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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- G N A T . L O C K _ F I L E S --
-- --
-- B o d y --
-- --
-- Copyright (C) 1998-2008, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with System;
package body GNAT.Lock_Files is
Dir_Separator : Character;
pragma Import (C, Dir_Separator, "__gnat_dir_separator");
---------------
-- Lock_File --
---------------
procedure Lock_File
(Directory : Path_Name;
Lock_File_Name : Path_Name;
Wait : Duration := 1.0;
Retries : Natural := Natural'Last)
is
Dir : aliased String := Directory & ASCII.NUL;
File : aliased String := Lock_File_Name & ASCII.NUL;
function Try_Lock (Dir, File : System.Address) return Integer;
pragma Import (C, Try_Lock, "__gnat_try_lock");
begin
-- If a directory separator was provided, just remove the one we have
-- added above.
if Directory (Directory'Last) = Dir_Separator
or else Directory (Directory'Last) = '/'
then
Dir (Dir'Last - 1) := ASCII.NUL;
end if;
-- Try to lock the file Retries times
for I in 0 .. Retries loop
if Try_Lock (Dir'Address, File'Address) = 1 then
return;
end if;
exit when I = Retries;
delay Wait;
end loop;
raise Lock_Error;
end Lock_File;
---------------
-- Lock_File --
---------------
procedure Lock_File
(Lock_File_Name : Path_Name;
Wait : Duration := 1.0;
Retries : Natural := Natural'Last)
is
begin
for J in reverse Lock_File_Name'Range loop
if Lock_File_Name (J) = Dir_Separator
or else Lock_File_Name (J) = '/'
then
Lock_File
(Lock_File_Name (Lock_File_Name'First .. J - 1),
Lock_File_Name (J + 1 .. Lock_File_Name'Last),
Wait,
Retries);
return;
end if;
end loop;
Lock_File (".", Lock_File_Name, Wait, Retries);
end Lock_File;
-----------------
-- Unlock_File --
-----------------
procedure Unlock_File (Lock_File_Name : Path_Name) is
S : aliased String := Lock_File_Name & ASCII.NUL;
procedure unlink (A : System.Address);
pragma Import (C, unlink, "unlink");
begin
unlink (S'Address);
end Unlock_File;
-----------------
-- Unlock_File --
-----------------
procedure Unlock_File (Directory : Path_Name; Lock_File_Name : Path_Name) is
begin
if Directory (Directory'Last) = Dir_Separator
or else Directory (Directory'Last) = '/'
then
Unlock_File (Directory & Lock_File_Name);
else
Unlock_File (Directory & Dir_Separator & Lock_File_Name);
end if;
end Unlock_File;
end GNAT.Lock_Files;
|
