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) 1985-2020, 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('$autoload', 38 [ '$find_library'/5, 39 '$in_library'/3, 40 '$define_predicate'/1, 41 '$update_library_index'/0, 42 '$autoload'/1, 43 44 make_library_index/1, 45 make_library_index/2, 46 reload_library_index/0, 47 autoload_path/1, 48 49 autoload/1, % +File 50 autoload/2, % +File, +Imports 51 52 require/1 % +Predicates 53 ]). 54 55:- meta_predicate 56 '$autoload'(), 57 autoload(), 58 autoload(, ), 59 require(). 60 61:- dynamic 62 library_index/3, % Head x Module x Path 63 autoload_directories/1, % List 64 index_checked_at/1. % Time 65:- volatile 66 library_index/3, 67 autoload_directories/1, 68 index_checked_at/1. 69 70user:file_search_path(autoload, swi(library)). 71user:file_search_path(autoload, pce(prolog/lib)). 72user:file_search_path(autoload, app_config(lib)).
83'$find_library'(Module, Name, Arity, LoadModule, Library) :-
84 load_library_index(Name, Arity),
85 functor(Head, Name, Arity),
86 ( library_index(Head, Module, Library),
87 LoadModule = Module
88 ; library_index(Head, LoadModule, Library)
89 ),
90 !.97'$in_library'(Name, Arity, Path) :- 98 atom(Name), integer(Arity), 99 !, 100 load_library_index(Name, Arity), 101 functor(Head, Name, Arity), 102 library_index(Head, _, Path). 103'$in_library'(Name, Arity, Path) :- 104 load_library_index(Name, Arity), 105 library_index(Head, _, Path), 106 functor(Head, Name, Arity).
113:- meta_predicate 114 '$define_predicate'(). 115 116'$define_predicate'(Head) :- 117 '$defined_predicate'(Head), 118 !. 119'$define_predicate'(Term) :- 120 Term = Module:Head, 121 ( compound(Head) 122 -> compound_name_arity(Head, Name, Arity) 123 ; Name = Head, Arity = 0 124 ), 125 '$undefined_procedure'(Module, Name, Arity, retry). 126 127 128 /******************************** 129 * UPDATE INDEX * 130 ********************************/ 131 132:- thread_local 133 silent/0.
142'$update_library_index' :- 143 setof(Dir, writable_indexed_directory(Dir), Dirs), 144 !, 145 setup_call_cleanup( 146 asserta(silent, Ref), 147 guarded_make_library_index(Dirs), 148 erase(Ref)), 149 ( flag('$modified_index', true, false) 150 -> reload_library_index 151 ; true 152 ). 153'$update_library_index'. 154 155guarded_make_library_index([]). 156guarded_make_library_index([Dir|Dirs]) :- 157 ( catch(make_library_index(Dir), E, 158 print_message(error, E)) 159 -> true 160 ; print_message(warning, goal_failed(make_library_index(Dir))) 161 ), 162 guarded_make_library_index(Dirs).
169writable_indexed_directory(Dir) :- 170 index_file_name(IndexFile, autoload('INDEX'), [access([read,write])]), 171 file_directory_name(IndexFile, Dir). 172writable_indexed_directory(Dir) :- 173 absolute_file_name(library('MKINDEX'), 174 [ file_type(prolog), 175 access(read), 176 solutions(all), 177 file_errors(fail) 178 ], MkIndexFile), 179 file_directory_name(MkIndexFile, Dir), 180 plfile_in_dir(Dir, 'INDEX', _, IndexFile), 181 access_file(IndexFile, write). 182 183 184 /******************************** 185 * LOAD INDEX * 186 ********************************/
192reload_library_index :- 193 context_module(M), 194 reload_library_index(M). 195 196reload_library_index(M) :- 197 with_mutex('$autoload', clear_library_index(M)). 198 199clear_library_index(M) :- 200 retractall(M:library_index(_, _, _)), 201 retractall(M:autoload_directories(_)), 202 retractall(M:index_checked_at(_)).
