86 lines
2.9 KiB
C#
86 lines
2.9 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Text;
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using System.Threading;
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using System.Net.Sockets;
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namespace ChatClient
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{
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class TcpClientConnector
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{
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/// <summary>
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/// 在指定时间内尝试连接指定主机上的指定端口。
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/// </summary>
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/// <param name="hostname">要连接到的远程主机的 DNS 名。</param>
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/// <param name="port">要连接到的远程主机的端口号。</param>
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/// <param name="millisecondsTimeout">要等待的毫秒数，或 -1 表示无限期等待。</param>
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/// <returns>已连接的一个 TcpClient 实例。</returns>
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/// <remarks>本方法可能抛出的异常与 TcpClient 的构造函数重载之一
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/// public TcpClient(string, int) 相同，并若指定的等待时间是个负数且不等于
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/// -1，将会抛出 ArgumentOutOfRangeException。</remarks>
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public static TcpClient Connect(string hostname, int port, int millisecondsTimeout)
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{
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ConnectorState cs = new ConnectorState();
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cs.Hostname = hostname;
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cs.Port = port;
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ThreadPool.QueueUserWorkItem(new WaitCallback(ConnectThreaded), cs);
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if (cs.Completed.WaitOne(millisecondsTimeout, false))
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{
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if (cs.TcpClient != null) return cs.TcpClient;
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throw cs.Exception;
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}
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else
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{
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cs.Abort();
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throw new SocketException(11001); // cannot connect
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}
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}
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private static void ConnectThreaded(object state)
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{
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ConnectorState cs = (ConnectorState)state;
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cs.Thread = Thread.CurrentThread;
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try
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{
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TcpClient tc = new TcpClient(cs.Hostname, cs.Port);
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if (cs.Aborted)
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{
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try { tc.GetStream().Close(); }
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catch { }
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try { tc.Close(); }
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catch { }
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}
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else
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{
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cs.TcpClient = tc;
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cs.Completed.Set();
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}
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}
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catch (Exception e)
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{
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cs.Exception = e;
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cs.Completed.Set();
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}
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}
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private class ConnectorState
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{
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public string Hostname;
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public int Port;
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public volatile Thread Thread;
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public readonly ManualResetEvent Completed = new ManualResetEvent(false);
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public volatile TcpClient TcpClient;
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public volatile Exception Exception;
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public volatile bool Aborted;
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public void Abort()
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{
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if (Aborted != true)
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{
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Aborted = true;
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try { Thread.Abort(); }
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catch { }
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}
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}
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}
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}
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} |