In case anyone is interested, I made a few changes to the User Guide
Gnogaboard example application to make *Users* a protected object for safe
concurrent access.
Attached is a diff showing the changes.
Regards,
David
--
David K. Trudgett
IT Systems and Software Engineer
Ph: 0467 312 782 (mobile)
Email: david.trudg...@eclecticse.com.au <dktrudg...@gmail.com>
Web: http://www.eclecticse.com.au/ (blog)
LinkedIn: https://au.linkedin.com/in/david-trudgett-6191ba103
ABN: 87 984 125 899
diff --git a/src/gnogaboard-controller.adb b/src/gnogaboard-controller.adb
index 5e7dd3c..8134a0f 100644
--- a/src/gnogaboard-controller.adb
+++ b/src/gnogaboard-controller.adb
@@ -4,7 +4,50 @@ with GnogaBoard.View;
package body GnogaBoard.Controller is
- Users : Gnoga.Gui.Base.Base_Type_Array;
+ protected Users is
+ procedure Add (View : in GnogaBoard.View.Default_View_Access);
+ procedure Remove (N : in Positive);
+ function Find_User (P : in out Gnoga.Gui.Base.Base_Type'Class) return Natural;
+ procedure Update_User_Views (X1, Y1, X2, Y2 : in Integer);
+ private
+ U : Gnoga.Gui.Base.Base_Type_Array;
+ end Users;
+
+ protected body Users is
+
+ procedure Add (View : in GnogaBoard.View.Default_View_Access) is
+ begin
+ U.Append (Gnoga.Gui.Base.Pointer_To_Base_Class (View));
+ end Add;
+
+ procedure Remove (N : Positive) is
+ begin
+ U.Delete (N);
+ end Remove;
+
+ function Find_User (P : in out Gnoga.Gui.Base.Base_Type'Class) return Natural is
+ begin
+ return U.Find_Index (P'Unchecked_Access);
+ end Find_User;
+
+ procedure Update_User_Views (X1, Y1, X2, Y2 : in Integer) is
+ begin
+ for I in U.First_Index .. U.Last_Index loop
+ declare
+ User_View : GnogaBoard.View.Default_View_Access :=
+ GnogaBoard.View.Default_View_Access (U.Element (I));
+ begin
+ User_View.Draw (X1, Y1, X2, Y2);
+ exception
+ -- Ignore error on attempting to draw to already-invalidated view.
+ when others =>
+ null;
+ end;
+ end loop;
+ end Update_User_Views;
+
+ end Users;
+
procedure On_Change (Object : in out Gnoga.Gui.Base.Base_Type'Class);
@@ -20,22 +63,16 @@ package body GnogaBoard.Controller is
use GnogaBoard.View;
View : Default_View_Type renames Default_View_Type (Object);
begin
- for I in Users.First_Index .. Users.Last_Index loop
- declare
- User_View : GnogaBoard.View.Default_View_Access := GnogaBoard.View.Default_View_Access (Users.Element (I));
- begin
- User_View.Draw (View.X1, View.Y1, View.X2, View.Y2);
- end;
- end loop;
+ Users.Update_User_Views (View.X1, View.Y1, View.X2, View.Y2);
end On_Change;
procedure On_Destroy (Object : in out Gnoga.Gui.Base.Base_Type'Class) is
use Gnoga.Gui.Base.Base_Type_Arrays;
- N : Integer := Users.Find_Index (Object'Unchecked_Access);
+ N : Natural := Users.Find_User (Object);
begin
if N /= No_Index then
- Users.Delete (N);
+ Users.Remove (N);
end if;
end On_Destroy;
@@ -50,7 +87,7 @@ package body GnogaBoard.Controller is
begin
View.Dynamic;
View.Create (Main_Window);
- Users.Append (Gnoga.Gui.Base.Pointer_To_Base_Class (View));
+ Users.Add (View);
View.On_Change := On_Change'Access;
View.On_Destroy_Handler (On_Destroy'Access);
end Default;
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