[Gnucash-changes] Eliminate a double free of memory.

[Chris Shoemaker]

On Thu, Jun 02, 2005 at 01:26:59PM -0400, David Hampton wrote:
> On Thu, 2005-06-02 at 13:00 -0400, Chris Shoemaker wrote:
> > On Thu, Jun 02, 2005 at 11:10:48AM -0400, David Hampton wrote:
> > > --- src/business/business-gnome/dialog-customer.c
> > > +++ src/business/business-gnome/dialog-customer.c
> > > @@ -383,7 +383,8 @@
> > >    CustomerWindow *cw = user_data;
> > >  
> > >    gtk_widget_destroy (cw->dialog);
> > > -  cw->dialog = NULL;
> > > +  // cw has already been freed by this point.
> > > +  // cw->dialog = NULL;
> > >  }
> > 
> Calling gtk_widget_destroy on this dialog eventually causes the
> gnc_customer_window_destroy_cb function to be called.  That function is
> where the free of the cw data structure occurs.
> 
> The pattern of having a destroy callback function that frees the data
> structure associated with a window is common in the gnucash code.  It
> allows one function to handle the cleanup of a dialog and any associated
> data structures, no matter how the dialog was closed.  This is
> particularly important because closing a window via the title bar close
> button translates directly to a call to gtk_widget_destroy on the window
> widget.  There's no other way for the code to know the window was closed
> this way, other than to attach a callback to the widget destruction.

Thanks for explaining.  I haven't looked at the details, but shouldn't
destroy signal handler just generate the right CM event, and then the
CM close handler for the cw structure actually frees cw.  I thought
that was the intended use of the CM.

-chris