774454ac02
2015-10-23 Hristian Kirtchev <kirtchev@adacore.com> * sem_util.adb (Denotes_Iterator): New routine. (Is_Iterator): Code cleanup. Factor out the detection of a predefined iterator. As a result this fixes a missing case where a tagged type implements interface Reversible_Iterator. 2015-10-23 Ed Schonberg <schonberg@adacore.com> * sem_attr.adb (Eval_Attribute): Constant-fold 'Enabled if not within a generic unit, even if expander is not active, so that instances of container packages remain preelaborable in -gnatc mode. 2015-10-23 Tristan Gingold <gingold@adacore.com> * init.c (__gnat_sigtramp): New assembly function for arm64-darwin. (__gnat_error_handler): Use trampoline for arm64. 2015-10-23 Ed Schonberg <schonberg@adacore.com> * exp_ch3.adb (Expand_N_Object_Declaration): if the type of the object is a class-wide limited interface type, the expression is not restricted to the forms specified for limited types. 2015-10-23 Vincent Celier <celier@adacore.com> * gnatname.adb: Code clean up. * s-taasde.ads: Fix comment. From-SVN: r229240
148 lines
6.1 KiB
Ada
148 lines
6.1 KiB
Ada
------------------------------------------------------------------------------
|
|
-- --
|
|
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
|
|
-- --
|
|
-- S Y S T E M . T A S K I N G . A S Y N C _ D E L A Y S --
|
|
-- --
|
|
-- S p e c --
|
|
-- --
|
|
-- Copyright (C) 1998-2015, Free Software Foundation, Inc. --
|
|
-- --
|
|
-- 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 3, 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. --
|
|
-- --
|
|
-- As a special exception under Section 7 of GPL version 3, you are granted --
|
|
-- additional permissions described in the GCC Runtime Library Exception, --
|
|
-- version 3.1, as published by the Free Software Foundation. --
|
|
-- --
|
|
-- You should have received a copy of the GNU General Public License and --
|
|
-- a copy of the GCC Runtime Library Exception along with this program; --
|
|
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
|
|
-- <http://www.gnu.org/licenses/>. --
|
|
-- --
|
|
-- GNARL was developed by the GNARL team at Florida State University. --
|
|
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
|
|
-- --
|
|
------------------------------------------------------------------------------
|
|
|
|
-- This package contains the procedures to implements timeouts (delays) for
|
|
-- asynchronous select statements.
|
|
|
|
-- Note: the compiler generates direct calls to this interface, via Rtsfind.
|
|
-- Any changes to this interface may require corresponding compiler changes.
|
|
|
|
package System.Tasking.Async_Delays is
|
|
|
|
-- Suppose the following source code is given:
|
|
|
|
-- select delay When;
|
|
-- ...continuation for timeout case...
|
|
-- then abort
|
|
-- ...abortable part...
|
|
-- end select;
|
|
|
|
-- The compiler should expand this to the following:
|
|
|
|
-- declare
|
|
-- DB : aliased Delay_Block;
|
|
-- begin
|
|
-- if System.Tasking.Async_Delays.Enqueue_Duration
|
|
-- (When, DB'Unchecked_Access)
|
|
-- then
|
|
-- begin
|
|
-- A101b : declare
|
|
-- procedure _clean is
|
|
-- begin
|
|
-- System.Tasking.Async_Delays.Cancel_Async_Delay
|
|
-- (DB'Unchecked_Access);
|
|
-- return;
|
|
-- end _clean;
|
|
-- begin
|
|
-- abort_undefer.all;
|
|
-- ...abortable part...
|
|
-- exception
|
|
-- when all others =>
|
|
-- declare
|
|
-- E105b : exception_occurrence;
|
|
-- begin
|
|
-- save_occurrence (E105b, get_current_excep.all.all);
|
|
-- _clean;
|
|
-- reraise_occurrence_no_defer (E105b);
|
|
-- end;
|
|
-- at end
|
|
-- _clean;
|
|
-- end A101b;
|
|
-- exception
|
|
-- when _abort_signal =>
|
|
-- abort_undefer.all;
|
|
-- end;
|
|
-- end if;
|
|
|
|
-- if Timed_Out (DB'Unchecked_Access) then
|
|
-- ...continuation for timeout case...
|
|
-- end if;
|
|
-- end;
|
|
|
|
-----------------
|
|
-- Delay_Block --
|
|
-----------------
|
|
|
|
type Delay_Block is limited private;
|
|
type Delay_Block_Access is access all Delay_Block;
|
|
|
|
function Enqueue_Duration
|
|
(T : Duration;
|
|
D : Delay_Block_Access) return Boolean;
|
|
-- Enqueue the specified relative delay. Returns True if the delay has
|
|
-- been enqueued, False if it has already expired. If the delay has been
|
|
-- enqueued, abort is deferred.
|
|
|
|
procedure Cancel_Async_Delay (D : Delay_Block_Access);
|
|
-- Cancel the specified asynchronous delay
|
|
|
|
function Timed_Out (D : Delay_Block_Access) return Boolean;
|
|
pragma Inline (Timed_Out);
|
|
-- Return True if the delay specified in D has timed out
|
|
|
|
-- There are child units for delays on Ada.Calendar.Time/Ada.Real_Time.Time
|
|
-- so that an application need not link in features that it is not using.
|
|
|
|
private
|
|
|
|
type Delay_Block is limited record
|
|
Self_Id : Task_Id;
|
|
-- ID of the calling task
|
|
|
|
Level : ATC_Level_Base;
|
|
-- Normally Level is the ATC nesting level of the asynchronous select
|
|
-- statement to which this delay belongs, but after a call has been
|
|
-- dequeued we set it to ATC_Level_Infinity so that the Cancel operation
|
|
-- can detect repeated calls, and act idempotently.
|
|
|
|
Resume_Time : Duration;
|
|
-- The absolute wake up time, represented as Duration
|
|
|
|
Timed_Out : Boolean := False;
|
|
-- Set to true if the delay has timed out
|
|
|
|
Succ, Pred : Delay_Block_Access;
|
|
-- A double linked list
|
|
end record;
|
|
|
|
-- The above "overlaying" of Self_Id and Level to hold other data that has
|
|
-- a non-overlapping lifetime is an unabashed hack to save memory.
|
|
|
|
procedure Time_Enqueue
|
|
(T : Duration;
|
|
D : Delay_Block_Access);
|
|
pragma Inline (Time_Enqueue);
|
|
-- Used by the child units to enqueue delays on the timer queue implemented
|
|
-- in the body of this package. T denotes a point in time as the duration
|
|
-- elapsed since the epoch of the Ada real-time clock.
|
|
|
|
end System.Tasking.Async_Delays;
|