Re: [wxlua-users] inconsistencies

[John L. <jla...@gm...>]

ps. Andre - your editor looks very good. It is a heck of a test of
wxLua with all the UPDATEUI and IDLE events. :)  Please keep us
updated with your progress.

Thanks,
    John

On 8/2/07, John Labenski <jla...@gm...> wrote:
> I have checked in a fix for it. For reference it can be duplicated
> with the code below. It was a tough problem to track down and it is
> still not clear to me why it happens on with wxPostEvent with the
> constraints that you have to Connect to the event that was posted and
> not for other cases I tried. The scenario below follows from tracking
> the memory of objects pushed into Lua.
>
> The problem was with the event pushed into Lua for the
> wxLuaCallback::CallFunction() event handler. Since we didn't create
> it, actually it's on the C++ stack not the heap, it gets deleted when
> it goes out of scope in C++ and the memory for it can be reused. Since
> Lua has an incremental garbage collector it doesn't call the __gc
> method soon enough to clear the key in the object table. Therefore a
> new object that by chance was created with the same memory address
> would be found in the object table and the old userdata was pushed
> into Lua as whatever type it was.
>
> Thanks for reporting it.
>     John Labenski
>
> =============================
>
> frame = nil
>
> function HandleEvents(event)
>     local name = event:GetEventObject():DynamicCast("wxWindow"):GetName()
>     frame:SetStatusText(string.format("%s - selected item %d '%s'",
> name, event:GetSelection(), event:GetString()), 0)
>
>     local e = wx.wxCommandEvent(wx.wxEVT_COMMAND_BUTTON_CLICKED, 10)
>     wx.wxPostEvent(frame, e)
> end
>
> function main()
>     frame = wx.wxFrame(wx.NULL, wx.wxID_ANY, "wxLua Choices",
>                        wx.wxDefaultPosition, wx.wxSize(550, 350))
>     frame:CreateStatusBar(1)
>
>     frame:Connect(wx.wxEVT_COMMAND_BUTTON_CLICKED, function(event)
> print("hi") end)
>
>     local notebook = wx.wxNotebook(frame, wx.wxID_ANY,
>                                    wx.wxDefaultPosition, wx.wxSize(410, 300))
>                                    --wx.wxNB_BOTTOM)
>
>     notebook:AddPage(wx.wxPanel(notebook, wx.wxID_ANY), "Page1")
>     notebook:AddPage(wx.wxPanel(notebook, wx.wxID_ANY), "Page2")
>     notebook:AddPage(wx.wxPanel(notebook, wx.wxID_ANY), "Page3")
>
>     frame:Connect(wx.wxID_ANY, wx.wxEVT_COMMAND_NOTEBOOK_PAGE_CHANGED,
> HandleEvents)
>
>     frame:Show(true)
> end
>
> main()
>
> =========================
>