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) 2002-2015, University of Amsterdam 7 VU University Amsterdam 8 All rights reserved. 9 10 Redistribution and use in source and binary forms, with or without 11 modification, are permitted provided that the following conditions 12 are met: 13 14 1. Redistributions of source code must retain the above copyright 15 notice, this list of conditions and the following disclaimer. 16 17 2. Redistributions in binary form must reproduce the above copyright 18 notice, this list of conditions and the following disclaimer in 19 the documentation and/or other materials provided with the 20 distribution. 21 22 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 30 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 32 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 POSSIBILITY OF SUCH DAMAGE. 34*/ 35 36:- module(time, 37 [ alarm/3, % +Time, :Callable, -Id 38 alarm/4, % +Time, :Callable, -Id, +Options 39 alarm_at/3, % +Time, :Callable, -Id 40 alarm_at/4, % +Time, :Callable, -Id, +Options 41 remove_alarm/1, % +Id 42 install_alarm/1, % +Id 43 install_alarm/2, % +Id, +Time 44 uninstall_alarm/1, % +Id 45 current_alarm/4, % ?At, ?:Goal, ?Id, ?Status 46 call_with_time_limit/2 % +Time, :Callable 47 ]). 48:- use_module(library(lists)). 49:- set_prolog_flag(generate_debug_info, false). 50 51:- meta_predicate 52 call_with_time_limit(, ), 53 alarm(, , ), 54 alarm(, , , ), 55 alarm_at(, , , ), 56 current_alarm(, , , ). 57 58:- predicate_options(alarm/4, 4, 59 [ remove(boolean), 60 install(boolean) 61 ]). 62 63 64/** <module> Time and alarm library 65*/ 66 67%! alarm(+Time, :Callable, -Id) is det. 68%! alarm(+Time, :Callable, -Id, +Options) is det. 69% 70% Set up an alarm to be signaled Time seconds from now. If the 71% alarm expires, Callable is called asynchronously. Callable can 72% be used to raise an exception using throw/1 to abort some 73% execution. 74% 75% Options is a list of Name(Value) options. Currently defined 76% options are: 77% 78% * remove(Bool) 79% If =true= (default =false=), remove the alarm-event (as 80% remove_alarm/1) after it has been fired. 81% * install(Bool) 82% If =false= (default =true=) do not install the alarm. 83% It must be installed separately using install_alarm/1. 84 85%! alarm_at(+Time, :Callable, -Id) is det. 86%! alarm_at(+Time, :Callable, -Id, +Options) is det. 87% 88% As alarm/3 and alarm/4, but schedule the alarm at an absolute 89% point in time. 90% 91% @see date_time_stamp/2. 92 93%! install_alarm(+Id) is det. 94%! install_alarm(+Id, +RelTime) is det. 95% 96% Install an alarm allocated using alarm/4 with the install(false) 97% option or de-activated using uninstall_alarm/1. With a given 98% RelTime, the alarm is scheduled at the RelTime from now. 99% Otherwise it is scheduled on the same (absolute) time on which 100% is was created. 101 102%! uninstall_alarm(+Id) is det. 103% 104% De-activate an alarm. This does _not_ invalidate Id, but ensures 105% that the alarm will not fire. The alarm can be rescheduled to 106% the original time using install_alarm/1 or to a new time using 107% install_alarm/2. 108 109%! remove_alarm(+Id) is det. 110% 111% Remove an alarm. If it has not yet been fired, it never will. 112 113%! current_alarm(?Time, :Goal, ?Id, ?Status) is nondet. 114% 115% Enumerate the alarms in the schedule. Time is the absolute time 116% the event is scheduled for (see also get_time/1). Goal is the 117% goal to execute, Id is the identifier and Status is the 118% scheduling status. It takes the value =done= if the alarm has 119% been fired, =next= if the event is the next to be executed and 120% =scheduled= otherwise. 121 122:- use_foreign_library(foreign(time)). 123:- public time_debug/1. % set debugging 124 125%! call_with_time_limit(+Time, :Goal) is semidet. 126% 127% Call Goal, while watching out for a (wall-time) limit. If this 128% limit is exceeded, the exception =time_limit_exceeded= is 129% raised. Goal is called as in once/1. 130% 131% @throws =time_limit_exceeded= 132 133call_with_time_limit(Time, Goal) :- 134 Time > 0, 135 !, 136 setup_call_cleanup(alarm(Time, time_limit_exceeded(Time), 137 Id, [install(false)]), 138 run_alarm_goal(Id, Goal), 139 remove_alarm_notrace(Id)). 140call_with_time_limit(_Time, _Goal) :- 141 throw(time_limit_exceeded). 142 143run_alarm_goal(AlarmID, Goal) :- 144 install_alarm(AlarmID), 145 , 146 !. 147 148time_limit_exceeded(_Time) :- 149 throw(time_limit_exceeded). 150 151current_alarm(Time, Goal, Id, Status) :- 152 current_alarms(Time, Goal, Id, Status, List), 153 member(alarm(Time, Goal, Id, Status), List). 154 155 /******************************* 156 * HANDLE MESSAGES * 157 *******************************/ 158 159:- multifile 160 prolog:message/3. 161 162prologmessage(time_limit_exceeded) --> 163 [ 'Time limit exceeded' ]. 164 165 /******************************* 166 * ALARM * 167 *******************************/ 168 169:- multifile sandbox:safe_meta_predicate/1. 170 171sandbox:safe_meta_predicate(time:call_with_time_limit/2).