Implemented manifest-based class-paths.

If you run a jar directly, like

  scala foo.jar

Then if a Class-Path attribute is present in the jar manifest, the
classpath will be constructed from that instead of the arguments. Some
things remain to be determined, like whether it's supposed to replace
a classpath given on the command line or supplement it, and whether
the master jar should be on the classpath or only and exactly the jars
listed in the manifest.

There's a really nice test case, which won't be run of course, but I
can't stand going any further without tests for these hard to test on
all platforms things. The faux .check file shows what I see.

Closes SI-4355, review by harrah.

4 files changed, 46 insertions, 13 deletions

diff --git a/src/compiler/scala/tools/nsc/MainGenericRunner.scala b/src/compiler/scala/tools/nsc/MainGenericRunner.scala
index cef13843dc..cc1139f8a7 100644
--- a/src/compiler/scala/tools/nsc/MainGenericRunner.scala
+++ b/src/compiler/scala/tools/nsc/MainGenericRunner.scala
@@ -7,13 +7,28 @@ package scala.tools.nsc
 
 import java.net.URL
 import scala.tools.util.PathResolver
-
 import io.{ File }
 import util.{ ClassPath, ScalaClassLoader }
 import Properties.{ versionString, copyrightString }
 import interpreter.{ ILoop }
 import GenericRunnerCommand._
 
+object JarRunner extends CommonRunner {
+  def runJar(settings: GenericRunnerSettings, jarPath: String, arguments: Seq[String]): Either[Throwable, Boolean] = {
+    val jar       = new io.Jar(jarPath)
+    val mainClass = jar.mainClass getOrElse sys.error("Cannot find main class for jar: " + jarPath)
+    val jarURLs   = ClassPath expandManifestPath jarPath
+    val urls      = if (jarURLs.isEmpty) File(jarPath).toURL +: settings.classpathURLs else jarURLs
+
+    if (settings.Ylogcp.value) {
+      Console.err.println("Running jar with these URLs as the classpath:")
+      urls foreach println
+    }
+
+    runAndCatch(urls, mainClass, arguments)
+  }
+}
+
 /** An object that runs Scala code.  It has three possible
   * sources for the code to run: pre-compiled code, a script file,
   * or interactive entry.
@@ -56,11 +71,7 @@ class MainGenericRunner {
       case AsScript =>
         ScriptRunner.runScriptAndCatch(settings, thingToRun, command.arguments)
       case AsJar    =>
-        ObjectRunner.runAndCatch(
-          File(thingToRun).toURL +: settings.classpathURLs,
-          new io.Jar(thingToRun).mainClass getOrElse sys.error("Cannot find main class for jar: " + thingToRun),
-          command.arguments
-        )
+        JarRunner.runJar(settings, thingToRun, command.arguments)
       case Error =>
         Right(false)
       case _  =>
diff --git a/src/compiler/scala/tools/nsc/ObjectRunner.scala b/src/compiler/scala/tools/nsc/ObjectRunner.scala
index 6ff0718de7..110de7aad5 100644
--- a/src/compiler/scala/tools/nsc/ObjectRunner.scala
+++ b/src/compiler/scala/tools/nsc/ObjectRunner.scala
@@ -11,12 +11,7 @@ import util.ScalaClassLoader
 import java.lang.reflect.InvocationTargetException
 import util.Exceptional.unwrap
 
-/** An object that runs another object specified by name.
- *
- *  @author  Lex Spoon
- *  @version 1.1, 2007/7/13
- */
-object ObjectRunner {
+trait CommonRunner {
   /** Check whether a class with the specified name
    *  exists on the specified class path. */
   def classExists(urls: List[URL], objectName: String): Boolean =
@@ -41,3 +36,10 @@ object ObjectRunner {
     catch { case e => Left(unwrap(e)) }
   }
 }
+
+/** An object that runs another object specified by name.
+ *
+ *  @author  Lex Spoon
+ *  @version 1.1, 2007/7/13
+ */
+object ObjectRunner extends CommonRunner { }
diff --git a/src/compiler/scala/tools/nsc/io/Jar.scala b/src/compiler/scala/tools/nsc/io/Jar.scala
index ad1598a85d..bbed5a9e20 100644
--- a/src/compiler/scala/tools/nsc/io/Jar.scala
+++ b/src/compiler/scala/tools/nsc/io/Jar.scala
@@ -40,7 +40,15 @@ class Jar(file: File) extends Iterable[JarEntry] {
 
   lazy val jarFile  = new JarFile(file.jfile)
   lazy val manifest = withJarInput(s => Option(s.getManifest))
+
   def mainClass     = manifest map (f => f(Name.MAIN_CLASS))
+  /** The manifest-defined classpath String if available. */
+  def classPathString: Option[String] =
+    for (m <- manifest ; cp <- m.attrs get Name.CLASS_PATH) yield cp
+  def classPathElements: List[String] = classPathString match {
+    case Some(s)  => s split "\\s+" toList
+    case _        => Nil
+  }
 
   def withJarInput[T](f: JarInputStream => T): T = {
     val in = new JarInputStream(file.inputStream())
diff --git a/src/compiler/scala/tools/nsc/util/ClassPath.scala b/src/compiler/scala/tools/nsc/util/ClassPath.scala
index 484f809e6f..622b4db2a2 100644
--- a/src/compiler/scala/tools/nsc/util/ClassPath.scala
+++ b/src/compiler/scala/tools/nsc/util/ClassPath.scala
@@ -13,6 +13,7 @@ import io.{ File, Directory, Path, Jar, AbstractFile, ClassAndJarInfo }
 import scala.tools.util.StringOps.splitWhere
 import Jar.isJarOrZip
 import File.pathSeparator
+import java.net.MalformedURLException
 
 /** <p>
  *    This module provides star expansion of '-classpath' option arguments, behaves the same as
@@ -110,11 +111,22 @@ object ClassPath {
       case dir  => dir filter (_.isClassContainer) map (x => new java.io.File(dir.file, x.name) getPath) toList
     }
   }
+  /** Expand manifest jar classpath entries: these are either urls, or paths
+   *  relative to the location of the jar.
+   */
+  def expandManifestPath(jarPath: String): List[URL] = {
+    val file = File(jarPath)
+    if (!file.isFile) return Nil
+
+    val baseDir = file.parent
+    new Jar(file).classPathElements map (elem =>
+      specToURL(elem) getOrElse (baseDir / elem).toURL
+    )
+  }
 
   /** A useful name filter. */
   def isTraitImplementation(name: String) = name endsWith "$class.class"
 
-  import java.net.MalformedURLException
   def specToURL(spec: String): Option[URL] =
     try Some(new URL(spec))
     catch { case _: MalformedURLException => None }