UdpProtocol.cs :  » Business-Application » DC » DCSharp » Backend » Protocols » Nmdc » C# / CSharp Open Source

/* 
 * Copyright (C) 2004-2005 Jonathan Bindel
 * Copyright (C) 2006-2007 Eskil Bylund
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

using System;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;

using DCSharp.Backend.Connections;
using DCSharp.Backend.Objects;

namespace DCSharp.Backend.Protocols.Nmdc{
  /// <summary>
  /// A class that handles NMDC messages sent over Udp.
  /// </summary>
  public class UdpProtocol : Protocol
  {
    private const int MaxActiveResults = 10;
    private const int MaxPassiveResults = 5;
    
    public UdpProtocol(ISearchResultHandler handler,
      ILegacyUserIdentifier userIdentifier)
    {
      if (handler == null)
      {
        throw new ArgumentNullException("handler");
      }
      if (userIdentifier == null)
      {
        throw new ArgumentNullException("userIdentifier");
      }
      this.handler = handler;
      this.userIdentifier = userIdentifier;
    }
    
    /// <summary>
    /// 
    /// </summary>
    public ISearchResultHandler ResultHandler
    {
      get { return handler; }
    }
    private ISearchResultHandler handler;
    
    /// <summary>
    /// 
    /// </summary>
    public ILegacyUserIdentifier UserIdentifier
    {
      get { return userIdentifier; }
    }
    private ILegacyUserIdentifier userIdentifier;
    
    protected override void Invoke(string command, string argument)
    {
      if (command == "$SR")
      {
        ParseSearchResult(argument);
      }
      else
      {
        base.Invoke(command, argument);
      }
    }
    
    protected void ParseSearchResult(string argument)
    {
      // $SR <nick> <result> <free slots>/<total slots><0x05><hubname> (<hubip:port>)
      //
      // <result> is one of the following:
      //
      // - For files: <filename><0x05><filesize>
      // - For directories: <directory>
      //
      // If it's a TTH search <hubname> is: TTH:<tth>
      
      int i = 0;
      
      int j = argument.IndexOf(' ');
      if (j <= 0)
        return;
      
      SearchResult result = new SearchResult();
      
      string nick = argument.Substring(0, j);
      
      string remaining = argument.Substring(j + 1);
      char bit = (char)5;
      int count = Regex.Matches(remaining, bit.ToString()).Count;
      
      if (count == 1)
      {
        // We have a directory...find the first space beyond the first 0x05 from the back 
        // (dirs might contain spaces as well...clever protocol, eh?)
        result.Type = ResultType.Directory;
        
        // Get past the hubname that might contain spaces
        j = remaining.LastIndexOf(bit);
        if (j < 0)
          return;
        
        j = remaining.LastIndexOf(' ', j - 1);
        if (j < 0)
          return;
        
        result.Path = remaining.Substring(0, j);
      }
      else if (count == 2)
      {
        result.Type = ResultType.File;
        
        j = remaining.IndexOf(bit);
        result.Path = remaining.Substring(0, j);
        
        i = j + 1;
        long size;
        
        j = remaining.IndexOf(' ', i);
        if (j < 0 || !long.TryParse(remaining.Substring(i, j - i), out size))
          return;
        
        result.Size = size;
      }
      else
      {
        return;
      }
      
      int slots;
      
      i = j + 1;
      j = remaining.IndexOf('/', i);
      if (j < 0 || !int.TryParse(remaining.Substring(i, j - i), out slots))  
        return;
      
      result.FreeSlots = slots;
      
      i = j + 1;
      j = remaining.IndexOf(bit, i);
      if (j < 0 || !int.TryParse(remaining.Substring(i, j - i), out slots))
        return;
      
      result.Slots = slots;
      
      i = j + 1;
      j = remaining.LastIndexOf(" (");
      if (j < 0)
        return;
      
      string hubName = remaining.Substring(i, j - i);
      if (hubName.StartsWith("TTH:"))
      {
        result.TTH = hubName.Substring(4);
        hubName = null;
      }
      
      i = j + 2;
      j = remaining.IndexOf(')', i);
      if (j < 0)
        return;
      
      string hubAddress = remaining.Substring(i, j - i);
      
      result.User = GetIdentity(nick, hubName, hubAddress);
      if (result.User != null)
      {
        handler.HandleSearchResult(result);
      }
    }
    
    protected virtual Identity GetIdentity(string nick, string hubName,
      string hubAddress)
    {
      Identity identity;
      HubConnection hub;
      
      userIdentifier.IdentifyUser(nick, hubName, hubAddress,
        out hub, out identity);
      
      return identity;
    }
  }
}