Threads in Plugins won't terminate when PVRX2/GBPVR exits

[ralphy]

My plugin starts a thread, but I cannot stop the thread when PVRX2 of GBPVR exits - same problem as here. Unfortunately, I've tried OldDog's solution

Code:

Application.ApplicationExit += new EventHandler(this.OnExit);

without success.

Debug breakpoints in OnExit() confirm that it is not being hit when PVRX2 exits. What am I doing wrong??

Here's the test code I am using (sorry about the formatting - seems to get altered with the cut and paste).

Code:

using System;
using System.Collections;
using System.Diagnostics;

using System.Threading;
using System.Windows.Forms;

using CommonGBPVRUtilities;
using GBPVR;
using GBPVR.Public;
using GBPVR.Backend.Common;


  
  public class PluginTask: /*IMenuTask , */IEventNotification
  {

    private Thread t;
    private bool stopRequested  = false;


    public   PluginTask()
    {
        if (PluginHelperFactory.getPluginHelper() == null) return;
        Logger.Info("PluginTask .ctr called by plugin");
        Start();
        Application.ApplicationExit += new EventHandler(this.OnExit);
        return;
    }
    
    ~PluginTask()
    {
        // this is never reached on PVRX2 exit
        Logger.Verbose("PluginTask: Destructor");
        stopRequested = true;
    }
        
//----------------------------------------------------------------------
// OnExit - Application exit event handler
//----------------------------------------------------------------------
    private void OnExit(object sender, EventArgs e)
    {
        //// this is never reached on PVRX2 exit either
        Logger.Verbose("PluginTask: Exit event.");
        stopRequested = true;
    //    t.Join();
    }
    
    
    
    
private void Start()
      {
          if (t != null && t.IsAlive) //Already started?
          {
              return;
          }  
            Logger.Info("PluginTask plugin starting...");
          try
          {
              //Start the background thread
              stopRequested = false;
              t = new Thread(new ThreadStart(Run));
              t.Priority = ThreadPriority.Lowest;
         //     t.IsBackground=true; //http://forums.nextpvr.com/showthread.php?t=4891&highlight=thread+destructor
              t.Name = "PluginTask";
              t.Start();
          
          }
          catch (Exception ex)
          {
              Logger.Info("DoStart: Exception while starting plugin: " + ex.Message);
              if (t != null && t.IsAlive)
              {
                  t.Abort();
              }
              t = null;
          }
      }
    
         private void Run()
         {
             try
             {
              while (!stopRequested)
            {
                Logger.Verbose("PluginTask Sleeping...");
                Thread.Sleep(15000);
            }
            
            Logger.Verbose("PluginTask  Stopping Plugin.");

                }
             catch (Exception ex)
            {
               Logger.Verbose(ex.ToString());
            }
        Logger.Verbose("PluginTask Exiting run loop.");
      }
        
   public void Notify(EventTypes eventType, string eventText)
    {    
         Logger.Verbose("PluginTask EVENTS NOTIFIED: eventType= " + eventType.ToString());
                 Logger.Verbose("PluginTask EVENTS NOTIFIED: eventText= '" + eventText +"'");
       }
        
  }

[sub]

Sorry, I dont really have any advice for you on this one - its not something I've ever tried myself.

[reven]

you tried just doing

Code:

Thread thread = new Thread();
thread.IsBackground = true;

that should make the thread die when the main thread finishes.

[ralphy]

you tried just doing

Code:

Thread thread = new Thread();
thread.IsBackground = true;

that should make the thread die when the main thread finishes.

Reven, I assume you effectively mean uncommenting the commented line "t.IsBackground=true" in the code shown in the original post, and repeated here

Code:

t = new Thread(new ThreadStart(Run));
              t.Priority = ThreadPriority.Lowest;
         //   t.IsBackground=true; //http://forums.nextpvr.com/showthread.php?t=4891&highlight=thread+destructor
              t.Name = "PluginTask";
              t.Start();

If so, then yes - I tried this - and just double checked - it does not solve the problem.


Sub - is it easy and appropriate to have GBPVR/PVRX2 call a "Stop()" method in a plugin, or alternatively, generate a new "stop" IEventNotification? (I was hoping you or someone else would know exactly what I was doing wrong here)

I don't understand why the Application.ApplicationExit worked for OldDog but not for the code in this thread.

[sub]

Sub - is it easy and appropriate to have GBPVR/PVRX2 call a "Stop()" method in a plugin, or alternatively, generate a new "stop" IEventNotification? (I was hoping you or someone else would know exactly what I was doing wrong here)

I might be able to add something for a future release, but its going to be awhile until next release (havnt started yet, been out of the country), so it'd probably be more timely for you to find your own work around for now. Even then there is likely to be some situations where the notification does not happen. For example, the Recording Service can terminate the MVP server process in some situations, which would mean the PVRX2.exe MVP server instance does not get a chance to notify its plugins of this.

What are you trying to do that needs to know the app is exiting?

[ralphy]

I might be able to add something for a future release, but its going to be awhile until next release (havnt started yet, been out of the country), so it'd probably be more timely for you to find your own work around for now. Even then there is likely to be some situations where the notification does not happen.

That would be great if something could be added in the furture. Perhaps calling a Stop() method, if possible, would be better than an event notification, if there are some situations when the notification does not happen. I see that the logs now log PVRX2 exiting. Perhaps somewhere around that code could be where the Stop() would be called?

What are you trying to do that needs to know the app is exiting?

The plugin is [yet another?] external display, so no menus are required - it just starts a thread to catch the IEventNotifications, and do other things in the background to PVRX2/GBPVR. As OldDog also originally reported, when GBPVR shuts down, the thread started in the plugin does not terminate. GBPVR will not start up again, because the thread is still running. My plugin also has some diagnostic forms opened by the thread and these don't close when GBPVR exits - so this is the obvious way I can tell if the thread has exited.

I know others have used timers to achieve similar functionality, but I'm trying to avoid this if possible, putting my thread to sleep instead instead of having lots of timers going off at different times.


Another problem I've got is with an XMLSerializer, but that might be the topic of another post if I can't resolve that.

[sub]

I cant change existing interfaces, so I'd have to think about whether I wanted to add another interface or an event. Its going to quite a while though, so you're probably best you just work around this for now. I havnt started development of the next release, so it'll be at least three months away.