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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 util
import java.io.{IOException, PrintWriter}
import java.util.jar.Attributes.{Name => AttributeName}
import scala.annotation.tailrec
/** Loads `library.properties` from the jar. */
object Properties extends PropertiesTrait {
protected def propCategory = "library"
protected def pickJarBasedOn = classOf[Option[_]]
/** Scala manifest attributes.
*/
val ScalaCompilerVersion = new AttributeName("Scala-Compiler-Version")
}
private[scala] trait PropertiesTrait {
protected def propCategory: String // specializes the remainder of the values
protected def pickJarBasedOn: Class[_] // props file comes from jar containing this
/** The name of the properties file */
protected val propFilename = "/" + propCategory + ".properties"
/** The loaded properties */
protected lazy val scalaProps: java.util.Properties = {
val props = new java.util.Properties
val stream = pickJarBasedOn getResourceAsStream propFilename
if (stream ne null)
quietlyDispose(props load stream, stream.close)
props
}
private def quietlyDispose(action: => Unit, disposal: => Unit) =
try { action }
finally {
try { disposal }
catch { case _: IOException => }
}
def propIsSet(name: String) = System.getProperty(name) != null
def propIsSetTo(name: String, value: String) = propOrNull(name) == value
def propOrElse(name: String, alt: => String) = Option(System.getProperty(name)).getOrElse(alt)
def propOrEmpty(name: String) = propOrElse(name, "")
def propOrNull(name: String) = propOrElse(name, null)
def propOrNone(name: String) = Option(propOrNull(name))
def propOrFalse(name: String) = propOrNone(name) exists (x => List("yes", "on", "true") contains x.toLowerCase)
def setProp(name: String, value: String) = System.setProperty(name, value)
def clearProp(name: String) = System.clearProperty(name)
def envOrElse(name: String, alt: => String) = Option(System getenv name) getOrElse alt
def envOrNone(name: String) = Option(System getenv name)
def envOrSome(name: String, alt: => Option[String]) = envOrNone(name) orElse alt
// for values based on propFilename, falling back to System properties
def scalaPropOrElse(name: String, alt: => String): String = scalaPropOrNone(name).getOrElse(alt)
def scalaPropOrEmpty(name: String): String = scalaPropOrElse(name, "")
def scalaPropOrNone(name: String): Option[String] = Option(scalaProps.getProperty(name)).orElse(propOrNone("scala." + name))
/** The numeric portion of the runtime Scala version, if this is a final
* release. If for instance the versionString says "version 2.9.0.final",
* this would return Some("2.9.0").
*
* @return Some(version) if this is a final release build, None if
* it is an RC, Beta, etc. or was built from source, or if the version
* cannot be read.
*/
val releaseVersion =
for {
v <- scalaPropOrNone("maven.version.number")
if !(v endsWith "-SNAPSHOT")
} yield v
/** The development Scala version, if this is not a final release.
* The precise contents are not guaranteed, but it aims to provide a
* unique repository identifier (currently the svn revision) in the
* fourth dotted segment if the running version was built from source.
*
* @return Some(version) if this is a non-final version, None if this
* is a final release or the version cannot be read.
*/
val developmentVersion =
for {
v <- scalaPropOrNone("maven.version.number")
if v endsWith "-SNAPSHOT"
ov <- scalaPropOrNone("version.number")
} yield ov
/** Either the development or release version if known, otherwise
* the empty string.
*/
def versionNumberString = scalaPropOrEmpty("version.number")
/** The version number of the jar this was loaded from plus "version " prefix,
* or "version (unknown)" if it cannot be determined.
*/
val versionString = "version " + scalaPropOrElse("version.number", "(unknown)")
val copyrightString = scalaPropOrElse("copyright.string", "Copyright 2002-2021, LAMP/EPFL and Lightbend, Inc.")
/** This is the encoding to use reading in source files, overridden with -encoding.
* Note that it uses "prop" i.e. looks in the scala jar, not the system properties.
*/
def sourceEncoding = scalaPropOrElse("file.encoding", "UTF-8")
def sourceReader = scalaPropOrElse("source.reader", "scala.tools.nsc.io.SourceReader")
/** This is the default text encoding, overridden (unreliably) with
* `JAVA_OPTS="-Dfile.encoding=Foo"`
*/
def encodingString = propOrElse("file.encoding", "UTF-8")
/** The default end of line character.
