decorator.py

"""
同时修饰classmethod，bound_method, function的decorator
"""


from functools import wraps
import types
class Profile:
    def __init__(self, func):
        wraps(func)(self)
        self.func_calls = 0

    def _profile_work(self):
        self.func_calls += 1
        print('func calls', self.func_calls)

    def __call__(self, *args, **kwargs):
        self._profile_work()
        return self.__wrapped__(*args, **kwargs)

    def __get__(self, instance, owner):
        if instance is None:
            print(owner)
            cm = self.__wrapped__
            self._profile_work()
            #对象或者类对classmethod或者method取值，得到的是经过他们__get__方法算出的结果，前者是绑定到class对象，后者绑定到调用者本身
            #classmethod和普通的function或者method都是descriptor对象，只不过__get__的时候会丢掉第一个参数(instance)
            return cm.__get__(None, owner)
        return types.MethodType(self, instance)

class Math:

    @Profile
    @classmethod
    def add(cls, a, b):
        return a + b

    @Profile
    def multi(self, a, b):
        return a * b

@Profile
def minus(a, b):
    return a - b

# print(Math().add(2, 3))
# print(Math().add(2, 3))
# print(Math().add(2, 3))
print(Math.add(2, 3))
print(Math.add(2, 3))
print(Math.add(2, 3))

math = Math()
math.multi(1, 2)
math.multi(1, 2)
math.multi(1, 2)


minus(2, 1)
minus(2, 1)
minus(2, 1)