1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (c) 2002-2020, University of Amsterdam 7 VU University Amsterdam 8 CWI, Amsterdam 9 All rights reserved. 10 11 Redistribution and use in source and binary forms, with or without 12 modification, are permitted provided that the following conditions 13 are met: 14 15 1. Redistributions of source code must retain the above copyright 16 notice, this list of conditions and the following disclaimer. 17 18 2. Redistributions in binary form must reproduce the above copyright 19 notice, this list of conditions and the following disclaimer in 20 the documentation and/or other materials provided with the 21 distribution. 22 23 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 26 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 27 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 28 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 29 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 31 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 33 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34 POSSIBILITY OF SUCH DAMAGE. 35*/ 36 37:- module(time, 38 [ alarm/3, % +Time, :Callable, -Id 39 alarm/4, % +Time, :Callable, -Id, +Options 40 alarm_at/3, % +Time, :Callable, -Id 41 alarm_at/4, % +Time, :Callable, -Id, +Options 42 remove_alarm/1, % +Id 43 install_alarm/1, % +Id 44 install_alarm/2, % +Id, +Time 45 uninstall_alarm/1, % +Id 46 current_alarm/4, % ?At, ?:Goal, ?Id, ?Status 47 call_with_time_limit/2 % +Time, :Callable 48 ]). 49:- autoload(library(lists),[member/2]). 50 51:- set_prolog_flag(generate_debug_info, false). 52 53:- meta_predicate 54 call_with_time_limit(, ), 55 alarm(, , ), 56 alarm(, , , ), 57 alarm_at(, , , ), 58 current_alarm(, , , ). 59 60:- predicate_options(alarm/4, 4, 61 [ remove(boolean), 62 install(boolean) 63 ]). 64 65 66/** <module> Time and alarm library 67*/ 68 69%! alarm(+Time, :Callable, -Id) is det. 70%! alarm(+Time, :Callable, -Id, +Options) is det. 71% 72% Set up an alarm to be signaled Time seconds from now. If the 73% alarm expires, Callable is called asynchronously. Callable can 74% be used to raise an exception using throw/1 to abort some 75% execution. 76% 77% Options is a list of Name(Value) options. Currently defined 78% options are: 79% 80% * remove(Bool) 81% If =true= (default =false=), remove the alarm-event (as 82% remove_alarm/1) after it has been fired. 83% * install(Bool) 84% If =false= (default =true=) do not install the alarm. 85% It must be installed separately using install_alarm/1. 86 87%! alarm_at(+Time, :Callable, -Id) is det. 88%! alarm_at(+Time, :Callable, -Id, +Options) is det. 89% 90% As alarm/3 and alarm/4, but schedule the alarm at an absolute 91% point in time. 92% 93% @see date_time_stamp/2. 94 95%! install_alarm(+Id) is det. 96%! install_alarm(+Id, +RelTime) is det. 97% 98% Install an alarm allocated using alarm/4 with the install(false) 99% option or de-activated using uninstall_alarm/1. With a given 100% RelTime, the alarm is scheduled at the RelTime from now. 101% Otherwise it is scheduled on the same (absolute) time on which 102% is was created. 103 104%! uninstall_alarm(+Id) is det. 105% 106% De-activate an alarm. This does _not_ invalidate Id, but ensures 107% that the alarm will not fire. The alarm can be rescheduled to 108% the original time using install_alarm/1 or to a new time using 109% install_alarm/2. 110 111%! remove_alarm(+Id) is det. 112% 113% Remove an alarm. If it has not yet been fired, it never will. 114 115%! current_alarm(?Time, :Goal, ?Id, ?Status) is nondet. 116% 117% Enumerate the alarms in the schedule. Time is the absolute time 118% the event is scheduled for (see also get_time/1). Goal is the 119% goal to execute, Id is the identifier and Status is the 120% scheduling status. It takes the value =done= if the alarm has 121% been fired, =next= if the event is the next to be executed and 122% =scheduled= otherwise. 123 124:- use_foreign_library(foreign(time)). 125:- public time_debug/1. % set debugging 126 127%! call_with_time_limit(+Time, :Goal) is semidet. 128% 129% Call Goal, while watching out for a (wall-time) limit. If this 130% limit is exceeded, the exception =time_limit_exceeded= is 131% raised. Goal is called as in once/1. 132% 133% @throws =time_limit_exceeded= 134 135call_with_time_limit(Time, Goal) :- 136 Time > 0, 137 !, 138 setup_call_cleanup(alarm(Time, time_limit_exceeded(Time), 139 Id, [install(false)]), 140 run_alarm_goal(Id, Goal), 141 remove_alarm_notrace(Id)). 142call_with_time_limit(_Time, _Goal) :- 143 throw(time_limit_exceeded). 144 145run_alarm_goal(AlarmID, Goal) :- 146 install_alarm(AlarmID), 147 , 148 !. 149 150time_limit_exceeded(_Time) :- 151 throw(time_limit_exceeded). 152 153current_alarm(Time, Goal, Id, Status) :- 154 current_alarms(Time, Goal, Id, Status, List), 155 member(alarm(Time, Goal, Id, Status), List). 156 157 /******************************* 158 * HANDLE MESSAGES * 159 *******************************/ 160 161:- multifile 162 prolog:message/3. 163 164prologmessage(time_limit_exceeded) --> 165 [ 'Time limit exceeded' ]. 166 167 /******************************* 168 * ALARM * 169 *******************************/ 170 171:- multifile sandbox:safe_meta_predicate/1. 172 173sandbox:safe_meta_predicate(time:call_with_time_limit/2)