为了清楚起见，重构嵌套IF语句 [英] Refactor nested IF statement for clarity

问题描述

我想重构这个mumbo jumbo一个方法，使其更易读，它的方式到许多嵌套的IF为我的喜好。

I want to refactor this mumbo jumbo of a method to make it more readible, it has way to many nested IF's for my liking.

如何重构这个？

public static void HandleUploadedFile(string filename)
{
  try
  {
    if(IsValidFileFormat(filename)
    {
      int folderID = GetFolderIDFromFilename(filename);
      if(folderID > 0)
      {
        if(HasNoViruses(filename)
        {
          if(VerifyFileSize(filename)
          {
            // file is OK
            MoveToSafeFolder(filename);
          }
          else
          {
            DeleteFile(filename);
            LogError("file size invalid");
          }
        }
        else
        {
          DeleteFile(filename);
          LogError("failed virus test");
        }
      }
      else
      {
        DeleteFile(filename);
        LogError("invalid folder ID");
      }
    }
    else
    {
      DeleteFile(filename);
      LogError("invalid file format");
    }
  }
  catch (Exception ex)
  {
    LogError("unknown error", ex.Message);
  }
  finally
  {
    // do some things
  }
}

推荐答案

我会将测试中的条件反转到 if bad then deleteAndLog

I would reverse the conditions in the test to if bad then deleteAndLog as the example below. This prevent nesting and puts the action near the test.

try{
    if(IsValidFileFormat(filename) == false){
        DeleteFile(filename);
        LogError("invalid file format");
        return;
    }

    int folderID = GetFolderIDFromFilename(filename);
    if(folderID <= 0){
        DeleteFile(filename);
        LogError("invalid folder ID");
        return;
    }
    ...

}...

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