usb1.py 文件源码

def _validContext(func):
        # Defined inside USBContext so we can access "self.__*".
        @contextlib.contextmanager
        def refcount(self):
            with self.__context_cond:
                if not self.__context_p and self.__auto_open:
                    # BBB
                    warnings.warn(
                        'Use "with USBContext() as context:" for safer cleanup'
                        ' on interpreter shutdown. See also USBContext.open().',
                        DeprecationWarning,
                    )
                    self.open()
                self.__context_refcount += 1
            try:
                yield
            finally:
                with self.__context_cond:
                    self.__context_refcount -= 1
                    if not self.__context_refcount:
                        self.__context_cond.notifyAll()
        if inspect.isgeneratorfunction(func):
            def wrapper(self, *args, **kw):
                with refcount(self):
                    if self.__context_p:
                        # pylint: disable=not-callable
                        for value in func(self, *args, **kw):
                            # pylint: enable=not-callable
                            yield value
        else:
            def wrapper(self, *args, **kw):
                with refcount(self):
                    if self.__context_p:
                        # pylint: disable=not-callable
                        return func(self, *args, **kw)
                        # pylint: enable=not-callable
        functools.update_wrapper(wrapper, func)
        return wrapper
    # pylint: enable=no-self-argument,protected-access