From 4ea25c98d377b6b0369fa20aa9d4bfd3a3223ef6 Mon Sep 17 00:00:00 2001
From: Philipp Haller <hallerp@gmail.com>
Date: Wed, 7 Dec 2011 16:51:55 +0100
Subject: Add future method to ExecutionContext trait. Log uncaught exceptions
 to stderr.

---
 src/library/scala/concurrent/ExecutionContext.scala | 16 +++++++---------
 src/library/scala/concurrent/ForkJoinTaskImpl.scala | 21 ++++++++++++++++-----
 src/library/scala/concurrent/package.scala          |  5 +++--
 3 files changed, 26 insertions(+), 16 deletions(-)

(limited to 'src')

diff --git a/src/library/scala/concurrent/ExecutionContext.scala b/src/library/scala/concurrent/ExecutionContext.scala
index d54b6c370e..9606c28bab 100644
--- a/src/library/scala/concurrent/ExecutionContext.scala
+++ b/src/library/scala/concurrent/ExecutionContext.scala
@@ -12,24 +12,22 @@ trait ExecutionContext {
   
   def execute(task: Runnable): Unit
   
-  def task[T](task: () => T): Task[T]
+  def task[T](task: => T): Task[T]
   
   def promise[T]: Promise[T]
   
+  def future[T](body: => T): Future[T] = {
+    val t = task(body)
+    t.start()
+    t.future
+  }
+
   /** Only callable from the tasks running on the same execution context. */
   def blockingCall[T](body: Blockable[T]): T
   
 }
 
 
-object ExecutionContext {
-
-  lazy val forNonBlocking = new ForkJoinExecutionContext
-
-  //lazy val forBlocking = new BlockingExecutionContext
-
-}
-
 
 sealed trait CanBlock
 
diff --git a/src/library/scala/concurrent/ForkJoinTaskImpl.scala b/src/library/scala/concurrent/ForkJoinTaskImpl.scala
index faa7ecb45a..9df4768ebb 100644
--- a/src/library/scala/concurrent/ForkJoinTaskImpl.scala
+++ b/src/library/scala/concurrent/ForkJoinTaskImpl.scala
@@ -13,7 +13,7 @@ import scala.annotation.tailrec
  * to avoid an object allocation per promise. This requires turning DefaultPromise
  * into a trait, i.e., removing its constructor parameters.
  */
-private[concurrent] class ForkJoinTaskImpl[T](val executionContext: ForkJoinExecutionContext, val body: () => T, val timeout: Timeout)
+private[concurrent] class ForkJoinTaskImpl[T](val executionContext: ForkJoinExecutionContext, body: => T, val timeout: Timeout)
 extends RecursiveAction with Task[T] with Future[T] {
   
   private val updater = AtomicReferenceFieldUpdater.newUpdater(classOf[ForkJoinTaskImpl[T]], classOf[State[T]], "state")
@@ -46,7 +46,7 @@ extends RecursiveAction with Task[T] with Future[T] {
     var cbs: List[Callback] = null
     
     try {
-      val res = body()
+      val res = body
       processCallbacks(trySucceedState(res), Right(res))
     } catch {
       case t if isFutureThrowable(t) =>
@@ -83,7 +83,9 @@ extends RecursiveAction with Task[T] with Future[T] {
     if (res != null) dispatch(new Runnable {
       override def run() =
         try callback(res)
-        catch handledFutureException
+        catch handledFutureException andThen {
+          t => Console.err.println(t)
+        }
     })
     
     this
@@ -130,7 +132,16 @@ case class Failure[T](throwable: Throwable) extends State[T]
 
 
 private[concurrent] final class ForkJoinExecutionContext extends ExecutionContext {
-  val pool = new ForkJoinPool
+  val pool = {
+    val p = new ForkJoinPool
+    p.setUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler {
+      def uncaughtException(t: Thread, throwable: Throwable) {
+        Console.err.println(throwable.getMessage)
+        throwable.printStackTrace(Console.err)
+      }
+    })
+    p
+  }
 
   @inline
   private def executeForkJoinTask(task: RecursiveAction) {
@@ -145,7 +156,7 @@ private[concurrent] final class ForkJoinExecutionContext extends ExecutionContex
     executeForkJoinTask(action)
   }
   
-  def task[T](body: () => T): Task[T] = {
+  def task[T](body: => T): Task[T] = {
     new ForkJoinTaskImpl(this, body, Timeout.never)
   }
   
diff --git a/src/library/scala/concurrent/package.scala b/src/library/scala/concurrent/package.scala
index b9e39a21a1..63faeef502 100644
--- a/src/library/scala/concurrent/package.scala
+++ b/src/library/scala/concurrent/package.scala
@@ -21,6 +21,9 @@ package object concurrent {
   type CancellationException = java.util.concurrent.CancellationException
   type TimeoutException = java.util.concurrent.TimeoutException
   
+  lazy val executionContext =
+    new ForkJoinExecutionContext
+
   private[concurrent] def currentExecutionContext: ThreadLocal[ExecutionContext] = new ThreadLocal[ExecutionContext] {
     override protected def initialValue = null
   }
@@ -59,8 +62,6 @@ package object concurrent {
     }
   }
   
-  def future[T](body: =>T): Future[T] = null // TODO
-  
   val handledFutureException: PartialFunction[Throwable, Throwable] = {
     case t: Throwable if isFutureThrowable(t) => t
   }
-- 
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