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// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.container.plugin.util
import java.io.{Closeable, FileOutputStream, OutputStream, FileInputStream, File}
import util.control.Exception
import scala.Either
/** Utility methods relating to IO
* @author tonytv
*/
object IO {
def withFileInputStream[T](file : File)(f : FileInputStream => T) = {
using(new FileInputStream(file), readOnly = true)(f)
}
/**
* Creates a new file and all it's parent directories,
* and provides a file output stream to the file.
*
* Exceptions from closing have priority over exceptions from f.
*/
def withFileOutputStream[T](file: File)(f: OutputStream => T) {
makeDirectoriesRecursive(file.getParentFile)
using(new FileOutputStream(file), readOnly = false )(f)
}
def makeDirectoriesRecursive(file: File) {
if (!file.mkdirs() && !file.isDirectory) {
throw new RuntimeException("Could not create directory " + file.getPath)
}
}
def using[RESOURCE <: Closeable, T](resource : RESOURCE, readOnly : Boolean)(f : RESOURCE => T) : T = {
def catchPromiscuously = Exception.catchingPromiscuously(classOf[Throwable])
val resultOrException = catchPromiscuously either f(resource)
val closeException = Exception.allCatch either resource.close()
prioritizeFirstException(
resultOrException,
if (readOnly) Right(()) else closeException) fold (throw _, identity)
}
private def prioritizeFirstException[T](first: Either[Throwable, T], second: Either[Throwable, Unit]) =
first fold ( Left(_), value => second fold ( Left(_), _ => Right(value) ) )
}
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