------------------------------------------------------------------------------
--                                                                          --
--                            Matreshka Project                             --
--                                                                          --
--         Localization, Internationalization, Globalization for Ada        --
--                                                                          --
--                        Runtime Library Component                         --
--                                                                          --
------------------------------------------------------------------------------
--                                                                          --
-- Copyright © 2011, Vadim Godunko <vgodunko@gmail.com>                     --
-- All rights reserved.                                                     --
--                                                                          --
-- Redistribution and use in source and binary forms, with or without       --
-- modification, are permitted provided that the following conditions       --
-- are met:                                                                 --
--                                                                          --
--  * Redistributions of source code must retain the above copyright        --
--    notice, this list of conditions and the following disclaimer.         --
--                                                                          --
--  * Redistributions in binary form must reproduce the above copyright     --
--    notice, this list of conditions and the following disclaimer in the   --
--    documentation and/or other materials provided with the distribution.  --
--                                                                          --
--  * Neither the name of the Vadim Godunko, IE nor the names of its        --
--    contributors may be used to endorse or promote products derived from  --
--    this software without specific prior written permission.              --
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-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS      --
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--                                                                          --
------------------------------------------------------------------------------
--  $Revision: 1793 $ $Date: 2011-06-11 11:40:44 +0400 (Sat, 11 Jun 2011) $
------------------------------------------------------------------------------
--  This package provides proxy settings storage which implements fallbacks
--  mechanism on top of several underling settings storages.
------------------------------------------------------------------------------
private with Ada.Containers.Vectors;

package Matreshka.Internals.Settings.Fallbacks is

   type Fallback_Settings is new Abstract_Settings with private;

   function Create
    (Manager : not null access Abstract_Manager'Class)
       return not null Settings_Access;
   --  Creates fallbacks proxy.

   procedure Add
    (Self    : not null access Fallback_Settings'Class;
     Storage : not null Settings_Access);
   --  Adds specified settings storage to be used to retrieve settings. First
   --  added storage is used to modify settings also.

private

   package Vectors is
     new Ada.Containers.Vectors (Positive, Settings_Access);

   type Fallback_Settings is new Abstract_Settings with record
      Storages : Vectors.Vector;
   end record;

   overriding function Contains
    (Self : Fallback_Settings;
     Key  : League.Strings.Universal_String) return Boolean;

   overriding procedure Finalize
    (Self : not null access Fallback_Settings);

   overriding function Name
    (Self : not null access Fallback_Settings)
       return League.Strings.Universal_String;
   --  Returns name of the first underling settings storage.

   overriding procedure Remove
    (Self : in out Fallback_Settings;
     Key  : League.Strings.Universal_String);

   overriding procedure Set_Value
    (Self  : in out Fallback_Settings;
     Key   : League.Strings.Universal_String;
     Value : League.Holders.Holder);

   overriding procedure Sync (Self : in out Fallback_Settings);

   overriding function Value
    (Self : Fallback_Settings;
     Key  : League.Strings.Universal_String)
       return League.Holders.Holder;

end Matreshka.Internals.Settings.Fallbacks;
