kenlistian

厚積薄發(fā). 勤為槳,思為帆

:: 管理 ::

73 隨筆 :: 4 文章 :: 22 評論 :: 0 Trackbacks

來自微軟的完成端口例子，就講解一下它的使用套路吧
反正編程這個玩意，只要用過，自然就知道什么回事，一次不會再看一次，學(xué)習(xí)這個玩意，無他，勤奮而已。
奢談效率等等，那只是孰能生巧上的功夫。

這個例子是在console下的例子,算是一個echo服務(wù)器吧,
跑起來后將在5150端口監(jiān)聽,一旦有個端口連接上來,發(fā)個數(shù)據(jù)給服務(wù)端口,它就echo回數(shù)據(jù)給那個端口. 直到那個連接中斷.

完成端口,其實理解成一個通道或管子就可以了,和管道也差不了多少,不過可以實現(xiàn)異步處理罷了,
你這邊往管子里丟數(shù)據(jù),通過GetQueuedCompletionStatus來查管子那頭出數(shù)據(jù)沒,出了就處理,這個管子就是通過一個自定義有點特殊的結(jié)構(gòu)來寫入或讀出數(shù)據(jù)而已.
那個完成端口,其實就相當(dāng)是標(biāo)識那個數(shù)據(jù)塊的句柄,

//下面請看例子
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>

#define PORT 5150
#define DATA_BUFSIZE 8192

#pragma comment(lib, "Ws2_32")

typedef struct //這個玩意就是灌數(shù)據(jù)，取數(shù)據(jù)的一個自定義數(shù)據(jù)結(jié)構(gòu)

                                              //和那個wm_data差不了多少，不過就是老要塞一個OverLapped結(jié)構(gòu)，
{
   OVERLAPPED Overlapped;
   WSABUF DataBuf;
   CHAR Buffer[DATA_BUFSIZE];
   DWORD BytesSEND;                                 //發(fā)送字節(jié)數(shù)
   DWORD BytesRECV;
} PER_IO_OPERATION_DATA, * LPPER_IO_OPERATION_DATA;

typedef struct
{
SOCKET Socket;
} PER_HANDLE_DATA, * LPPER_HANDLE_DATA;

DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID);

void main(void)
{
   SOCKADDR_IN InternetAddr;
   SOCKET Listen;
   SOCKET Accept;
   HANDLE CompletionPort;
   SYSTEM_INFO SystemInfo;
   LPPER_HANDLE_DATA PerHandleData;
   LPPER_IO_OPERATION_DATA PerIoData;
   int i;
   DWORD RecvBytes;
   DWORD Flags;
   DWORD ThreadID;
   WSADATA wsaData;
   DWORD Ret;

   if ((Ret = WSAStartup(0x0202, &wsaData)) != 0)
   {
      printf("WSAStartup failed with error %d\n", Ret);
      return;
   }

   //
   //完成端口的建立得搞2次，這是第一次調(diào)用，至于為什么？我問問你
   //
   if ((CompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0)) == NULL)
   {
      printf( "CreateIoCompletionPort failed with error: %d\n", GetLastError());
      return;
   }
   //老套子api，不談也罷
   GetSystemInfo(&SystemInfo);

   //發(fā)現(xiàn)2個CPU，那就開個雙倍的線程跑吧
   for(i = 0; i < SystemInfo.dwNumberOfProcessors * 2; i++)
   {
      HANDLE ThreadHandle;

      //
      //完成端口掛到線程上面來了，就像管子把灌數(shù)據(jù)的和讀數(shù)據(jù)的兩頭都連上了,
     //
      if ((ThreadHandle = CreateThread(NULL, 0, ServerWorkerThread, CompletionPort,
         0, &ThreadID)) == NULL)
      {
         printf("CreateThread() failed with error %d\n", GetLastError());
         return;
      }
      CloseHandle(ThreadHandle);
   }

