IOCP三部曲一之异步通知IO模型手绘图

异步通知IO模型

要素

1. 套接字 socket 数组
2. 事件对象 Event 数组
3. 一个 WSANETWORKEVENTS 结构体

注意图上面的眼睛(监视!!!)

下面是一个用异步IO实现回声服务器的示例代码，此图依据该代码手绘。

#include <stdio.h>
#include <string.h>
#include <winsock2.h>

#define BUF_SIZE 100

void CompressSockets(SOCKET hSockArr[], int idx, int total);
void CompressEvents(WSAEVENT hEventArr[], int idx, int total);
void ErrorHandling(char *msg);

int main(int argc, char *argv[])
{
    
    
	WSADATA wsaData;
	SOCKET hServSock, hClntSock;
	SOCKADDR_IN servAdr, clntAdr;

	SOCKET hSockArr[WSA_MAXIMUM_WAIT_EVENTS]; 
	WSAEVENT hEventArr[WSA_MAXIMUM_WAIT_EVENTS];
	WSAEVENT newEvent;
	WSANETWORKEVENTS netEvents;

	int numOfClntSock=0;
	int strLen, i;
	int posInfo, startIdx;
	int clntAdrLen;
	char msg[BUF_SIZE];
	
	if(argc!=2) {
    
    
		printf("Usage: %s <port>\n", argv[0]);
		exit(1);
	}
	if(WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
		ErrorHandling("WSAStartup() error!");

	hServSock=socket(PF_INET, SOCK_STREAM, 0);
	memset(&servAdr, 0, sizeof(servAdr));
	servAdr.sin_family=AF_INET;
	servAdr.sin_addr.s_addr=htonl(INADDR_ANY);
	servAdr.sin_port=htons(atoi(argv[1]));

	if(bind(hServSock, (SOCKADDR*) &servAdr, sizeof(servAdr))==SOCKET_ERROR)
		ErrorHandling("bind() error");

	if(listen(hServSock, 5)==SOCKET_ERROR)
		ErrorHandling("listen() error");

	newEvent=WSACreateEvent();
	if(WSAEventSelect(hServSock, newEvent, FD_ACCEPT)==SOCKET_ERROR)
		ErrorHandling("WSAEventSelect() error");

	hSockArr[numOfClntSock]=hServSock;
	hEventArr[numOfClntSock]=newEvent;
	numOfClntSock++;

	while(1)
	{
    
    
		posInfo=WSAWaitForMultipleEvents(
			numOfClntSock, hEventArr, FALSE, WSA_INFINITE, FALSE);
		startIdx=posInfo-WSA_WAIT_EVENT_0;

		for(i=startIdx; i<numOfClntSock; i++)
		{
    
    
			int sigEventIdx=
				WSAWaitForMultipleEvents(1, &hEventArr[i], TRUE, 0, FALSE);
			if((sigEventIdx==WSA_WAIT_FAILED || sigEventIdx==WSA_WAIT_TIMEOUT))
			{
    
    
				continue;
			}
			else
			{
    
    
				sigEventIdx=i;
				WSAEnumNetworkEvents(
					hSockArr[sigEventIdx], hEventArr[sigEventIdx], &netEvents);
				if(netEvents.lNetworkEvents & FD_ACCEPT)
				{
    
    
					if(netEvents.iErrorCode[FD_ACCEPT_BIT]!=0)
					{
    
    
						puts("Accept Error");
						break;
					}
					clntAdrLen=sizeof(clntAdr);
					hClntSock=accept(
						hSockArr[sigEventIdx], (SOCKADDR*)&clntAdr, &clntAdrLen);
					newEvent=WSACreateEvent();
					WSAEventSelect(hClntSock, newEvent, FD_READ|FD_CLOSE);

					hEventArr[numOfClntSock]=newEvent;
					hSockArr[numOfClntSock]=hClntSock;
					numOfClntSock++;
					puts("connected new client...");
				}

				if(netEvents.lNetworkEvents & FD_READ)
				{
    
    
					if(netEvents.iErrorCode[FD_READ_BIT]!=0)
					{
    
    
						puts("Read Error");
						break;
					}
					strLen=recv(hSockArr[sigEventIdx], msg, sizeof(msg), 0);
					send(hSockArr[sigEventIdx], msg, strLen, 0);
				}

				if(netEvents.lNetworkEvents & FD_CLOSE)
				{
    
    
					if(netEvents.iErrorCode[FD_CLOSE_BIT]!=0)	
					{
    
    
						puts("Close Error");
						break;
					}
					WSACloseEvent(hEventArr[sigEventIdx]);
					closesocket(hSockArr[sigEventIdx]);
					
					numOfClntSock--;
					CompressSockets(hSockArr, sigEventIdx, numOfClntSock);
					CompressEvents(hEventArr, sigEventIdx, numOfClntSock);
				}
			}
		}
	}
	WSACleanup();
	return 0;
}

void CompressSockets(SOCKET hSockArr[], int idx, int total)
{
    
    
	int i;
	for(i=idx; i<total; i++)
		hSockArr[i]=hSockArr[i+1];
}
void CompressEvents(WSAEVENT hEventArr[], int idx, int total)
{
    
    
	int i;
	for(i=idx; i<total; i++)
		hEventArr[i]=hEventArr[i+1];
}
void ErrorHandling(char *msg)
{
    
    	
	fputs(msg, stderr);
	fputc('\n', stderr);
	exit(1);
}