cache.py 文件源码

def underscore_memoization(func):
    """
    Decorator for methods::

        class A(object):
            def x(self):
                if self._x:
                    self._x = 10
                return self._x

    Becomes::

        class A(object):
            @underscore_memoization
            def x(self):
                return 10

    A now has an attribute ``_x`` written by this decorator.
    """
    name = '_' + func.__name__

    def wrapper(self):
        try:
            return getattr(self, name)
        except AttributeError:
            result = func(self)
            if inspect.isgenerator(result):
                result = list(result)
            setattr(self, name, result)
            return result

    return wrapper