1 files changed, 43 insertions, 0 deletions
diff --git a/gi/overrides/__init__.py b/gi/overrides/__init__.py
index e69de29..d4cd80b 100644
--- a/gi/overrides/__init__.py
+++ b/gi/overrides/__init__.py
@@ -0,0 +1,43 @@
+import gobject
+
+registry = None
+class _Registry(dict):
+    def __setitem__(self, key, value):
+        '''We do checks here to make sure only submodules of the override 
+        module are added.  Key and value should be the same object and come
+        from the gi.override module.  
+
+        We add the override to the dict as "override_module.name".  For instance
+        if we were overriding Gtk.Button you would retrive it as such:
+        registry['Gtk.Button']
+        ''' 
+        if not key == value:
+            raise KeyError('You have tried to modify the registry.  This should only be done by the override decorator')
+
+        info = getattr(value, '__info__')
+        if info == None:
+            raise KeyError('Can not override a type %s, which is not in a gobject introspection typelib' % value.__name__)
+
+        if not value.__module__.startswith('gi.overrides'):
+            raise KeyError('You have tried to modify the registry outside of the overrides module.  This is not allowed')
+
+        g_type = info.get_g_type()
+        assert g_type != gobject.TYPE_NONE
+        if g_type != gobject.TYPE_INVALID:
+            g_type.pytype = value 
+
+            # strip gi.overrides from module name
+            module =  value.__module__[13:]
+            key = "%s.%s" % (module, value.__name__)
+            super(_Registry, self).__setitem__(key, value)
+
+    def register(self, override_class):
+        self[override_class] = override_class
+
+registry = _Registry()
+
+def override(type_):
+    '''Decorator for registering an override'''
+    registry.register(type_)
+    return type_
+