[pygobject] Gtk: add an override for Gtk.main_quit

[John Palmieri <johnp src gnome org>]

commit cda317195566711d66190145b545e26ed7226172
Author: Johan Dahlin <johan gnome org>
Date:   Thu Dec 2 23:47:40 2010 -0200

    Gtk: add an override for Gtk.main_quit
    
    Override gtk.main_quit so that it can be used as a callback
    to signals, most importantly to the destroy signal of a widget:
    
       widget.connect('destroy', gtk.main_quit)
    
    This is compatible with what PyGTK does.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=636336

 gi/overrides/Gtk.py      |    5 ++++-
 gi/overrides/__init__.py |   27 +++++++++++++++++++++++++--
 2 files changed, 29 insertions(+), 3 deletions(-)
---
diff --git a/gi/overrides/Gtk.py b/gi/overrides/Gtk.py
index ca39682..6e8e566 100644
--- a/gi/overrides/Gtk.py
+++ b/gi/overrides/Gtk.py
@@ -1044,7 +1044,10 @@ class Button(Gtk.Button, Container):
 Button = override(Button)
 __all__.append('Button')
 
-import sys
+_Gtk_main_quit = Gtk.main_quit
+ override(Gtk.main_quit)
+def main_quit(*args):
+    _Gtk_main_quit()
 
 initialized, argv = Gtk.init_check(sys.argv)
 sys.argv = list(argv)
diff --git a/gi/overrides/__init__.py b/gi/overrides/__init__.py
index d4cd80b..c634a2f 100644
--- a/gi/overrides/__init__.py
+++ b/gi/overrides/__init__.py
@@ -1,3 +1,6 @@
+import sys
+import types
+
 import gobject
 
 registry = None
@@ -34,10 +37,30 @@ class _Registry(dict):
     def register(self, override_class):
         self[override_class] = override_class
 
+
+class overridefunc(object):
+    '''decorator for overriding a function'''
+    def __init__(self, func):
+        if not hasattr(func, '__info__'):
+            raise TypeError("func must be an gi function")
+        from ..importer import modules
+        self.module = modules[func.__module__].introspection_module
+
+    def __call__(self, func):
+        def wrapper(*args, **kwargs):
+            return func(*args, **kwargs)
+        wrapper.__name__ = func.__name__
+        setattr(self.module, func.__name__, wrapper)
+        return wrapper
+
 registry = _Registry()
 
 def override(type_):
     '''Decorator for registering an override'''
-    registry.register(type_)
-    return type_
+    if type(type_) == types.FunctionType:
+        return overridefunc(type_)
+    else:
+        registry.register(type_)
+        return type_
+