org.scalatra.util.io.package.scala Maven / Gradle / Ivy

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package org.scalatra.util

import scala.annotation.tailrec
import java.io._

/**
 * A collection of I/O ulility methods.
 */
package object io {
  /**
   * Copies the input stream to the output stream.
   *
   * @param in the input stream to read
   * @param out the output stream to write
   * @param bufferSize the size of buffer to use for each read
   */
  def copy(in: InputStream, out: OutputStream, bufferSize: Int = 4096): Unit = {
    val buf = new Array[Byte](bufferSize)
    @tailrec
    def loop() {
      val n = in.read(buf)
      if (n >= 0) {
        out.write(buf, 0, n)
        loop()
      }
    }
    loop()
    in.close()
  }

  /**
   * Creates a temp file, passes it to a block, and removes the temp file on the block's completion.
   *
   * @tparam A the return type of the block
   * @param content The content of the file
   * @param prefix The prefix of the temp file; must be at least three characters long
   * @param suffix The suffix of the temp file
   * @param directory The directory of the temp file; a system dependent temp directory if None
   * @param f the block
   * @return the result of f
   */
  def withTempFile[A](content: String, prefix: String = "scalatra", suffix: String = ".tmp",  directory: Option[File] = None)(f: File => A) = {
    val tmp = File.createTempFile(prefix, suffix, directory.getOrElse(null))
    try {
      using(new BufferedWriter(new FileWriter(tmp))) { out =>
        out.write(content)
        out.flush()
      }
      f(tmp)
    }
    finally {
      tmp.delete()
    }
  }
}