SystemVSM::GetMembership和SystemVSM::RefleshNodeID应该消除不必要的拷贝

[dyx2025]

SystemVSM::GetMembership和SystemVSM::RefleshNodeID应该消除不必要的拷贝

原代码路径：
src/config/system_v_sm.cpp

void SystemVSM :: GetMembership(NodeInfoList & vecNodeInfoList, uint64_t & llVersion)
{
    //must must get version first!
    llVersion = m_oSystemVariables.version();                                                                                                                                       

    for (int i = 0; i < m_oSystemVariables.membership_size(); i++)
    {   
        PaxosNodeInfo oNodeInfo = m_oSystemVariables.membership(i); // 不必要的拷贝

        NodeInfo tTmpNode(oNodeInfo.nodeid());
        vecNodeInfoList.push_back(tTmpNode); // 不必要的临时对象tTmpNode拷贝
    }   
}

// ...

void SystemVSM :: RefleshNodeID()
{
    m_setNodeID.clear();

    NodeInfoList vecNodeInfoList;
    
    for (int i = 0; i < m_oSystemVariables.membership_size(); i++)
    {
        PaxosNodeInfo oNodeInfo = m_oSystemVariables.membership(i); // 不必要的拷贝
        NodeInfo tTmpNode(oNodeInfo.nodeid());

        PLG1Head("ip %s port %d nodeid %lu", 
                tTmpNode.GetIP().c_str(), tTmpNode.GetPort(), tTmpNode.GetNodeID());

        m_setNodeID.insert(tTmpNode.GetNodeID());

        vecNodeInfoList.push_back(tTmpNode); // 不必要的临时对象tTmpNode拷贝
    }

    if (m_pMembershipChangeCallback != nullptr)
    {
        m_pMembershipChangeCallback(m_iMyGroupIdx, vecNodeInfoList);
    }
}

修改后的代码：
src/config/system_v_sm.cpp

void SystemVSM :: GetMembership(NodeInfoList & vecNodeInfoList, uint64_t & llVersion)
{
    //must must get version first!
    llVersion = m_oSystemVariables.version();                                                                                                                                       

    for (int i = 0; i < m_oSystemVariables.membership_size(); i++)
    {   
        // PaxosNodeInfo oNodeInfo = m_oSystemVariables.membership(i);
        const PaxosNodeInfo& oNodeInfo = m_oSystemVariables.membership(i);  // 避免拷贝

        /*
        NodeInfo tTmpNode(oNodeInfo.nodeid());
        vecNodeInfoList.push_back(tTmpNode);
        */
        vecNodeInfoList.emplace_back(oNodeInfo.nodeid()); // 原地构造，避免拷贝临时对象
    }   
}

// ...

void SystemVSM :: RefleshNodeID()
{
    m_setNodeID.clear();

    NodeInfoList vecNodeInfoList;
    
    for (int i = 0; i < m_oSystemVariables.membership_size(); i++)
    {
        //PaxosNodeInfo oNodeInfo = m_oSystemVariables.membership(i);
        const PaxosNodeInfo& oNodeInfo = m_oSystemVariables.membership(i); // 避免拷贝       

        /*
        NodeInfo tTmpNode(oNodeInfo.nodeid());

        PLG1Head("ip %s port %d nodeid %lu", 
                tTmpNode.GetIP().c_str(), tTmpNode.GetPort(), tTmpNode.GetNodeID());

        m_setNodeID.insert(tTmpNode.GetNodeID());

        vecNodeInfoList.push_back(tTmpNode);
        */
       
        m_setNodeID.insert(oNodeInfo.nodeid());

        vecNodeInfoList.emplace_back(oNodeInfo.nodeid()); // 原地构造，避免拷贝临时对象

        const NodeInfo& tTmpNode = vecNodeInfoList.back();
        PLG1Head("ip %s port %d nodeid %lu", 
                tTmpNode.GetIP().c_str(), tTmpNode.GetPort(), tTmpNode.GetNodeID());
        
    }

    if (m_pMembershipChangeCallback != nullptr)
    {
        m_pMembershipChangeCallback(m_iMyGroupIdx, vecNodeInfoList);
    }
}