On Fri, Mar 7, 2008 at 9:32 AM, Eero Pajarre <[EMAIL PROTECTED]> wrote:
> > I got rid of the previous crash, but still there is something causing
> > memory corruption according to the "free"-function with debugging
> > builds. My code calls Lua incremental GC during execution, so
> > I guess I maybe more sensitive for these, but this is of course
> > good so that the bugs don't stay hidden.
> >
>
> SetColAttr and related functions seem also be part of the problem,
> and IncRef makes the symptoms less, but these functions also
> contain a call to wxluaO_undeletegcobject so I guess I should need
> to understand more of wxLua internals...
Heh, hopefully it won't be too difficult.
> Also using IncRef here is propably not ok in case the same Attribute
> set is used on multiple colums/rows, although a minor memory leak
> is not the worst thing now.
>
> (I have been using IncRef so that the wxWidget object does
> not get destroyed when the Lua object is garbage collected, after the
> wxWidget-object has been given to
> the custody of some other object)
After looking into it a little more, I think the best solution is to
use the %ungc tag in the interface file so that we have:
wxGrid::SetCellEditor(int row, int col, %ungc wxGridCellEditor *editor)
This means that Lua will not try to delete the editor and it's up to
the wxGrid (actually wxGridCellAttr) to delete it by calling DecRef().
You can retrieve it using :
wxGridCellEditor* GetCellEditor(int row, int col)
and the returned wxGridCellEditor will not be garbage collected by Lua.
This is not perfectly ideal in that I would think this code should be
all you need.
edit = wx.wxGridCellBoolEditor(...) -- same for wxGridCellXXXRenderer
-- ref count for edit == 1
edit:IncRef()
-- ref count for edit == 2
grid:SetCellEditor(1,2,edit)
-- ref count for edit == 2
*** If you have the code below it works great, without it the program
crashes in the way I described before. When the wxGrid is destroyed,
it destroys the children windows including the m_control of the
wxGridCellEditor and then later Lua will delete the wxGridCellEditor
(which is completely valid since it has a ref count of 1), but the
m_control pointer is not NULL, but points to nothing since it was
deleted, and the wxGridCellEditor tries to delete it again.
edit = nil
collectgarbage("collect")
-- ref count for edit == 1 and the wxGrid will delete it
A vaguely similar scenario happens for Renderers and Attributes.
Regards,
John
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