魔兽世界服务器Trinitycore分析二：auth server的main函数

         TrinityCore由生成两个运行文件authserver和world server以及一堆DLL（或so）文件的子项目组成（先忽略map_extractor等几个工具项目）。

         authserver是登录验证服，它主要提供登录验证和获取服务器（区服）列表的功能。world server是真正的游戏服务器，提供游戏里的一切功能。相对而言，auth server比較简单，那我就从它入手啊，先看一下它的main函数，在源代码的基础上，我加上了凝视。

//该函数在srcserverauthserverMain.cpp中  
int main(int argc, char** argv)  
{  
    std::string configFile = _TRINITY_REALM_CONFIG;  
  
    //读取程序的參数，存入variables_map中  
    //假设參数中含有help，则输出信息，中止程序  
    auto vm = GetConsoleArguments(argc, argv, configFile);  
    // exit if help is enabled  
    if (vm.count("help"))  
        return 0;  
  
    //读取配置文件  
    std::string configError;  
    if (!sConfigMgr->LoadInitial(configFile, configError))  
    {  
        printf("Error in config file: %s
", configError.c_str());  
        return 1;  
    }  
  
    //向控制台输出一配置信息  
    TC_LOG_INFO("server.authserver", "%s (authserver)", _FULLVERSION);  
    TC_LOG_INFO("server.authserver", "<Ctrl-C> to stop.
");  
    TC_LOG_INFO("server.authserver", "Using configuration file %s.", configFile.c_str());  
    TC_LOG_INFO("server.authserver", "Using SSL version: %s (library: %s)", OPENSSL_VERSION_TEXT, SSLeay_version(SSLEAY_VERSION));  
    TC_LOG_INFO("server.authserver", "Using Boost version: %i.%i.%i", BOOST_VERSION / 100000, BOOST_VERSION / 100 % 1000, BOOST_VERSION % 100);  
  
    // authserver PID file creation  
    //创建一个文件，向当中写入PID  
    std::string pidFile = sConfigMgr->GetStringDefault("PidFile", "");  
    if (!pidFile.empty())  
    {  
        if (uint32 pid = CreatePIDFile(pidFile))  
            TC_LOG_INFO("server.authserver", "Daemon PID: %u
", pid);  
        else  
        {  
            TC_LOG_ERROR("server.authserver", "Cannot create PID file %s.
", pidFile.c_str());  
            return 1;  
        }  
    }  
  
    // Initialize the database connection  
    //初始化程序的数据库连接  
    if (!StartDB())  
        return 1;  
  
    // Get the list of realms for the server  
    //初始化world server列表  
    //也就是在auth数据库运行："SELECT id, name, address, localAddress, localSubnetMask, port, icon,   
    //flag, timezone, allowedSecurityLevel, population, gamebuild FROM realmlist WHERE flag <> 3 ORDER BY name"  
    //并将结果存入单例类RealmList的m_realms中  
    sRealmList->Initialize(_ioService, sConfigMgr->GetIntDefault("RealmsStateUpdateDelay", 20));  
  
    if (sRealmList->size() == 0)  
    {  
        TC_LOG_ERROR("server.authserver", "No valid realms specified.");  
        StopDB();  
        return 1;  
    }  
  
    // Start the listening port (acceptor) for auth connections  
    //从配置文件里读取监听的IP和端口  
    int32 port = sConfigMgr->GetIntDefault("RealmServerPort", 3724);  
    if (port < 0 || port > 0xFFFF)  
    {  
        TC_LOG_ERROR("server.authserver", "Specified port out of allowed range (1-65535)");  
        StopDB();  
        return 1;  
    }  
  
    std::string bindIp = sConfigMgr->GetStringDefault("BindIP", "0.0.0.0");  
  
    //初始化auth server  
    AsyncAcceptor<AuthSession> authServer(_ioService, bindIp, port);  
  
    // Set signal handlers  
    //绑定SIGINT（退出）信号的处理函数  
    boost::asio::signal_set signals(_ioService, SIGINT, SIGTERM);  
#if PLATFORM == PLATFORM_WINDOWS  
    signals.add(SIGBREAK);  
#endif  
    signals.async_wait(SignalHandler);  
  
    // Set process priority according to configuration settings  
    //设置进程（线程）的优先级  
    SetProcessPriority("server.authserver");  
  
    // Enabled a timed callback for handling the database keep alive ping  
    //添加一个定时器，用于与数据库保持心跳连接  
    _dbPingInterval = sConfigMgr->GetIntDefault("MaxPingTime", 30);  
    _dbPingTimer.expires_from_now(boost::posix_time::minutes(_dbPingInterval));  
    _dbPingTimer.async_wait(KeepDatabaseAliveHandler);  
  
    // Start the io service worker loop  
    //開始事件循环  
    _ioService.run();  
  
    // Close the Database Pool and library  
    //关闭数据库  
    StopDB();  
  
    TC_LOG_INFO("server.authserver", "Halting process...");  
    return 0;  
}