proof-of-concept for a simple AOP implementation

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@1968 fd906abe-77d9-0310-91a1-e0d9ade77398

util/aop.py

@@ -25,16 +25,12 @@ $Id$
 
 def getNotifier(method):
     if isinstance(method, (Notifier, BoundNotifier)):
+        # already wrapped
         return method
     if method.im_self is not None:
-        name = method.im_func.func_name
-        classMethod = getattr(method.im_class, name)
-        if not isinstance(classMethod, Notifier):
-            classMethod = Notifier(classMethod)
-            setattr(method.im_class, name, classMethod)
-        notifier = BoundNotifier(classMethod, method.im_self)
-        setattr(method.im_self, name, notifier)
-        return notifier
+        # wrapping instance method - let's also wrap the class-level method
+        classNotifier = getNotifier(getattr(method.im_class, method.im_func.func_name))
+        return BoundNotifier(classNotifier, method.im_self)
     return Notifier(method)
 
 
@@ -56,9 +52,7 @@ class Notifier(object):
         if isinstance(existing, BoundNotifier):
             # the instance's method is already wrapped
             return existing
-        notifier = BoundNotifier(self, instance)
-        setattr(instance, self.name, notifier)
-        return notifier
+        return BoundNotifier(self, instance)
 
     def __call__(self, *args, **kw):
         for sub, sargs, skw in self.beforeSubs:
@@ -80,6 +74,7 @@ class BoundNotifier(object):
     def __init__(self, context, instance):
         self.context = context
         self.instance = instance
+        setattr(instance, context.name, self)
         self.beforeSubs = []
         self.afterSubs = []
 

util/aop.txt

@@ -84,7 +84,3 @@ Combining class and instance level wrapping
   logging: after foo, result=48
   48
 
-TODO: check case where instance is wrapped first, then class -
-that means: always wrap class when wrapping an instance, and always
-wrap instance with BoundNotifier.
-