Winsock的事件I/O非同步模型（開發網路通訊程式入門的繼續）

       前面討論的開發網路通訊的經典入門採用的是WSAAsyncSelect的非同步I/O模型，本文將討論WSAEventSelect非同步I/O模型。

       WSAEventSelect模型有點類似WSAAsyncSelect模型，不同的是他不是用訊息映射的方式來響應網路事件，而是用等待多重事件的方式來響應網路事件。下面是用WSAEventSelect模型和多線程機製做的一個簡單的伺服器程式的.cpp和.h檔案，應用程式基底於MFC的標準對話方塊。實現接受多個用戶端的串連請求，並記錄下所有用戶端的相關資訊，顯示在列表框中。

// serverDlg.cpp : implementation file
//

#include "stdafx.h"
#include "server.h"
#include "serverDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

SOCKET Accept; file://用於新的一個串連通訊的通訊端
WSAEVENT NewEvent; file://對應於新的通訊端的新事件
SOCKET Socket[WSA_MAXIMUM_WAIT_EVENTS];  file://存放所有產生的通訊端
WSAEVENT Event[WSA_MAXIMUM_WAIT_EVENTS]; file://存放所有產生的事件對象
int EventTotal; file://建立的事件總數
int Index;      file://等待多重事件函數的傳回值
WSANETWORKEVENTS NetworkEvents; file://用於接收通訊端上發生的網路事件類型以及可能出現的錯
誤代碼

/////////////////////////////////////////////////////////////////////////////
// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
 CAboutDlg();

// Dialog Data
 file://{{AFX_DATA(CAboutDlg)
 enum { IDD = IDD_ABOUTBOX };
 file://}}AFX_DATA

 // ClassWizard generated virtual function overrides
 file://{{AFX_VIRTUAL(CAboutDlg)
 protected:
 virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
 file://}}AFX_VIRTUAL

// Implementation
protected:
 file://{{AFX_MSG(CAboutDlg)
 file://}}AFX_MSG
 DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
 file://{{AFX_DATA_INIT(CAboutDlg)
 file://}}AFX_DATA_INIT
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
 CDialog::DoDataExchange(pDX);
 file://{{AFX_DATA_MAP(CAboutDlg)
 file://}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
 file://{{AFX_MSG_MAP(CAboutDlg)
  // No message handlers
 file://}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CServerDlg dialog

CServerDlg::CServerDlg(CWnd* pParent /*=NULL*/)
 : CDialog(CServerDlg::IDD, pParent)
{
 file://{{AFX_DATA_INIT(CServerDlg)
  // NOTE: the ClassWizard will add member initialization here
 file://}}AFX_DATA_INIT
 // Note that LoadIcon does not require a subsequent DestroyIcon in Win32
 m_Connectnum = 0;
 m_NetworkID = 0;
 EventTotal = 0;
    for(int i = 0; i < MAX_CLIENT_NUM; i++)
 {
  ZeroMemory(&m_ClientInfo[i], sizeof(client_info));
 }

 m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CServerDlg::DoDataExchange(CDataExchange* pDX)
{
 CDialog::DoDataExchange(pDX);
 file://{{AFX_DATA_MAP(CServerDlg)
  // NOTE: the ClassWizard will add DDX and DDV calls here
 file://}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CServerDlg, CDialog)
 file://{{AFX_MSG_MAP(CServerDlg)
 ON_WM_SYSCOMMAND()
 ON_WM_PAINT()
 ON_WM_QUERYDRAGICON()
 ON_WM_TIMER()
 file://}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CServerDlg message handlers

BOOL CServerDlg::OnInitDialog()
{
 CDialog::OnInitDialog();

 // Add "About..." menu item to system menu.

 // IDM_ABOUTBOX must be in the system command range.
 ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
 ASSERT(IDM_ABOUTBOX < 0xF000);

 CMenu* pSysMenu = GetSystemMenu(FALSE);
 if (pSysMenu != NULL)
 {
  CString strAboutMenu;
  strAboutMenu.LoadString(IDS_ABOUTBOX);
  if (!strAboutMenu.IsEmpty())
  {
   pSysMenu->AppendMenu(MF_SEPARATOR);
   pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
  }
 }

 // Set the icon for this dialog.  The framework does this automatically
 //  when the application's main window is not a dialog
 SetIcon(m_hIcon, TRUE);   // Set big icon
 SetIcon(m_hIcon, FALSE);  // Set small icon
 
 // TODO: Add extra initialization here

 WSADATA wsaData;
 int ret;

 ret = WSAStartup(MAKEWORD(2,2), &wsaData);
 if(ret != 0)
 {
  MessageBox("初始化通訊端失敗!");
  return FALSE;
 }

 file://建立一個通訊端
 m_ListenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        if(m_ListenSocket == INVALID_SOCKET)
 {
  MessageBox("建立通訊端失敗!");
  closesocket(m_ListenSocket);
  WSACleanup();
  return FALSE;
 }

 file://綁定到指定的連接埠上
 sockaddr_in localaddr;
 localaddr.sin_family = AF_INET;
 localaddr.sin_port = htons(1688);
 localaddr.sin_addr.s_addr = 0;

 if(bind(m_ListenSocket, (const struct sockaddr*)&localaddr, sizeof(sockaddr))
                                                                 == SOCKET_ERROR)
 {
  MessageBox("綁定地址失敗!");
  closesocket(m_ListenSocket);
  WSACleanup();
  return FALSE;
 }
 
 NewEvent = WSACreateEvent(); file://建立一個新的事件對象

 file://將建立的事件對象與前面建立的通訊端關聯在一起,並註冊網路事件類型
        if(WSAEventSelect(m_ListenSocket, NewEvent, FD_ACCEPT | FD_CLOSE) == SOCKET_ERROR)
 {
  MessageBox("註冊網路事件失敗!");
  closesocket(m_ListenSocket);
  WSACleanup();
  return FALSE;
 }

 file://讓建立的通訊端處於監聽狀態
 listen(m_ListenSocket, 5);

 Event[EventTotal] = NewEvent;
 Socket[EventTotal] = m_ListenSocket;
 EventTotal++;

        file://設定List控制項的圖象列表
 HICON hIcon;

 m_imagelist.Create(16, 16, 0, 4, 4); // 32, 32 for large icons
 hIcon = AfxGetApp()->LoadIcon(IDI_CLIENT_INFO);
 
 m_imagelist.SetBkColor (RGB(248,232,224));
 m_imagelist.Add(hIcon);

 pList = (CListCtrl*)GetDlgItem(IDC_CLIENT_INFO);
 pList->SetImageList(&m_imagelist, LVSIL_SMALL);
 pList->SetBkColor(RGB(248,232,224));
 pList->SetTextBkColor(RGB(248,232,224));

 pList->InsertColumn(0,"   客戶名",LVCFMT_CENTER,90, 0);
 pList->InsertColumn(1,"網路ID",LVCFMT_CENTER,50,1);
 pList->InsertColumn(2,"IP地址",LVCFMT_CENTER,100,2);
 pList->InsertColumn (3,"登入時間",LVCFMT_CENTER,120,3);
 pList->InsertColumn (4,"線上時間",LVCFMT_CENTER,100,4);

 SetTimer(1, 1000, NULL);

 file://啟動核心處理線程
 AfxBeginThread(KernelWorkThread,this,THREAD_PRIORITY_NORMAL);

 return TRUE;  // return TRUE  unless you set the focus to a control
}

void CServerDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
 if ((nID & 0xFFF0) == IDM_ABOUTBOX)
 {
  CAboutDlg dlgAbout;
  dlgAbout.DoModal();
 }
 else
 {
  CDialog::OnSysCommand(nID, lParam);
 }
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CServerDlg::OnPaint()
{
 if (IsIconic())
 {
  CPaintDC dc(this); // device context for painting

  SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

  // Center icon in client rectangle
  int cxIcon = GetSystemMetrics(SM_CXICON);
  int cyIcon = GetSystemMetrics(SM_CYICON);
  CRect rect;
  GetClientRect(&rect);
  int x = (rect.Width() - cxIcon + 1) / 2;
  int y = (rect.Height() - cyIcon + 1) / 2;

