sbt/project/build/ProguardProject.scala

package sbt

import java.io.File

object ProguardProject
{
	val ProguardDescription = "Produces the final compacted jar that contains only the minimum classes needed using proguard."
	val WriteProguardDescription = "Creates the configuration file to use with proguard."
}
import ProguardProject._
trait ProguardProject extends BasicScalaProject
{
	def rawJarPath: Path
	def rawPackage: Task

	def proguardConfigurationPath: Path = outputPath / "proguard.pro"
	def outputJar: Path
	def rootProjectDirectory = rootProject.info.projectPath

	val toolsConfig = config("tools") hide
	val proguardJar = "net.sf.proguard" % "proguard" % "4.4" % "tools"

	lazy val proguard = proguardAction
	def proguardAction = proguardTask dependsOn(writeProguardConfiguration) describedAs(ProguardDescription)
	lazy val writeProguardConfiguration = writeProguardConfigurationAction
	def writeProguardConfigurationAction = writeProguardConfigurationTask dependsOn rawPackage describedAs WriteProguardDescription

	def basicOptions: Seq[String] =
		Seq(
				"-keep,allowoptimization,allowshrinking class * { *; }",
				"-keepattributes SourceFile,LineNumberTable",
				"-dontnote",
				"-dontwarn",
				 "-ignorewarnings") ++
		optimizeOptions
	
	def keepFullClasses: Seq[String] = Nil
	def keepClasses: Seq[String] = Nil
	def optimize: Int = 0
	def optimizeOptions = if(optimize <= 0) Seq("-dontoptimize") else Seq( "-optimizationpasses 2", "-optimizations !code/allocation/variable")

	def mapInJars(inJars: Seq[File]): Seq[String] = inJars.map(f => "-injars " + mkpath(f))
	def mapLibraryJars(libraryJars: Seq[File]): Seq[String] = libraryJars.map(f => "-libraryjars " + mkpath(f))
	def mapOutJar(outJar: File) = "-outjars " + mkpath(outJar)

	def template(inJars: Seq[File], libraryJars: Seq[File], outJar: File, options: Seq[String], mainClass: Option[String], keepClasses: Seq[String]) =
	{
		val keepMain =
			"""-keep public class %s {
				|    public static void main(java.lang.String[]);
				|}"""

		val lines =
			options ++
			keepFullClasses.map("-keep public class " + _  + " {\n public protected * ;\n}") ++
			keepClasses.map("-keep class " + _  + " {}") ++
			mapInJars(inJars) ++
			 Seq("-injars " + mkpath(rawJarPath.asFile),
				mapOutJar(outJar)) ++
			mapLibraryJars(libraryJars) ++
			mainClass.map(main => keepMain.stripMargin.format(main)).toList
		lines.mkString("\n")
	}

	def mkpath(f: File) : String = mkpath(f.getAbsolutePath, '\"')
	def mkpath(path: String, delimiter : Char) : String = delimiter + path + delimiter
	protected def proguardTask =
		task
		{
			FileUtilities.clean(outputJar :: Nil, log)
			val proguardClasspathString = Path.makeString(managedClasspath(toolsConfig).get) 
			val configFile = mkpath(proguardConfigurationPath.asFile.getAbsolutePath, '\'')
			val exitValue = Process("java", List("-Xmx256M", "-cp", proguardClasspathString, "proguard.ProGuard", "-include " + configFile)) ! log
			if(exitValue == 0) None else Some("Proguard failed with nonzero exit code (" + exitValue + ")")
		}
	protected def writeProguardConfigurationTask =
		task
		{
			val dependencies = mainDependencies.snapshot
			log.debug("proguard configuration, all dependencies:\n\t" + dependencies.all.mkString("\n\t"))
			val externalJars = dependencies.external
			log.debug("proguard configuration external dependencies: \n\t" + externalJars.mkString("\n\t"))
			// partition jars from the external jar dependencies of this project by whether they are located in the project directory
			// if they are, they are specified with -injars, otherwise they are specified with -libraryjars
			val libraryJars = dependencies.libraries ++ dependencies.scalaJars
			log.debug("proguard configuration library jars locations:\n\t" + libraryJars.mkString("\n\t"))

			val proguardConfiguration = template(libraryJars, externalJars, outputJar.asFile, basicOptions, getMainClass(false), keepClasses)
			log.debug("Proguard configuration written to " + proguardConfigurationPath)
			FileUtilities.write(proguardConfigurationPath.asFile, proguardConfiguration, log)
		}
}