------------------------------------------------------------------------------ -- -- -- 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;