重构oceanbase的一个函数

我去，今天读了一下ob的源码，感觉有点乱啊！！！好吧，当作练手，我重构了一个函数

void* ObMySQLCallback::decode(easy_message_t* m)

    {

      uint32_t pkt_len = 0;

      uint8_t pkt_seq = 0;

      uint8_t pkt_type = 0;

      ObMySQLCommandPacket* packet = NULL;

      char* buffer = NULL;

      int32_t len = 0;



      if (NULL == m)

      {

        TBSYS_LOG(ERROR, "invalid argument m is %p", m);

      }

      else if (NULL == m->input)

      {

        TBSYS_LOG(ERROR, "invalide argument m->input is %p", m->input);

      }

      else

      {

        if ((len = static_cast<int32_t>(m->input->last - m->input->pos)) >= OB_MYSQL_PACKET_HEADER_SIZE)

        {

          //1. decode length from net buffer

          //2. decode seq from net buffer

          ObMySQLUtil::get_uint3(m->input->pos, pkt_len);

          ObMySQLUtil::get_uint1(m->input->pos, pkt_seq);



          //message has enough buffer

          if (pkt_len <= m->input->last - m->input->pos)

          {

            ObMySQLUtil::get_uint1(m->input->pos, pkt_type);

            //利用message带的pool进行应用层内存的分配

            buffer = reinterpret_cast<char*>(easy_pool_alloc(m->pool,

                                                              static_cast<uint32_t>(sizeof(ObMySQLCommandPacket) + pkt_len)));

            if (NULL == buffer)

            {

              TBSYS_LOG(ERROR, "alloc packet buffer(length=%lu) from m->pool failed", sizeof(ObMySQLCommandPacket) + pkt_len);

            }

            else

            {

              TBSYS_LOG(DEBUG, "alloc packet buffer length = %lu", sizeof(ObMySQLCommandPacket) + pkt_len);

              packet = new(buffer)ObMySQLCommandPacket();

              packet->set_header(pkt_len, pkt_seq);

              packet->set_type(pkt_type);

              packet->set_receive_ts(tbsys::CTimeUtil::getTime());

              memcpy(buffer + sizeof(ObMySQLCommandPacket), m->input->pos, pkt_len - 1);

              packet->get_command().assign(buffer + sizeof(ObMySQLCommandPacket), pkt_len - 1);

              TBSYS_LOG(DEBUG, "decode comand packet command is \"%.*s\"", packet->get_command().length(),

                        packet->get_command().ptr());

              if (PACKET_RECORDER_FLAG)

              {

                // record the packet to FIFO stream if required

                ObMySQLServer* server = reinterpret_cast<ObMySQLServer*>(m->c->handler->user_data);

                ObMySQLCommandPacketRecord record;

                record.socket_fd_ = m->c->fd;

                record.cseq_ = m->c->seq;

                record.addr_ = m->c->addr;

                record.pkt_length_ = pkt_len;

                record.pkt_seq_ = pkt_seq;

                record.cmd_type_ = pkt_type;

                struct iovec buffers[2];

                buffers[0].iov_base = &record;

                buffers[0].iov_len = sizeof(record);

                buffers[1].iov_base = m->input->pos;

                buffers[1].iov_len = pkt_len - 1;

                int err = OB_SUCCESS;

                if (OB_SUCCESS != (err = server->get_packet_recorder().push(buffers, 2)))

                {

                

                  TBSYS_LOG(WARN, "failed to record MySQL packet, err=%d", err);

                }

              }

              m->input->pos += pkt_len - 1;

            }

          }

          else

          {

            m->next_read_len = static_cast<int>(pkt_len - (m->input->last - m->input->pos));

            TBSYS_LOG(DEBUG, "not enough data in message, packet length = %u, data in message is %ld",

                      pkt_len, m->input->last - m->input->pos);

            m->input->pos -= OB_MYSQL_PACKET_HEADER_SIZE;

          }

        }

      }

      return packet;

    }

 

问题：代码好长。。。嵌套太深。。。

ObMySQLCommandPacket* ObMySQLCallback::make_packet(easy_message_t* m, uint32_t *pkt_len, uint8_t *pkt_seq, uint8_t *pkt_type)

