Using java.lang.Process in Scala.

TtyOutput.scala

package jp.segfault.cvs.util

import scala.concurrent.duration.Duration
import scala.collection.mutable.ArrayBuffer
import scala.util.Try

import java.io._

case class TtyOutput(data:Array[Byte], isError:Boolean)

object TtyOutput {

  def exec(cmd:Array[String], timeout:Duration):Try[Seq[TtyOutput]] =
    Try(Runtime.getRuntime.exec(cmd)) flatMap (read _)

  def read(process:Process):Try[Seq[TtyOutput]] = Try {

    val stdout = process.getInputStream
    val stderr = process.getErrorStream
    var flag = false
    val out1 = new ByteArrayOutputStream()
    val out2 = new ByteArrayOutputStream()
    val tmp = new ArrayBuffer[TtyOutput]()
    val buf = new Array[Byte](2048)

    def flow(in:InputStream, out:OutputStream) {
      var n = in.available()
      while (n > 0) {
        in.read(buf, 0, buf.length min n) match {
          case -1 => n  = 0
          case  m => n -= m
            out.write(buf, 0, m)
        }
      }
    }

    while (Try(process.exitValue()).isFailure) {
      Thread.sleep(1)
      flow(stdout, out1)
      flow(stderr, out2)
      flag = if (out1.size() * out2.size() == 0) out2.size() > 0
      else {
        val out = if (flag) out2 else out1
        tmp += TtyOutput(out.toByteArray, flag)
        out.reset()
        !flag
      }
    }
    val out = if (flag) out2 else out1
    if (out.size() > 0) {
      tmp += TtyOutput(out.toByteArray, flag)
    }
    tmp.toSeq
  }

}