212:- meta_predicate load_library_index(, , ). 213:- public load_library_index/3. 214 215load_library_index(Name, Arity) :- 216 load_library_index(Name, Arity, autoload('INDEX')). 217 218load_library_index(Name, Arity, M:_Spec) :- 219 atom(Name), integer(Arity), 220 functor(Head, Name, Arity), 221 M:library_index(Head, _, _), 222 !. 223load_library_index(_, _, Spec) :- 224 notrace(with_mutex('$autoload', load_library_index_p(Spec))). 225 226load_library_index_p(M:_) :- 227 M:index_checked_at(Time), 228 get_time(Now), 229 Now-Time < 60, 230 !. 231load_library_index_p(M:Spec) :- 232 findall(Index, index_file_name(Index, Spec, [access(read)]), List0), 233 '$list_to_set'(List0, List), 234 retractall(M:index_checked_at(_)), 235 get_time(Now), 236 assert(M:index_checked_at(Now)), 237 ( M:autoload_directories(List) 238 -> true 239 ; retractall(M:library_index(_, _, _)), 240 retractall(M:autoload_directories(_)), 241 read_index(List, M), 242 assert(M:autoload_directories(List)) 243 ).
autoload.
253index_file_name(IndexFile, FileSpec, Options) :- 254 absolute_file_name(FileSpec, 255 IndexFile, 256 [ file_type(prolog), 257 solutions(all), 258 file_errors(fail) 259 | Options 260 ]). 261 262read_index([], _) :- !. 263read_index([H|T], M) :- 264 !, 265 read_index(H, M), 266 read_index(T, M). 267read_index(Index, M) :- 268 print_message(silent, autoload(read_index(Dir))), 269 file_directory_name(Index, Dir), 270 setup_call_cleanup( 271 '$push_input_context'(autoload_index), 272 setup_call_cleanup( 273 open(Index, read, In), 274 read_index_from_stream(Dir, In, M), 275 close(In)), 276 '$pop_input_context'). 277 278read_index_from_stream(Dir, In, M) :- 279 repeat, 280 read(In, Term), 281 assert_index(Term, Dir, M), 282 !. 283 284assert_index(end_of_file, _, _) :- !. 285assert_index(index(Name, Arity, Module, File), Dir, M) :- 286 !, 287 functor(Head, Name, Arity), 288 atomic_list_concat([Dir, '/', File], Path), 289 assertz(M:library_index(Head, Module, Path)), 290 fail. 291assert_index(Term, Dir, _) :- 292 print_message(error, illegal_autoload_index(Dir, Term)), 293 fail. 294 295 296 /******************************** 297 * CREATE INDEX.pl * 298 ********************************/
INDEX.pl. In Dir contains a file
MKINDEX.pl, this file is loaded and we assume that the index is
created by directives that appearin this file. Otherwise, all
source files are scanned for their module-header and all
exported predicates are added to the autoload index.
311make_library_index(Dir0) :- 312 forall(absolute_file_name(Dir0, Dir, 313 [ expand(true), 314 file_type(directory), 315 file_errors(fail), 316 solutions(all) 317 ]), 318 make_library_index2(Dir)). 319 320make_library_index2(Dir) :- 321 plfile_in_dir(Dir, 'MKINDEX', _MkIndex, AbsMkIndex), 322 access_file(AbsMkIndex, read), 323 !, 324 load_files(user:AbsMkIndex, [silent(true)]). 325make_library_index2(Dir) :- 326 findall(Pattern, source_file_pattern(Pattern), PatternList), 327 make_library_index2(Dir, PatternList).
INDEX.pl for Dir by scanning all files
that match any of the file-patterns in Patterns. Typically, this
appears as a directive in MKINDEX.pl. For example:
:- prolog_load_context(directory, Dir), make_library_index(Dir, ['*.pl']).
