重叠(overlapped)模型

///////////////////////////////////////////////////////// OverlappedServer.cpp文件#include <winsock2.h>#include <Mswsock.h>#include <stdio.h>#include <windows.h>#pragma comment(lib, "WS2_32")#define BUFFER_SIZE 1024typedef struct _SOCKET_OBJ{SOCKET s;// 套节字句柄int nOutstandingOps;// 记录此套节字上的重叠I/O数量LPFN_ACCEPTEX lpfnAcceptEx;// 扩展函数AcceptEx的指针（仅对监听套节字而言）} SOCKET_OBJ, *PSOCKET_OBJ;typedef struct _BUFFER_OBJ{OVERLAPPED ol;// 重叠结构char *buff;// send/recv/AcceptEx所使用的缓冲区int nLen;// buff的长度PSOCKET_OBJ pSocket;// 此I/O所属的套节字对象int nOperation;// 提交的操作类型#define OP_ACCEPT1#define OP_READ2#define OP_WRITE3SOCKET sAccept;// 用来保存AcceptEx接受的客户套节字（仅对监听套节字而言）_BUFFER_OBJ *pNext;} BUFFER_OBJ, *PBUFFER_OBJ;HANDLE g_events[WSA_MAXIMUM_WAIT_EVENTS];// I/O事件句柄数组int g_nBufferCount;// 上数组中有效句柄数量PBUFFER_OBJ g_pBufferHead, g_pBufferTail;// 记录缓冲区对象组成的表的地址// 申请套节字对象和释放套节字对象的函数PSOCKET_OBJ GetSocketObj(SOCKET s){PSOCKET_OBJ pSocket = (PSOCKET_OBJ)::GlobalAlloc(GPTR, sizeof(SOCKET_OBJ));if(pSocket != NULL){pSocket->s = s;}return pSocket;}void FreeSocketObj(PSOCKET_OBJ pSocket){if(pSocket->s != INVALID_SOCKET)::closesocket(pSocket->s);::GlobalFree(pSocket);}PBUFFER_OBJ GetBufferObj(PSOCKET_OBJ pSocket, ULONG nLen){if(g_nBufferCount > WSA_MAXIMUM_WAIT_EVENTS - 1)return NULL;PBUFFER_OBJ pBuffer = (PBUFFER_OBJ)::GlobalAlloc(GPTR, sizeof(BUFFER_OBJ));if(pBuffer != NULL){pBuffer->buff = (char*)::GlobalAlloc(GPTR, nLen);pBuffer->ol.hEvent = ::WSACreateEvent();pBuffer->pSocket = pSocket;pBuffer->sAccept = INVALID_SOCKET;// 将新的BUFFER_OBJ添加到列表中if(g_pBufferHead == NULL){g_pBufferHead = g_pBufferTail = pBuffer;}else{g_pBufferTail->pNext = pBuffer;g_pBufferTail = pBuffer;}g_events[++ g_nBufferCount] = pBuffer->ol.hEvent;}return pBuffer;}void FreeBufferObj(PBUFFER_OBJ pBuffer){// 从列表中移除BUFFER_OBJ对象PBUFFER_OBJ pTest = g_pBufferHead;BOOL bFind = FALSE;if(pTest == pBuffer){g_pBufferHead = g_pBufferTail = NULL;bFind = TRUE;}else{while(pTest != NULL && pTest->pNext != pBuffer)pTest = pTest->pNext;if(pTest != NULL){pTest->pNext = pBuffer->pNext;if(pTest->pNext == NULL)g_pBufferTail = pTest;bFind = TRUE;}}// 释放它占用的内存空间if(bFind){g_nBufferCount --;::CloseHandle(pBuffer->ol.hEvent);::GlobalFree(pBuffer->buff);::GlobalFree(pBuffer);}}PBUFFER_OBJ FindBufferObj(HANDLE hEvent){PBUFFER_OBJ pBuffer = g_pBufferHead;while(pBuffer != NULL){if(pBuffer->ol.hEvent == hEvent)break;pBuffer = pBuffer->pNext;}return pBuffer;}void RebuildArray(){PBUFFER_OBJ pBuffer = g_pBufferHead;int i =  1;while(pBuffer != NULL){g_events[i++] = pBuffer->ol.hEvent;pBuffer = pBuffer->pNext;}}BOOL PostAccept(PBUFFER_OBJ pBuffer){PSOCKET_OBJ pSocket = pBuffer->pSocket;if(pSocket->lpfnAcceptEx != NULL){// 设置I/O类型，增加套节字上的重叠I/O计数pBuffer->nOperation = OP_ACCEPT;pSocket->nOutstandingOps ++;// 投递此重叠I/O  DWORD dwBytes;pBuffer->sAccept = ::WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, WSA_FLAG_OVERLAPPED);BOOL b = pSocket->lpfnAcceptEx(pSocket->s, pBuffer->sAccept,pBuffer->buff, BUFFER_SIZE - ((sizeof(sockaddr_in) + 16) * 2),sizeof(sockaddr_in) + 16, sizeof(sockaddr_in) + 16, &dwBytes, &pBuffer->ol);if(!b){if(::WSAGetLastError() != WSA_IO_PENDING)return FALSE;}return TRUE;}return FALSE;};BOOL PostRecv(PBUFFER_OBJ pBuffer){// 设置I/O类型，增加套节字上的重叠I/O计数pBuffer->nOperation = OP_READ;pBuffer->pSocket->nOutstandingOps ++;// 投递此重叠I/ODWORD dwBytes;DWORD dwFlags = 0;WSABUF buf;buf.buf = pBuffer->buff;buf.len = pBuffer->nLen;if(::WSARecv(pBuffer->pSocket->s, &buf, 1, &dwBytes, &dwFlags, &pBuffer->ol, NULL) != NO_ERROR){if(::WSAGetLastError() != WSA_IO_PENDING)return FALSE;}return TRUE;}BOOL PostSend(PBUFFER_OBJ pBuffer){// 设置I/O类型，增加套节字上的重叠I/O计数pBuffer->nOperation = OP_WRITE;pBuffer->pSocket->nOutstandingOps ++;// 投递此重叠I/ODWORD dwBytes;DWORD dwFlags = 0;WSABUF buf;buf.buf = pBuffer->buff;buf.len = pBuffer->nLen;if(::WSASend(pBuffer->pSocket->s, &buf, 1, &dwBytes, dwFlags, &pBuffer->ol, NULL) != NO_ERROR){if(::WSAGetLastError() != WSA_IO_PENDING)return FALSE;}return TRUE;}BOOL HandleIO(PBUFFER_OBJ pBuffer){PSOCKET_OBJ pSocket = pBuffer->pSocket; // 从BUFFER_OBJ对象中提取SOCKET_OBJ对象指针，为的是方便引用pSocket->nOutstandingOps --;// 获取重叠操作结果DWORD dwTrans;DWORD dwFlags;BOOL bRet = ::WSAGetOverlappedResult(pSocket->s, &pBuffer->ol, &dwTrans, FALSE, &dwFlags);if(!bRet){// 在此套节字上有错误发生，因此，关闭套节字，移除此缓冲区对象。// 如果没有其它抛出的I/O请求了，释放此缓冲区对象，否则，等待此套节字上的其它I/O也完成if(pSocket->s != INVALID_SOCKET){::closesocket(pSocket->s);pSocket->s = INVALID_SOCKET;}if(pSocket->nOutstandingOps == 0)FreeSocketObj(pSocket);FreeBufferObj(pBuffer);return FALSE;}// 没有错误发生，处理已完成的I/Oswitch(pBuffer->nOperation){case OP_ACCEPT:// 接收到一个新的连接，并接收到了对方发来的第一个封包{// 为新客户创建一个SOCKET_OBJ对象PSOCKET_OBJ pClient = GetSocketObj(pBuffer->sAccept);// 为发送数据创建一个BUFFER_OBJ对象，这个对象会在套节字出错或者关闭时释放PBUFFER_OBJ pSend = GetBufferObj(pClient, BUFFER_SIZE);if(pSend == NULL){printf(" Too much connections! \n");FreeSocketObj(pClient);return FALSE;}RebuildArray();// 将数据复制到发送缓冲区pSend->nLen = dwTrans;memcpy(pSend->buff, pBuffer->buff, dwTrans);// 投递此发送I/O（将数据回显给客户）if(!PostSend(pSend)){// 万一出错的话，释放上面刚申请的两个对象FreeSocketObj(pSocket);FreeBufferObj(pSend);return FALSE;}// 继续投递接受I/OPostAccept(pBuffer);}break;case OP_READ:// 接收数据完成{if(dwTrans > 0){// 创建一个缓冲区，以发送数据。