   //
   //啟動一個監(jiān)聽socket ，以下都是長長的交代
   //
   if ((Listen = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0,
      WSA_FLAG_OVERLAPPED)) == INVALID_SOCKET)
   {
      printf("WSASocket() failed with error %d\n", WSAGetLastError());
      return;
   }

   InternetAddr.sin_family = AF_INET;
   InternetAddr.sin_addr.s_addr = htonl(INADDR_ANY);
   InternetAddr.sin_port = htons(PORT);

   if (bind(Listen, (PSOCKADDR) &InternetAddr, sizeof(InternetAddr)) == SOCKET_ERROR)
   {
      printf("bind() failed with error %d\n", WSAGetLastError());
      return;
   }

   if (listen(Listen, 5) == SOCKET_ERROR)
   {
      printf("listen() failed with error %d\n", WSAGetLastError());
      return;
   }

   //
   // 監(jiān)聽端口打開，就開始在這里循環(huán)，一有socket連上，WSAAccept就創(chuàng)建一個socket，
   // 這個socket 又和完成端口聯(lián)上,
   //
   // 嘿嘿，完成端口第二次調(diào)用那個createxxx函數(shù)，為什么，留給人思考思考可能更深刻，
   // 反正這套路得來2次，
   // 完成端口completionport和accept socket掛起來了，
   //
   while(TRUE)
   {

    //主線程跑到這里就等啊等啊，但是線程卻開工了，
      if ((Accept = WSAAccept(Listen, NULL, NULL, NULL, 0)) == SOCKET_ERROR)
      {
         printf("WSAAccept() failed with error %d\n", WSAGetLastError());
         return;
      }

      if ((PerHandleData = (LPPER_HANDLE_DATA) GlobalAlloc(GPTR, sizeof(PER_HANDLE_DATA))) == NULL)
      {
         printf("GlobalAlloc() failed with error %d\n", GetLastError());
         return;
      }

      PerHandleData->Socket = Accept;

      //
     //把這頭和完成端口completionPort連起來
     //就像你把漏斗接到管子口上,開始要灌數(shù)據(jù)了
     //
      if (CreateIoCompletionPort((HANDLE) Accept, CompletionPort, (DWORD) PerHandleData,
         0) == NULL)
      {
         printf("CreateIoCompletionPort failed with error %d\n", GetLastError());
         return;
      }

      //
      //清管子的數(shù)據(jù)結(jié)構(gòu),準(zhǔn)備往里面灌數(shù)據(jù)
      //
      if ((PerIoData = (LPPER_IO_OPERATION_DATA) GlobalAlloc(GPTR,sizeof(PER_IO_OPERATION_DATA))) == NULL)
      {
         printf("GlobalAlloc() failed with error %d\n", GetLastError());
         return;
      }

      ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));
      PerIoData->BytesSEND = 0;
      PerIoData->BytesRECV = 0;
      PerIoData->DataBuf.len = DATA_BUFSIZE;
      PerIoData->DataBuf.buf = PerIoData->Buffer;

      Flags = 0;

      //
      // accept接到了數(shù)據(jù)，就放到PerIoData中,而perIoData又通過線程中的函數(shù)取出,
     //
      if (WSARecv(Accept, &(PerIoData->DataBuf), 1, &RecvBytes, &Flags,
         &(PerIoData->Overlapped), NULL) == SOCKET_ERROR)
      {
         if (WSAGetLastError() != ERROR_IO_PENDING)
         {
            printf("WSARecv() failed with error %d\n", WSAGetLastError());
            return;
         }
      }
   }
}

//
//線程一但調(diào)用，就老在里面循環(huán)，
// 注意，傳入的可是完成端口啊，就是靠它去取出管子中的數(shù)據(jù)
//
DWORD WINAPI ServerWorkerThread(LPVOID CompletionPortID)
{
   HANDLE CompletionPort = (HANDLE) CompletionPortID;

