mkdirlockfile.py 文件源码

def acquire(self, timeout=None):
        timeout = timeout if timeout is not None else self.timeout
        end_time = time.time()
        if timeout is not None and timeout > 0:
            end_time += timeout

        if timeout is None:
            wait = 0.1
        else:
            wait = max(0, timeout / 10)

        while True:
            try:
                os.mkdir(self.lock_file)
            except OSError:
                err = sys.exc_info()[1]
                if err.errno == errno.EEXIST:
                    # Already locked.
                    if os.path.exists(self.unique_name):
                        # Already locked by me.
                        return
                    if timeout is not None and time.time() > end_time:
                        if timeout > 0:
                            raise LockTimeout("Timeout waiting to acquire"
                                              " lock for %s" %
                                              self.path)
                        else:
                            # Someone else has the lock.
                            raise AlreadyLocked("%s is already locked" %
                                                self.path)
                    time.sleep(wait)
                else:
                    # Couldn't create the lock for some other reason
                    raise LockFailed("failed to create %s" % self.lock_file)
            else:
                open(self.unique_name, "wb").close()
                return