这里就使用原来的缓冲区PBUFFER_OBJ pSend = pBuffer;pSend->nLen = dwTrans;// 投递发送I/O（将数据回显给客户）PostSend(pSend);}else// 套节字关闭{// 必须先关闭套节字，以便在此套节字上投递的其它I/O也返回if(pSocket->s != INVALID_SOCKET){::closesocket(pSocket->s);pSocket->s = INVALID_SOCKET;}if(pSocket->nOutstandingOps == 0)FreeSocketObj(pSocket);FreeBufferObj(pBuffer);return FALSE;}}break;case OP_WRITE:// 发送数据完成{if(dwTrans > 0){// 继续使用这个缓冲区投递接收数据的请求pBuffer->nLen = BUFFER_SIZE;PostRecv(pBuffer);}else// 套节字关闭{// 同样，要先关闭套节字if(pSocket->s != INVALID_SOCKET){::closesocket(pSocket->s);pSocket->s = INVALID_SOCKET;}if(pSocket->nOutstandingOps == 0)FreeSocketObj(pSocket);FreeBufferObj(pBuffer);return FALSE;}}break;}return TRUE;}void main(){WSADATA wsaData;WORD sockVersion = MAKEWORD(2, 0);WSAStartup(sockVersion, &wsaData);// 创建监听套节字，绑定到本地端口，进入监听模式int nPort = 4567;SOCKET sListen = ::WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);SOCKADDR_IN si;si.sin_family = AF_INET;si.sin_port = ::ntohs(nPort);si.sin_addr.S_un.S_addr = INADDR_ANY;::bind(sListen, (sockaddr*)&si, sizeof(si));::listen(sListen, 200);// 为监听套节字创建一个SOCKET_OBJ对象PSOCKET_OBJ pListen = GetSocketObj(sListen);// 加载扩展函数AcceptExGUID GuidAcceptEx = WSAID_ACCEPTEX;DWORD dwBytes;WSAIoctl(pListen->s, SIO_GET_EXTENSION_FUNCTION_POINTER, &GuidAcceptEx, sizeof(GuidAcceptEx),&pListen->lpfnAcceptEx, sizeof(pListen->lpfnAcceptEx), &dwBytes, NULL, NULL);// 创建用来重新建立g_events数组的事件对象g_events[0] = ::WSACreateEvent();// 在此可以投递多个接受I/O请求for(int i=0; i<5; i++){PostAccept(GetBufferObj(pListen, BUFFER_SIZE));}::WSASetEvent(g_events[0]);while(TRUE){int nIndex = ::WSAWaitForMultipleEvents(g_nBufferCount + 1, g_events, FALSE, WSA_INFINITE, FALSE);if(nIndex == WSA_WAIT_FAILED){printf("WSAWaitForMultipleEvents() failed \n");break;}nIndex = nIndex - WSA_WAIT_EVENT_0;for(int i=0; i<=nIndex; i++){int nRet = ::WSAWaitForMultipleEvents(1, &g_events[i], TRUE, 0, FALSE);if(nRet == WSA_WAIT_TIMEOUT)continue;else{::WSAResetEvent(g_events[i]);// 重新建立g_events数组if(i == 0){RebuildArray();continue;}// 处理这个I/OPBUFFER_OBJ pBuffer = FindBufferObj(g_events[i]);if(pBuffer != NULL){if(!HandleIO(pBuffer))RebuildArray();}}}}::WSACleanup();}