Convert a SBT Logger to an OutputStream

LoggerOutputStream.scala

private object LoggerOutputStream {

  def info(logger: Logger, charset: Charset = StandardCharsets.UTF_8, maxMessageSize: Int = 8192): OutputStream =
    apply(logger, Level.Info, charset, maxMessageSize)

  def error(logger: Logger, charset: Charset = StandardCharsets.UTF_8, maxMessageSize: Int = 8192): OutputStream =
    apply(logger, Level.Error, charset, maxMessageSize)

  def apply(logger: Logger, level: Level.Value, charset: Charset = StandardCharsets.UTF_8, maxMessageSize: Int = 8192): OutputStream =
    new LoggerOutputStream(logger, level, charset, maxMessageSize)

  private class LoggerOutputStream(logger: Logger, level: Level.Value, charset: Charset, maxMessageSize: Int) extends OutputStream {

    private val decoder = charset.newDecoder()
    private val in = ByteBuffer.allocate(maxMessageSize)
    private val out = CharBuffer.allocate(maxMessageSize)
    private var closed = false

    override def write(b: Int): Unit = {
      ensureOpen()
      if (!in.hasRemaining) {
        flush()
      }
      in.put(b.toByte)
    }

    @tailrec
    override final def write(b: Array[Byte], off: Int, len: Int): Unit = {
      ensureOpen()
      val canFitLen = math.min(len, in.remaining)
      in.put(b, off, canFitLen)
      if (canFitLen < len) {
        flush()
        write(b, off + canFitLen, len - canFitLen)
      }
    }

    override def flush(): Unit = flush(false)

    def flush(closing: Boolean): Unit = {
      ensureOpen()
      in.flip()
      val result = decoder.decode(in, out, closing)
      if (result.isError) {
        result.throwException()
      }
      in.compact()
      out.flip()
      if (out.hasRemaining) {
        logger.log(level, StringUtils.chomp(out.toString))
        out.position(out.limit)
      }
      out.compact()
    }
    
    private def ensureOpen(): Unit = {
      if (closed) throw new IOException("LoggerOutputStream has been closed.")
    }

    override def close(): Unit = {
      if (!closed) {
        flush(true)
      }
      closed = true
    }
  }
}