#3 Glow::NumToplevelWindows bad values

[John Nagle]

Glow::NumToplevelWindows returns an incorrect count of the number of top level windows.

The bug is in glow.cpp:

void Glow::_RemoveWindow(
int windowNum)
{
// Find entry in registry
_WindowRegistryIterator iter = _windowRegistry.find(windowNum);
if (iter != _windowRegistry.end())
{
// Update numToplevelWindows
GlowSubwindow* wind = (*iter).second;
if (dynamic_cast<GlowWindow*>(wind) != 0)
{
--_numToplevelWindows;
}
...

The dynamic cast to GlowWindow* always fails, because _RemoveWindow
is called from the destructor of GlowSubwindow. GlowWindow is derived
from GlowSubwindow, so the destructor for GlowWindow is
called before the destructor for GlowSubwindow.
At the point the destructor for GlowSubwindow is called, the object
is no longer a GlowWindow. Thus, the dynamic cast always fails.

Checking instead whether the window has a parent might work.

[Compiled with VC++ 6.0 SP 5]

[John Nagle]

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I fixed this by checking for

!wind->Parent()

instead of the dynamic cast. I also added an assert at exit to check that the number of top-level windows
was 0, and it is. But I haven't tried modal GLOW windows, or running this under X-windows, so it needs
more testing.

[Daniel Azuma]

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user_id=18901

John's fix approved and checked in on the trunk and the
1.0.x branch.