342make_library_index(Dir0, Patterns) :- 343 forall(absolute_file_name(Dir0, Dir, 344 [ expand(true), 345 file_type(directory), 346 file_errors(fail), 347 solutions(all) 348 ]), 349 make_library_index2(Dir, Patterns)). 350 351make_library_index2(Dir, Patterns) :- 352 plfile_in_dir(Dir, 'INDEX', _Index, AbsIndex), 353 ensure_slash(Dir, DirS), 354 pattern_files(Patterns, DirS, Files), 355 ( library_index_out_of_date(Dir, AbsIndex, Files) 356 -> do_make_library_index(AbsIndex, DirS, Files), 357 flag('$modified_index', _, true) 358 ; true 359 ). 360 361ensure_slash(Dir, DirS) :- 362 ( sub_atom(Dir, _, _, 0, /) 363 -> DirS = Dir 364 ; atom_concat(Dir, /, DirS) 365 ). 366 367source_file_pattern(Pattern) :- 368 user:prolog_file_type(PlExt, prolog), 369 PlExt \== qlf, 370 atom_concat('*.', PlExt, Pattern). 371 372plfile_in_dir(Dir, Base, PlBase, File) :- 373 file_name_extension(Base, pl, PlBase), 374 atomic_list_concat([Dir, '/', PlBase], File). 375 376pattern_files([], _, []). 377pattern_files([H|T], DirS, Files) :- 378 atom_concat(DirS, H, P0), 379 expand_file_name(P0, Files0), 380 '$append'(Files0, Rest, Files), 381 pattern_files(T, DirS, Rest). 382 383library_index_out_of_date(_Dir, Index, _Files) :- 384 \+ exists_file(Index), 385 !. 386library_index_out_of_date(Dir, Index, Files) :- 387 time_file(Index, IndexTime), 388 ( time_file(Dir, DotTime), 389 DotTime > IndexTime 390 ; '$member'(File, Files), 391 time_file(File, FileTime), 392 FileTime > IndexTime 393 ), 394 !. 395 396 397do_make_library_index(Index, Dir, Files) :- 398 ensure_slash(Dir, DirS), 399 '$stage_file'(Index, StagedIndex), 400 setup_call_catcher_cleanup( 401 open(StagedIndex, write, Out), 402 ( print_message(informational, make(library_index(Dir))), 403 index_header(Out), 404 index_files(Files, DirS, Out) 405 ), 406 Catcher, 407 install_index(Out, Catcher, StagedIndex, Index)). 408 409install_index(Out, Catcher, StagedIndex, Index) :- 410 catch(close(Out), Error, true), 411 ( silent 412 -> OnError = silent 413 ; OnError = error 414 ), 415 ( var(Error) 416 -> TheCatcher = Catcher 417 ; TheCatcher = exception(Error) 418 ), 419 '$install_staged_file'(TheCatcher, StagedIndex, Index, OnError).
425index_files([], _, _). 426index_files([File|Files], DirS, Fd) :- 427 ( catch(exports(File, Module, Public), E, 428 print_message(warning, E)), 429 nonvar(Module) 430 -> atom_concat(DirS, Local, File), 431 file_name_extension(Base, _, Local), 432 forall(public_predicate(Public, Name/Arity), 433 format(Fd, 'index((~k), ~k, ~k, ~k).~n', 434 [Name, Arity, Module, Base])) 435 ; true 436 ), 437 index_files(Files, DirS, Fd). 438 439public_predicate(Public, PI) :- 440 '$member'(PI0, Public), 441 canonical_pi(PI0, PI). 442 443canonical_pi(Var, _) :- 444 var(Var), !, fail. 445canonical_pi(Name/Arity, Name/Arity). 446canonical_pi(Name//A0, Name/Arity) :- 447 Arity is A0 + 2. 448 449 450index_header(Fd):- 451 format(Fd, '/* Creator: make/0~n~n', []), 452 format(Fd, ' Purpose: Provide index for autoload~n', []), 453 format(Fd, '*/~n~n', []). 454 455exports(File, Module, Exports) :- 456 ( current_prolog_flag(xref, Old) 457 -> true 458 ; Old = false 459 ), 460 setup_call_cleanup( 461 set_prolog_flag(xref, true), 462 exports_(File, Module, Exports), 463 set_prolog_flag(xref, Old)). 464 465exports_(File, Module, Exports) :- 466 State = state(true, _, []), 467 ( '$source_term'(File, _,_,Term0,_,_,[syntax_errors(quiet)]), 468 ( is_list(Term0) 469 -> '$member'(Term, Term0) 470 ; Term = Term0 471 ), 472 ( Term = (:- module(M,Public)), 473 is_list(Public), 474 arg(1, State, true) 475 -> nb_setarg(1, State, false), 476 nb_setarg(2, State, M), 477 nb_setarg(3, State, Public), 478 fail 479 ; nb_setarg(1, State, false), 480 fail 481 ; Term = (:- export(PI)), 482 ground(PI) 483 -> arg(3, State, E0), 484 '$append'(E0, [PI], E1), 485 nb_setarg(3, State, E1), 486 fail 487 ; Term = (:- use_foreign_library(Lib)), 488 nonvar(Lib), 489 arg(2, State, M), 490 atom(M) 491 -> catch('$syspreds':use_foreign_library_noi(M:Lib), error(_,_), true), 492 fail 493 ; Term = (:- Directive), 494 nonvar(Directive) 495 -> fail 496 ; ! 497 ) 498 ; true 499 ), 500 arg(2, State, Module), 501 arg(3, State, Exports). 502 503 504 /******************************* 505 * EXTENDING * 506 *******************************/
autoload and reloads the library
index. For example:
:- autoload_path(library(http)).