   DWORD BytesTransferred;
   LPOVERLAPPED Overlapped;
   LPPER_HANDLE_DATA PerHandleData;
   LPPER_IO_OPERATION_DATA PerIoData;
   DWORD SendBytes, RecvBytes;
   DWORD Flags;

   while(TRUE)
   {
      //
      //在這里檢查完成端口部分的數(shù)據(jù)buf區(qū)，數(shù)據(jù)來了嗎？
      // 這個函數(shù)參數(shù)要看說明，
      // PerIoData 就是從管子流出來的數(shù)據(jù),
      //PerHandleData 也是從管子里取出的，是何時塞進來的，
     //就是在建立第2次createIocompletionPort時
    //

      if (GetQueuedCompletionStatus(CompletionPort, &BytesTransferred,
         (LPDWORD)&PerHandleData, (LPOVERLAPPED *) &PerIoData, INFINITE) == 0)
      {
         printf("GetQueuedCompletionStatus failed with error %d\n", GetLastError());
         return 0;
      }

      // 檢查數(shù)據(jù)傳送完了嗎
      if (BytesTransferred == 0)
      {
         printf("Closing socket %d\n", PerHandleData->Socket);

         if (closesocket(PerHandleData->Socket) == SOCKET_ERROR)
         {
            printf("closesocket() failed with error %d\n", WSAGetLastError());
            return 0;
         }

         GlobalFree(PerHandleData);
         GlobalFree(PerIoData);
         continue;
      }
     //
    //看看管子里面有數(shù)據(jù)來了嗎？=0，那是剛收到數(shù)據(jù)
    //
      if (PerIoData->BytesRECV == 0)
      {
         PerIoData->BytesRECV = BytesTransferred;
         PerIoData->BytesSEND = 0;
      }
      else   //來了，
      {
         PerIoData->BytesSEND += BytesTransferred;
      }

      //
      // 數(shù)據(jù)沒發(fā)完？繼續(xù)send出去
     //
     if (PerIoData->BytesRECV > PerIoData->BytesSEND)
      {

         ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED)); //清0為發(fā)送準(zhǔn)備
         PerIoData->DataBuf.buf = PerIoData->Buffer + PerIoData->BytesSEND;
         PerIoData->DataBuf.len = PerIoData->BytesRECV - PerIoData->BytesSEND;

       //1個字節(jié)一個字節(jié)發(fā)送發(fā)送數(shù)據(jù)出去
         if (WSASend(PerHandleData->Socket, &(PerIoData->DataBuf), 1, &SendBytes, 0,
            &(PerIoData->Overlapped), NULL) == SOCKET_ERROR)
         {
            if (WSAGetLastError() != ERROR_IO_PENDING)
            {
               printf("WSASend() failed with error %d\n", WSAGetLastError());
               return 0;
            }
         }
      }
      else
      {
         PerIoData->BytesRECV = 0;

Flags = 0;
ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));

PerIoData->DataBuf.len = DATA_BUFSIZE;
PerIoData->DataBuf.buf = PerIoData->Buffer;

         if (WSARecv(PerHandleData->Socket, &(PerIoData->DataBuf), 1, &RecvBytes, &Flags,
            &(PerIoData->Overlapped), NULL) == SOCKET_ERROR)
         {
            if (WSAGetLastError() != ERROR_IO_PENDING)
            {
               printf("WSARecv() failed with error %d\n", WSAGetLastError());
               return 0;
            }
         }
      }
   }
}

posted on 2006-05-25 22:27 kenlistian 閱讀(2466) 評論(0) 編輯收藏引用

只有注冊用戶登錄后才能發(fā)表評論。
【推薦】100%開源！大型工業(yè)跨平臺軟件C++源碼提供，建模，組態(tài)！



網(wǎng)站導(dǎo)航: 博客園 IT新聞 BlogJava 博問 Chat2DB 管理

kenlistian

常用鏈接

留言簿(5)

隨筆分類(28)

隨筆檔案(73)

文章檔案(4)

積分與排名

最新隨筆

最新評論