Support kotlin continuations

[yschimke]

e.g. feel free to adapt if useful, I'm using this in my own project.

import okio.ByteString
import org.apache.commons.io.input.NullInputStream
import org.zeroturnaround.exec.ProcessExecutor
import org.zeroturnaround.exec.ProcessResult
import org.zeroturnaround.exec.listener.ProcessListener
import org.zeroturnaround.exec.stream.slf4j.Slf4jStream
import java.nio.charset.StandardCharsets
import kotlin.coroutines.experimental.suspendCoroutine

data class ExecResult(val exitCode: Int, val output: ByteString?) {
  val success = exitCode == 0
  val outputString by lazy {
    output?.string(StandardCharsets.UTF_8)!!
  }
}

val stdErrLogging = Slf4jStream.ofCaller().asInfo()

suspend fun exec(vararg command: String): ExecResult {
  return exec(command.toList()) {
    readOutput(true)
    redirectError(stdErrLogging)
    redirectInput(NullInputStream(0))
  }
}

suspend fun exec(command: List<String>, configure: ProcessExecutor.() -> Unit = {}): ExecResult {
  var outputRequested = false

  val pe = object : ProcessExecutor() {
    override fun readOutput(readOutput: Boolean): ProcessExecutor {
      outputRequested = readOutput
      return super.readOutput(readOutput)
    }
  }

  pe.command(command.toList())

  configure(pe)

  return suspendCoroutine { cont ->
    pe.addListener(object : ProcessListener() {
      override fun afterFinish(process: Process, result: ProcessResult) {
        try {
          val outputString = if (outputRequested) {
            val output = result.output()
            ByteString.of(output, 0, output.size)
          } else {
            null
          }

          cont.resume(ExecResult(result.exitValue, outputString))
        } catch (e: Exception) {
          cont.resumeWithException(e)
        }
      }
    })

    try {
      pe.start()
    } catch (e: Exception) {
      cont.resumeWithException(e)
    }
  }
}

[yschimke]

    val result = exec(command) {
      timeout(5, TimeUnit.SECONDS)
      redirectError(stdErrLogging)
      readOutput(true)
    }

    println(result.output)