  // Draw the icon
  dc.DrawIcon(x, y, m_hIcon);
 }
 else
 {
  CDialog::OnPaint();
 }
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CServerDlg::OnQueryDragIcon()
{
 return (HCURSOR) m_hIcon;
}

file://核心處理線程, 響應並處理各種網路事件
UINT KernelWorkThread(LPVOID pParam)
{
 int len = sizeof(sockaddr);

 CServerDlg* dlg;
 dlg = (CServerDlg*)pParam;

 while(1)
 {
         Index = WSAWaitForMultipleEvents(EventTotal, Event, FALSE, WSA_INFINITE, FALSE);

  WSAEnumNetworkEvents(Socket[Index - WSA_WAIT_EVENT_0],
                     Event[Index - WSA_WAIT_EVENT_0],
                                     &NetworkEvents);
 
  if(NetworkEvents.lNetworkEvents & FD_ACCEPT)
  file://串連事件
  {
   if(NetworkEvents.iErrorCode[FD_ACCEPT_BIT] != 0)
   {
    dlg->MessageBox("接受串連事件失敗!");
    break;
   }

   Accept = accept(Socket[Index - WSA_WAIT_EVENT_0],
                                 (struct sockaddr*)&(dlg->clientaddr), &len);
   if(Accept == INVALID_SOCKET)
   {
    dlg->MessageBox("接受串連失敗!");
    break;
   }
   
   if(EventTotal > WSA_MAXIMUM_WAIT_EVENTS)
   {
    dlg->MessageBox("串連個數溢出,拒絕接受!");
    break;
   }

   NewEvent = WSACreateEvent();

   if(WSAEventSelect(Accept, NewEvent, FD_READ | FD_WRITE | FD_CLOSE)
                                                                   == SOCKET_ERROR)
   {
    dlg->MessageBox("註冊網路事件失敗!");
    closesocket(Accept);
    break;
   }

   Event[EventTotal] = NewEvent;
   Socket[EventTotal] = Accept;
   EventTotal ++;
  }

  if(NetworkEvents.lNetworkEvents & FD_READ)
  file://讀取資料事件
  {
   if(NetworkEvents.iErrorCode[FD_READ_BIT] != 0)
   {
    dlg->MessageBox("讀事件失敗!");
    break;
   }

   if(dlg->OnReceive(Socket[Index - WSA_WAIT_EVENT_0]) == FALSE)
   {
    dlg->MessageBox("讀取資料失敗!");
    break;
   }
  }

  if(NetworkEvents.lNetworkEvents & FD_CLOSE)
  file://關閉通訊端事件
  {
   if(NetworkEvents.iErrorCode[FD_CLOSE_BIT] != 0)
   {
    dlg->MessageBox("關閉事件失敗!");
    break;
   }

   if(dlg->OnClose(Socket[Index - WSA_WAIT_EVENT_0]) == FALSE)
   {
    dlg->MessageBox("關閉通訊端失敗!");
    break;
   }
  }
 }

 return 0;
}

BOOL CServerDlg::OnClose(SOCKET pSocket)
{
 int i, exitnum;
 
 for(i = 0; i < m_Connectnum; i++)
 {
  if(m_ClientInfo[i].Client_Socket == pSocket)
  {
   exitnum = i;
  }
 }
 for(i = exitnum; i < m_Connectnum; i++)
 {
  memcpy(&m_ClientInfo[i], &m_ClientInfo[i+1], sizeof(client_info));
 }

 m_Connectnum --;

 file://向所有用戶端發送線上客戶資訊的報文
 cmd_client_info ClientInfo;
 ClientInfo.cmd_type = CMD_CLIENT_INFO;
 ClientInfo.client_num = m_Connectnum;
 
 for(i=0; i<=m_Connectnum; i++)
 {
  ClientInfo.Networks_ID[i] = m_ClientInfo[i].Network_ID;
  strcpy(ClientInfo.users_name[i], m_ClientInfo[i].User_Name);
  strcpy(ClientInfo.clients_ipaddr[i], inet_ntoa(m_ClientInfo[i].Client_Addr.sin_addr));
 }
 for(i=0; i<=m_Connectnum; i++)
 {
  send(m_ClientInfo[i].Client_Socket, (char*)&ClientInfo, sizeof(cmd_client_info), NULL);
 }
 closesocket(pSocket);

