【问题标题】:Understanding compiler-generated type in dotPeek decompiled code了解 dotPeek 反编译代码中编译器生成的类型
【发布时间】:2013-04-01 16:12:19
【问题描述】:

嘿嘿。我正在阅读Digi Traffic Accelerator 的反编译源代码(我认为这是最好的学习方式),直到我得到一些无法理解的代码!请看:

  internal class ProxyFarm
  {
    private static Random rand = new Random();
    private static Regex UserPassAtHostPort = new Regex("\r\n                ^\r\n                (?<user>[^:]+?) : (?<pass>[^@]+?)\r\n                @\r\n                (?<host>[^:]+? (?: : \\d+)? )\r\n                $", RegexOptions.IgnorePatternWhitespace);
    private static Regex HostPortUserPass = new Regex("\r\n                ^\r\n                (?<host>[^:]+? : \\d+) : (?<user>[^:]+?) : (?<pass>.+?)\r\n                $", RegexOptions.IgnorePatternWhitespace);
    public const string NEW = "new";
    public const string ACTIVE = "active";
    public const string BLOCKED_BY_GOOGLE = "blocked by Google";
    public const string INACTIVE = "inactive";
    public const string CHECKING = "Checking...";

    static ProxyFarm()
    {
    }

    public static StorageDataSet.ProxiesRow GetRandomProxy(bool WillUseRecaptcha = true)
    {
      // some normal code
    }

    public static WebProxy MakeWebProxy(StorageDataSet.ProxiesRow row)
    {
      // some normal code
    }

    public static void CheckProxy(StorageDataSet.ProxiesRow proxy)
    {
      // ISSUE: object of a compiler-generated type is created
      // ISSUE: variable of a compiler-generated type
      ProxyFarm.\u003C\u003Ec__DisplayClass5 cDisplayClass5 = new ProxyFarm.\u003C\u003Ec__DisplayClass5();
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.proxy = proxy;
      // ISSUE: reference to a compiler-generated field
      if (cDisplayClass5.proxy == null)
        return;
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.logger = LogManager.GetLogger("Program");
      // ISSUE: reference to a compiler-generated field
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.state = new ProxyFarm.CallbackState()
      {
        Proxy = cDisplayClass5.proxy,
        Google = ProxyFarm.CheckStatus.NotChecked,
        Post = ProxyFarm.CheckStatus.NotChecked
      };
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.r = (HttpWebRequest) WebRequest.Create("http://www.digitrafficgenerator.com/post_test.php");
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.r.Method = "POST";
      try
      {
        // ISSUE: reference to a compiler-generated field
        // ISSUE: reference to a compiler-generated field
        cDisplayClass5.r.Proxy = (IWebProxy) ProxyFarm.MakeWebProxy(cDisplayClass5.proxy);
      }
      catch (Exception ex)
      {
        // ISSUE: reference to a compiler-generated field
        // ISSUE: reference to a compiler-generated field
        cDisplayClass5.logger.Warn((object) ("Invalid proxy entered: " + cDisplayClass5.proxy.Address), ex);
        // ISSUE: reference to a compiler-generated field
        ProxyFarm.ChangeStatus(cDisplayClass5.proxy, "inactive");
        return;
      }
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.r.ConnectionGroupName = Guid.NewGuid().ToString();
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.byteArray = Encoding.UTF8.GetBytes("q=test");
      // ISSUE: reference to a compiler-generated field
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.r.ContentLength = (long) cDisplayClass5.byteArray.Length;
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.r.ContentType = "application/x-www-form-urlencoded";
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.r.Referer = "http://www.digitrafficgenerator.com/post_test.php";
      // ISSUE: reference to a compiler-generated field
      cDisplayClass5.r.Timeout = 20000;
      // ISSUE: reference to a compiler-generated field
      // ISSUE: reference to a compiler-generated method
      IAsyncResult res = cDisplayClass5.r.BeginGetRequestStream(new AsyncCallback(cDisplayClass5.\u003CCheckProxy\u003Eb__1), (object) null);
      // ISSUE: reference to a compiler-generated field
      WebObject.AbortRequestAfterTimeout(res, cDisplayClass5.r);
      try
      {
        // ISSUE: reference to a compiler-generated field
        // ISSUE: reference to a compiler-generated method
        // ISSUE: reference to a compiler-generated field
        res = cDisplayClass5.r.BeginGetResponse(new AsyncCallback(cDisplayClass5.\u003CCheckProxy\u003Eb__2), (object) cDisplayClass5.r);
      }
      catch (Exception ex)
      {
        // ISSUE: reference to a compiler-generated field
        // ISSUE: reference to a compiler-generated field
        cDisplayClass5.logger.Info((object) ("Got an exception using " + cDisplayClass5.proxy.Address), ex);
      }
      // ISSUE: reference to a compiler-generated field
      WebObject.AbortRequestAfterTimeout(res, cDisplayClass5.r);
      HttpWebRequest request = (HttpWebRequest) WebRequest.Create("http://www.google.com/recaptcha/api/js/recaptcha.js");
      request.Method = "GET";
      // ISSUE: reference to a compiler-generated field
      request.Proxy = (IWebProxy) ProxyFarm.MakeWebProxy(cDisplayClass5.proxy);
      request.Timeout = 20000;
      request.ConnectionGroupName = Guid.NewGuid().ToString();
      // ISSUE: reference to a compiler-generated method
      WebObject.AbortRequestAfterTimeout(request.BeginGetResponse(new AsyncCallback(cDisplayClass5.\u003CCheckProxy\u003Eb__3), (object) request), request);
    }

