137 lines
5.1 KiB
Ada
137 lines
5.1 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- G N A T . L O C K _ F I L E S --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1998-2001 Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with System;
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package body GNAT.Lock_Files is
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Dir_Separator : Character;
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pragma Import (C, Dir_Separator, "__gnat_dir_separator");
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---------------
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-- Lock_File --
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---------------
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procedure Lock_File
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(Directory : Path_Name;
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Lock_File_Name : Path_Name;
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Wait : Duration := 1.0;
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Retries : Natural := Natural'Last)
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is
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Dir : aliased String := Directory & ASCII.NUL;
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File : aliased String := Lock_File_Name & ASCII.NUL;
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function Try_Lock (Dir, File : System.Address) return Integer;
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pragma Import (C, Try_Lock, "__gnat_try_lock");
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begin
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-- If a directory separator was provided, just remove the one we have
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-- added above.
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if Directory (Directory'Last) = Dir_Separator
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or else Directory (Directory'Last) = '/'
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then
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Dir (Dir'Last - 1) := ASCII.Nul;
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end if;
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-- Try to lock the file Retries times
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for I in 0 .. Retries loop
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if Try_Lock (Dir'Address, File'Address) = 1 then
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return;
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end if;
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exit when I = Retries;
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delay Wait;
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end loop;
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raise Lock_Error;
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end Lock_File;
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---------------
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-- Lock_File --
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---------------
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procedure Lock_File
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(Lock_File_Name : Path_Name;
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Wait : Duration := 1.0;
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Retries : Natural := Natural'Last)
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is
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begin
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for J in reverse Lock_File_Name'Range loop
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if Lock_File_Name (J) = Dir_Separator
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or else Lock_File_Name (J) = '/'
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then
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Lock_File
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(Lock_File_Name (Lock_File_Name'First .. J - 1),
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Lock_File_Name (J + 1 .. Lock_File_Name'Last),
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Wait,
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Retries);
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return;
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end if;
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end loop;
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Lock_File (".", Lock_File_Name, Wait, Retries);
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end Lock_File;
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-----------------
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-- Unlock_File --
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-----------------
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procedure Unlock_File (Lock_File_Name : Path_Name) is
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S : aliased String := Lock_File_Name & ASCII.NUL;
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procedure unlink (A : System.Address);
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pragma Import (C, unlink, "unlink");
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begin
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unlink (S'Address);
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end Unlock_File;
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-----------------
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-- Unlock_File --
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-----------------
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procedure Unlock_File (Directory : Path_Name; Lock_File_Name : Path_Name) is
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begin
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if Directory (Directory'Last) = Dir_Separator
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or else Directory (Directory'Last) = '/'
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then
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Unlock_File (Directory & Lock_File_Name);
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else
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Unlock_File (Directory & Dir_Separator & Lock_File_Name);
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end if;
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end Unlock_File;
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end GNAT.Lock_Files;
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