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Standard library for the Scala Programming Language
/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala
package sys
package process
import processInternal._
import ProcessBuilder._
import scala.language.implicitConversions
/** Represents a process that is running or has finished running.
* It may be a compound process with several underlying native processes (such as `a #&& b`).
*
* This trait is often not used directly, though its companion object contains
* factories for [[scala.sys.process.ProcessBuilder]], the main component of this
* package.
*
* It is used directly when calling the method `run` on a `ProcessBuilder`,
* which makes the process run in the background. The methods provided on `Process`
* make it possible for one to block until the process exits and get the exit value,
* or destroy the process altogether.
*
* @see [[scala.sys.process.ProcessBuilder]]
*/
trait Process {
/** Returns this process alive status */
def isAlive(): Boolean
/** Blocks until this process exits and returns the exit code.*/
def exitValue(): Int
/** Destroys this process. */
def destroy(): Unit
}
/** Methods for constructing simple commands that can then be combined. */
object Process extends ProcessImpl with ProcessCreation { }
/** Factories for creating [[scala.sys.process.ProcessBuilder]]. They can be
* found on and used through [[scala.sys.process.Process]]'s companion object.
*/
trait ProcessCreation {
/** Creates a [[scala.sys.process.ProcessBuilder]] from a `String`, including the
* parameters.
*
* @example {{{ apply("cat file.txt") }}}
*/
def apply(command: String): ProcessBuilder = apply(command, None)
/** Creates a [[scala.sys.process.ProcessBuilder]] from a sequence of `String`,
* where the head is the command and each element of the tail is a parameter.
*
* @example {{{ apply("cat" :: files) }}}
*/
def apply(command: scala.collection.Seq[String]): ProcessBuilder = apply(command, None)
/** Creates a [[scala.sys.process.ProcessBuilder]] from a command represented by a `String`,
* and a sequence of `String` representing the arguments.
*
* @example {{{ apply("cat", files) }}}
*/
def apply(command: String, arguments: scala.collection.Seq[String]): ProcessBuilder = apply(command +: arguments, None)
/** Creates a [[scala.sys.process.ProcessBuilder]] with working dir set to `File` and extra
* environment variables.
*
* @example {{{ apply("java", new java.io.File("/opt/app"), "CLASSPATH" -> "library.jar") }}}
*/
def apply(command: String, cwd: File, extraEnv: (String, String)*): ProcessBuilder =
apply(command, Some(cwd), extraEnv: _*)
/** Creates a [[scala.sys.process.ProcessBuilder]] with working dir set to `File` and extra
* environment variables.
*
* @example {{{ apply("java" :: javaArgs, new java.io.File("/opt/app"), "CLASSPATH" -> "library.jar") }}}
*/
def apply(command: scala.collection.Seq[String], cwd: File, extraEnv: (String, String)*): ProcessBuilder =
apply(command, Some(cwd), extraEnv: _*)
/** Creates a [[scala.sys.process.ProcessBuilder]] with working dir optionally set to
* `File` and extra environment variables.
*
* @example {{{ apply("java", params.get("cwd"), "CLASSPATH" -> "library.jar") }}}
*/
def apply(command: String, cwd: Option[File], extraEnv: (String, String)*): ProcessBuilder =
apply(Parser.tokenize(command), cwd, extraEnv: _*)
/** Creates a [[scala.sys.process.ProcessBuilder]] with working dir optionally set to
* `File` and extra environment variables.
*
* @example {{{ apply("java" :: javaArgs, params.get("cwd"), "CLASSPATH" -> "library.jar") }}}
*/
def apply(command: scala.collection.Seq[String], cwd: Option[File], extraEnv: (String, String)*): ProcessBuilder = {
val jpb = new JProcessBuilder(command.toArray: _*)
cwd foreach (jpb directory _)
extraEnv foreach { case (k, v) => jpb.environment.put(k, v) }
apply(jpb)
}
/** Creates a [[scala.sys.process.ProcessBuilder]] from a `java.lang.ProcessBuilder`.
*
* @example {{{
* apply((new java.lang.ProcessBuilder("ls", "-l")) directory new java.io.File(System.getProperty("user.home")))
* }}}
*/
def apply(builder: JProcessBuilder): ProcessBuilder = new Simple(builder)
/** Creates a [[scala.sys.process.ProcessBuilder]] from a `java.io.File`. This
* `ProcessBuilder` can then be used as a `Source` or a `Sink`, so one can
* pipe things from and to it.
