1 files changed, 77 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/nsc/ClassPathMemoryConsumptionTester.scala b/src/compiler/scala/tools/nsc/ClassPathMemoryConsumptionTester.scala
new file mode 100644
index 0000000000..2faf6c6272
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/ClassPathMemoryConsumptionTester.scala
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2014 Contributor. All rights reserved.
+ */
+package scala.tools.nsc
+
+import scala.io.StdIn.readLine
+
+/**
+ * Simple application to check out amount of memory used by chosen classpath representation.
+ * It allows us to create many scalac-like calls based on specified parameters, where each main retains Global.
+ * And we need additional tool (e.g. profiler) to measure memory consumption itself.
+ */
+object ClassPathMemoryConsumptionTester {
+
+  private class TestSettings extends Settings {
+    val requiredInstances = IntSetting("-requiredInstances",
+      "Determine how many times classpath should be loaded", 10, Some((1, 10000)), (_: String) => None)
+  }
+
+  private class MainRetainsGlobal extends scala.tools.nsc.MainClass {
+    var retainedGlobal: Global = _
+    override def doCompile(compiler: Global) {
+      retainedGlobal = compiler
+      super.doCompile(compiler)
+    }
+  }
+
+  def main(args: Array[String]): Unit = {
+    if (args contains "-help") usage()
+    else doTest(args)
+  }
+
+  private def doTest(args: Array[String]) = {
+    val settings = loadSettings(args.toList)
+
+    val mains = (1 to settings.requiredInstances.value) map (_ => new MainRetainsGlobal)
+
+    // we need original settings without additional params to be able to use them later
+    val baseArgs = argsWithoutRequiredInstances(args)
+
+    println(s"Loading classpath ${settings.requiredInstances.value} times")
+    val startTime = System.currentTimeMillis()
+
+    mains map (_.process(baseArgs))
+
+    val elapsed = System.currentTimeMillis() - startTime
+    println(s"Operation finished - elapsed $elapsed ms")
+    println("Memory consumption can be now measured")
+
+    var textFromStdIn = ""
+    while (textFromStdIn.toLowerCase != "exit")
+      textFromStdIn = readLine("Type 'exit' to close application: ")
+  }
+
+  /**
+   * Prints usage information
+   */
+  private def usage(): Unit =
+    println( """Use classpath and sourcepath options like in the case of e.g. 'scala' command.
+               | There's also one additional option:
+               | -requiredInstances <int value> Determine how many times classpath should be loaded
+             """.stripMargin.trim)
+
+  private def loadSettings(args: List[String]) = {
+    val settings = new TestSettings()
+    settings.processArguments(args, processAll = true)
+    if (settings.classpath.isDefault)
+      settings.classpath.value = sys.props("java.class.path")
+    settings
+  }
+
+  private def argsWithoutRequiredInstances(args: Array[String]) = {
+    val instancesIndex = args.indexOf("-requiredInstances")
+    if (instancesIndex == -1) args
+    else args.dropRight(args.length - instancesIndex) ++ args.drop(instancesIndex + 2)
+  }
+}