Refactor system properties lookup

core/src/main/scala/sbt/internal/librarymanagement/LMSysProp.scala

@@ -0,0 +1,58 @@
+/*
+ * sbt
+ * Copyright 2011 - 2018, Lightbend, Inc.
+ * Copyright 2008 - 2010, Mark Harrah
+ * Licensed under Apache License 2.0 (see LICENSE)
+ */
+
+package sbt
+package internal
+package librarymanagement
+
+import java.util.Locale
+
+object LMSysProp {
+  def booleanOpt(name: String): Option[Boolean] =
+    sys.props.get(name).flatMap { x =>
+      x.toLowerCase(Locale.ENGLISH) match {
+        case "1" | "always" | "true" => Some(true)
+        case "0" | "never" | "false" => Some(false)
+        case "auto"                  => None
+        case _                       => None
+      }
+    }
+
+  def getOrFalse(name: String): Boolean = booleanOpt(name).getOrElse(false)
+  def getOrTrue(name: String): Boolean = booleanOpt(name).getOrElse(true)
+
+  // System property style:
+  //   1. use sbt. prefix
+  //   2. prefer short nouns
+  //   3. use dot for namespacing, and avoid making dot-separated English phrase
+  //   4. make active/enable properties, instead of "sbt.disable."
+  //
+  // Good: sbt.offline
+  //
+  // Bad:
+  // sbt.disable.interface.classloader.cache
+  // sbt.task.timings.on.shutdown
+  // sbt.skip.version.write -> sbt.genbuildprops=false
+
+  val useSecureResolvers: Boolean = getOrTrue("sbt.repository.secure")
+
+  def modifyVersionRange: Boolean = getOrTrue("sbt.modversionrange")
+
+  lazy val isJavaVersion9Plus: Boolean = javaVersion > 8
+  lazy val javaVersion: Int = {
+    // See Oracle section 1.5.3 at:
+    // https://docs.oracle.com/javase/8/docs/technotes/guides/versioning/spec/versioning2.html
+    val version = sys.props("java.specification.version").split("\\.").toList.map(_.toInt)
+    version match {
+      case 1 :: minor :: _ => minor
+      case major :: _      => major
+      case _               => 0
+    }
+  }
+
+  lazy val useGigahorse: Boolean = getOrTrue("sbt.gigahorse")
+}

core/src/main/scala/sbt/librarymanagement/ResolverExtra.scala

@@ -95,8 +95,7 @@ private[sbt] class FakeRepository(resolver: AnyRef, name: String) extends xsbti.
 }
 
 private[librarymanagement] abstract class ResolverFunctions {
-  private[sbt] def useSecureResolvers =
-    sys.props.get("sbt.repository.secure") map { _.toLowerCase == "true" } getOrElse true
+  import sbt.internal.librarymanagement.LMSysProp.useSecureResolvers
 
   val TypesafeRepositoryRoot = typesafeRepositoryRoot(useSecureResolvers)
   val SbtRepositoryRoot = sbtRepositoryRoot(useSecureResolvers)

ivy/src/main/scala/sbt/internal/librarymanagement/CustomPomParser.scala

@@ -242,9 +242,6 @@ object CustomPomParser {
         transform(dd, _ => newId)
       case None => dd
     }
-  private[sbt] lazy val versionRangeFlag = sys.props.get("sbt.modversionrange") map {
-    _.toLowerCase == "true"
-  } getOrElse true
 
   import collection.JavaConverters._
   def addExtra(
@@ -281,7 +278,7 @@ object CustomPomParser {
       addExtra(dd, dependencyExtra)
     }
     val withVersionRangeMod: Seq[DependencyDescriptor] =
-      if (versionRangeFlag) withExtra map { stripVersionRange } else withExtra
+      if (LMSysProp.modifyVersionRange) withExtra map { stripVersionRange } else withExtra
     val unique = IvySbt.mergeDuplicateDefinitions(withVersionRangeMod)
     unique foreach dmd.addDependency
 

ivy/src/main/scala/sbt/internal/librarymanagement/ivyint/ErrorMessageAuthenticator.scala

@@ -15,7 +15,8 @@ object ErrorMessageAuthenticator {
   private var securityWarningLogged = false
 
   private def originalAuthenticator: Option[Authenticator] = {
-    if (isJavaVersion9Plus) getDefaultAuthenticator else getTheAuthenticator
+    if (LMSysProp.isJavaVersion9Plus) getDefaultAuthenticator
+    else getTheAuthenticator
   }
 
   private[this] def getTheAuthenticator: Option[Authenticator] = {
@@ -100,15 +101,6 @@ object ErrorMessageAuthenticator {
       }
     doInstallIfIvy(originalAuthenticator)
   }
-
-  private[this] def isJavaVersion9Plus = javaVersion > 8
-  private[this] def javaVersion = {
-    // See Oracle section 1.5.3 at:
-    // https://docs.oracle.com/javase/8/docs/technotes/guides/versioning/spec/versioning2.html
-    val version = sys.props("java.specification.version").split("\\.").map(_.toInt)
-    if (version(0) == 1) version(1) else version(0)
-  }
-
 }
 
 /**

ivy/src/main/scala/sbt/librarymanagement/ivy/UpdateOptions.scala

@@ -4,6 +4,7 @@ package ivy
 import org.apache.ivy.plugins.resolver.DependencyResolver
 import org.apache.ivy.core.settings.IvySettings
 import sbt.util.Logger
+import sbt.internal.librarymanagement.LMSysProp
 
 /**
  * Represents configurable options for update task.
@@ -109,7 +110,7 @@ object UpdateOptions {
       interProjectFirst = true,
       latestSnapshots = true,
       cachedResolution = false,
-      gigahorse = sys.props.get("sbt.gigahorse") map { _.toLowerCase == "true" } getOrElse true,
+      gigahorse = LMSysProp.useGigahorse,
       resolverConverter = PartialFunction.empty,
       moduleResolvers = Map.empty
     )