Avoid race condition between the Stopped and Abort methods that may lead to NullReferenceExceptions being triggered

Author: obones

project/core/ProjectIntegrator.cs

@@ -358,7 +358,9 @@ private void Stopped()
         {
             // the state was set to 'Stopping', so set it to 'Stopped'
             state = ProjectIntegratorState.Stopped;
-            thread = null;
+            lock(this)
+              thread = null;
+
             // Ensure that any queued integrations are cleared for this project.
             integrationQueue.RemoveProject(project);
             Log.Info("Integrator for project: " + project.Name + " is now stopped.");
@@ -393,10 +395,13 @@ public void Stop(bool restarting)
         /// </summary>
         public void Abort()
         {
-            if (thread != null)
+            lock(this)
             {
-                Log.Info("Aborting integrator for project: " + project.Name);
-                thread.Abort();
+              if (thread != null)
+              {
+                  Log.Info("Aborting integrator for project: " + project.Name);
+                  thread.Abort();
+              }
             }
         }