allow global sbt directory to be configured. fixes #96

main/Build.scala

@@ -9,7 +9,7 @@ package sbt
 	import complete.DefaultParsers.validID
 	import Compiler.Compilers
 	import Project.{ScopedKey, Setting}
-	import Keys.Streams
+	import Keys.{globalBaseDirectory, Streams}
 	import Scope.GlobalScope
 	import scala.annotation.tailrec
 
@@ -231,10 +231,15 @@ object BuildPaths
 	import Path._
 	import GlobFilter._
 
-	def defaultStaging = Path.userHome / ConfigDirectoryName / "staging"
-	def defaultGlobalPlugins = Path.userHome / ConfigDirectoryName / PluginsDirectoryName
+	def getGlobalBase(state: State): File  =  state get globalBaseDirectory orElse systemGlobalBase getOrElse defaultGlobalBase
+	def systemGlobalBase: Option[File] = Option(System.getProperty(GlobalBaseProperty)) flatMap { path =>
+		if(path.isEmpty) None else Some(new File(path))
+	}
+		
 	def defaultGlobalBase = Path.userHome / ConfigDirectoryName
-	def defaultGlobalSettings = configurationSources(defaultGlobalBase)
+	def defaultStaging(globalBase: File) = globalBase / "staging"
+	def defaultGlobalPlugins(globalBase: File) = globalBase / PluginsDirectoryName
+	def defaultGlobalSettings(globalBase: File) = configurationSources(globalBase)
 	
 	def definitionSources(base: File): Seq[File] = (base * "*.scala").get
 	def configurationSources(base: File): Seq[File] = (base * "*.sbt").get
@@ -256,6 +261,7 @@ object BuildPaths
 	final val PluginsDirectoryName = "plugins"
 	final val DefaultTargetName = "target"
 	final val ConfigDirectoryName = ".sbt"
+	final val GlobalBaseProperty = "sbt.global.base"
 
 	def crossPath(base: File, instance: ScalaInstance): File = base / ("scala_" + instance.version)
 }

main/GlobalPlugin.scala

@@ -32,7 +32,7 @@ object GlobalPlugin
 	{
 		val (structure, state) = build(base, s, config)
 		val data = extract(state, structure)
-		GlobalPlugin(data, structure, inject(data))
+		GlobalPlugin(data, structure, inject(data), base)
 	}
 	def extract(state: State, structure: BuildStructure): GlobalPluginData =
 	{
@@ -63,4 +63,4 @@ object GlobalPlugin
 	))
 }
 final case class GlobalPluginData(projectID: ModuleID, dependencies: Seq[ModuleID], descriptors: Map[ModuleRevisionId, ModuleDescriptor], fullClasspath: Classpath, internalClasspath: Classpath)
-final case class GlobalPlugin(data: GlobalPluginData, structure: BuildStructure, inject: Seq[Setting[_]])
+final case class GlobalPlugin(data: GlobalPluginData, structure: BuildStructure, inject: Seq[Setting[_]], base: File)

main/Keys.scala

@@ -57,6 +57,7 @@ object Keys
 
 	// Path Keys
 	val baseDirectory = SettingKey[File]("base-directory", "The base directory.  Depending on the scope, this is the base directory for the build, project, configuration, or task.")
+	val globalBaseDirectory = AttributeKey[File]("global-base-directory", "The base directory for global sbt configuration and staging.")
 	val target = SettingKey[File]("target", "Main directory for files generated by the build.")
 	val crossTarget = SettingKey[File]("cross-target", "Main directory for files generated by the build that are cross-built.")
 

main/Load.scala

@@ -24,14 +24,24 @@ object Load
 	import BuildPaths._
 	import BuildStreams._
 	import Locate.DefinesClass
-
+	
 	// note that there is State passed in but not pulled out
 	def defaultLoad(state: State, baseDirectory: File, log: Logger): (() => Eval, BuildStructure) =
+	{
+		val globalBase = BuildPaths.getGlobalBase(state)
+		val base = baseDirectory.getCanonicalFile
+		val definesClass = FileValueCache(Locate.definesClass _)
+		val rawConfig = defaultPreGlobal(state, base, definesClass.get, globalBase, log)
+		val config = defaultWithGlobal(state, base, rawConfig, globalBase, log)
+		val result = apply(base, state, config)
+		definesClass.clear()
+		result
+	}
+	def defaultPreGlobal(state: State, baseDirectory: File, definesClass: DefinesClass, globalBase: File, log: Logger): LoadBuildConfiguration =
 	{
 		val provider = state.configuration.provider
 		val scalaProvider = provider.scalaProvider
-		val stagingDirectory = defaultStaging.getCanonicalFile
-		val base = baseDirectory.getCanonicalFile
+		val stagingDirectory = defaultStaging(globalBase).getCanonicalFile
 		val loader = getClass.getClassLoader
 		val classpath = Attributed.blankSeq(provider.mainClasspath ++ scalaProvider.jars)
 		val compilers = Compiler.compilers(ClasspathOptions.boot)(state.configuration, log)
@@ -39,14 +49,14 @@ object Load
 		val delegates = defaultDelegates
 		val injectGlobal: Seq[Project.Setting[_]] = ((appConfiguration in GlobalScope) :== state.configuration) +: EvaluateTask.injectSettings
 		val inject = InjectSettings(injectGlobal, Nil, const(Nil))
-		val definesClass = FileValueCache(Locate.definesClass _)
-		val rawConfig = new LoadBuildConfiguration(stagingDirectory, classpath, loader, compilers, evalPluginDef, definesClass.get, delegates, EvaluateTask.injectStreams, inject, None, log)
-		val withGlobal = loadGlobal(state, baseDirectory, defaultGlobalPlugins, rawConfig)
-		val config = loadGlobalSettings(baseDirectory, defaultGlobalBase, defaultGlobalSettings, withGlobal)
-		val result = apply(base, state, config)
-		definesClass.clear()
-		result
+		new LoadBuildConfiguration(stagingDirectory, classpath, loader, compilers, evalPluginDef, definesClass, delegates, EvaluateTask.injectStreams, inject, None, log)
 	}
+	def defaultWithGlobal(state: State, base: File, rawConfig: LoadBuildConfiguration, globalBase: File, log: Logger): LoadBuildConfiguration =
+	{
+		val withGlobal = loadGlobal(state, base, defaultGlobalPlugins(globalBase), rawConfig)
+		loadGlobalSettings(base, globalBase, defaultGlobalSettings(globalBase), withGlobal)
+	}
+
 	def loadGlobalSettings(base: File, globalBase: File, files: Seq[File], config: LoadBuildConfiguration): LoadBuildConfiguration =
 	{
 		val compiled: ClassLoader => Seq[Setting[_]]  =