1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker and Anjo Anjewierden 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org/ 6 Copyright (c) 2011-2018, 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(prolog_breakpoints, 38 [ set_breakpoint/4, % +File, +Line, +CharPos, -Id 39 set_breakpoint/5, % +Owner, +File, +Line, +CharPos, -Id 40 delete_breakpoint/1, % +Id 41 breakpoint_property/2 % ?Id, ?Property 42 ]). 43:- autoload(library(debug), [debug/3]). 44:- autoload(library(error), [existence_error/2]). 45:- autoload(library(lists), [nth1/3, member/2]). 46:- autoload(library(prolog_clause), [clause_info/4, clause_name/2]).
First, '$clause_from_source'/4 uses the SWI-Prolog clause-source information to find the last clause starting before Line. '$break_pc' generated (on backtracking), a list of possible break-points.
Note that in addition to setting the break-point, the system must be in debug mode for the breakpoint to take effect. With threading enabled, there are various different ways this may be done. See debug/0, tdebug/0 and tdebug/1. Therefore, this predicate does not enable debug mode.
85set_breakpoint(File, Line, Char, Id) :- 86 set_breakpoint(File, File, Line, Char, Id). 87set_breakpoint(Owner, File, Line, Char, Id) :- 88 debug(break, 'break_at(~q, ~d, ~d).', [File, Line, Char]), 89 '$clause_from_source'(Owner, File, Line, ClauseRefs), 90 member(ClauseRef, ClauseRefs), 91 clause_info(ClauseRef, InfoFile, TermPos, _NameOffset), 92 ( InfoFile == File 93 -> '$break_pc'(ClauseRef, PC, NextPC), 94 debug(break, 'Clause ~p, PC=~p NextPC=~p', [ClauseRef, PC, NextPC]), 95 '$clause_term_position'(ClauseRef, NextPC, List), 96 debug(break, 'Location = ~w', [List]), 97 range(List, TermPos, SubPos), 98 arg(1, SubPos, A), 99 arg(2, SubPos, Z), 100 debug(break, 'Term from ~w-~w', [A, Z]), 101 Z >= Char, !, 102 Len is Z - A, 103 b_setval('$breakpoint', file_location(File, Line, A, Len)) 104 ; print_message(warning, breakpoint(no_source(ClauseRef, File, Line))), 105 '$break_pc'(ClauseRef, PC, _), !, 106 nb_delete('$breakpoint') 107 ), 108 debug(break, 'Break at clause ~w, PC=~w', [ClauseRef, PC]), 109 '$break_at'(ClauseRef, PC, true), 110 nb_delete('$breakpoint'), 111 known_breakpoint(ClauseRef, PC, _Location, Id). 112 113range(_, Pos, _), var(Pos) => 114 fail. 115range(List, parentheses_term_position(_,_,Pos), SubPos) => 116 range(List, Pos, SubPos). 117range([], Pos, SubPos) => 118 SubPos = Pos. 119range([H|T], term_position(_, _, _, _, PosL), SubPos) => 120 nth1(H, PosL, Pos), 121 range(T, Pos, SubPos). 122range(exit, Pos, SubPos) => 123 arg(2, Pos, End), 124 Dot is End, 125 EndDot is Dot+1, 126 SubPos = Dot-EndDot. 127 128:- dynamic 129 known_breakpoint/4, % ClauseRef, PC, Location, Id 130 break_id/1. 131 132next_break_id(Id) :- 133 retract(break_id(Id0)), 134 !, 135 Id is Id0+1, 136 asserta(break_id(Id)). 137next_break_id(1) :- 138 asserta(break_id(1)).
print_message(breakpoint(delete, Id)) is called. Message hooks
working on this message may still call breakpoint_property/2.
148delete_breakpoint(Id) :- 149 integer(Id), 150 known_breakpoint(ClauseRef, PC, _Location, Id), 151 !, 152 '$break_at'(ClauseRef, PC, false). 153delete_breakpoint(Id) :- 154 existence_error(breakpoint, Id).
172breakpoint_property(Id, file(File)) :- 173 known_breakpoint(ClauseRef,_,_,Id), 174 clause_property(ClauseRef, file(File)). 175breakpoint_property(Id, line_count(Line)) :- 176 known_breakpoint(_,_,Location,Id), 177 location_line(Location, Line). 178breakpoint_property(Id, character_range(Start, Len)) :- 179 known_breakpoint(ClauseRef,PC,Location,Id), 180 ( Location = file_location(_File, _Line, Start, Len) 181 -> true 182 ; break_location(ClauseRef, PC, _File, Start-End), 183 Len is End+1-Start 184 ). 185breakpoint_property(Id, clause(Reference)) :- 186 known_breakpoint(Reference,_,_,Id). 187 188location_line(file_location(_File, Line, _Start, _Len), Line). 189location_line(file_character_range(File, Start, _Len), Line) :- 190 file_line(File, Start, Line). 191location_line(file_line(_File, Line), Line).
