gcc/ada/s-taprob.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
   4 --                                                                          --
   5 --      S Y S T E M . T A S K I N G . P R O T E C T E D _ O B J E C T S     --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --                                                                          --
  10 --             Copyright (C) 1991-2001 Florida State University             --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University. It is --
  31 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  32 -- State University (http://www.gnat.com).                                  --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 pragma Polling (Off);
  37 --  Turn off polling, we do not want ATC polling to take place during
  38 --  tasking operations. It causes infinite loops and other problems.
  39
  40 with System.Task_Primitives.Operations;
  41 --  used for Write_Lock
  42 --           Unlock
  43
  44 with System.Parameters;
  45 --  used for Runtime_Traces
  46
  47 with System.Traces;
  48 --  used for Send_Trace_Info
  49
  50 package body System.Tasking.Protected_Objects is
  51
  52    use System.Task_Primitives.Operations;
  53    use System.Traces;
  54
  55    -------------------------
  56    -- Finalize_Protection --
  57    -------------------------
  58
  59    procedure Finalize_Protection (Object : in out Protection) is
  60    begin
  61       Finalize_Lock (Object.L'Unrestricted_Access);
  62    end Finalize_Protection;
  63
  64    ---------------------------
  65    -- Initialize_Protection --
  66    ---------------------------
  67
  68    procedure Initialize_Protection
  69      (Object           : Protection_Access;
  70       Ceiling_Priority : Integer)
  71    is
  72       Init_Priority : Integer := Ceiling_Priority;
  73    begin
  74       if Init_Priority = Unspecified_Priority then
  75          Init_Priority  := System.Priority'Last;
  76       end if;
  77
  78       Initialize_Lock (Init_Priority, Object.L'Access);
  79       Object.Ceiling := System.Any_Priority (Init_Priority);
  80    end Initialize_Protection;
  81
  82    ----------
  83    -- Lock --
  84    ----------
  85
  86    procedure Lock (Object : Protection_Access) is
  87       Ceiling_Violation : Boolean;
  88    begin
  89       --  The lock is made without defering abortion.
  90
  91       --  Therefore the abortion has to be deferred before calling this
  92       --  routine. This means that the compiler has to generate a Defer_Abort
  93       --  call before the call to Lock.
  94
  95       --  The caller is responsible for undeferring abortion, and compiler
  96       --  generated calls must be protected with cleanup handlers to ensure
  97       --  that abortion is undeferred in all cases.
  98
  99       Write_Lock (Object.L'Access, Ceiling_Violation);
 100
 101       if Parameters.Runtime_Traces then
 102          Send_Trace_Info (PO_Lock);
 103       end if;
 104
 105       if Ceiling_Violation then
 106          raise Program_Error;
 107       end if;
 108    end Lock;
 109
 110    --------------------
 111    -- Lock_Read_Only --
 112    --------------------
 113
 114    procedure Lock_Read_Only (Object : Protection_Access) is
 115       Ceiling_Violation : Boolean;
 116    begin
 117       Read_Lock (Object.L'Access, Ceiling_Violation);
 118
 119       if Parameters.Runtime_Traces then
 120          Send_Trace_Info (PO_Lock);
 121       end if;
 122
 123       if Ceiling_Violation then
 124          raise Program_Error;
 125       end if;
 126    end Lock_Read_Only;
 127
 128    ------------
 129    -- Unlock --
 130    ------------
 131
 132    procedure Unlock (Object : Protection_Access) is
 133    begin
 134       Unlock (Object.L'Access);
 135
 136       if Parameters.Runtime_Traces then
 137          Send_Trace_Info (PO_Unlock);
 138       end if;
 139    end Unlock;
 140
 141 end System.Tasking.Protected_Objects;