{

    ObMySQLUtil::get_uint1(m->input->pos, *pkt_type);

    //利用message带的pool进行应用层内存的分配

    char* buffer = reinterpret_cast<char*>(easy_pool_alloc(m->pool,

                static_cast<uint32_t>(sizeof(ObMySQLCommandPacket) + *pkt_len)));

                

    if (NULL == buffer)

    {

        TBSYS_LOG(ERROR, "alloc packet buffer(length=%lu) from m->pool failed", sizeof(ObMySQLCommandPacket) + *pkt_len);

        return NULL;

    }



    TBSYS_LOG(DEBUG, "alloc packet buffer length = %lu", sizeof(ObMySQLCommandPacket) + *pkt_len);

    ObMySQLCommandPacket* packet = new(buffer)ObMySQLCommandPacket();

    packet->set_header(*pkt_len, *pkt_seq);

    packet->set_type(*pkt_type);

    packet->set_receive_ts(tbsys::CTimeUtil::getTime());

    memcpy(buffer + sizeof(ObMySQLCommandPacket), m->input->pos, *pkt_len - 1);

    packet->get_command().assign(buffer + sizeof(ObMySQLCommandPacket), *pkt_len - 1);

    TBSYS_LOG(DEBUG, "decode comand packet command is \"%.*s\"", packet->get_command().length(),

            packet->get_command().ptr());

    return packet;

}



void ObMySQLCallback::record_packet(easy_message_t* m, uint32_t *pkt_len, uint8_t *pkt_seq, uint8_t *pkt_type)

{

    // record the packet to FIFO stream if required

    ObMySQLServer* server = reinterpret_cast<ObMySQLServer*>(m->c->handler->user_data);

    ObMySQLCommandPacketRecord record;

    record.socket_fd_ = m->c->fd;

    record.cseq_ = m->c->seq;

    record.addr_ = m->c->addr;

    record.pkt_length_ = *pkt_len;

    record.pkt_seq_ = *pkt_seq;

    record.cmd_type_ = *pkt_type;

    struct iovec buffers[2];

    buffers[0].iov_base = &record;

    buffers[0].iov_len = sizeof(record);

    buffers[1].iov_base = m->input->pos;

    buffers[1].iov_len = pkt_len - 1;

    int err = OB_SUCCESS;

    if (OB_SUCCESS != (err = server->get_packet_recorder().push(buffers, 2)))

    {

        TBSYS_LOG(WARN, "failed to record MySQL packet, err=%d", err);

    }

}



void ObMySQLCallback::init_pkt_variables(uint32_t *pkt_len, uint8_t *pkt_seq)

{

    //1. decode length from net buffer

    //2. decode seq from net buffer 

    

    ObMySQLUtil::get_uint3(m->input->pos, *pkt_len);

    ObMySQLUtil::get_uint1(m->input->pos, *pkt_seq);

}



void* ObMySQLCallback::decode(easy_message_t* m)

{

    uint32_t pkt_len = 0,  pkt_seq = 0 ,  pkt_type = 0;

    

    if (NULL == m || NULL == m->input)

    {

        TBSYS_LOG(ERROR, "invalid argument m %p", m);

        return NULL;

    }

    

    int32_t msg_buffer_size = static_cast<int32_t>(m->input->last - m->input->pos);

    if ( msg_buffer_size < OB_MYSQL_PACKET_HEADER_SIZE)

    {

        return NULL;

    }

    

    init_pkt_variables(&pkt_len, &pkt_seq);

    if (pkt_len > msg_buffer_size) //message has not enough buffer

    {

        m->next_read_len = static_cast<int>(pkt_len - msg_buffer_size);

        TBSYS_LOG(DEBUG, "not enough data in message, packet length = %u, data in message is %ld",pkt_len, msg_buffer_size);

        m->input->pos -= OB_MYSQL_PACKET_HEADER_SIZE;

        return NULL;

    }

    

    ObMySQLCommandPacket* packet = make_packet(m, &pkt_len,  &pkt_seq ,  &pkt_type);

    if (PACKET_RECORDER_FLAG)

    {

        record_packet(m, &pkt_len,  &pkt_seq ,  &pkt_type);

    }

    m->input->pos += pkt_len - 1;

    return packet;

}