Merge pull request #4051 from heathermiller/repl-cp-fix2

SI-6502 Reenables loading jars into the running REPL (regression in 2.10)

3 files changed, 165 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 9cc9712b44..430424d0f8 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -8,12 +8,13 @@ package tools
 package nsc
 
 import java.io.{ File, FileOutputStream, PrintWriter, IOException, FileNotFoundException }
+import java.net.URL
 import java.nio.charset.{ Charset, CharsetDecoder, IllegalCharsetNameException, UnsupportedCharsetException }
 import scala.compat.Platform.currentTime
 import scala.collection.{ mutable, immutable }
 import io.{ SourceReader, AbstractFile, Path }
 import reporters.{ Reporter, ConsoleReporter }
-import util.{ ClassPath, StatisticsInfo, returning, stackTraceString }
+import util.{ ClassPath, MergedClassPath, StatisticsInfo, returning, stackTraceString }
 import scala.reflect.ClassTag
 import scala.reflect.internal.util.{ OffsetPosition, SourceFile, NoSourceFile, BatchSourceFile, ScriptSourceFile }
 import scala.reflect.internal.pickling.{ PickleBuffer, PickleFormat }
@@ -841,6 +842,150 @@ class Global(var currentSettings: Settings, var reporter: Reporter)
     } reverse
   }
 
+  // ------------ REPL utilities ---------------------------------
+
+  /** Extend classpath of `platform` and rescan updated packages. */
+  def extendCompilerClassPath(urls: URL*): Unit = {
+    val newClassPath = platform.classPath.mergeUrlsIntoClassPath(urls: _*)
+    platform.currentClassPath = Some(newClassPath)
+    // Reload all specified jars into this compiler instance
+    invalidateClassPathEntries(urls.map(_.getPath): _*)
+  }
+
+  // ------------ Invalidations ---------------------------------
+
+  /** Is given package class a system package class that cannot be invalidated?
+   */
+  private def isSystemPackageClass(pkg: Symbol) =
+    pkg == RootClass || (pkg.hasTransOwner(definitions.ScalaPackageClass) && !pkg.hasTransOwner(this.rootMirror.staticPackage("scala.tools").moduleClass.asClass))
+
+  /** Invalidates packages that contain classes defined in a classpath entry, and
+   *  rescans that entry.
+   *
+   *  First, the classpath entry referred to by one of the `paths` is rescanned,
+   *  so that any new files or changes in subpackages are picked up.
+   *  Second, any packages for which one of the following conditions is met is invalidated:
+   *   - the classpath entry contained during the last compilation run now contains classfiles
+   *     that represent a member in the package;
+   *   - the classpath entry now contains classfiles that represent a member in the package;
+   *   - the set of subpackages has changed.
+   *
+   *  The invalidated packages are reset in their entirety; all member classes and member packages
+   *  are re-accessed using the new classpath.
+   *
+   *  System packages that the compiler needs to access as part of standard definitions
+   *  are not invalidated. A system package is:
+   *  Any package rooted in "scala", with the exception of packages rooted in "scala.tools".
+   *
+   *  @param paths  Fully-qualified names that refer to directories or jar files that are
+   *                entries on the classpath.
+   */
+  def invalidateClassPathEntries(paths: String*): Unit = {
+    implicit object ClassPathOrdering extends Ordering[PlatformClassPath] {
+      def compare(a:PlatformClassPath, b:PlatformClassPath) = a.asClasspathString compare b.asClasspathString
+    }
+    val invalidated, failed = new mutable.ListBuffer[ClassSymbol]
+    classPath match {
+      case cp: MergedClassPath[_] =>
+        def assoc(path: String): List[(PlatformClassPath, PlatformClassPath)] = {
+          val dir = AbstractFile.getDirectory(path)
+          val canonical = dir.canonicalPath
+          def matchesCanonical(e: ClassPath[_]) = e.origin match {
+            case Some(opath) =>
+              AbstractFile.getDirectory(opath).canonicalPath == canonical
+            case None =>
+              false
+          }
+          cp.entries find matchesCanonical match {
+            case Some(oldEntry) =>
+              List(oldEntry -> cp.context.newClassPath(dir))
+            case None =>
+              error(s"Error adding entry to classpath. During invalidation, no entry named $path in classpath $classPath")
+              List()
+          }
+        }
+        val subst = immutable.TreeMap(paths flatMap assoc: _*)
+        if (subst.nonEmpty) {
+          platform updateClassPath subst
+          informProgress(s"classpath updated on entries [${subst.keys mkString ","}]")
+          def mkClassPath(elems: Iterable[PlatformClassPath]): PlatformClassPath =
+            if (elems.size == 1) elems.head
+            else new MergedClassPath(elems, classPath.context)
+          val oldEntries = mkClassPath(subst.keys)
+          val newEntries = mkClassPath(subst.values)
+          mergeNewEntries(newEntries, RootClass, Some(classPath), Some(oldEntries), invalidated, failed)
+        }
+    }
+    def show(msg: String, syms: scala.collection.Traversable[Symbol]) =
+      if (syms.nonEmpty)
+        informProgress(s"$msg: ${syms map (_.fullName) mkString ","}")
+    show("invalidated packages", invalidated)
+    show("could not invalidate system packages", failed)
+  }
+
+  /** Merges new classpath entries into the symbol table
+   *
+   *  @param newEntries   The new classpath entries
+   *  @param root         The root symbol to be resynced (a package class)
+   *  @param allEntries   Optionally, the corresponding package in the complete current classpath
+   *  @param oldEntries   Optionally, the corresponding package in the old classpath entries
+   *  @param invalidated  A listbuffer collecting the invalidated package classes
+   *  @param failed       A listbuffer collecting system package classes which could not be invalidated
+   *
+   * The merging strategy is determined by the absence or presence of classes and packages.
+   *
+   * If either oldEntries or newEntries contains classes, root is invalidated provided that a corresponding package
+   * exists in allEntries. Otherwise it is removed.
+   * Otherwise, the action is determined by the following matrix, with columns:
+   *
+   *      old sym   action
+   *       +   +    recurse into all child packages of newEntries
+   *       -   +    invalidate root
+   *       -   -    create and enter root
+   *
+   *  Here, old means classpath, and sym means symboltable. + is presence of an entry in its column, - is absence.
+   */
+  private def mergeNewEntries(newEntries: PlatformClassPath, root: ClassSymbol,
+             allEntries: OptClassPath, oldEntries: OptClassPath,
+             invalidated: mutable.ListBuffer[ClassSymbol], failed: mutable.ListBuffer[ClassSymbol]) {
+    ifDebug(informProgress(s"syncing $root, $oldEntries -> $newEntries"))
+
+    val getName: ClassPath[AbstractFile] => String = (_.name)
+    def hasClasses(cp: OptClassPath) = cp.isDefined && cp.get.classes.nonEmpty
+    def invalidateOrRemove(root: ClassSymbol) = {
+      allEntries match {
+        case Some(cp) => root setInfo new loaders.PackageLoader(cp)
+        case None => root.owner.info.decls unlink root.sourceModule
+      }
+      invalidated += root
+    }
+    def subPackage(cp: PlatformClassPath, name: String): OptClassPath =
+      cp.packages find (cp1 => getName(cp1) == name)
+
+    val classesFound = hasClasses(oldEntries) || newEntries.classes.nonEmpty
+    if (classesFound && !isSystemPackageClass(root)) {
+      invalidateOrRemove(root)
+    } else {
+      if (classesFound) {
+        if (root.isRoot) invalidateOrRemove(EmptyPackageClass)
+        else failed += root
+      }
+      if (!oldEntries.isDefined) invalidateOrRemove(root)
+      else
+        for (pstr <- newEntries.packages.map(getName)) {
+          val pname = newTermName(pstr)
+          val pkg = (root.info decl pname) orElse {
+            // package does not exist in symbol table, create symbol to track it
+            assert(!subPackage(oldEntries.get, pstr).isDefined)
+            loaders.enterPackage(root, pstr, new loaders.PackageLoader(allEntries.get))
+          }
+          mergeNewEntries(subPackage(newEntries, pstr).get, pkg.moduleClass.asClass,
+                          subPackage(allEntries.get, pstr), subPackage(oldEntries.get, pstr),
+                          invalidated, failed)
+        }
+    }
+  }
+
   // ----------- Runs ---------------------------------------
 
