Scala JLine input with support of navigation using CTRL+arrow

ScalaJlineNavigation.scala

/**
 *            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
 *                    Version 2, December 2004
 * 
 * Copyright (C) 2015 Lukáš Karas <lukas.karas@centrum.cz>
 * 
 * Everyone is permitted to copy and distribute verbatim or modified
 * copies of this license document, and changing it is allowed as long
 * as the name is changed.
 * 
 *             DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
 *   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 * 
 *  0. You just DO WHAT THE FUCK YOU WANT TO.
 */

import java.awt.event.{ActionEvent, ActionListener}
import scala.tools.jline.console.ConsoleReader

/**
 * JLine don't support skipping words on input by classic shortcut 
 * (CTRL + Left / Right arrow). Terminal generates sequence of 
 * virtual keys when CTRL + other char is pressed (49 59 53 ...). 
 * So it is simple to write listener on these sequences.
 */
object Console{


  class HistoryInputStream(in: InputStream, bufferLen: Int) extends InputStream {
    var offset: Int = 0
    val ringBuffer = new Array[Int](bufferLen)

    def history(histOff: Int): Int = {
      val off = histOff - 1
      if (off > 0 || (bufferLen + off) < 0) 0
      else ringBuffer((offset + bufferLen + off) % bufferLen)
    }

    override def read(): Int = {
      val i = in.read()
      ringBuffer(offset) = i
      offset = (offset + 1) % bufferLen
      i
    }
  }

  def apply(): ConsoleReader = {
    val characterInput = new HistoryInputStream(new FileInputStream(FileDescriptor.in), 8)
    val consoleReader = new ConsoleReader(characterInput, System.out, null, null)
    val terminal = consoleReader.getTerminal
    val cursorBuffer = consoleReader.getCursorBuffer()

    def skipWord(ch: () => Char, move: () => Boolean): Unit = {
      while (ch().isWhitespace && move()) {}
      while (!ch().isWhitespace && move()) {}
    }

    if (terminal.isSupported && terminal.isInstanceOf[UnixTerminal]) {
      consoleReader.addTriggeredAction(49, new ActionListener {

        override def actionPerformed(e: ActionEvent): Unit = {

          // This is little bit hack. Ctrl prefix is consumed by UnixTerminal, we have to look into history...
          if (characterInput.history(-2) != 27 /*ARROW_START*/ || characterInput.history(-1) != 91 /*ARROW_PREFIX*/ ) {
            consoleReader.putString(49.toChar.toString) // if Ctrl prefix not found in history, 49 is just character "1"
          } else {
            if (characterInput.read() == 59 && characterInput.read() == 53) {
              // Ctrl + ...
              characterInput.read() match {
                // Ctrl + Right Arrow
                case 67 => skipWord(
                  () => cursorBuffer.charAtCursor(),
                  () => consoleReader.moveCursor(+1) != 0)

                // Ctrl + Left Arrow
                case 68 => skipWord(
                  () => cursorBuffer.charLeftOfCursor(),
                  () => consoleReader.moveCursor(-1) != 0)

                case _ => {}
              }

            }
          }
        }
      })
    }
    consoleReader
  }
}