    protected static void ProxyChecked(IAsyncResult result, HttpWebRequest req, ProxyFarm.CallbackState state)
    {
      ILog logger = LogManager.GetLogger("Program");
      ProxyFarm.CheckStatus checkStatus = ProxyFarm.CheckStatus.NotOk;
      try
      {
        HttpWebResponse httpWebResponse = (HttpWebResponse) req.EndGetResponse(result);
        if (req.RequestUri == httpWebResponse.ResponseUri)
        {
          if (httpWebResponse.StatusCode == HttpStatusCode.OK)
            checkStatus = ProxyFarm.CheckStatus.Ok;
        }
      }
      catch (Exception ex)
      {
      }
      lock (state)
      {
        if (req.RequestUri.Authority.Contains("google.com"))
          state.Google = checkStatus;
        else
          state.Post = checkStatus;
        if (state.Post == ProxyFarm.CheckStatus.NotOk)
        {
          ProxyFarm.ChangeStatus(state.Proxy, "inactive");
          logger.Info((object) ("Marking " + state.Proxy.Address + " as inactive as it cannot POST"));
        }
        else if (state.Google == ProxyFarm.CheckStatus.NotOk)
        {
          ProxyFarm.ChangeStatus(state.Proxy, "inactive");
          logger.Info((object) ("Marking " + state.Proxy.Address + " as inactive as it is blocked by google"));
        }
        else
        {
          if (state.Google != ProxyFarm.CheckStatus.Ok || state.Post != ProxyFarm.CheckStatus.Ok)
            return;
          ProxyFarm.ChangeStatus(state.Proxy, "active");
        }
      }
    }

    public static void ReportBrokenProxy(StorageDataSet.ProxiesRow proxy, bool recaptcha_fail = false)
    {
      // some normal code
    }

    private static void ChangeStatus(StorageDataSet.ProxiesRow Proxy, string status)
    {
      // some normal code
    }

    public enum CheckStatus
    {
      NotChecked,
      Ok,
      NotOk,
    }

    protected class CallbackState
    {
      public StorageDataSet.ProxiesRow Proxy { get; set; }

      public ProxyFarm.CheckStatus Post { get; set; }

      public ProxyFarm.CheckStatus Google { get; set; }
    }
  }

如您所见,似乎在CheckProxy 方法中,编译器生成了一个新类型!你知道这种方法到底发生了什么吗?如何理解代码?

【问题讨论】:

  • 这是一个反编译器缺陷,报告它。
  • 这是五年前的事情,我认为 dotPeek 现在可以更好地处理其中一些字符。但它仍然会做一些奇怪的事情。如果标识符中有美元符号 ($)(在 C# 中无效,但在 IL 中有效),则在某些情况下,dotPeek 会正确显示 $,并且在您搜索标识符时也可以工作。在其他上下文中,它显示一个 $ 字符,但在幕后它已将其转换为“\u0024”。如果您对文本编辑器进行复制和粘贴,这一点就会变得很明显,这也意味着在尝试查找该标识符时找不到这些行。

标签: c# decompiler dotpeek compiler-generated


【解决方案1】:

\u003C\u003E 分别是 &lt;&gt; 的 unicode 表示。

这些字符在 IL 中是有效的。所以编译器将生成具有类似名称的变量以避免冲突。

您的反编译器只是不知道如何将其转换为 &lt;&gt; 并且没有删除临时变量。

【讨论】:

  • 感谢回答。我明白。那么如果你想重写CheckProxy方法,你会怎么做呢?我的意思是,为什么编译器会生成 &lt;&gt;__DisplayClass5 类?哪些条件使编译器可以做这些事情?
  • 编译器将为闭包、匿名类型或通过try..finally 子句使用对象时执行此操作。我不熟悉的确切语义..但这并不是真正的问题。
【解决方案2】:

dnSpy 中打开它并四处寻找匹配的方法(ish)。它们的顺序不同,但 dnSpy 在反编译 lambda 方面做得不错。

【讨论】:

  • 感谢您,与 dotpeek 相比,这获得了更好的结果
  • 我遵循了这个答案并得到了 dnSpy,但是在尝试构建它然后调试(不要尝试发布它!)之后,最终结果并不比 dotPeek 更清晰
  • 谢谢你,dnSpy 的结果更准确
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