ProtoBuf练习（二）

重复数据类型

protobuf语言的重复字段类型相当于C++的std::list数据类型

工程目录结构

$ ls proto/

TServer.proto  TSession.proto

proto文件

$ cat TSession.proto

syntax = "proto3";

//枚举类型可以放外面，也可以放message里面

enum Status

{

    INVALID = 0;

    VALID = 1;

};

message TSession

{

    string owner = 1;

    Status status = 2;

};

$ cat TServer.proto

syntax = "proto3";

import "TSession.proto";

//通过repeated来模拟链表的可变长度

message TServer

{

    repeated TSession sessions = 1;

};

读写源文件

$ cat writer.cpp

#include <fstream>

#include <iostream>

#include <string>

#include "TServer.pb.h"

using namespace std;

int main(int argc, char *argv[])

{

    TServer srv;

    std::string owner;

    while(true)

    {

        std::getline(std::cin, owner);

        if (owner.empty())

            break;

        //自动生成一个新的节点，并返回对象指针

        TSession* s = srv.add_sessions();

        s->set_owner(owner);

        s->set_status(Status::VALID);

    }

    fstream output("./log", ios::out | ios::trunc | ios::binary);

    cout << "Serialize start." << endl;

    if (!srv.SerializeToOstream(&output))

        {

                cout << "Serialize failed." << endl;

                return -1;

        }

    output.close();

    cout << "Serialize end." << endl;

    return 0;

}

$ cat reader.cpp

#include <fstream>

#include <iostream>

#include "TServer.pb.h"

using namespace std;

int main(int argc, char *argv[])

{

    fstream input("./log", ios::in | ios::binary);

    cout << "Deserialize start." << endl;

    TServer srv;

    if (!srv.ParseFromIstream(&input))

    {

        cout << "Deserialize failed." << endl;

        return -1;

    }

    cout << "First Method" << endl;

    for (int i = 0; i < srv.sessions_size(); i++)

        srv.sessions(i).PrintDebugString();

    cout << "Second Method" << endl;

    auto sessions = srv.sessions();

    for (auto iter = sessions.begin(); iter != sessions.end(); iter++)

        iter->PrintDebugString();

    cout << "Deserialize end." << endl;

    input.close();

    return 0;

}