[Pyobjc-dev] PyObjcC class method swizzling

[Lukas P. | D. V. <lu...@dr...>]

Hi everyone!

I've just recently started to explore the power of PyObjC by rewriting  
the GPGMail plugin and I'm more than impressed.
A big compliment to the developers!

Unfortunately at the moment I'm stuck with class method swizzling.  
I've found a very nice decorator which can be used
to swizzle instance methods:

def swizzle(*args):
     cls, SEL = args
     def decorator(func):
         oldIMP      = cls.instanceMethodForSelector_(SEL)
         def wrapper(self, *args, **kwargs):
             return func(self, oldIMP, *args, **kwargs)
         newMethod   = objc.selector(wrapper,
                                     selector  = oldIMP.selector,
                                     signature = oldIMP.signature)
         objc.classAddMethod(cls, SEL, newMethod)
         return wrapper
     return decorator

My poor attempt to convert this into a decorator which swizzles class  
methods looks like the one below, but unfortunately doesn't
work.

def swizzleClassMethod(*args):
     cls, SEL = args
     def decorator(func):
         oldIMP      = cls.methodForSelector_(SEL)
         def wrapper(klass, *args, **kwargs):
             return func(klass, oldIMP, *args, **kwargs)
         newMethod   = objc.selector(wrapper,
                                     selector  = oldIMP.selector,
                                     signature = oldIMP.signature)
         objc.classAddMethod(cls, SEL, newMethod)
         return wrapper
     return decorator

I'd really appreciate it, if someone could help me to find out how to  
do this.
What I wanna do with that is replacing the + sharedPreferences class  
method of the NSPreferences class
with my own implementation and call the original method from within  
there.

Please anyone point me into the right direction, so I can finally  
finish the GPGMail plugin.

Thanks in advance

Lukas