[gtkada] Signal handler

[Dmitry A. Kazakov]

On Mon, 1 Aug 2011 15:32:34 +0200, you wrote:

> I was thinking that the problem might be in GtkAda's "ada_tree_iter_copy" called 
> in the body of Gtk.Tree_Model.Get_Tree_Iter. Is there a reason why it was written
> in C and not Ada?

No, iterator can be copied in Ada, it is a plain C structure,

> Here's the example:
> --------- fill_entry.ads -------
> 
> with Glib.Object;
> with Glib.Values; use Glib.Values;
> 
>    function Fill_Entry (Object : access Glib.Object.GObject_Record'Class;
>                         Params : in GValues) return Boolean;
> 
> --------- fill_entry.adb -------
> 
> with Gtk.Enums;            use Gtk.Enums;
> with Gtk.Entry_Completion; use Gtk.Entry_Completion;
> with Gtk.GEntry;           use Gtk.GEntry;
> with Gtk.Tree_Model;       use Gtk.Tree_Model;
> 
>    function Fill_Entry (Object : access Glib.Object.GObject_Record'Class;
>                         Params : in GValues) return Boolean is
>       Model : Gtk_Tree_Model;
>       Iter  : Gtk_Tree_Iter;
>    begin
>       Model := Get_Model(Gtk_Entry_Completion(Object));
>       Get_Tree_Iter (Nth (Params, 1), Iter);
>       Set_Text (Gtk_Entry(Get_Entry(Gtk_Entry_Completion(Object))), Get_String(Model, Iter, 1));

Two issues here:

1. The model passed to the handler is not the model of the completion
object. I didn't look in the sources, but I suspect they create a derived
model (sorted or filtered) and pass this model instead of the original one.

2. The iterator is the second argument.

Therefore it should be:

   Model : aliased Gtk_Tree_Model_Record;
   Iter  : Gtk_Tree_Iter;
begin
   Model.Set_Object (Get_Address (Nth (Params, 1))); -- Get the model
   Get_Tree_Iter (Nth (Params, 2), Iter); -- Get the iterator
   Set_Text
   (  Gtk_Entry (Get_Entry (Gtk_Entry_Completion (Object))),
      Get_String (Model'Access, Iter, 1)
   );

>       return True;
>    end Fill_Entry;
> 
> --------- signal_match_test.adb -------
> 
[...] 
>    Gtk_New (Compl);
>    Set_Text_Column (Compl, 0);
>    Set_Text_Column (Compl, 1);
>    Set_Text_Column (Compl, 2);
>    Set_Property (Compl, Text_Column_Property, 0);
>    Set_Model (Compl, Gtk_Tree_Model(List));

Note that this leaks. Gtk_List_Store is not a floating object. After
Set_Model its reference count is 2. So you have to add:

   Unref (List);

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de