/* Part of SWI-Prolog Author: Jan Wielemaker and Anjo Anjewierden E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org/ Copyright (c) 2011-2018, University of Amsterdam VU University Amsterdam CWI, Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(prolog_breakpoints, [ set_breakpoint/4, % +File, +Line, +CharPos, -Id set_breakpoint/5, % +Owner, +File, +Line, +CharPos, -Id delete_breakpoint/1, % +Id breakpoint_property/2 % ?Id, ?Property ]). :- autoload(library(debug),[debug/3]). :- autoload(library(error),[existence_error/2]). :- autoload(library(lists),[nth1/3]). :- autoload(library(prolog_clause),[clause_info/4,clause_name/2]). /** 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. */ %! set_breakpoint(+File, +Line, +Char, -Id) is det. %! set_breakpoint(+Owner, +File, +Line, +Char, -Id) is det. % % Put a breakpoint at the indicated source-location. File is a current % sourcefile (as reported by source_file/1). Line is the 1-based line % in which Char is. Char is the position of the break. % % 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. % % @arg Owner denotes the file that _owns_ the clause. set_breakpoint/5 % is used to set breakpoints in an included file in the context of the % Owner main file. See source_file_property/2. set_breakpoint(File, Line, Char, Id) :- set_breakpoint(File, File, Line, Char, Id). set_breakpoint(Owner, File, Line, Char, Id) :- debug(break, 'break_at(~q, ~d, ~d).', [File, Line, Char]), '$clause_from_source'(Owner, File, Line, ClauseRef), clause_info(ClauseRef, InfoFile, TermPos, _NameOffset), ( InfoFile == File -> '$break_pc'(ClauseRef, PC, NextPC), debug(break, 'Clause ~p, PC=~p NextPC=~p', [ClauseRef, PC, NextPC]), '$clause_term_position'(ClauseRef, NextPC, List), debug(break, 'Location = ~w', [List]), range(List, TermPos, A, Z), debug(break, 'Term from ~w-~w', [A, Z]), Z >= Char, !, Len is Z - A, b_setval('$breakpoint', file_location(File, Line, A, Len)) ; print_message(warning, breakpoint(no_source(ClauseRef, File, Line))), '$break_pc'(ClauseRef, PC, _), !, nb_delete('$breakpoint') ), debug(break, 'Break at clause ~w, PC=~w', [ClauseRef, PC]), '$break_at'(ClauseRef, PC, true), nb_delete('$breakpoint'), known_breakpoint(ClauseRef, PC, _Location, Id). range(_, Pos, _, _) :- var(Pos), !, fail. range([], Pos, A, Z) :- arg(1, Pos, A), arg(2, Pos, Z). range([H|T], term_position(_, _, _, _, PosL), A, Z) :- nth1(H, PosL, Pos), range(T, Pos, A, Z). :- dynamic known_breakpoint/4, % ClauseRef, PC, Location, Id break_id/1. next_break_id(Id) :- retract(break_id(Id0)), !, Id is Id0+1, asserta(break_id(Id)). next_break_id(1) :- asserta(break_id(1)). %! delete_breakpoint(+Id) is det. % % Delete breakpoint with given Id. If successful, % print_message(breakpoint(delete, Id)) is called. Message hooks % working on this message may still call breakpoint_property/2. % % @error existence_error(breakpoint, Id). delete_breakpoint(Id) :- integer(Id), known_breakpoint(ClauseRef, PC, _Location, Id), !, '$break_at'(ClauseRef, PC, false). delete_breakpoint(Id) :- existence_error(breakpoint, Id). %! breakpoint_property(?Id, ?Property) is nondet. % % True when Property is a property of the breakpoint Id. Defined % properties are: % % * file(File) % Provided if the breakpoint is in a clause associated to a % file. May not be known. % * line_count(Line) % Line of the breakpoint. May not be known. % * character_range(Start, Len) % One-based character offset of the break-point. May not be % known. % * clause(Reference) % Reference of the clause in which the breakpoint resides. breakpoint_property(Id, file(File)) :- known_breakpoint(ClauseRef,_,_,Id), clause_property(ClauseRef, file(File)). breakpoint_property(Id, line_count(Line)) :- known_breakpoint(_,_,Location,Id), location_line(Location, Line). breakpoint_property(Id, character_range(Start, Len)) :- known_breakpoint(ClauseRef,PC,Location,Id), ( Location = file_location(_File, _Line, Start, Len) -> true ; break_location(ClauseRef, PC, _File, Start-End), Len is End+1-Start ). breakpoint_property(Id, clause(Reference)) :- known_breakpoint(Reference,_,_,Id). location_line(file_location(_File, Line, _Start, _Len), Line). location_line(file_character_range(File, Start, _Len), Line) :- file_line(File, Start, Line). location_line(file_line(_File, Line), Line). %! file_line(+File, +StartIndex, -Line) is det. % % True when Line is the 1-based line offset in which we find % character StartIndex. file_line(File, Start, Line) :- setup_call_cleanup( prolog_clause:try_open_source(File, In), stream_line(In, Start, 1, Line), close(In)). stream_line(In, _, Line0, Line) :- at_end_of_stream(In), !, Line = Line0. stream_line(In, Index, Line0, Line) :- skip(In, 0'\n), character_count(In, At), ( At > Index -> Line = Line0 ; Line1 is Line0+1, stream_line(In, Index, Line1, Line) ). /******************************* * FEEDBACK * *******************************/ :- initialization prolog_unlisten(break, onbreak), prolog_listen(break, onbreak). onbreak(exist, ClauseRef, PC) :- known_breakpoint(ClauseRef, PC, _Location, Id), !, break_message(breakpoint(exist, Id)). onbreak(true, ClauseRef, PC) :- !, debug(break, 'Trap in Clause ~p, PC ~d', [ClauseRef, PC]), with_mutex('$break', next_break_id(Id)), ( nb_current('$breakpoint', Location) -> true ; break_location(ClauseRef, PC, File, A-Z) -> Len is Z+1-A, Location = file_character_range(File, A, Len) ; clause_property(ClauseRef, file(File)), clause_property(ClauseRef, line_count(Line)) -> Location = file_line(File, Line) ; Location = unknown ), asserta(known_breakpoint(ClauseRef, PC, Location, Id)), break_message(breakpoint(set, Id)). onbreak(false, ClauseRef, PC) :- debug(break, 'Remove breakpoint from ~p, PC ~d', [ClauseRef, PC]), clause(known_breakpoint(ClauseRef, PC, _Location, Id), true, Ref), call_cleanup(break_message(breakpoint(delete, Id)), erase(Ref)). onbreak(gc, ClauseRef, PC) :- debug(break, 'Remove breakpoint from ~p, PC ~d (due to CGC)', [ClauseRef, PC]), retractall(known_breakpoint(ClauseRef, PC, _Location, _Id)). break_message(Message) :- print_message(informational, Message). %! break_location(+ClauseRef, +PC, -File, -AZ) is det. % % True when File and AZ represent the location of the goal called % at PC in ClauseRef. % % @param AZ is a term A-Z, where A and Z are character positions % in File. break_location(ClauseRef, PC, File, A-Z) :- clause_info(ClauseRef, File, TermPos, _NameOffset), '$fetch_vm'(ClauseRef, PC, NPC, _VMI), '$clause_term_position'(ClauseRef, NPC, List), debug(break, 'ClausePos = ~w', [List]), range(List, TermPos, A, Z), debug(break, 'Range: ~d .. ~d', [A, Z]). /******************************* * MESSAGES * *******************************/ :- multifile prolog:message/3. prolog:message(breakpoint(no_source(ClauseRef, _File, Line))) --> [ 'Failed to find line ~d in body of clause ~p. Breaking at start of body.'- [Line, ClauseRef] ]. prolog:message(breakpoint(SetClear, Id)) --> setclear(SetClear), breakpoint(Id). setclear(set) --> ['Breakpoint ']. setclear(exist) --> ['Existing breakpoint ']. setclear(delete) --> ['Deleted breakpoint ']. breakpoint(Id) --> breakpoint_name(Id), ( { breakpoint_property(Id, file(File)), file_base_name(File, Base), breakpoint_property(Id, line_count(Line)) } -> [ ' at ~w:~d'-[Base, Line] ] ; [] ). breakpoint_name(Id) --> { breakpoint_property(Id, clause(ClauseRef)) }, ( { clause_property(ClauseRef, erased) } -> ['~w'-[Id]] ; { clause_name(ClauseRef, Name) }, ['~w in ~w'-[Id, Name]] ).