blob: 55c95da8532f47244d57a77e20fc7376502cb388 [file] [log] [blame]
xf.li86118912025-03-19 20:07:27 -07001class Delegator:
2
3 def __init__(self, delegate=None):
4 self.delegate = delegate
5 self.__cache = set()
6 # Cache is used to only remove added attributes
7 # when changing the delegate.
8
9 def __getattr__(self, name):
10 attr = getattr(self.delegate, name) # May raise AttributeError
11 setattr(self, name, attr)
12 self.__cache.add(name)
13 return attr
14
15 def resetcache(self):
16 "Removes added attributes while leaving original attributes."
17 # Function is really about resetting delegator dict
18 # to original state. Cache is just a means
19 for key in self.__cache:
20 try:
21 delattr(self, key)
22 except AttributeError:
23 pass
24 self.__cache.clear()
25
26 def setdelegate(self, delegate):
27 "Reset attributes and change delegate."
28 self.resetcache()
29 self.delegate = delegate
30
31if __name__ == '__main__':
32 from unittest import main
33 main('idlelib.idle_test.test_delegator', verbosity=2)