*/
def lineSeparator = System.lineSeparator()
/* Various well-known properties. */
def javaClassPath = propOrEmpty("java.class.path")
def javaHome = propOrEmpty("java.home")
def javaVendor = propOrEmpty("java.vendor")
def javaVersion = propOrEmpty("java.version")
def javaVmInfo = propOrEmpty("java.vm.info")
def javaVmName = propOrEmpty("java.vm.name")
def javaVmVendor = propOrEmpty("java.vm.vendor")
def javaVmVersion = propOrEmpty("java.vm.version")
def javaSpecVersion = propOrEmpty("java.specification.version")
def javaSpecVendor = propOrEmpty("java.specification.vendor")
def javaSpecName = propOrEmpty("java.specification.name")
def osName = propOrEmpty("os.name")
def scalaHome = propOrEmpty("scala.home")
def tmpDir = propOrEmpty("java.io.tmpdir")
def userDir = propOrEmpty("user.dir")
def userHome = propOrEmpty("user.home")
def userName = propOrEmpty("user.name")
/* Some derived values. */
/** Returns `true` iff the underlying operating system is a version of Microsoft Windows. */
def isWin = osName startsWith "Windows"
// See https://mail.openjdk.java.net/pipermail/macosx-port-dev/2012-November/005148.html for
// the reason why we don't follow developer.apple.com/library/mac/#technotes/tn2002/tn2110.
/** Returns `true` iff the underlying operating system is a version of Apple Mac OSX. */
def isMac = osName startsWith "Mac OS X"
/** Returns `true` iff the underlying operating system is a Linux distribution. */
def isLinux = osName startsWith "Linux"
/* Some runtime values. */
private[scala] def isAvian = javaVmName contains "Avian"
private[scala] def coloredOutputEnabled: Boolean = propOrElse("scala.color", "auto") match {
case "auto" => System.console() != null && !isWin
case s => s == "" || "true".equalsIgnoreCase(s)
}
// This is looking for javac, tools.jar, etc.
// Tries JDK_HOME first, then the more common but likely jre JAVA_HOME,
// and finally the system property based javaHome.
def jdkHome = envOrElse("JDK_HOME", envOrElse("JAVA_HOME", javaHome))
private[scala] def versionFor(command: String) = s"Scala $command $versionString -- $copyrightString"
def versionMsg = versionFor(propCategory)
def scalaCmd = if (isWin) "scala.bat" else "scala"
def scalacCmd = if (isWin) "scalac.bat" else "scalac"
/** Compares the given specification version to the specification version of the platform.
*
* @param version a specification version number (legacy forms acceptable)
* @return `true` if the specification version of the current runtime
* is equal to or higher than the version denoted by the given string.
* @throws NumberFormatException if the given string is not a version string
*
* @example {{{
* // In this example, the runtime's Java specification is assumed to be at version 8.
* isJavaAtLeast("1.8") // true
* isJavaAtLeast("8") // true
* isJavaAtLeast("9") // false
* isJavaAtLeast("9.1") // false
* isJavaAtLeast("1.9") // throws
* }}}
*/
def isJavaAtLeast(version: String): Boolean = {
def versionOf(s: String, depth: Int): (Int, String) =
s.indexOf('.') match {
case 0 =>
(-2, s.substring(1))
case 1 if depth == 0 && s.charAt(0) == '1' =>
val r0 = s.substring(2)
val (v, r) = versionOf(r0, 1)
val n = if (v > 8 || r0.isEmpty) -2 else v // accept 1.8, not 1.9 or 1.
(n, r)
case -1 =>
val n = if (!s.isEmpty) s.toInt else if (depth == 0) -2 else 0
(n, "")
case i =>
val r = s.substring(i + 1)
val n = if (depth < 2 && r.isEmpty) -2 else s.substring(0, i).toInt
(n, r)
}
@tailrec
def compareVersions(s: String, v: String, depth: Int): Int = {
if (depth >= 3) 0
else {
val (sn, srest) = versionOf(s, depth)
val (vn, vrest) = versionOf(v, depth)
if (vn < 0) -2
else if (sn < vn) -1
else if (sn > vn) 1
else compareVersions(srest, vrest, depth + 1)
}
}
compareVersions(javaSpecVersion, version, 0) match {
case -2 => throw new NumberFormatException(s"Not a version: $version")
case i => i >= 0
}
}
/** Compares the given specification version to the major version of the platform.
* @param version a specification major version number
*/
def isJavaAtLeast(version: Int): Boolean = isJavaAtLeast(math.max(version, 0).toString)
// provide a main method so version info can be obtained by running this
def main(args: Array[String]): Unit = {
val writer = new PrintWriter(Console.err, true)
writer println versionMsg
}
}