name' attribute of the
+class, and the 'priority' attribute controls priority. The prioritized()
+method returns the registered classes in priority order.
+
+Subclasses of ClassRegistry may define an 'implemented' property to exert
+control over whether the class will be added to the registry (e.g. to keep
+abstract base classes out of the registry)."""
+    priority = 0
+    def __init__(cls, name, bases, attrs):
+        super(ClassRegistry, cls).__init__(name, bases, attrs)
+        try:
+            if not cls.implemented:
+                return
+        except AttributeError:
+            pass
+
+        try:
+            cls.name
+        except AttributeError:
+            cls.name = name
+        cls.registry[cls.name] = cls
+
+    @classmethod
+    def prioritized(tcls):
+        return sorted(list(tcls.registry.values()),
+                      key=lambda v: (v.priority, v.name), reverse=True)
+
+    def unregister(cls):
+        for key in cls.registry.keys():
+            if cls.registry[key] is cls:
+                del cls.registry[key]