------------------------------------------------------------------------------
--                                  G P S                                   --
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--                     Copyright (C) 2003-2013, AdaCore                     --
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--  ??? Description of this package

with Ada.Unchecked_Deallocation;
with GNAT.Strings;

generic
   type Data_Type (<>) is private;

   with procedure Free (Data : in out Data_Type) is <>;
   --  Free memory allocated to Data

package Commands.Generic_Asynchronous is

   type Iteration_Procedure is access procedure
     (Data    : in out Data_Type;
      Command : Command_Access;
      Result  : out Command_Return_Type);
   --  Do one iteration. Initialize Data at first iteration if needed.
   --  Command points to the current command. Progress fields can be set
   --  accordingly

   type Generic_Asynchronous_Command is new Root_Command with private;
   type Generic_Asynchronous_Command_Access is
     access all Generic_Asynchronous_Command;

   procedure Create
     (Command     : out Generic_Asynchronous_Command_Access;
      Description : String;
      Data        : Data_Type;
      Iterate     : Iteration_Procedure);

   overriding procedure Free (D : in out Generic_Asynchronous_Command);
   --  Free memory associated to D

   overriding function Execute
     (Command : access Generic_Asynchronous_Command)
      return Command_Return_Type;
   --  Execute Command. Will fail if Command has not been created using Create

   overriding function Name
     (Command : access Generic_Asynchronous_Command) return String;
   --  Return the name of the command

   procedure Set_Data
     (Command : access Generic_Asynchronous_Command;
      Data : Data_Type);
   --  Change the data associated to a command

   function Get_Data (Command : access Generic_Asynchronous_Command)
      return Data_Type;
   --  Return the data associated to this command.

private

   type Data_Access is access Data_Type;

   procedure Unchecked_Free is new Ada.Unchecked_Deallocation
     (Data_Type, Data_Access);

   type Generic_Asynchronous_Command is new Root_Command with record
      Data        : Data_Access;
      Iterate     : Iteration_Procedure;
      Description : GNAT.Strings.String_Access;
   end record;

end Commands.Generic_Asynchronous;
