a-rttiev.adb, [...]: New files.

2006-02-13  Pat Rogers  <rogers@adacore.com>

	* a-rttiev.adb, a-rttiev.ads: New files.

From-SVN: r111040

gcc/ada/a-rttiev.ads

+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT RUN-TIME COMPONENTS                         --
+--                                                                          --
+--          A D A . R E A L _ T I M E . T I M I N G _ E V E N T S           --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--           Copyright (C) 2005-2006, Free Software Foundation, Inc.        --
+--                                                                          --
+-- This specification is derived from the Ada Reference Manual for use with --
+-- GNAT. The copyright notice above, and the license provisions that follow --
+-- apply solely to the  contents of the part following the private keyword. --
+--                                                                          --
+-- 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 Ada.Finalization;
+
+package Ada.Real_Time.Timing_Events is
+
+   type Timing_Event is tagged limited private;
+
+   type Timing_Event_Handler
+     is access protected procedure (Event : in out Timing_Event);
+
+   procedure Set_Handler
+     (Event   : in out Timing_Event;
+      At_Time : Time;
+      Handler : Timing_Event_Handler);
+
+   procedure Set_Handler
+     (Event   : in out Timing_Event;
+      In_Time : Time_Span;
+      Handler : Timing_Event_Handler);
+
+   function Current_Handler
+     (Event : Timing_Event) return Timing_Event_Handler;
+
+   procedure Cancel_Handler
+     (Event     : in out Timing_Event;
+      Cancelled : out Boolean);
+
+   function Time_Of_Event (Event : Timing_Event) return Time;
+
+private
+
+   protected type Event_State is
+
+      --  D.15 (22/2) requires atomicity with respect to the operations
+      --  provided by the package and the timing events they manipulate. On
+      --  real-time operating systems suitable for implementing this package, a
+      --  different implementation strategy would be employed to meet that
+      --  requirement.
+
+      entry Set (Timeout : Time;  Handler : Timing_Event_Handler);
+      --  Changes the timeout and handler values for procedure Set_Handler. Can
+      --  only execute when the event is 'available', to prevent a race
+      --  condition between the caller of Set_Handler and the internal Timer
+      --  task that processes the events. In particular, D.15 (22/2) requires
+      --  that there be no possibility of a new handler executing in response
+      --  to an old timeout.
+
+      procedure Reset;
+      --  First resets the timeout to Time_First and the handler to
+      --  null. Indicates that Set (for Set_Handler) can now change the timeout
+      --  and/or handler.  Called only by the interal Timer task.
+
+      procedure Cancel;
+      --  Resets the timeout to Time_First and the handler to
+      --  null. Called by procedure Cancel_Handler and by procedure Reset.
+
+      function Current_Timeout return Time;
+      --  Returns the currently set timeout. The value Time_First is returned
+      --  if the Timing_Event is in the "cleared" state. Called by function
+      --  Time_of_Event.
+
+      function Current_Handler return Timing_Event_Handler;
+      --  Returns the currently set handler. The value null is returned if the
+      --  Timing_Event is in the "cleared" state. Called by function
+      --  Curent_Handler.
+
+   private
+      Timeout : Time := Time_First;
+      --  The time at which the user's handler should be invoked when the
+      --  event is "set" (i.e., when Handler is not null).
+
+      Handler : Timing_Event_Handler;
+      --  An access value designating the protected procedure to be invoked
+      --  at the Timeout time in the future.  When this value is null the event
+      --  is said to be "cleared" and no timeout is processed.
+
+      Available : Boolean := True;
+      --  A flag controlling when users can change the Timeout and Handler
+      --  tuple. In particular the entry Set, called by procedure Set_Handler,
+      --  is controlled by this flag.
+
+   end Event_State;
+
+   type Timing_Event is new Ada.Finalization.Limited_Controlled with record
+      Control : Event_State;
+   end record;
+
+   overriding procedure Finalize (This : in out Timing_Event);
+   --  Finalization procedure is required to satisfy (RM D.15 (19/2)), which
+   --  says that the object must be cleared on finalization.
+
+end Ada.Real_Time.Timing_Events;