lock.py 文件源码

def _update(self, mode):
        if mode is None:
            if self.locked:
                fcntl.lockf(self.fd, fcntl.LOCK_UN)
                self.locked = False
        elif self.mode is not mode or not self.locked:
            self.mode = mode
            self.locked = True
            for offset in self.locks:
                fcntl.lockf(self.fd, self.mode, 1, offset)