private void ConfigureFromUri()

in src/log4net/Config/XmlConfiguratorAttribute.cs [301:403]
87 lines of code
14 McCabe index (conditional complexity)

  private void ConfigureFromUri(ILoggerRepository targetRepository)
  {
    // Work out the full path to the config file
    Uri? fullPath2ConfigFile = null;

    // Select the config file
    if (string.IsNullOrEmpty(ConfigFile))
    {
      if (string.IsNullOrEmpty(ConfigFileExtension))
      {
        string? systemConfigFilePath = null;
        try
        {
          systemConfigFilePath = SystemInfo.ConfigurationFileLocation;
        }
        catch (Exception e) when (!e.IsFatal())
        {
          LogLog.Error(_declaringType, "XmlConfiguratorAttribute: Exception getting ConfigurationFileLocation. Must be able to resolve ConfigurationFileLocation when ConfigFile and ConfigFileExtension properties are not set.", e);
        }

        if (systemConfigFilePath is not null)
        {
          // Use the default .config file for the AppDomain
          fullPath2ConfigFile = new Uri(systemConfigFilePath);
        }
      }
      else
      {
        // Force the extension to start with a '.'
        if (ConfigFileExtension![0] != '.')
        {
          ConfigFileExtension = '.' + ConfigFileExtension;
        }

        string? systemConfigFilePath = null;
        try
        {
          systemConfigFilePath = SystemInfo.ConfigurationFileLocation;
        }
        catch (Exception e) when (!e.IsFatal())
        {
          LogLog.Error(_declaringType, "XmlConfiguratorAttribute: Exception getting ConfigurationFileLocation. Must be able to resolve ConfigurationFileLocation when the ConfigFile property are not set.", e);
        }

        if (systemConfigFilePath is not null)
        {
          var builder = new UriBuilder(new Uri(systemConfigFilePath));

          // Remove the current extension from the systemConfigFileUri path
          string path = builder.Path;
          int startOfExtension = path.LastIndexOf('.');
          if (startOfExtension >= 0)
          {
            path = path.Substring(0, startOfExtension);
          }
          path += ConfigFileExtension;

          builder.Path = path;
          fullPath2ConfigFile = builder.Uri;
        }
      }
    }
    else
    {
      string? applicationBaseDirectory = null;
      try
      {
        applicationBaseDirectory = SystemInfo.ApplicationBaseDirectory;
      }
      catch (Exception e) when (!e.IsFatal())
      {
        LogLog.Warn(_declaringType, $"Exception getting ApplicationBaseDirectory. ConfigFile property path [{ConfigFile}] will be treated as an absolute URI.", e);
      }

      if (applicationBaseDirectory is not null)
      {
        // Just the base dir + the config file
        fullPath2ConfigFile = new Uri(new Uri(applicationBaseDirectory), ConfigFile!);
      }
      else
      {
        fullPath2ConfigFile = new Uri(ConfigFile!);
      }
    }

    if (fullPath2ConfigFile is not null)
    {
      if (fullPath2ConfigFile.IsFile)
      {
        // The ConfigFile could be an absolute local path, therefore we have to be
        // prepared to switch back to using FileInfos here
        ConfigureFromFile(targetRepository, new FileInfo(fullPath2ConfigFile.LocalPath));
      }
      else
      {
        if (Watch)
        {
          LogLog.Warn(_declaringType, "XmlConfiguratorAttribute: Unable to watch config file loaded from a URI");
        }
        XmlConfigurator.Configure(targetRepository, fullPath2ConfigFile);
      }
    }
  }