*/
def apply(file: File): FileBuilder = new FileImpl(file)
/** Creates a [[scala.sys.process.ProcessBuilder]] from a `java.net.URL`. This
* `ProcessBuilder` can then be used as a `Source`, so that one can pipe things
* from it.
*/
def apply(url: URL): URLBuilder = new URLImpl(url)
/** Creates a [[scala.sys.process.ProcessBuilder]] from a `Boolean`. This can be
* to force an exit value.
*/
def apply(value: Boolean): ProcessBuilder = apply(value.toString, if (value) 0 else 1)
/** Creates a [[scala.sys.process.ProcessBuilder]] from a `String` name and a
* `Boolean`. This can be used to force an exit value, with the name being
* used for `toString`.
*/
def apply(name: String, exitValue: => Int): ProcessBuilder = new Dummy(name, exitValue)
/** Creates a sequence of [[scala.sys.process.ProcessBuilder.Source]] from a sequence of
* something else for which there's an implicit conversion to `Source`.
*/
def applySeq[T](builders: scala.collection.Seq[T])(implicit convert: T => Source): scala.collection.Seq[Source] = builders.map(convert)
/** Creates a [[scala.sys.process.ProcessBuilder]] from one or more
* [[scala.sys.process.ProcessBuilder.Source]], which can then be
* piped to something else.
*
* This will concatenate the output of all sources. For example:
*
* {{{
* import scala.sys.process._
* import scala.sys.process.Process.cat
* import java.net.URL
* import java.io.File
*
* val spde = new URL("http://technically.us/spde.html")
* val dispatch = new URL("https://dispatchhttp.org/Dispatch.html")
* val build = new File("project/build.properties")
* cat(spde, dispatch, build) #| "grep -i scala" !
* }}}
*/
def cat(file: Source, files: Source*): ProcessBuilder = cat(file +: files)
/** Creates a [[scala.sys.process.ProcessBuilder]] from a non-empty sequence
* of [[scala.sys.process.ProcessBuilder.Source]], which can then be
* piped to something else.
*
* This will concatenate the output of all sources.
*/
def cat(files: scala.collection.Seq[Source]): ProcessBuilder = {
require(files.nonEmpty)
files.map(_.cat).reduceLeft(_ #&& _)
}
}
/** Provide implicit conversions for the factories offered by [[scala.sys.process.Process]]'s
* companion object. These implicits can then be used to decrease the noise in a pipeline
* of commands, making it look more shell-like. They are available through the package object
* [[scala.sys.process]].
*/
trait ProcessImplicits {
import Process._
/** Return a sequence of [[scala.sys.process.ProcessBuilder.Source]] from a sequence
* of values for which an implicit conversion to `Source` is available.
*/
implicit def buildersToProcess[T](builders: scala.collection.Seq[T])(implicit convert: T => Source): scala.collection.Seq[Source] = applySeq(builders)
/** Implicitly convert a `java.lang.ProcessBuilder` into a Scala one. */
implicit def builderToProcess(builder: JProcessBuilder): ProcessBuilder = apply(builder)
/** Implicitly convert a `java.io.File` into a
* [[scala.sys.process.ProcessBuilder.FileBuilder]], which can be used as
* either input or output of a process. For example:
* {{{
* import scala.sys.process._
* "ls" #> new java.io.File("dirContents.txt") !
* }}}
*/
implicit def fileToProcess(file: File): FileBuilder = apply(file)
/** Implicitly convert a `java.net.URL` into a
* [[scala.sys.process.ProcessBuilder.URLBuilder]] , which can be used as
* input to a process. For example:
* {{{
* import scala.sys.process._
* Seq("xmllint", "--html", "-") #< new java.net.URL("https://www.scala-lang.org") #> new java.io.File("fixed.html") !
* }}}
*/
implicit def urlToProcess(url: URL): URLBuilder = apply(url)
/** Implicitly convert a `String` into a [[scala.sys.process.ProcessBuilder]]. */
implicit def stringToProcess(command: String): ProcessBuilder = apply(command)
/** Implicitly convert a sequence of `String` into a
* [[scala.sys.process.ProcessBuilder]]. The first argument will be taken to
* be the command to be executed, and the remaining will be its arguments.
* When using this, arguments may contain spaces.
*/
implicit def stringSeqToProcess(command: scala.collection.Seq[String]): ProcessBuilder = apply(command)
}