MSBuild ToolLocationHelper

gistfile1.txt

 while (!string.IsNullOrEmpty(path))
  {
      path = ChainReferenceAssemblyPath(path);
      if (!string.IsNullOrEmpty(path))
      {
          if (list.Contains(path))
          {
              return list;
          }
          list.Add(path);
      }
      else if (path == null)
      {
          list.Clear();
          return list;
      }
  }

ToolLocationHelper.cs

internal static string ChainReferenceAssemblyPath(string targetFrameworkDirectory)
{
    string fullPath = Path.GetFullPath(targetFrameworkDirectory);
    lock (locker)
    {
        chainedReferenceAssemblyPath = chainedReferenceAssemblyPath ?? new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
        cachedTargetFrameworkDisplayNames = cachedTargetFrameworkDisplayNames ?? new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
        string str2 = null;
        if (chainedReferenceAssemblyPath.TryGetValue(fullPath, out str2))
        {
            return str2;
        }
    }
    string path = Path.Combine(Path.Combine(fullPath, "RedistList"), "FrameworkList.xml");
    if (!File.Exists(path))
    {
        lock (locker)
        {
            chainedReferenceAssemblyPath[fullPath] = null;
            cachedTargetFrameworkDisplayNames[fullPath] = null;
        }
        return null;
    }
    string str5 = null;
    string str6 = null;
    try
    {
        using (XmlTextReader reader = new XmlTextReader(path))
        {
            reader.DtdProcessing = DtdProcessing.Ignore;
            while (reader.Read())
            {
                if ((reader.NodeType == XmlNodeType.Element) && string.Equals(reader.Name, "FileList", StringComparison.OrdinalIgnoreCase))
                {
                    reader.MoveToFirstAttribute();
                    do
                    {
                        if (string.Equals(reader.Name, "IncludeFramework", StringComparison.OrdinalIgnoreCase))
                        {
                            str5 = reader.Value;
                        }
                        else if (string.Equals(reader.Name, "Name", StringComparison.OrdinalIgnoreCase))
                        {
                            str6 = reader.Value;
                        }
                    }
                    while (reader.MoveToNextAttribute());
                    reader.MoveToElement();
                    goto Label_01CB;
                }
            }
        }
    }
    catch (XmlException exception)
    {
        ErrorUtilities.ThrowInvalidOperation("ToolsLocationHelper.InvalidRedistFile", new object[] { path, exception.Message });
    }
    catch (Exception exception2)
    {
        if (ExceptionHandling.NotExpectedException(exception2))
        {
            throw;
        }
        ErrorUtilities.ThrowInvalidOperation("ToolsLocationHelper.InvalidRedistFile", new object[] { path, exception2.Message });
    }
Label_01CB:
    if (str6 != null)
    {
        lock (locker)
        {
            cachedTargetFrameworkDisplayNames[fullPath] = str6;
        }
    }
    string fullName = string.Empty;
    try
    {
        if (!string.IsNullOrEmpty(str5))
        {
            fullName = fullPath;
            fullName = Directory.GetParent(fullName).FullName;
            fullName = Path.Combine(fullName, str5);
            fullName = Path.GetFullPath(fullName);
            if (!Directory.Exists(fullName))
            {
                fullName = null;
            }
        }
        lock (locker)
        {
            chainedReferenceAssemblyPath[fullPath] = fullName;
        }
        return fullName;
    }
    catch (Exception exception3)
    {
        if (ExceptionHandling.IsCriticalException(exception3))
        {
            throw;
        }
        ErrorUtilities.ThrowInvalidOperation("ToolsLocationHelper.CouldNotCreateChain", new object[] { fullPath, fullName, exception3.Message });
    }
    return null;
}