private[scala] def deconstructInterpolatedMessage()

in log4j-api-scala_3/src/main/scala/org/apache/logging/log4j/scala/LoggerMacro.scala [499:532]

28 lines of code
9 McCabe index (conditional complexity)


  private[scala] def deconstructInterpolatedMessage(message: Expr[CharSequence])(using Quotes): (Expr[CharSequence], Seq[Expr[Any]]) = {
    import quotes.reflect.*
    import util.*

    message.asTerm match{
      case Inlined(_, _, Apply(Select(Apply(Select(Select(_, "StringContext"), _), messageNode), _), argumentsNode)) =>
        val messageTextPartsOpt: Option[List[String]] =
          messageNode.collectFirst{
            case Typed(Repeated(ls, _), _) =>
              ls.collect{ case Literal(StringConstant(s)) => s}
          }
        val argsOpt: Option[List[Term]] =
          argumentsNode.collectFirst {
            case Typed(Repeated(ls, _), _) => ls
          }

        (messageTextPartsOpt, argsOpt) match{
          case (Some(messageTextParts), Some(args)) =>
            val format = messageTextParts.iterator
              // Emulate standard interpolator escaping
              .map(StringContext.processEscapes)
              // Escape literal log4j format anchors if the resulting call will require a format string
              .map(str => if (args.nonEmpty) str.replace("{}", "\\{}") else str)
              .mkString("{}")

            val formatArgs = args.map(_.asExpr)

            (Expr(format), formatArgs)
          case _ =>
            (message, Seq.empty)
        }
      case _ => (message, Seq.empty)
    }
  }