在windows平台上，处理总多的TCP连接的机制中效率最高的是完成端口模型，关于完成端口模型的介绍可参照《Win32 多线程程序设计》（侯捷翻译）和《windows网络编程》。
异步机制是完成端口的基础，完成端口模型的本质思想是将"启动异步操作的线程"和"提供服务的线程"（即工作者线程）拆伙。
先看看所有TCP连接管理组件都要实现的接口 ITcpManager
#ifndef ITCPMANAGER_H
#define ITCPMANAGER_H
#include "../../Infrastructure/IEvent.h"
#include "IMessageDispatcher.h"
/*
ITcpManager 所有基于TCP网络管理者的基础接口 。
创 作 者：sky
时 间：2005.6
修订时间：2005.6
*/
enum TcpUserAction
{
UA_Connected , UA_Disconnected , UA_FunctionAccess , //标准的功能访问
};
enum DisconnectedCause
{
Logoff ,
LineOff ,
ServerStopped , //服务器停止时关闭连接
InvalidUser , //强行关闭非法用户的连接
TimeOut //在一段时间内没有收到check消息
};
interface ITcpClientsController
{
public:
virtual ~ITcpClientsController(){}
//主动给某个客户发信息 ，线程安全
virtual void SendData(int ConnectID, byte* data ,int offset ,int size) = 0 ;
//主动关闭连接
virtual void DisposeOneConnection(int connectID ,DisconnectedCause cause) = 0 ;
};
class UserActionEventArgs
{
public:
int ConnectID ;
TcpUserAction action ;
};
class ServiceCommittedEventArgs
{
public:
char* data ;
int length ;
int connectID ;
};
interface ITcpManager : public ITcpClientsController
{
public:
virtual ~ITcpManager(){}
//Events
IEvent<ITcpManager* ,int>* ConnectionCountChanged ;
IEvent<ITcpManager* ,ServiceCommittedEventArgs&>* ServiceCommitted ;
IEvent<ITcpManager* ,UserActionEventArgs&>* UserAction ;
//Method
virtual void Start() = 0 ;
virtual void Stop() = 0 ;
virtual int ConnectionCount() = 0 ;
};
#endif
接口的定义很清晰明了－－这也是接口的本质，如果你对IEvent事件还不是很熟悉，请参见我前面的文章。
接下来看看实现了ITcpManager的完成端口组件的头文件：
#ifndef COMPLETINGPORT_H
#define COMPLETINGPORT_H
#include <WINSOCK2.H>
#include <afx.h>
#include "../Foundation/ITcpManager.h"
#include "../Foundation/TCPListener.h"
#include "../Foundation/IMessageDispatcher.h"
#include "../../Collection/SafeObjectList.h"
#include "WorkerThreadAssistant.h"
#include "ContextKeyManager.h"
typedef SafeObjectList<HANDLE> OverlapEventList ;
void WorkerThreadStart(void* para) ;
void ListenThreadStart(void* para) ;
class CompletingPortManager :public ITcpManager ,public IEventHandler<ContextKeyManager* ,int>
{
private:
WorkerThreadAssistant workerThread_assistant ;
OverlapEventList overlapEventList ;
ContextKeyManager* context_manager ;
TcpListener* listener ;
IMessageDispatcher* curDispatcher ;
HANDLE completing_port ;
int workThreadNum ;
volatile bool isStop ;
public: //interface接口
//Events
IEvent<ITcpManager* ,int>* ConnectionCountChanged ;
IEvent<ITcpManager* ,ServiceCommittedEventArgs&>* ServiceCommitted ;
IEvent<ITcpManager* ,UserActionEventArgs&>* UserAction ;
//Method
void Start() ;
void Stop() ;
int ConnectionCount() ;
//主动给某个客户发信息
void SendData(int ConnectID, byte* data ,int offset ,int size) ;
//主动关闭连接
void DisposeOneConnection(int connectID ,DisconnectedCause cause) ;
public:
friend void WorkerThreadStart(void* para) ;
friend void ListenThreadStart(void* para) ;
CompletingPortManager(IMessageDispatcher* i_dispatcher ,int port ,int workThread_Num )
{
this->isStop = true ;
this->workThreadNum = workThread_Num ;
this->context_manager = new ContextKeyManager() ;
this->listener = new TcpListener(port) ;
this->curDispatcher = i_dispatcher ;
//subscribe Event
this->context_manager->ConnectionCountChanged->Register(this) ;
//event
this->ConnectionCountChanged = new EventPublisher<ITcpManager* ,int> ;
this->ServiceCommitted = new EventPublisher<ITcpManager* ,ServiceCommittedEventArgs&> ;
this->UserAction = new EventPublisher<ITcpManager* ,UserActionEventArgs&> ;
this->completing_port = CreateIoCompletionPort(INVALID_HANDLE_VALUE ,NULL ,0 ,0 ) ;
}
~CompletingPortManager()
{
CloseHandle(this->completing_port) ;
delete this->context_manager ;
delete this->listener ;
//event
delete this->ConnectionCountChanged ;
delete this->ServiceCommitted ;
delete this->UserAction ;
}
//ContextKeyManager::ConnectionCountChanged事件
