select多路單線程伺服器

#include <stdio.h>#include <stdlib.h>#include <string.h>#ifdef WIN32#pragma warning(disable: 4996)#define WIN32_LEAN_AND_MEAN// Exclude rarely-used stuff from Windows headers#include <winsock2.h>#include <conio.h>#include <tchar.h>#else #include <socket.h>#endif#include <vector>//Buffer Length #define MAX_BUFFER_LEN 256class CClientContext  //To store and manage client related information{private:int               m_nTotalBytes;int               m_nSentBytes;SOCKET            m_Socket;  //accepted socketchar              m_szBuffer[MAX_BUFFER_LEN];CClientContext  * m_pNext;   //this will be a singly linked listpublic://Get/Set callsvoid SetTotalBytes(int n){m_nTotalBytes = n;}int GetTotalBytes(){return m_nTotalBytes;}void SetSentBytes(int n){m_nSentBytes = n;}void IncrSentBytes(int n){m_nSentBytes += n;}int GetSentBytes(){return m_nSentBytes;}void SetSocket(SOCKET s){m_Socket = s;}SOCKET GetSocket(){return m_Socket;}void SetBuffer(char *szBuffer){strcpy(m_szBuffer, szBuffer);}void GetBuffer(char *szBuffer){strcpy(szBuffer, m_szBuffer);}char* GetBuffer(){return m_szBuffer;}void ZeroBuffer(){ZeroMemory(m_szBuffer, MAX_BUFFER_LEN);}CClientContext* GetNext(){return m_pNext;}void SetNext(CClientContext *pNext){m_pNext = pNext;}//ConstructorCClientContext(){m_Socket =  SOCKET_ERROR;ZeroMemory(m_szBuffer, MAX_BUFFER_LEN);m_nTotalBytes = 0;m_nSentBytes = 0;m_pNext = NULL;}//destructor~CClientContext(){closesocket(m_Socket);}};//Head of the client context singly linked listCClientContext    *g_pClientContextHead = NULL;//Global FD Setsfd_set g_ReadSet, g_WriteSet, g_ExceptSet;//global functionsvoid AcceptConnections(SOCKET ListenSocket);void InitSets(SOCKET ListenSocket);int GetSocketSpecificError(SOCKET Socket);CClientContext* GetClientContextHead();void AddClientContextToList(CClientContext *pClientContext);CClientContext* DeleteClientContext(CClientContext *pClientContext);int main(int argc, char *argv[]){     //Validate the input     if (argc < 2)      {          printf("\nUsage: %s port.", argv[0]);          goto error;     }     // Initialize Winsock     WSADATA wsaData;     int nResult;     nResult = WSAStartup(MAKEWORD(2,2), &wsaData);     if (NO_ERROR != nResult)     {          printf("\nError occurred while executing WSAStartup().");          return 1; //error     }     else     {          printf("\nWSAStartup() successful.");     }     SOCKET ListenSocket;      int    nPortNo;     struct sockaddr_in ServerAddress;     //Create a socket     ListenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);     if (INVALID_SOCKET == ListenSocket)      {          printf("\nError occurred while opening socket: %ld.", WSAGetLastError());          goto error;     }     else     {          printf("\nsocket() successful.");     }     //Cleanup and Init with 0 the ServerAddress     ZeroMemory((char *)&ServerAddress, sizeof(ServerAddress));     //Port number will be supplied as a commandline argument     nPortNo = atoi(argv[1]);     //Fill up the address structure     ServerAddress.sin_family = AF_INET;     ServerAddress.sin_addr.s_addr = INADDR_ANY; //WinSock will supply address     ServerAddress.sin_port = htons(nPortNo);    //comes from commandline     //Assign local address and port number     if (SOCKET_ERROR == bind(ListenSocket, (struct sockaddr *) &ServerAddress, sizeof(ServerAddress)))      {          closesocket(ListenSocket);          printf("\nError occurred while binding.");          goto error;     }     else     {          printf("\nbind() successful.");     }     //Make the socket a listening socket     if (SOCKET_ERROR == listen(ListenSocket,SOMAXCONN))     {          closesocket(ListenSocket);          printf("\nError occurred while listening.");          goto error;     }     else     {          printf("\nlisten() successful.");     }     //This function will take are of multiple clients using select()/accept()     AcceptConnections(ListenSocket);     //Close open sockets     closesocket(ListenSocket);     //Cleanup Winsock     WSACleanup();     return 0; //successerror:     // Cleanup Winsock     WSACleanup();     return 1; //error}//Initialize the Setsvoid InitSets(SOCKET ListenSocket) {     //Initialize     FD_ZERO(&g_ReadSet);     FD_ZERO(&g_WriteSet);     FD_ZERO(&g_ExceptSet);     //Assign the ListenSocket to Sets     FD_SET(ListenSocket, &g_ReadSet);     FD_SET(ListenSocket, &g_ExceptSet);     //Iterate the client context list and assign the sockets to Sets     CClientContext   *pClientContext  = GetClientContextHead();     while(pClientContext)     {          if(pClientContext->GetSentBytes() < pClientContext->GetTotalBytes())          {               //We have data to send               FD_SET(pClientContext->GetSocket(), &g_WriteSet);          }          else          {               //We can read on this socket               FD_SET(pClientContext->GetSocket(), &g_ReadSet);          }          //Add it to Exception Set          FD_SET(pClientContext->GetSocket(), &g_ExceptSet);           //Move to next node on the list          pClientContext = pClientContext->GetNext();     }}//This function will loop on while it will manage multiple clients using select()void AcceptConnections(SOCKET ListenSocket){     while (true)     {          InitSets(ListenSocket);          if (select(0, &g_ReadSet, &g_WriteSet, &g_ExceptSet, 0) > 0)           {               //One of the socket changed state, let's process it.               //ListenSocket?  Accept the new connection               if (FD_ISSET(ListenSocket, &g_ReadSet))                {                    sockaddr_in ClientAddress;                    int nClientLength = sizeof(ClientAddress);                    //Accept remote connection attempt from the client                    SOCKET Socket = accept(ListenSocket, (sockaddr*)&ClientAddress, &nClientLength);                    if (INVALID_SOCKET == Socket)                    {                         printf("\nError occurred while accepting socket: %ld.", GetSocketSpecificError(ListenSocket));                    }                    //Display Client's IP                    printf("\nClient connected from: %s", inet_ntoa(ClientAddress.sin_addr));                     //Making it a non blocking socket                    u_long nNoBlock = 1;                    ioctlsocket(Socket, FIONBIO, &nNoBlock);                    CClientContext   *pClientContext  = new CClientContext;                    pClientContext->SetSocket(Socket);                    //Add the client context to the list                    AddClientContextToList(pClientContext);               }               //Error occured for ListenSocket?               