File : s-taprob.adb
------------------------------------------------------------------------------
-- --
-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- 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 --
-- --
-- B o d y --
-- --
-- $Revision: 1.76 $
-- --
-- Copyright (C) 1991-1998 Florida State University --
-- --
-- GNARL 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. GNARL 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 GNARL; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, 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. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. It is --
-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
-- State University (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
pragma Polling (Off);
-- Turn off polling, we do not want ATC polling to take place during
-- tasking operations. It causes infinite loops and other problems.
with System.Task_Primitives.Operations;
-- used for Write_Lock
-- Unlock
with Ada.Exceptions;
-- used for Raise_Exception
package body System.Tasking.Protected_Objects is
use Ada.Exceptions;
use System.Task_Primitives.Operations;
-- Compiler interface only.
-- Do not call this procedure from within the run-time system.
procedure Initialize_Protection
(Object : Protection_Access;
Ceiling_Priority : Integer)
is
Init_Priority : Integer := Ceiling_Priority;
begin
if Init_Priority = Unspecified_Priority then
Init_Priority := System.Priority'Last;
end if;
Initialize_Lock (Init_Priority, Object.L'Access);
Object.Ceiling := System.Any_Priority (Init_Priority);
end Initialize_Protection;
-- Compiler interface only.
-- Do not call this procedure from within the runtime system.
procedure Lock (Object : Protection_Access) is
Ceiling_Violation : Boolean;
begin
-- The lock is made without defering abortion.
-- Therefore the abortion has to be deferred before calling this
-- routine. This means that the compiler has to generate a Defer_Abort
-- call before the call to Lock.
-- The caller is responsible for undeferring abortion, and compiler
-- generated calls must be protected with cleanup handlers to ensure
-- that abortion is undeferred in all cases.
pragma Assert (Self.Deferral_Level > 0);
Write_Lock (Object.L'Access, Ceiling_Violation);
if Ceiling_Violation then
Raise_Exception (Program_Error'Identity, "Ceiling Violation");
end if;
end Lock;
-- Compiler interface only.
-- Do not call this procedure from within the runtime system.
procedure Lock_Read_Only (Object : Protection_Access) is
Ceiling_Violation : Boolean;
begin
Read_Lock (Object.L'Access, Ceiling_Violation);
if Ceiling_Violation then
Raise_Exception (Program_Error'Identity, "Ceiling Violation");
end if;
end Lock_Read_Only;
procedure Unlock (Object : Protection_Access) is
begin
Unlock (Object.L'Access);
end Unlock;
end System.Tasking.Protected_Objects;