Wait for eventhandler to shut down before exiting

dart/runtime/bin/eventhandler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/dartutils.h"
 #include "bin/eventhandler.h"
+#include "bin/lockers.h"
 #include "bin/socket.h"
+#include "bin/thread.h"
 
 #include "include/dart_api.h"
 
 
 namespace dart {
 namespace bin {
 
 static const intptr_t kTimerId = -1;
 static const intptr_t kInvalidId = -2;
 
@@ skipping 32 matching lines @@
     if (next_timeout_ == NULL ||
         current->timeout() < next_timeout_->timeout()) {
       next_timeout_ = current;
     }
     current = current->next();
   }
 }
 
 
 static EventHandler* event_handler = NULL;
+static Monitor *shutdown_monitor = NULL;
 
 
 void EventHandler::Start() {
   ASSERT(event_handler == NULL);
+  shutdown_monitor = new Monitor();
   event_handler = new EventHandler();
   event_handler->delegate_.Start(event_handler);
 }
 
 
-void EventHandler::Stop() {
-  if (event_handler == NULL) return;
-  event_handler->delegate_.Shutdown();
-  event_handler = NULL;
+void EventHandler::NotifyShutdownDone() {
+  MonitorLocker ml(shutdown_monitor);
+  ml.Notify();
 }
 
 
+void EventHandler::Stop() {
+  if (event_handler == NULL) return;
+
+  // Wait until it has stopped.
+  {
+    MonitorLocker ml(shutdown_monitor);
+
+    // Signal to event handler that we want it to stop.
+    event_handler->delegate_.Shutdown();
+    ml.Wait(Monitor::kNoTimeout);
+  }
+
+  // Cleanup
+  delete event_handler;
+  event_handler = NULL;
+  delete shutdown_monitor;
+  shutdown_monitor = NULL;
+}
+
+
 EventHandlerImplementation* EventHandler::delegate() {
   if (event_handler == NULL) return NULL;
   return &event_handler->delegate_;
 }
 
 
 /*
  * Send data to the EventHandler thread to register for a given instance
  * args[0] a ReceivePort args[1] with a notification event args[2].
  */
@@ skipping 13 matching lines @@
   if (Dart_IsError(handle)) {
     Dart_PropagateError(handle);
     UNREACHABLE();
   }
   int64_t data = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 2));
   event_handler->SendData(id, dart_port, data);
 }
 
 }  // namespace bin
 }  // namespace dart