if (FD_ISSET(ListenSocket, &g_ExceptSet))                {                    printf("\nError occurred while accepting socket: %ld.", GetSocketSpecificError(ListenSocket));                    continue;               }               //Iterate the client context list to see if any of the socket there has changed its state               CClientContext   *pClientContext  = GetClientContextHead();               while (pClientContext)               {                    //Check in Read Set                    if (FD_ISSET(pClientContext->GetSocket(), &g_ReadSet))                    {                         int nBytes = recv(pClientContext->GetSocket(), pClientContext->GetBuffer(), MAX_BUFFER_LEN, 0);                         if ((0 == nBytes) || (SOCKET_ERROR == nBytes))                         {                              if (0 != nBytes) //Some error occured, client didn't close the connection                              {                                   printf("\nError occurred while recieving on the socket: %d.", GetSocketSpecificError(pClientContext->GetSocket()));                              }                              //In either case remove the client from list                              pClientContext = DeleteClientContext(pClientContext);                              continue;                         }                         //Set the buffer                         pClientContext->SetTotalBytes(nBytes);                         pClientContext->SetSentBytes(0);                         printf("\nThe following message was received: %s", pClientContext->GetBuffer());                    }                    //Check in Write Set                    if (FD_ISSET(pClientContext->GetSocket(), &g_WriteSet))                    {                         int nBytes = 0;                         if (0 < (pClientContext->GetTotalBytes() - pClientContext->GetSentBytes()))                         {                              nBytes = send(pClientContext->GetSocket(), (pClientContext->GetBuffer() + pClientContext->GetSentBytes()), (pClientContext->GetTotalBytes() - pClientContext->GetSentBytes()), 0);                              if (SOCKET_ERROR == nBytes)                              {                                   printf("\nError occurred while sending on the socket: %d.", GetSocketSpecificError(pClientContext->GetSocket()));                                   pClientContext = DeleteClientContext(pClientContext);                                   continue;                              }                              if (nBytes == (pClientContext->GetTotalBytes() - pClientContext->GetSentBytes()))                              {                                   //We are done sending the data, reset Buffer Size                                   pClientContext->SetTotalBytes(0);                                   pClientContext->SetSentBytes(0);                              }                              else                              {                                   pClientContext->IncrSentBytes(nBytes);                              }                         }                    }                    //Check in Exception Set                    if (FD_ISSET(pClientContext->GetSocket(), &g_ExceptSet))                    {                         printf("\nError occurred on the socket: %d.", GetSocketSpecificError(pClientContext->GetSocket()));                         pClientContext = DeleteClientContext(pClientContext);                         continue;                    }                    //Move to next node on the list                    pClientContext = pClientContext->GetNext();               }//while          }          else //select          {               printf("\nError occurred while executing select(): %ld.", WSAGetLastError());               return; //Get out of this function          }     }}//When using select() multiple sockets may have errors//This function will give us the socket specific error//WSAGetLastError() can't be relied uponint GetSocketSpecificError(SOCKET Socket){     int nOptionValue;     int nOptionValueLength = sizeof(nOptionValue);     //Get error code specific to this socket     getsockopt(Socket, SOL_SOCKET, SO_ERROR, (char*)&nOptionValue, &nOptionValueLength);     return nOptionValue;}//Get the head node pointerCClientContext* GetClientContextHead(){     return g_pClientContextHead;}//Add a new client context to the listvoid AddClientContextToList(CClientContext *pClientContext){     //Add the new client context right at the head     pClientContext->SetNext(g_pClientContextHead);     g_pClientContextHead = pClientContext;}//This function will delete the node and will return the next node of the listCClientContext * DeleteClientContext(CClientContext *pClientContext){     //See if we have to delete the head node     if (pClientContext == g_pClientContextHead)      {          CClientContext *pTemp = g_pClientContextHead;          g_pClientContextHead = g_pClientContextHead->GetNext();          delete pTemp;          return g_pClientContextHead;     }     //Iterate the list and delete the appropriate node     CClientContext *pPrev = g_pClientContextHead;     CClientContext *pCurr = g_pClientContextHead->GetNext();     while (pCurr)     {          if (pCurr == pClientContext)          {               CClientContext *pTemp = pCurr->GetNext();               pPrev->SetNext(pTemp);               delete pCurr;               return pTemp;          }          pPrev = pCurr;          pCurr = pCurr->GetNext();     }     return NULL;}