   private var curRun: Run = null
diff --git a/src/compiler/scala/tools/nsc/backend/JavaPlatform.scala b/src/compiler/scala/tools/nsc/backend/JavaPlatform.scala
index 7236bf70d5..4877bd9b80 100644
--- a/src/compiler/scala/tools/nsc/backend/JavaPlatform.scala
+++ b/src/compiler/scala/tools/nsc/backend/JavaPlatform.scala
@@ -16,7 +16,7 @@ trait JavaPlatform extends Platform {
   import global._
   import definitions._
 
-  private var currentClassPath: Option[MergedClassPath[AbstractFile]] = None
+  private[nsc] var currentClassPath: Option[MergedClassPath[AbstractFile]] = None
 
   def classPath: ClassPath[AbstractFile] = {
     if (currentClassPath.isEmpty) currentClassPath = Some(new PathResolver(settings).result)
diff --git a/src/compiler/scala/tools/nsc/util/ClassPath.scala b/src/compiler/scala/tools/nsc/util/ClassPath.scala
index e89f08ec6b..e78dee5eee 100644
--- a/src/compiler/scala/tools/nsc/util/ClassPath.scala
+++ b/src/compiler/scala/tools/nsc/util/ClassPath.scala
@@ -197,6 +197,23 @@ abstract class ClassPath[T] {
   def packages: IndexedSeq[ClassPath[T]]
   def sourcepaths: IndexedSeq[AbstractFile]
 
+  /** The entries this classpath is composed of. In class `ClassPath` it's just the singleton list containing `this`.
+   *  Subclasses such as `MergedClassPath` typically return lists with more elements.
+   */
+  def entries: IndexedSeq[ClassPath[T]] = IndexedSeq(this)
+
+  /** Merge classpath of `platform` and `urls` into merged classpath */
+  def mergeUrlsIntoClassPath(urls: URL*): MergedClassPath[T] = {
+    // Collect our new jars/directories and add them to the existing set of classpaths
+    val allEntries =
+      (entries ++
+       urls.map(url => context.newClassPath(io.AbstractFile.getURL(url)))
+      ).distinct
+
+    // Combine all of our classpaths (old and new) into one merged classpath
+    new MergedClassPath(allEntries, context)
+  }
+
   /**
    * Represents classes which can be loaded with a ClassfileLoader and/or SourcefileLoader.
    */
@@ -322,7 +339,7 @@ extends MergedClassPath[T](original.entries map (e => subst getOrElse (e, e)), o
  * A classpath unifying multiple class- and sourcepath entries.
  */
 class MergedClassPath[T](
-  val entries: IndexedSeq[ClassPath[T]],
+  override val entries: IndexedSeq[ClassPath[T]],
   val context: ClassPathContext[T])
 extends ClassPath[T] {
   def this(entries: TraversableOnce[ClassPath[T]], context: ClassPathContext[T]) =