void HandleEvent(ContextKeyManager* sender ,int para)
{
((EventPublisher<ITcpManager* ,int>*)(this->ConnectionCountChanged))->Invoke(this ,para) ;
}
private:
void ListenThread() ;
void CreateWorkerThreads() ;
void ServeCmpltdOverlap() ;
void BindConnectionToCompPort(SOCKET connection ,ContextKey** out_pky);
//进行异步接收数据
void RecieveData(ContextKey* pkey);
void CloseAllWorkerThread() ;
void CloseAllOverlapEvent() ;
void ClearRespondStreamList(RespondStreamList* rs_list) ;
};
#endif
完成端口组件的.CPP文件如下：
#include "CompletingPortManager.h"
#include "../../Threading/Thread.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
//global
void WorkerThreadStart(void* para)
{
CompletingPortManager* cpm = (CompletingPortManager*)para ;
cpm->ServeCmpltdOverlap() ;
}
void ListenThreadStart(void* para)
{
CompletingPortManager* cpm = (CompletingPortManager*)para ;
cpm->ListenThread() ;
}
//public
void CompletingPortManager::Start()
{
if(this->isStop)
{
this->isStop = FALSE ;
this->CreateWorkerThreads() ;
Thread thread ;
thread.Start(ListenThreadStart ,this) ;
//unsigned int dwThreadId;
//HANDLE hThread = (HANDLE)_beginthreadex(NULL, 0 , (unsigned int (_stdcall*)(void*))&ListenThreadStart , this, 0, &dwThreadId);
}
}
//public
void CompletingPortManager::Stop()
{
if(this->isStop)
{
return ;
}
this->isStop = true ;
Sleep(500) ; //等待监听线程结束
this->listener->Close() ;
this->CloseAllWorkerThread() ;//等所有线程退出后才返回
this->context_manager->ClearAllKeys() ; //关闭所有连接
this->CloseAllOverlapEvent() ;
}
//public
int CompletingPortManager::ConnectionCount()
{
return this->context_manager->GetConnectionCount() ;
}
//public
void CompletingPortManager::SendData(int ConnectID, byte* data ,int offset ,int size)
{
ContextKey* key = this->context_manager->GetContextKey(ConnectID) ;
if(key != NULL)
{
key->netStream->Write((char*)(data +offset) ,size) ;
}
}
//public
void CompletingPortManager::DisposeOneConnection(int connectID ,DisconnectedCause cause)
{
this->context_manager->ClearPkey(connectID) ;
UserActionEventArgs args ;
args.action = UA_Disconnected ;
args.ConnectID = connectID ;
((EventPublisher<ITcpManager* ,UserActionEventArgs&>*)(this->UserAction))->Invoke(this ,args) ;
}
//private
void CompletingPortManager::CloseAllWorkerThread()
{
while(! this->workerThread_assistant.IsSafeToExit())//等待到达安全点
{
Sleep(200) ;
}
}
//private
void CompletingPortManager::CloseAllOverlapEvent()
{
int count = this->overlapEventList.Count() ;
for(int i=0 ;i<count ;i++)
{
HANDLE handle ;
this->overlapEventList.GetElement(i ,handle) ;
CloseHandle(handle) ;
}
this->overlapEventList.Clear() ;
}
//private
void CompletingPortManager::CreateWorkerThreads()
{
SYSTEM_INFO sysinfo;
DWORD dwThreads;
DWORD i;
GetSystemInfo(&sysinfo);
dwThreads = this->workThreadNum ; //sysinfo.dwNumberOfProcessors * 32 + 2;
for (i=0; i<dwThreads; i++)
{
Thread thread ;
thread.Start(WorkerThreadStart ,this) ;
// HANDLE hThread;
// hThread = (HANDLE)_beginthreadex(NULL, 0, (unsigned int (_stdcall*)(void*))&WorkerThreadStart , this, 0, &dwThreadId);
workerThread_assistant.IncreaseWorkingThreadNum() ;
}
}
//private
void CompletingPortManager::BindConnectionToCompPort(SOCKET connection ,ContextKey** out_pky)
{
ContextKey* pkey = new ContextKey(connection) ;
*out_pky = pkey ;
CreateIoCompletionPort((HANDLE)connection ,this->completing_port ,(DWORD)pkey ,0);
}
//public
void CompletingPortManager::ListenThread()
{
if(! this->isStop)
{
return ;
}
SOCKET connection ;
BOOL succeed = this->listener->Start() ;
if(!succeed)
{
MessageBox(NULL ,"无法启动监听线程 !" ,"Tip" ,0) ;
return ;
}
ContextKey* pkey ;
while((! this->isStop) && (this->listener->Pending()))
{
connection = this->listener->AcceptSocket() ; //当关闭监听socket时，该函数也会返回
if(this->isStop)
{
closesocket(connection) ;
break ;
}
this->BindConnectionToCompPort(connection ,&pkey) ;
