From 7affb3526f33e9934b51e149ff3eb31053c444aa Mon Sep 17 00:00:00 2001
From: Mark Harrah <dmharrah@gmail.com>
Date: Tue, 24 Nov 2009 08:56:23 -0500
Subject: [PATCH] Cache reflective lookups in the compiler interface

---
 compile/interface/Analyzer.scala     | 22 +++++++++++-----------
 compile/interface/CachedMethod.scala | 27 +++++++++++++++++++++++++++
 notes                                |  9 +++++++++
 3 files changed, 47 insertions(+), 11 deletions(-)
 create mode 100644 compile/interface/CachedMethod.scala

diff --git a/compile/interface/Analyzer.scala b/compile/interface/Analyzer.scala
index f5fccbcd0..bc4930ebb 100644
--- a/compile/interface/Analyzer.scala
+++ b/compile/interface/Analyzer.scala
@@ -190,27 +190,27 @@ final class Analyzer(val global: Global, val callback: AnalysisCallback) extends
 	}
 	private class NewFinder extends ClassFinder
 	{
+		private val findClass0 = reflect[Option[AnyRef]]("findClass", classOf[String])
+		findClass0.force(classPath) // force discovery, so that an exception is thrown if method doesn't exist
+		private val extractClass0 = reflect[Option[AbstractFile]]("binary")
 		def findClass(name: String): Option[AbstractFile] =
-			call[Option[AnyRef]](classPath, "findClass", classOf[String])(name).flatMap(extractClass)
-		private def extractClass(a: AnyRef) =
-			call[Option[AbstractFile]](a, "binary")()
+			findClass0(classPath, name).flatMap(a => extractClass0(a))
 	}
 	private class LegacyFinder extends ClassFinder
 	{
-		private val root = call[AnyRef](classPath, "root")()
+		private val root = { val m = reflect[AnyRef]("root"); m(classPath) }
+		private val find0 = reflect[AnyRef]("find", classOf[String], classOf[Boolean])
+		find0.force(root) // force discovery, so that an exception is thrown if method doesn't exist
+		private val classFile = reflect[AbstractFile]("classFile")
 		def findClass(name: String): Option[AbstractFile] =
 		{
-			val entry = call[AnyRef](root, "find", classOf[String], classOf[Boolean])(name, boolean2Boolean(false))
+			val entry = find0(root, name, boolean2Boolean(false))
 			if (entry eq null)
 				None
 			else
-				Some( call[AbstractFile](entry, "classFile")() )
+				Some( classFile(entry) )
 		}
 	}
 	import scala.reflect.Manifest
-	private def call[T  <: AnyRef](on: AnyRef, name: String, tpes: Class[_]*)(args: AnyRef*)(implicit mf: Manifest[T]): T =
-	{
-		val result = on.getClass.getMethod(name, tpes : _*).invoke(on, args : _*)
-		mf.erasure.cast(result).asInstanceOf[T]
-	}
+	private def reflect[T](name: String, tpes: Class[_]*)(implicit mf: Manifest[T]) = new CachedMethod(name, tpes : _*)(mf)
 }
\ No newline at end of file
diff --git a/compile/interface/CachedMethod.scala b/compile/interface/CachedMethod.scala
new file mode 100644
index 000000000..943968fec
--- /dev/null
+++ b/compile/interface/CachedMethod.scala
@@ -0,0 +1,27 @@
+package xsbt
+
+import java.lang.ref.WeakReference
+import java.lang.reflect.Method
+import scala.reflect.Manifest
+
+// replacement for structural type cache, which doesn't use weak references
+// assumes type of target doesn't change
+// not thread safe
+private final class CachedMethod[T](name: String, tpes: Class[_]*)(mf: Manifest[T]) extends NotNull
+{
+	private var method = new WeakReference[Method](null)
+	private def getMethod(on: AnyRef): Method =
+	{
+		val m = on.getClass.getMethod(name, tpes : _*)
+		method = new WeakReference(m)
+		m
+	}
+	def force(on: AnyRef) { getMethod(on) }
+	def apply(on: AnyRef, args: AnyRef*): T =
+	{
+		val cached = method.get
+		val m = if(cached ne null) cached else getMethod(on)
+		val result = m.invoke(on, args : _*)
+		mf.erasure.cast(result).asInstanceOf[T]
+	}
+}
\ No newline at end of file
diff --git a/notes b/notes
index 845b4e7a0..4873309c4 100644
--- a/notes
+++ b/notes
@@ -1,3 +1,8 @@
+DONE
+-fix caching issue for compiler interface
+-fix test ClassLoader
+
+
 Goals/Guidelines for xsbt
 =====
 As usual:
@@ -13,6 +18,10 @@ TODO
  - allow comments in datatype definition file
  - tests for API extractor
 
+update 0_6_Summary to mention different output directories.
+look at permgen in Josh's ScalaTest
+TrapExit handles System.exit(0) as nonzero exit code
+
 Task engine
 - method tasks will be normal tasks that pull the command line from a CommandLine task
 - per task configuration, including logging (e.g. 'task compile log debug')