我一直在尝试创建一个基于继承的 TCP 服务器模型,并取得了不同程度的成功。这些服务器由一个单例管理,其任务是关闭这些服务器和其他简单的维护功能:
class TCPServer {
public:
TCPServer();
~TCPServer();
void Bind(TCPDaemon *daemon) {
if(!daemon->IsRunning()) {
throw TCPBindException("Daemon is inactive");
}
// if the port is not taken, bind this daemon to it
if(this->servers.count(daemon->port())==0) {
this->servers[daemon->port()]=daemon;
...
} else {
throw TCPBindException("Port is taken");
}
}
void Shutdown() {
MASON::UINT16 i;
for(i=0;i<this->servers.size();i++) {
this->Shutdown((*this->servers.begin()).first);
}
}
void Shutdown(unsigned short port) {
if(this->servers.count(port)) {
if(this->servers[port]->IsRunning()) {
this->servers[port]->Stop();
}
delete this->servers[port];
this->servers.erase(port);
}
}
private:
std::map<unsigned short, TCPDaemon*> servers;
};
TCPDaemon 类的 Stop() 函数是纯虚函数。我的问题是,当调用 Shutdown() 函数时,它试图调用这个纯虚拟而不是派生类的版本。我怎样才能强迫它做正确的事?
提前致谢
[编辑] 抱歉,我之前没有包含 TCPDaemon 代码,它派生自 TCPSocket 类(我已经检查过它是 100% 工作的,并且相当不言自明)。这里是:
class TCPDaemon: public TCPSocket {
public:
TCPDaemon(unsigned short port) {
this->_enabled=false;
this->_host.ipaddr(INADDR_ANY);
this->_host.port(port);
this->paused=false;
struct sockaddr_in opts=this->_host.Compile();
#ifdef PLATFORM_WINDOWS
WSADATA wsaData;
if(WSAStartup(0x0202, &wsaData)) {
throw TCPDaemonException("Failed to start WSA");
}
#endif
this->raw_socket=socket(AF_INET, SOCK_STREAM, 0);
if(this->raw_socket<=0) {
throw TCPDaemonException("Failed to create socket");
}
if(int status=bind(this->raw_socket, (sockaddr*)&opts, sizeof(sockaddr))) {
printf("error [%i]\r\n", status);
throw TCPDaemonException("Failed to bind to port");
}
if(listen(this->raw_socket, 5)) {
throw TCPDaemonException("Failed to listen on port");
}
this->_enabled=true;
}
virtual ~TCPDaemon() {
this->Shutdown();
}
virtual void Start()=0;
virtual void Run(TCPSocket*)=0;
virtual void Stop()=0;
unsigned short port() {
return this->host().port();
}
bool IsRunning() {
return this->_enabled;
}
TCPSocket *Accept() {
SOCKET client;
struct sockaddr client_addr;
int len=sizeof(client_addr);
client=accept(this->raw_socket, &client_addr, &len);
return new TCPSocket(client, &client_addr);
}
void Shutdown() {
}
private:
bool _enabled;
bool paused;
};
这是一个示例派生服务器及其创建方法:
class EchoServer: public TCPDaemon {
public:
EchoServer(MASON::UINT16 port): TCPDaemon(port) {
}
~EchoServer() {}
virtual void Start() {
}
virtual void Run(TCPSocket *client) {
printf("RUN\r\n");
Accessor<TCPSocket> acc_client=client;
acc_client->Write(Accessor<Blob> (new Blob(std::string("hello!"))));
acc_client->Disconnect();
}
virtual void Stop() {
}
};
myTCPServer->Bind(new EchoServer(8008));
[edit+1] 我认为问题归结为这个(我很容易出错):我有一个基类 TCPDaemon 的 std::map,它有一个纯虚拟/抽象函数 Stop()。看来,当我通过映射中的一个条目调用 Stop() 时,它正在尝试调用 TCPDaemon::Stop(),而不是覆盖函数 EchoServer::Stop()。这可能是问题吗?如果是这样,我该如何解决?