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  1. import sys
  2. import warnings
  3. from gc import get_referrers
  4. from weakref import WeakKeyDictionary
  5. from types import FunctionType, CodeType, CellType
  6.  
  7. referrer_types = {
  8.     CodeType: [FunctionType],
  9.     FunctionType: [dict, CellType],
  10.     CellType: [tuple],
  11.     tuple: [FunctionType],
  12.     dict: [type]
  13. }
  14.  
  15. def get_class(obj):
  16.     if next_types := referrer_types.get(type(obj)):
  17.         for referrer in get_referrers(obj):
  18.             if issubclass(referrer_type := type(referrer), type):
  19.                 return referrer
  20.             if referrer_type in next_types and (cls := get_class(referrer)):
  21.                 return cls
  22.  
  23. def make_protector(action):
  24.     def decorator(func):
  25.         def wrapper(*args, **kwargs):
  26.             func_code = func.__code__
  27.             if func_code not in class_of:
  28.                 class_of[func_code] = get_class(func_code)
  29.             caller_code = sys._getframe(1).f_code
  30.             if caller_code not in class_of:
  31.                 class_of[caller_code] = get_class(caller_code)
  32.             if not (class_of[caller_code] and
  33.                     class_of[func_code] in class_of[caller_code].mro()):
  34.                 action(func.__qualname__)
  35.             return func(*args, **kwargs)
  36.         class_of = WeakKeyDictionary()
  37.         return wrapper
  38.     return decorator
  39.  
  40. @make_protector
  41. def protected(name):
  42.     warnings.warn(f'{name} is protected.', stacklevel=3)
  43.  
  44. @make_protector
  45. def private(name):
  46.     raise Exception(f'{name} is private.')
  47.  
  48. class C:
  49.     def A_factory(self):
  50.         class A:
  51.             @protected
  52.             def protected_func(self):
  53.                 print('protected is running')
  54.                 self.private_func()
  55.  
  56.             @private
  57.             def private_func(self):
  58.                 print('private is running')
  59.  
  60.         return A
  61.  
  62. a = C().A_factory()
  63.  
  64. class B(a):
  65.     def foo(self):
  66.         super().private_func()
  67.  
  68. b = B()
  69. b.foo()  # Runs without complaint because of inheritance
  70. b.protected_func()  # Runs with protected warning
  71. b.private_func()  # Raises Exception
Runtime error #stdin #stdout #stderr 0.19s 26112KB
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stdin
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Standard input is empty
stdout
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private is running
protected is running
private is running
stderr
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./prog.py:70: UserWarning: C.A_factory.<locals>.A.protected_func is protected.
Traceback (most recent call last):
  File "./prog.py", line 71, in <module>
  File "./prog.py", line 34, in wrapper
  File "./prog.py", line 46, in private
Exception: C.A_factory.<locals>.A.private_func is private.
https://ideone.com/o5aQae
language:
Python 3 (python  3.12)
created:
1 year ago
visibility:
secret

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