File : agpl-safe_file.ads


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--                         ADAGIO - ADALID - AENEA.                         --

--                                                                          --

--                            Copyright (C) 2003                            --

--                                 A. Mosteo.                               --

--                                                                          --

--  Authors: A. Mosteo. (adagio@mosteo.com)                                 --

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--  them to the above email.                                                --

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--  This program is free software; you can redistribute it and/or modify    --

--  it under the terms of the GNU General Public License as published by    --

--  the Free Software Foundation; either version 2 of the License, or (at   --

--  your option) any later version.                                         --

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--  This program is distributed in the hope that it will be useful, but     --

--  WITHOUT ANY WARRANTY; without even the implied warranty of              --

--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU       --

--  General Public License for more details.                                --

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--  You should have received a copy of the GNU General Public License       --

--  along with this library; if not, write to the Free Software Foundation, --

--  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.          --

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--  $Id: agpl-safe_file.ads,v 1.3 2004/01/21 21:05:25 Jano Exp $


--  Facilities for saving/loading from a file in a way that it doesn't 

--  overwrite the previous version.

--  When opening for writing, a temporary is used. After completion, the

--  original file is removed and the temporary renamed.

--  When opening for reading, regular filename is tried. If missing, a check

--  for a temporary is made, and if it exists, it is renamed to the regular

--  name and opened. If neither regular and temporary exists, error.


with Ada.Streams.Stream_IO;
use  Ada.Streams;
use  Ada;

package Agpl.Safe_file is

   File_Not_Found : exception;
   
   ------------------------------------------------------------------------

   -- Exists_for_reading                                                 --

   ------------------------------------------------------------------------

   function Exists_for_reading (Name : in String) return Boolean;

   ------------------------------------------------------------------------

   -- Get_Real_Name                                                      --

   ------------------------------------------------------------------------

   -- Gets the real name found (i.e. the supplied or the backup one

   -- May raise File_Not_Found

   function Get_Real_Name (Name : in String) return String;

   ------------------------------------------------------------------------

   -- Open                                                               --

   ------------------------------------------------------------------------

   procedure Open (
      File : in out Stream_IO.File_type;
      Mode : in     Stream_IO.File_mode;
      Name : in     String := "";
      Form : in     String := "");

   ------------------------------------------------------------------------

   -- Close                                                              --

   ------------------------------------------------------------------------

   procedure Close (File : in out Stream_IO.File_type);

end Agpl.Safe_file;