1 files changed, 43 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/nsc/util/WorkScheduler.scala b/src/compiler/scala/tools/nsc/util/WorkScheduler.scala
new file mode 100644
index 0000000000..7bcd3b7a8e
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/util/WorkScheduler.scala
@@ -0,0 +1,43 @@
+package scala.tools.nsc.util
+
+import scala.collection.mutable.Queue
+
+class WorkScheduler {
+
+  type Action = () => Unit
+
+  private var todo = new Queue[Action]
+
+  /** Called from server */
+  def waitForMoreWork() = synchronized {
+    do { wait() } while (todo.isEmpty)
+  }
+
+  /** called from Server */
+  def moreWork(): Boolean = synchronized {
+    todo.nonEmpty
+  }
+
+  /** Called from server */
+  def nextWorkItem(): Option[Action] = synchronized {
+    if (!todo.isEmpty) Some(todo.dequeue()) else None
+  }
+
+  /** Called from client */
+  def postWorkItem(action: Action) {
+    todo enqueue action
+    notify()
+  }
+
+  /** Called from client */
+  def cancel() = synchronized {
+    todo.clear()
+  }
+
+  /** Called from client */
+  def raise(exc: Exception) = synchronized {
+    todo.clear()
+    todo enqueue (() => throw exc)
+  }
+}
+