zeroconf.py 文件源码

def write_record(self, record, now):
        """Writes a record (answer, authoritative answer, additional) to
        the packet"""
        if self.state == self.State.finished:
            return 1

        start_data_length, start_size = len(self.data), self.size
        self.write_name(record.name)
        self.write_short(record.type)
        if record.unique and self.multicast:
            self.write_short(record.class_ | _CLASS_UNIQUE)
        else:
            self.write_short(record.class_)
        if now == 0:
            self.write_int(record.ttl)
        else:
            self.write_int(record.get_remaining_ttl(now))
        index = len(self.data)

        # Adjust size for the short we will write before this record
        self.size += 2
        record.write(self)
        self.size -= 2

        length = sum((len(d) for d in self.data[index:]))
        # Here is the short we adjusted for
        self.insert_short(index, length)

        # if we go over, then rollback and quit
        if self.size > _MAX_MSG_ABSOLUTE:
            while len(self.data) > start_data_length:
                self.data.pop()
            self.size = start_size
            self.state = self.State.finished
            return 1
        return 0