        pList->DeleteItem(exitnum);
 
 return TRUE;
}

BOOL CServerDlg::OnReceive(SOCKET pSocket)
{
    static char rcvbuf[65535];   file://接收緩衝區
    int ret;
 int offset=0;
 find_type* pFindType;
 int i = 0;
 CTime m_current_time=CTime::GetCurrentTime ();
 CString strTime = m_current_time.Format("%c");
 CString networkid; file://列表框的網路ID項

    ret = recv(pSocket, rcvbuf, 65535, 0);
 if(ret == OPERATION_ERROR)
  return FALSE;

 while(offset < ret)
 {
  pFindType = (find_type*)(rcvbuf+offset);
  switch(pFindType->cmd_type)
  {
  case CMD_HELLO: 
   cmd_hello Hello;
   memcpy(&Hello, rcvbuf+offset, sizeof(cmd_hello));
   offset+=sizeof(cmd_hello);

   cmd_hello_resp HelloResp;
   m_NetworkID ++;
   HelloResp.cmd_type = CMD_HELLO_RESP;
   HelloResp.Network_ID = m_NetworkID;
   strcpy(HelloResp.user_name, Hello.user_name);

   memcpy((struct sockaddr*)&(m_ClientInfo[m_Connectnum].Client_Addr),
    (const struct sockaddr*)&clientaddr, sizeof(sockaddr));
   m_ClientInfo[m_Connectnum].Client_Socket = Accept;
   strcpy(m_ClientInfo[m_Connectnum].User_Name, HelloResp.user_name);
   m_ClientInfo[m_Connectnum].Network_ID = m_NetworkID;
   m_ClientInfo[m_Connectnum].Login_Time = m_current_time;
   send(pSocket, (char*)&HelloResp, sizeof(cmd_hello_resp), NULL);

   file://向登入的用戶端發送回應報文
   Sleep(200);

   cmd_client_info ClientInfo;
   ClientInfo.cmd_type = CMD_CLIENT_INFO;
   ClientInfo.client_num = m_Connectnum +1;

   for(i=0; i<=m_Connectnum; i++)
   {
    ClientInfo.Networks_ID[i] = m_ClientInfo[i].Network_ID;
    strcpy(ClientInfo.users_name[i], m_ClientInfo[i].User_Name);
                                strcpy(ClientInfo.clients_ipaddr[i],
                                       inet_ntoa(m_ClientInfo[i].Client_Addr.sin_addr));
   }

   file://向所有線上用戶端發送線上客戶資訊報文
   for(i=0; i<=m_Connectnum; i++)
   {
    send(m_ClientInfo[i].Client_Socket, (char*)&ClientInfo,
                                     sizeof(cmd_client_info), NULL);
   }

   file://重新整理用戶端資訊列表
   networkid.Format("%d", m_NetworkID);

   LVITEM lvinsert;
   lvinsert.mask=LVIF_TEXT|LVIF_IMAGE|LVIF_PARAM;
   lvinsert.iItem=m_Connectnum;
   lvinsert.iSubItem=0;
   lvinsert.cchTextMax=20;
   lvinsert.pszText=HelloResp.user_name;
   lvinsert.iImage = 0;
   pList->InsertItem (&lvinsert);
   pList->SetItemText (m_Connectnum,1,networkid);
   pList->SetItemText(m_Connectnum,2,
                               inet_ntoa(m_ClientInfo[m_Connectnum].Client_Addr.sin_addr));
   pList->SetItemText (m_Connectnum,3,strTime);

   m_Connectnum ++;

