WinSock学习笔记6：IOCP完成端口模型

WinSock学习笔记6：IOCP完成端口模型

unit Unit1;

interface

uses
  WinSock2, Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  //单IO数据结构
  LPER_IO_OPERATION_DATA = ^TPER_IO_OPERATION_DATA;
  TPER_IO_OPERATION_DATA = packed record
    Overlapped: WSAOverlapped;
    DataBuf: WSABuf;
    Buff: array [0..10] of Char;
    BytesSend: DWORD;
    BytesRecv: DWORD;
  end;

  //单句柄数据结构
  LPER_HANDLE_DATA = ^TPER_HANDLE_DATA;
  TPER_HANDLE_DATA = packed record
    Socket: TSocket;
  end;

  TListenThread = class(TThread)
  private
  protected
    procedure Execute;override;
  public
    constructor Create;
  end;

  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  ServerSocket: TSocket;

implementation

{$R *.dfm}

//工作者线程
function WorkThread(CompletionPortID: Pointer):DWORD; stdcall;
var
  CompletionPort: THandle;
  BytesTransferred: DWORD;
  PerHandleData: LPER_HANDLE_DATA;
  PerIOData: LPER_IO_OPERATION_DATA;
  Flags: DWORD;
  RecvBytes: DWORD;
begin
  CompletionPort:= THandle(CompletionPortID);

  while True do
  begin
    //获取完成端口上的队列的完成状态
    GetQueuedCompletionStatus(CompletionPort, BytesTransferred, DWORD(PerHandleData),
      POverlapped(PerIOData), INFINITE);

    //判断是客户端发来的数据还是服务端发出的数据
    if PerIOData.BytesRecv = 0 then
    begin
      PerIOData.BytesRecv:= BytesTransferred;
      PerIOData.BytesSend:= 0;
    end else
      PerIOData.BytesSend:= PerIOData.BytesSend + BytesTransferred;

    if PerIOData.BytesRecv > PerIOData.BytesSend then
    begin
      ZeroMemory(@(PerIOData.Overlapped), SizeOf(WSAOverlapped));
      PerIOData.DataBuf.buf:= PerIOData.Buff + PerIOData.BytesSend;
      PerIOData.DataBuf.len:= PerIOData.BytesRecv - PerIOData.BytesSend;

      //显示收到的数据，这样做是不安全的，示例而已 :)
      Form1.Memo1.Lines.Add(PerIOData.Buff);
    end;

    //重置数据
    PerIOData.BytesRecv:= 0;
    PerIOData.DataBuf.len:= 22;
    PerIOData.DataBuf.buf:= @PerIOData.Buff;

    //再次投递
    WSARecv(PerHandleData.Socket, @(PerIOData.DataBuf), 1, RecvBytes, Flags,
      @(PerIOData.Overlapped), nil);
  end;
end;

{ TWorkThread }

constructor TListenThread.Create;
begin
  inherited Create(False);
  FreeOnTerminate:= True;
end;

procedure TListenThread.Execute;
var
  WSData: TWSAData;
  CompletionPort: THandle;
  lpSystemInfo: TSystemInfo;
  Idx: Integer;
  ThreadID: DWORD;
  LocalAddr: TSockaddr;
  ClientAddr: TSockaddr;
  ClientSocket: TSocket;

  PER_HANDLE_DATA: LPER_HANDLE_DATA;
  PER_IO_OPERATION_DATA: LPER_IO_OPERATION_DATA;

  RecvBytes: DWORD;
  Flags: DWORD;
begin
  inherited;

  //初始化Winsock
  WSAStartUp($202, WSData);
  //创建完成端口
  CompletionPort:= CreateIOCompletionPort(INVALID_HANDLE_VALUE, 0, 0, 0);
  //根据处理器数量创建工作者线程的数量(网上流传的说法是线程数量=cpu数量*2+2)
  GetSystemInfo(lpSystemInfo);
  for Idx := 1 to lpSystemInfo.dwNumberOfProcessors *2 + 2 do
    //创建工作者线程，并将完成端口句柄传递给线程
    CreateThread(nil, 0, @WorkThread, Pointer(CompletionPort), 0, ThreadID);
  //创建监听套接字
  ServerSocket:= WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, nil, 0, WSA_FLAG_OVERLAPPED);
  //设置LocalAddr的参数
  LocalAddr.sin_family:= AF_INET;   //IPV4族
  LocalAddr.sin_addr.S_addr:= INADDR_ANY;//这里不能写Inet_addr('127.0.0.1')，否则会绑定失败，不清楚原因是什么;
  LocalAddr.sin_port:= Htons(1077); //Host To Net Short，主机字节顺序转为网络字节顺序
  //绑定本机IP地址、端口，绑定之前先设置好LocalAddr的参数
  Bind(ServerSocket, @LocalAddr, SizeOf(LocalAddr));
  //开始监听
  Listen(ServerSocket, 5);

  while not Terminated do
  begin
    ClientSocket:= WSAAccept(ServerSocket, ClientAddr, nil, nil, 0);
    //创建TPER_HANDLE_DATA结构的变量保存客户端Socket
    PER_HANDLE_DATA:= LPER_HANDLE_DATA(GlobalAlloc(GPTR, SizeOf(TPER_HANDLE_DATA)));
    PER_HANDLE_DATA.Socket:= ClientSocket;
    //把完成端口和客户端套接字关联起来
    CreateIOCompletionPort(ClientSocket, CompletionPort, DWORD(PER_HANDLE_DATA), 0);
    //创建TPER_IO_OPERATION_DATA结构的变量，关联WSARecv函数
    PER_IO_OPERATION_DATA:= LPER_IO_OPERATION_DATA(GlobalAlloc(GPTR, SizeOf(TPER_IO_OPERATION_DATA)));
    ZeroMemory(@PER_IO_OPERATION_DATA.Overlapped, SizeOf(WSAOverlapped));
    PER_IO_OPERATION_DATA.BytesSend:= 0;
    PER_IO_OPERATION_DATA.BytesRecv:= 0;
    PER_IO_OPERATION_DATA.DataBuf.len:= 22;
    PER_IO_OPERATION_DATA.DataBuf.buf:= @PER_IO_OPERATION_DATA.Buff;

    WSARecv(ClientSocket, @(PER_IO_OPERATION_DATA.DataBuf), 1, RecvBytes,
      Flags, @(PER_IO_OPERATION_DATA.Overlapped), nil);
  end;
end;


procedure TForm1.FormCreate(Sender: TObject);
begin
  //创建监听线程
  TListenThread.Create();
end;


end.

该代码仅仅是练习IOCP的函数使用和大体的实现步骤，里面很多细节并不是唯一的方法，例如单IO数据结构和单句柄数据结构的定义等等。