Cosmos/source2/Debug/Cosmos.Debug.Common/PipeClient.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Pipes;
using System.Linq;
using System.Text;

namespace Cosmos.Debug.Common {
  public class PipeClient {
    private string mPipeName;
    private NamedPipeClientStream mPipe;
    private StreamWriter mWriter;

    public PipeClient(string aPipeName) {
      mPipeName = aPipeName;
    }

    public void SendCommand(byte aCmd) {
      // Necessary to do it this way else C# using a literal null
      // cant determine which of the overloads to call.
      byte[] xData = null;
      SendCommand(aCmd, xData);
    }

    public void SendCommand(byte aCmd, string aData) {
      SendCommand(aCmd, Encoding.UTF8.GetBytes(aData)); 
    }

    public void SendCommand(byte aCmd, byte[] aData) {
      // We need to delay creation and connect until its used, so we guarantee
      // that the server side is active and ready.

      // Because we have a timeout in connect this can happen more than once
      // concurrently if the user is quick. I had this issue several times during
      // testing. To avoid this, we block with a lock.
      lock (this) {
        if (mPipe == null) {
          var xPipe = new NamedPipeClientStream(".", mPipeName, PipeDirection.Out);
          try {
            // For now we assume its there or not from the first call.
            // If we don't find the server, we disable it to avoid causing lag.
            // TODO: In future - try this instead:
            // String[] listOfPipes = System.IO.Directory.GetFiles(@"\.\pipe\");
            // or maybe not - what we have seems to work just fine...

            xPipe.Connect(500);
          } catch (TimeoutException ex) {
            xPipe.Close();
            return;
          }
          mWriter = new StreamWriter(xPipe);
          // Only set mPipe if we are truly ready. Other code can check it.
          mPipe = xPipe;
        }
      }

      mPipe.WriteByte(aCmd);

      byte[] xData = aData;
      if (xData == null) {
        xData = new byte[0];
      }
      int xLength = Math.Min(xData.Length, 32768);
      mPipe.WriteByte((byte)(xLength >> 8));
      mPipe.WriteByte((byte)(xLength & 0xFF));
      if (xLength > 0) {
        mPipe.Write(xData, 0, xLength);
      }

      mPipe.Flush();
    }

  }
}