this->context_manager->RegisterContextKey(pkey) ;
UserActionEventArgs args ;
args.action = UA_Connected ;
args.ConnectID = connection ;
((EventPublisher<ITcpManager* ,UserActionEventArgs&>*)(this->UserAction))->Invoke(this ,args) ;
this->RecieveData(pkey) ;
}
}
//private 进行异步接收数据
void CompletingPortManager::RecieveData(ContextKey* pkey)
{
if(this->context_manager->ContainsPkey(pkey))
{
DWORD Flags = 0;
pkey->wsa_buf.len = pkey->requestData.BufferSize() - pkey->requestData.LeftDataLength ;
pkey->wsa_buf.buf = (char*)(pkey->requestData.Buff + pkey->requestData.LeftDataLength) ;
ZeroMemory(&(pkey->ovlapped) ,sizeof(OVERLAPPED)) ;
unsigned long numRead = 0 ;
pkey->netStream->AsynRead(pkey->wsa_buf ,&numRead ,&(pkey->ovlapped)) ;
}
}
//private 工作者线程
void CompletingPortManager::ServeCmpltdOverlap()
{
BOOL bResult;
int dwNumRead;
ContextKey *pkey;
LPOVERLAPPED lpOverlapped;
DWORD temp ;
//回复客户
RespondStreamList* respond_list = new RespondStreamList() ;
RespondStream* respond_stream = NULL ;
BOOL socket_closed = FALSE ;
BOOL succeed = FALSE ;
// DWORD bytes_send ;
// WSABUF wsabuff_send ;
OVERLAPPED ovlapped_send ;
memset(&ovlapped_send ,0 ,sizeof(OVERLAPPED)) ;
ovlapped_send.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
this->overlapEventList.Add(ovlapped_send.hEvent) ;
ovlapped_send.hEvent = (HANDLE)((DWORD)ovlapped_send.hEvent | 0x1);//表示不关心异步结果,避免Completion Packets
while(! this->isStop)
{
bResult = GetQueuedCompletionStatus( //在底层由系统提供高效的同步机制
this->completing_port,
(DWORD*)&dwNumRead,
&temp,
&lpOverlapped,
10
);
if(bResult == 0)
{
DWORD rc = GetLastError() ;
if((this->isStop) &&(rc == WAIT_TIMEOUT))
{
break ;
}
else
{
continue ;
}
}
pkey = (ContextKey *)temp ;
socket_closed = FALSE ;
if ((bResult == FALSE) || (dwNumRead == 0)) //当客户端正常关闭socket或掉线时，异步WSARecv调用会向队列投递一个特殊的Completion Packets－并且读到的字节长度为0
{
socket_closed = TRUE ;
}
else// Got a valid data block! 处理数据
{
try
{
pkey->requestData.ValidCount = dwNumRead + pkey->requestData.LeftDataLength ;
succeed = this->curDispatcher->DealRequestMessage(pkey->requestData ,respond_list) ;
if(succeed)
{
int count = respond_list->Count() ;
for(int i=0 ;i<count ;i++)
{
respond_stream = respond_list->GetElement(i) ;
//同步发送
BOOL sendSucceed = pkey->netStream->Write(respond_stream->data ,respond_stream->length) ;
if(! sendSucceed)
{
socket_closed = TRUE ;
break ;
}
else
{
ServiceCommittedEventArgs arg ;
arg.connectID = pkey->netStream->SocketID() ;
arg.data = respond_stream->data ;
arg.length = respond_stream->length ;
((EventPublisher<ITcpManager* ,ServiceCommittedEventArgs&>*)this->ServiceCommitted)->Invoke(this,arg) ;
UserActionEventArgs actArgs ;
actArgs.action = UA_Connected ;
actArgs.ConnectID = pkey->netStream->SocketID() ;
((EventPublisher<ITcpManager* ,UserActionEventArgs&>*)this->UserAction)->Invoke(this ,actArgs);
}
respond_stream = NULL ;
}
}
else
{
socket_closed = TRUE ;
}
}
catch(...)//(ContextKey* )
{
socket_closed = TRUE ;
}
if(socket_closed)
{
this->DisposeOneConnection(pkey->netStream->SocketID() ,LineOff) ;
}
this->ClearRespondStreamList(respond_list) ; //清空并删除所有的RespondStream
if((! this->isStop) && (!socket_closed))
{
if(pkey->requestData.IsFirstMsg)
{
pkey->requestData.IsFirstMsg = false ;
}
this->RecieveData(pkey) ;//继续从socket接收消息
}
}
}
delete respond_list ;
this->workerThread_assistant.DecreaseWorkingThreadNum() ; //工作线程正常退出
}
//private
void CompletingPortManager::ClearRespondStreamList(RespondStreamList* rs_list)
{
RespondStream* respond_stream = NULL ;
int count = rs_list->Count() ;
for(int i=0 ;i<count ;i++)
{
respond_stream = rs_list->GetElement(i) ;
respond_stream->ClearAll() ;
delete respond_stream ;
respond_stream = NULL ;
}
rs_list->Clear() ;
}
当然，还有很多的基本设施没有包含进来，所以如果你打算使用我的这个完成端口组件可email至sky.zhuwei@163.com索取所有相关的源码。
