[Qt-interest] gui disabled issue with PACE copy protection dialogsinside Qt (OSX/Carbon)

[Ross Bencina]

Replying to my own message for the benefit of the next unfortunate soul who 
comes accross this bug...

Apparently Qt/Carbon's QApplicationPrivate::globalEventProcessor() function 
was implemented with the assumption that the only windows in the application 
would be created by Qt. As a result, it eats kEventWindowActivated and 
kEventWindowDeactivated events for non-Qt windows, which the PACE iLok 
dialog (naturally) expects to recieve. This is a pretty bad bug in Qt, I was 
lead to believe it would leave events alone which were destined for non-Qt 
Windows.

In any case, here's a patch if anyone ever needs it. It sets handled_event 
to false if the event is not associated with a QWidget:

-- qapplication_mac.4.6.3.mm 2010-06-02 12:00:19.000000000 +1000
+++ qapplication_mac.mm 2010-07-20 08:04:33.000000000 +1000
@@ -2327,9 +2327,16 @@
                 }
                 QMenuBar::macUpdateMenuBar();
             }
+
+   if( !widget )
+    handled_event = false;
+
         } else if(ekind == kEventWindowDeactivated) {
             if(widget && QApplicationPrivate::active_window == widget)
                 app->setActiveWindow(0);
+
+   if( !widget )
+    handled_event = false;
         } else {
             handled_event = false;
         }


Now my plugin's PACE dialog's activate correctly.

Would be nice to hear from someone who can explain why this wasn't done 
right in the first place.

I now suspect that it's also eating mouse (and perhaps other) events under 
some conditions since I have some plugin windows which don't respond to 
mouse events, and some that don't always redraw. If anyone is working on 
more patches/fixes for this kind of thing I'd love to hear about it.

Thanks

Ross.

----- Original Message ----- 
From: "Ross Bencina" <rossb-lists at audiomulch.com>
To: "Qt-Interest" <qt-interest at trolltech.com>
Sent: Wednesday, July 14, 2010 9:21 PM
Subject: [Qt-interest] gui disabled issue with PACE copy protection 
dialogsinside Qt (OSX)


> Hi Everyone
>
> My Qt app hosts plugins developed by 3rd party developers. Some plugins 
> use
> PACE copy protection (paceap.com). The problem is, when they get loaded 
> they
> display an iLok or PACE dialog and then hang with all of the buttons on 
> the
> PACE dialog disabled. This is a non-Qt dialog that the copy protection 
> code
> displays. As far as I can tell, the dialog is running its own nested event
> loop, although a few things in my Qt UI are still active (hover, some
> clicks, tooltips). This is on OSX.
>
> I have only tested this with demo versions of plugins but my users are
> reporting similar problems with their licenced versions. If I try to use 
> gdb
> naturally PACE exits immediatly so it's hard to even give info about 
> threads
> etc.
>
> I am guessing that Qt might be doing something (or not doing something) 
> with
> event processing that is causing this but I wonder whether anyone has
> encountered this before and has any ideas how I might solve it. I guess
> there would be similar issues in displaying any 3rd party dialog inside a 
> Qt
> GUI.
>
> Any and all thoughts and help appreciated.
>
> Many thanks
>
> Ross.
>
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