199file_line(File, Start, Line) :- 200 setup_call_cleanup( 201 prolog_clause:try_open_source(File, In), 202 stream_line(In, Start, 1, Line), 203 close(In)). 204 205stream_line(In, _, Line0, Line) :- 206 at_end_of_stream(In), 207 !, 208 Line = Line0. 209stream_line(In, Index, Line0, Line) :- 210 skip(In, 0'\n), 211 character_count(In, At), 212 ( At > Index 213 -> Line = Line0 214 ; Line1 is Line0+1, 215 stream_line(In, Index, Line1, Line) 216 ). 217 218 219 /******************************* 220 * FEEDBACK * 221 *******************************/ 222 223:- initialization 224 prolog_unlisten(break, onbreak), 225 prolog_listen(break, onbreak). 226 227onbreak(exist, ClauseRef, PC) :- 228 known_breakpoint(ClauseRef, PC, _Location, Id), 229 !, 230 break_message(breakpoint(exist, Id)). 231onbreak(true, ClauseRef, PC) :- 232 !, 233 debug(break, 'Trap in Clause ~p, PC ~d', [ClauseRef, PC]), 234 with_mutex('$break', next_break_id(Id)), 235 ( nb_current('$breakpoint', Location) 236 -> true 237 ; break_location(ClauseRef, PC, File, A-Z) 238 -> Len is Z+1-A, 239 Location = file_character_range(File, A, Len) 240 ; clause_property(ClauseRef, file(File)), 241 clause_property(ClauseRef, line_count(Line)) 242 -> Location = file_line(File, Line) 243 ; Location = unknown 244 ), 245 asserta(known_breakpoint(ClauseRef, PC, Location, Id)), 246 break_message(breakpoint(set, Id)). 247onbreak(false, ClauseRef, PC) :- 248 debug(break, 'Remove breakpoint from ~p, PC ~d', [ClauseRef, PC]), 249 clause(known_breakpoint(ClauseRef, PC, _Location, Id), true, Ref), 250 call_cleanup(break_message(breakpoint(delete, Id)), erase(Ref)). 251onbreak(gc, ClauseRef, PC) :- 252 debug(break, 'Remove breakpoint from ~p, PC ~d (due to CGC)', 253 [ClauseRef, PC]), 254 retractall(known_breakpoint(ClauseRef, PC, _Location, _Id)). 255 256break_message(Message) :- 257 print_message(informational, Message).
267break_location(ClauseRef, PC, File, A-Z) :- 268 clause_info(ClauseRef, File, TermPos, _NameOffset), 269 '$fetch_vm'(ClauseRef, PC, NPC, _VMI), 270 '$clause_term_position'(ClauseRef, NPC, List), 271 debug(break, 'ClausePos = ~w', [List]), 272 range(List, TermPos, A, Z), 273 debug(break, 'Range: ~d .. ~d', [A, Z]). 274 275 276 /******************************* 277 * MESSAGES * 278 *******************************/ 279 280:- multifile 281 prolog:message/3. 282 283prologmessage(breakpoint(no_source(ClauseRef, _File, Line))) --> 284 [ 'Failed to find line ~d in body of clause ~p. Breaking at start of body.'- 285 [Line, ClauseRef] 286 ]. 287prologmessage(breakpoint(SetClear, Id)) --> 288 setclear(SetClear), 289 breakpoint(Id). 290 291setclear(set) --> 292 ['Breakpoint ']. 293setclear(exist) --> 294 ['Existing breakpoint ']. 295setclear(delete) --> 296 ['Deleted breakpoint ']. 297 298breakpoint(Id) --> 299 breakpoint_name(Id), 300 ( { breakpoint_property(Id, file(File)), 301 breakpoint_property(Id, line_count(Line)) 302 } 303 -> [ ' at ', url(File:Line) ] 304 ; [] 305 ). 306 307breakpoint_name(Id) --> 308 { breakpoint_property(Id, clause(ClauseRef)) }, 309 ( { clause_property(ClauseRef, erased) } 310 -> ['~w'-[Id]] 311 ; { clause_name(ClauseRef, Name) }, 312 ['~w in ~w'-[Id, Name]] 313 )
Manage Prolog break-points
This module provides an interface for development tools to set and delete break-points, giving a location in the source. Development tools that want to track changes to breakpoints must use user:message_hook/3 to intercept these message terms:
breakpoint(set, Id)breakpoint(delete, Id)Note that the hook must fail after creating its side-effects to give other hooks the opportunity to react. */