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[/] [openrisc/] [trunk/] [gnu-stable/] [gcc-4.5.1/] [gcc/] [ada/] [s-gloloc.adb] - Blame information for rev 826

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1 281 jeremybenn
------------------------------------------------------------------------------
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--                                                                          --
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--                         GNAT COMPILER COMPONENTS                         --
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--                                                                          --
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--                  S Y S T E M . G L O B A L _ L O C K S                   --
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--                                                                          --
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--                                 B o d y                                  --
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--                                                                          --
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--          Copyright (C) 1999-2009, 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 3,  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.                                     --
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--                                                                          --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception,   --
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-- version 3.1, as published by the Free Software Foundation.               --
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--                                                                          --
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-- You should have received a copy of the GNU General Public License and    --
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-- a copy of the GCC Runtime Library Exception along with this program;     --
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-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
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-- <http://www.gnu.org/licenses/>.                                          --
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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.Soft_Links;
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package body System.Global_Locks is
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   type String_Access is access String;
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   Dir_Separator : Character;
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   pragma Import (C, Dir_Separator, "__gnat_dir_separator");
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   type Lock_File_Entry is record
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      Dir  : String_Access;
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      File : String_Access;
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   end record;
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   Last_Lock  : Lock_Type := Null_Lock;
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   Lock_Table : array (Lock_Type range 1 .. 15) of Lock_File_Entry;
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   procedure Lock_File
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     (Dir     : String;
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      File    : String;
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      Wait    : Duration := 0.1;
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      Retries : Natural  := Natural'Last);
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   --  Create a lock file File in directory Dir. If the file  cannot be
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   --  locked because someone already owns the lock, this procedure
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   --  waits Wait seconds and retries at most Retries times. If the file
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   --  still cannot be locked, Lock_Error is raised. The default is to try
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   --  every second, almost forever (Natural'Last times).
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   ------------------
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   -- Acquire_Lock --
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   ------------------
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   procedure Acquire_Lock (Lock : in out Lock_Type) is
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   begin
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      Lock_File
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        (Lock_Table (Lock).Dir.all,
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         Lock_Table (Lock).File.all);
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   end Acquire_Lock;
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   -----------------
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   -- Create_Lock --
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   -----------------
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   procedure Create_Lock (Lock : out Lock_Type; Name : String) is
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      L : Lock_Type;
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   begin
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      System.Soft_Links.Lock_Task.all;
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      Last_Lock := Last_Lock + 1;
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      L := Last_Lock;
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      System.Soft_Links.Unlock_Task.all;
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      if L > Lock_Table'Last then
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         raise Lock_Error;
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      end if;
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      for J in reverse Name'Range loop
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         if Name (J) = Dir_Separator then
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            Lock_Table (L).Dir := new String'(Name (Name'First .. J - 1));
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            Lock_Table (L).File := new String'(Name (J + 1 .. Name'Last));
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            exit;
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         end if;
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      end loop;
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      if Lock_Table (L).Dir = null then
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         Lock_Table (L).Dir  := new String'(".");
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         Lock_Table (L).File := new String'(Name);
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      end if;
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      Lock := L;
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   end Create_Lock;
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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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     (Dir     : String;
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      File    : String;
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      Wait    : Duration := 0.1;
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      Retries : Natural  := Natural'Last)
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   is
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      C_Dir  : aliased String := Dir & ASCII.NUL;
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      C_File : aliased String := File & 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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      for I in 0 .. Retries loop
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         if Try_Lock (C_Dir'Address, C_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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   -- Release_Lock --
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   ------------------
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   procedure Release_Lock (Lock : in out Lock_Type) is
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      S : aliased String :=
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            Lock_Table (Lock).Dir.all & Dir_Separator &
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            Lock_Table (Lock).File.all & 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 Release_Lock;
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end System.Global_Locks;

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