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

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                  S Y S T E M . G L O B A L _ L O C K S                   --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--                     Copyright (C) 1999-2005, AdaCore                     --

--                                                                          --

-- 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.      --

--                                                                          --

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

--  This implementation is specific to NT

with GNAT.Task_Lock;

with Interfaces.C.Strings;

with System.OS_Interface;

package body System.Global_Locks is

   package TSL renames GNAT.Task_Lock;

   package OSI renames System.OS_Interface;

   package ICS renames Interfaces.C.Strings;

   subtype Lock_File_Entry is OSI.HANDLE;

   Last_Lock  : Lock_Type := Null_Lock;

   Lock_Table : array (Lock_Type range 1 .. 15) of Lock_File_Entry;

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

   -- Create_Lock --

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

   procedure Create_Lock

     (Lock : out Lock_Type;

      Name : in String)

   is

      L : Lock_Type;

   begin

      TSL.Lock;

      Last_Lock := Last_Lock + 1;

      L := Last_Lock;

      TSL.Unlock;

      if L > Lock_Table'Last then

         raise Lock_Error;

      end if;

      Lock_Table (L) :=

        OSI.CreateMutex (null, OSI.BOOL (False), ICS.New_String (Name));

      Lock := L;

   end Create_Lock;

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

   -- Acquire_Lock --

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

   procedure Acquire_Lock

     (Lock : in out Lock_Type)

   is

      use type OSI.DWORD;

      Res : OSI.DWORD;

   begin

      Res := OSI.WaitForSingleObject (Lock_Table (Lock), OSI.Wait_Infinite);

      if Res = OSI.WAIT_FAILED then

         raise Lock_Error;

      end if;

   end Acquire_Lock;

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

   -- Release_Lock --

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

   procedure Release_Lock

     (Lock : in out Lock_Type)

   is

      use type OSI.BOOL;

      Res : OSI.BOOL;

   begin

      Res := OSI.ReleaseMutex (Lock_Table (Lock));

      if Res = OSI.False then

         raise Lock_Error;

      end if;

   end Release_Lock;

end System.Global_Locks;