[mythtv-commits] Ticket #2725: dynamic_cast can return NULL, must test

[MythTV]

#2725: dynamic_cast can return NULL, must test
--------------------+-------------------------------------------------------
 Reporter:  nigel   |        Owner:  nigel  
     Type:  defect  |       Status:  closed 
 Priority:  minor   |    Milestone:  unknown
Component:  mythtv  |      Version:  0.20   
 Severity:  medium  |   Resolution:  invalid
--------------------+-------------------------------------------------------
Comment (by nigel):

 I suspect there is something seriously wrong with the GCC vtable parsing,
 but I haven't found it. The following:
 {{{
 Index: mythmainwindow.cpp
 ===================================================================
 --- mythmainwindow.cpp  (revision 11820)
 +++ mythmainwindow.cpp  (working copy)
 @@ -1089,9 +1089,32 @@
      {
          case QEvent::KeyPress:
          {
 +            QKeyEvent *ke = dynamic_cast<QKeyEvent*>(e);
 +
 +            if (!ke)
 +            {
 +                //puts("Dynamic_cast of a QtEvent failed!!!");
 +
 +                // In some strange situations, e is already a QKeyEvent
 +                ke = new QKeyEvent(QEvent::KeyPress, 0, 0, 0);
 +
 +                if (strcmp(typeid(*e).name(), typeid(*ke).name()) == 0)
 +                {
 +                    delete ke;
 +
 +                    // Same typeid? Safe to do a plain-old cast:
 +                    ke = static_cast<QKeyEvent*>(e);
 +                }
 +                else
 +                {
 +                    delete ke;
 +                    //puts("Did you use -fno-rtti to build?");
 +                    return false;
 +                }
 +            }
 +
 }}}
 works. Some debuging reveals typeid(e).name() == "P9QKeyEvent"
 (QKeyEvent*), and typeid(*e).name() == "9QKeyEvent" (QKeyEvent). Freaking
 weird.
 [[BR]]
 A few other random dynamic_cast values that aren't checked:
 libmyth/settings.cpp line 611, 671, 718, 765, 796, 1402,
 libmythtv/darwinfirewirerecorder.cpp line 17, libmythtv/diseqcsettings.cpp
 line 1362-3, 1375-6, 1388-89, 1400, 1411, 1422-23, 1434-35, 1447-48,
 1473-74

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Ticket URL: <http://svn.mythtv.org/trac/ticket/2725#comment:3>
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