   break;
  case CMD_ASK:
   cmd_ask Ask;
   cmd_ask_resp AskResp;
   memcpy(&Ask,rcvbuf+offset,sizeof(cmd_ask));
   offset+=sizeof(cmd_ask);
   AskResp.cmd_type = CMD_ASK_RESP;
   AskResp.Network_ID = Ask.Network_ID;
   for(i=0; i<m_Connectnum; i++)
   {
    if(m_ClientInfo[i].Network_ID == Ask.Network_ID)
    {
     strcpy(AskResp.pData1,m_ClientInfo[i].User_Name);
     strcat(AskResp.pData1, ":");
    }
   }
   strcpy(AskResp.pData2, Ask.pData);
   for(i=0; i<m_Connectnum; i++)
   {
    send(m_ClientInfo[i].Client_Socket, (char*)&AskResp, sizeof(AskResp), 0);
   }

   break;
  case CMD_GOODBYE:
   closesocket(pSocket);
   break;
  default:
   break;
  }
 }

 return TRUE;
}
BOOL CServerDlg::OnSend(SOCKET pSocket)
{
 return TRUE;
}

void CServerDlg::OnOK()
{
 closesocket(m_ListenSocket);
 WSACleanup();
 CDialog::OnOK();
}

void CServerDlg::OnTimer(UINT nIDEvent)
{
 CTime m_current_time = CTime::GetCurrentTime();
 CTimeSpan logintimes;
 CString login_times;
 CString networkid; file://列表框的網路ID項
 
 for(int i=0; i<m_Connectnum; i++)
 {
  logintimes = m_current_time - m_ClientInfo[i].Login_Time;
  login_times.Format("%d小時%d分%d秒", logintimes.GetHours(),
                                    logintimes.GetMinutes(),
            logintimes.GetSeconds());
 
  pList->SetItemText (i,4,login_times);
 }

 CDialog::OnTimer(nIDEvent);
}

// serverDlg.h : header file
//

#if !defined(AFX_SERVERDLG_H__B0AA0367_C1F4_11D4_AB1C_0080C8D6FEA5__INCLUDED_)
#define AFX_SERVERDLG_H__B0AA0367_C1F4_11D4_AB1C_0080C8D6FEA5__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include "global.h"

/////////////////////////////////////////////////////////////////////////////
// CServerDlg dialog

class CServerDlg : public CDialog
{
file://全域函數
    friend UINT KernelWorkThread(LPVOID pParam);
// Construction
public:
 CListCtrl* pList; file://用戶端線上資訊列表框對象
 CImageList m_imagelist;

 SOCKET m_ListenSocket; file://用於監聽連接埠的通訊端
 client_info m_ClientInfo[MAX_CLIENT_NUM]; file://儲存線上用戶端資訊的結構體數組
 sockaddr_in clientaddr; file://儲存發起串連的用戶端地址
 int m_Connectnum; file://線上用戶端個數
 int m_NetworkID;  file://返回給用戶端的網路ID號

 BOOL OnSend(SOCKET pSocket);    file://發送資料網路事件的響應函數
 BOOL OnReceive(SOCKET pSocket); file://接收資料網路事件的響應函數 
 BOOL OnClose(SOCKET pSocket);   file://關閉通訊端網路事件的響應函數

 CServerDlg(CWnd* pParent = NULL); // standard constructor

// Dialog Data
 file://{{AFX_DATA(CServerDlg)
 enum { IDD = IDD_SERVER_DIALOG };
  // NOTE: the ClassWizard will add data members here
 file://}}AFX_DATA

 // ClassWizard generated virtual function overrides
 file://{{AFX_VIRTUAL(CServerDlg)
 protected:
 virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support
 file://}}AFX_VIRTUAL

// Implementation
protected:
 HICON m_hIcon;

 // Generated message map functions
 file://{{AFX_MSG(CServerDlg)
 virtual BOOL OnInitDialog();
 afx_msg void OnSysCommand(UINT nID, LPARAM lParam);
 afx_msg void OnPaint();
 afx_msg HCURSOR OnQueryDragIcon();
 virtual void OnOK();
 afx_msg void OnTimer(UINT nIDEvent);
 file://}}AFX_MSG
 DECLARE_MESSAGE_MAP()
};

file://{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_SERVERDLG_H__B0AA0367_C1F4_11D4_AB1C_0080C8D6FEA5__INCLUDED_)