当然TCP方式的模型还有事件选择模型。
就是把所有的网络事件和我们的一个程序里定义的事件梆定。
这个有它的好处，可能可以让我们更好的写一个线程来管理
接收与发送。
现在来讲一下一个完成端口模型。
完成端口
一个完成端口其实就是一个通知队列，由操作系统把已经完成的重叠I/O请求的通知
放入其中。当某项I/O操作一旦完成，某个可以对该操作结果进行处理的工作者线程
就会收到一则通知。而套接字在被创建后，可以在任何时候与某个完成端口进行关
联。
步骤:
1、创建一个空的完成端口；
2、得到本地机器的CPU个数；
3、开启CPU*2个工作线程(又名线程池),全部都在等待完成端口的完成包;
4、创建TCP的监听socket，使用事件邦定，创建监听线程;
5、当有人连接进入的时候，将Client socket保存到一个我们自己定义的关键键，
并把它与我们创建的完成端口关联；
6、使用WSARecv和WSASend函数投递一些请求，这是使用重叠I/O的方式;
7、重复5~6;
注：1、重叠I/O的方式中，接收与发送数据包的时候，一定要进行投递请求这是
它们这个体系结构的特点
当然，在完成端口方式中，不是直接使用的WSARecv和WSASend函数进行请求
的投递的。而是使用的ReadFile,Write的方式
2、完成端口使用了系统内部的一些模型，所以我们只要按照一定的顺序调用就
可以完成了。
3、完成端口是使用在这样的情况下，有成千上万的用户连接的时候，它能够
保证性能不会降低。
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>
#define PORT 5150
#define DATA_BUFSIZE 8192
//关键项
typedef struct
{
OVERLAPPED Overlapped;
WSABUF DataBuf;
CHAR Buffer[DATA_BUFSIZE];
DWORD BytesSEND;
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;
}
//打开一个空的完成端口
if ((CompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0)) == NULL)
{
printf( "CreateIoCompletionPort failed with error: %d\n", GetLastError());
return;
}
// Determine how many processors are on the system.
GetSystemInfo(&SystemInfo);
// 开启cpu个数的2倍个的线程
for(i = 0; i < SystemInfo.dwNumberOfProcessors * 2; i++)
{
HANDLE ThreadHandle;
// Create a server worker thread and pass the completion port to the thread.
if ((ThreadHandle = CreateThread(NULL, 0, ServerWorkerThread, CompletionPort,
0, &ThreadID)) == NULL)
{
printf("CreateThread() failed with error %d\n", GetLastError());
return;
}
// Close the thread handle
CloseHandle(ThreadHandle);
}
//打开一个服务器socket
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;
}
//开始接收从客户端来的连接
while(TRUE)
{
if ((Accept = WSAAccept(Listen, NULL, NULL, NULL, 0)) == SOCKET_ERROR)
{
printf("WSAAccept() failed with error %d\n", WSAGetLastError());
return;
}
// 创建一个关键项用于保存这个客户端的信息，用户接收发送的重叠结构，
// 还有使用到的缓冲区
if ((PerHandleData = (LPPER_HANDLE_DATA) GlobalAlloc(GPTR,
sizeof(PER_HANDLE_DATA))) == NULL)
{
printf("GlobalAlloc() failed with error %d\n", GetLastError());
return;
}
// Associate the accepted socket with the original completion port.
printf("Socket number %d connected\n", Accept);
PerHandleData->Socket = Accept;
//与我们的创建的那个完成端口关联起来,将关键项也与指定的一个完成端口关联
if (CreateIoCompletionPort((HANDLE) Accept, CompletionPort, (DWORD) PerHandleData,
0) == NULL)
{
printf("CreateIoCompletionPort failed with error %d\n", GetLastError());
return;
}
// 投递一次接收，由于接收都需要使用这个函数来投递一个接收的准备
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;
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;
}
}
}
}
//工作线程
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)
{
//完成端口有消息来了
if (GetQueuedCompletionStatus(CompletionPort, &BytesTransferred,
(LPDWORD)&PerHandleData, (LPOVERLAPPED *) &PerIoData, INFINITE) == 0)
{
printf("GetQueuedCompletionStatus failed with error %d\n", GetLastError());
return 0;
}
//是不是有人退出了
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;
}
//
if (PerIoData->BytesRECV == 0)
{
PerIoData->BytesRECV = BytesTransferred;
PerIoData->BytesSEND = 0;
}
else
{
PerIoData->BytesSEND += BytesTransferred;
}
if (PerIoData->BytesRECV > PerIoData->BytesSEND)
{
// Post another WSASend() request.
// Since WSASend() is not gauranteed to send all of the bytes requested,
// continue posting WSASend() calls until all received bytes are sent.
ZeroMemory(&(PerIoData->Overlapped), sizeof(OVERLAPPED));
PerIoData->DataBuf.buf = PerIoData->Buffer + PerIoData->BytesSEND;
PerIoData->DataBuf.len = PerIoData->BytesRECV - PerIoData->BytesSEND;
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;
// Now that there are no more bytes to send post another WSARecv() request.
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;
}
}
}
}
}
