[ scummvm-Bugs-2210082 ] GUI:

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Bugs item #2210082, was opened at 2008-10-30 18:21
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Category: GUI
Group: None
Status: Open
Resolution: None
Priority: 7
Private: No
Submitted By: Max Horn (fingolfin)
Assigned to: Nobody/Anonymous (nobody)
Summary: GUI: 

Initial Comment:
Today, I noticed that I could sometimes trigger a weird crash in latest SVN. It seems to be a bug in either the GUI or the RTL / GMM code. I still have no good way to trigger it, but will try to find one when I have more time. Here is what I did: Started a game (in this case, DOTT in the SCUMM engine), opened the GMM menu via F6. Then I changed the scaler from 1x to 2x and back, and it suddenly crashed. This happened a few times to me now, though I have still not figured out when exactly it happens, and it is a bit harder to try for long due to another bug I am about to report... :)

Here is a partial backtrace:

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0xc000000f
0x006989e3 in GUI::Dialog::handleMouseMoved (this=0x111fd40, x=-33, y=216, button=0) at gui/dialog.cpp:257
257			int wx = w->getAbsX() - _x;
(gdb) bt
#0  0x006989e3 in GUI::Dialog::handleMouseMoved (this=0x111fd40, x=-33, y=216, button=0) at gui/dialog.cpp:257
#1  0x006acaa4 in GUI::NewGui::runLoop (this=0x1866600) at gui/newgui.cpp:262
#2  0x00699179 in GUI::Dialog::runModal (this=0x111fd40) at gui/dialog.cpp:73
#3  0x000c548b in Scumm::ScummEngine::runDialog (this=0x165db000, dialog=@0x111fd40) at engines/scumm/scumm.cpp:2277
#4  0x00777013 in Engine::openMainMenuDialog (this=0x165db000) at engines/engine.cpp:234
#5  0x0077afad in DefaultEventManager::pollEvent (this=0x117c710, event=@0xbfffd828) at backends/events/default/default-events.cpp:419
#6  0x0006d7b2 in Scumm::ScummEngine::parseEvents (this=0x165db000) at engines/scumm/input.cpp:62
#7  0x000c44e0 in Scumm::ScummEngine::waitForTimer (this=0x165db000, msec_delay=100) at engines/scumm/scumm.cpp:1781
#8  0x000c480a in Scumm::ScummEngine::go (this=0x165db000) at engines/scumm/scumm.cpp:1749
#9  0x0000bbac in runGame (plugin=0x1146000, system=@0x1828000, edebuglevels=@0xbfffe154) at base/main.cpp:216
#10 0x0000c494 in scummvm_main (argc=1, argv=0x11099f0) at base/main.cpp:309

The odd thing is that I am not quite sure why it crashes exactly there; maybe the trace is just wrong, but FYI:

(gdb) p this
$5 = (class GUI::Dialog * const) 0x111fd40
(gdb) p w
$6 = (class GUI::Widget *) 0x17cb4ad0

So neither w nor "this" are zero. Maybe the vtable got corrupt, but I have no idea how to print that. Some more data:

(gdb) p *w
$11 = {
  <GUI::GuiObject> = {
    <GUI::CommandReceiver> = {
      _vptr$CommandReceiver = 0xc0000003
    }, 
    members of GUI::GuiObject: 
    _x = 3, 
    _y = -16384, 
    _w = 7, 
    _h = 12, 
    _name = {
      static _builtinCapacity = 24, 
      _size = 16, 
      _str = 0x17cb4ae4 "GlobalMenu.Title", 
      {
        _storage = "GlobalMenu.Title\000\000\000\000??\032\001", 
        _extern = {
          _refCount = 0x626f6c47, 
          _capacity = 1699572833
        }
      }, 
      static emptyString = {
        static _builtinCapacity = 24, 
        _size = 0, 
        _str = 0x957388 "", 
        {
          _storage = '\0' <repeats 23 times>, 
          _extern = {
            _refCount = 0x0, 
            _capacity = 0
          }
        }, 
        static emptyString = <same as static member of an already seen type>
      }
    }, 
    _firstWidget = 0x0
  }, 
  members of GUI::Widget: 
  _type = 1413830740, 
  _boss = 0x111fd40, 
  _next = 0x0, 
  _id = 0, 
  _hasFocus = true, 
  _state = GUI::Theme::kStateEnabled, 
  _flags = 1
}

(gdb) p *this
$12 = (MainMenuDialog) {
  <GlobalDialog> = {
    <GUI::Dialog> = {
      <GUI::GuiObject> = {
        <GUI::CommandReceiver> = {
          _vptr$CommandReceiver = 0x8edce8
        }, 
        members of GUI::GuiObject: 
        _x = 199, 
        _y = 110, 
        _w = 242, 
        _h = 260, 
        _name = {
          static _builtinCapacity = 24, 
          _size = 10, 
          _str = 0x111fd54 "GlobalMenu", 
          {
            _storage = "GlobalMenu\000\001", '\0' <repeats 11 times>, 
            _extern = {
              _refCount = 0x626f6c47, 
              _capacity = 1699572833
            }
          }, 
          static emptyString = {
            static _builtinCapacity = 24, 
            _size = 0, 
            _str = 0x957388 "", 
            {
              _storage = '\0' <repeats 23 times>, 
              _extern = {
                _refCount = 0x0, 
                _capacity = 0
              }
            }, 
            static emptyString = <same as static member of an already seen type>
          }
        }, 
        _firstWidget = 0x11a4e00
      }, 
      members of GUI::Dialog: 
      _mouseWidget = 0x0, 
      _focusedWidget = 0x17cb4ad0, 
      _dragWidget = 0x0, 
      _visible = true, 
      _backgroundType = GUI::Theme::kDialogBackgroundSpecial, 
      _result = 0
    }, <No data fields>}, 
  members of MainMenuDialog: 
  _engine = 0x165db000, 
  _logo = 0x11a4e00, 
  _rtlButton = 0x17ca8d70, 
  _aboutDialog = 0x17ca8e70, 
  _optionsDialog = 0x17cad600
}


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