I/O异步demo

HANDLE WINAPI CreateIoCompletionPort(
__in          HANDLE FileHandle,
__in          HANDLE ExistingCompletionPort,
__in          ULONG_PTR CompletionKey,
__in          DWORD NumberOfConcurrentThreads
);
/*
这个函数完成两个不同的任务：1、创建一个完成端口对象；2、将一个或者多个文件句柄关联到I/O完成端口对象。可分成两个小函数对CreateIoCompletionPort调用进行抽象。
*/
//1、创建I/O完成端口
HANDLE CreateNewCompletionPort(DWORD dwNumberOfConcurrentThreads)
{
return (CreateNewCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, dwNumberOfConcurrentThreads));
}
//2、将设备与I/O完成端口关联起来
BOOL AssociateDeviceWithCompletionPort(HANDLE hCompletionPort, HANDLE hDevice, DWORD dwCompletionKey)
{
HANDLE h = CreateIoCompletionPort(hDevice, hCompletionPort, dwCompletionKey, 0);
return (h == hCompletionPort);
}

/////////////////////////////////////////////////
// IOCPDemo.cpp文件            调试通过

#include "WSAInit.h"
#include <stdio.h>
#include <windows.h>

// 初始化Winsock库
CWSAInit theSock;

#define BUFFER_SIZE 1024
#define OP_READ   1
#define OP_WRITE  2
#define OP_ACCEPT 3

typedef struct _PER_HANDLE_DATA        // per-handle数据
{
SOCKET s;            // 对应的套节字句柄
sockaddr_in addr;    // 客户方地址
char buf[BUFFER_SIZE];    // 数据缓冲区
int nOperationType;        // 操作类型
} PER_HANDLE_DATA, *PPER_HANDLE_DATA;

DWORD WINAPI ServerThread(LPVOID lpParam)
{
// 得到完成端口对象句柄
HANDLE hCompletion = (HANDLE)lpParam;

DWORD dwTrans;
PPER_HANDLE_DATA pPerHandle;
OVERLAPPED *pOverlapped;
while(TRUE)
{
// 在关联到此完成端口的所有套节字上等待I/O完成
BOOL bOK = ::GetQueuedCompletionStatus(hCompletion,
&dwTrans, (PULONG_PTR)&pPerHandle, &pOverlapped, WSA_INFINITE);
if(!bOK)                        // 在此套节字上有错误发生
{
::closesocket(pPerHandle->s);
::GlobalFree(pPerHandle);
::GlobalFree(pOverlapped);
continue;
}

if(dwTrans == 0 &&                // 套节字被对方关闭
(pPerHandle->nOperationType == OP_READ || pPerHandle->nOperationType == OP_WRITE))

{
::closesocket(pPerHandle->s);
::GlobalFree(pPerHandle);
::GlobalFree(pOverlapped);
continue;
}

switch(pPerHandle->nOperationType)    // 通过per-I/O数据中的nOperationType域查看什么I/O请求完成了
{
case OP_READ:    // 完成一个接收请求
{
pPerHandle->buf[dwTrans] = '\0';
printf(pPerHandle-> buf);

// 继续投递接收I/O请求
WSABUF buf;
buf.buf = pPerHandle->buf ;
buf.len = BUFFER_SIZE;
pPerHandle->nOperationType = OP_READ;

DWORD nFlags = 0;
::WSARecv(pPerHandle->s, &buf, 1, &dwTrans, &nFlags, pOverlapped, NULL);
}
break;
case OP_WRITE: // 本例中没有投递这些类型的I/O请求
case OP_ACCEPT:
break;
}
}
return 0;
}

void main()
{
int nPort = 4567;
// 创建完成端口对象，创建工作线程处理完成端口对象中事件
HANDLE hCompletion = ::CreateIoCompletionPort(INVALID_HANDLE_VALUE, 0, 0, 0);
::CreateThread(NULL, 0, ServerThread, (LPVOID)hCompletion, 0, 0);

// 创建监听套节字，绑定到本地地址，开始监听
SOCKET sListen = ::socket(AF_INET, SOCK_STREAM, 0);
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, 5);

// 循环处理到来的连接
while(TRUE)
{
// 等待接受未决的连接请求
SOCKADDR_IN saRemote;
int nRemoteLen = sizeof(saRemote);
SOCKET sNew = ::accept(sListen, (sockaddr*)&saRemote, &nRemoteLen);
// 接受到新连接之后，为它创建一个per-handle数据，并将它们关联到完成端口对象。
PPER_HANDLE_DATA pPerHandle =
(PPER_HANDLE_DATA)::GlobalAlloc(GPTR, sizeof(PER_HANDLE_DATA));
pPerHandle->s = sNew;
memcpy(&pPerHandle->addr, &saRemote, nRemoteLen);
pPerHandle->nOperationType = OP_READ;
::CreateIoCompletionPort((HANDLE)pPerHandle->s, hCompletion, (ULONG_PTR)pPerHandle, 0);
// 投递一个接收请求
OVERLAPPED *pol = (OVERLAPPED *)::GlobalAlloc(GPTR, sizeof(OVERLAPPED));
WSABUF buf;
buf.buf = pPerHandle->buf;
buf.len = BUFFER_SIZE;
DWORD dwRecv;
DWORD dwFlags = 0;
::WSARecv(pPerHandle->s, &buf, 1, &dwRecv, &dwFlags, pol, NULL);
}
}