If this call appears as a directive, it is term-expanded into a clause for file_search_path/2 and a directive calling reload_library_index/0. This keeps source information and allows for removing this directive.
523autoload_path(Alias) :- 524 ( user:file_search_path(autoload, Alias) 525 -> true 526 ; assertz(user:file_search_path(autoload, Alias)), 527 reload_library_index 528 ). 529 530systemterm_expansion((:- autoload_path(Alias)), 531 [ user:file_search_path(autoload, Alias), 532 (:- reload_library_index) 533 ]). 534 535 536 /******************************* 537 * RUNTIME AUTOLOADER * 538 *******************************/
current_prolog_flag(autoload, true) holds.548'$autoload'(PI) :- 549 source_location(File, _Line), 550 !, 551 setup_call_cleanup( 552 '$start_aux'(File, Context), 553 '$autoload2'(PI), 554 '$end_aux'(File, Context)). 555'$autoload'(PI) :- 556 '$autoload2'(PI). 557 558'$autoload2'(PI) :- 559 setup_call_cleanup( 560 leave_sandbox(Old), 561 '$autoload3'(PI), 562 restore_sandbox(Old)). 563 564leave_sandbox(Sandboxed) :- 565 current_prolog_flag(sandboxed_load, Sandboxed), 566 set_prolog_flag(sandboxed_load, false). 567restore_sandbox(Sandboxed) :- 568 set_prolog_flag(sandboxed_load, Sandboxed). 569 570'$autoload3'(PI) :- 571 autoload_from(PI, LoadModule, FullFile), 572 do_autoload(FullFile, PI, LoadModule).
579autoload_from(Module:PI, LoadModule, FullFile) :- 580 autoload_in(Module, explicit), 581 current_autoload(Module:File, Ctx, import(Imports)), 582 memberchk(PI, Imports), 583 library_info(File, Ctx, FullFile, LoadModule, Exports), 584 ( pi_in_exports(PI, Exports) 585 -> ! 586 ; autoload_error(Ctx, not_exported(PI, File, FullFile, Exports)), 587 fail 588 ). 589autoload_from(Module:Name/Arity, LoadModule, FullFile) :- 590 autoload_in(Module, explicit), 591 PI = Name/Arity, 592 current_autoload(Module:File, Ctx, all), 593 library_info(File, Ctx, FullFile, LoadModule, Exports), 594 pi_in_exports(PI, Exports). 595autoload_from(Module:Name/Arity, LoadModule, Library) :- 596 autoload_in(Module, general), 597 '$find_library'(Module, Name, Arity, LoadModule, Library). 598 599:- public autoload_in/2. % used in syspred 600 601autoload_in(Module, How) :- 602 current_prolog_flag(autoload, AutoLoad), 603 autoload_in(AutoLoad, How, Module), 604 !.
608autoload_in(true, _, _). 609autoload_in(explicit, explicit, _). 610autoload_in(user, _, user). 611autoload_in(user_or_explicit, explicit, _). 612autoload_in(user_or_explicit, _, user).
user. '$c_current_predicate'/2
verifies the predicate really exists, but doesn't validate
that it is defined.628do_autoload(Library, Module:Name/Arity, LoadModule) :- 629 functor(Head, Name, Arity), 630 '$update_autoload_level'([autoload(true)], Old), 631 verbose_autoload(Module:Name/Arity, Library), 632 '$compilation_mode'(OldComp, database), 633 ( Module == LoadModule 634 -> ensure_loaded(Module:Library) 635 ; ( '$c_current_predicate'(_, LoadModule:Head), 636 '$get_predicate_attribute'(LoadModule:Head, defined, 1), 637 \+ '$loading'(Library) 638 -> Module:import(LoadModule:Name/Arity) 639 ; use_module(Module:Library, [Name/Arity]) 640 ) 641 ), 642 '$set_compilation_mode'(OldComp), 643 '$set_autoload_level'(Old), 644 '$c_current_predicate'(_, Module:Head). 645 646verbose_autoload(PI, Library) :- 647 current_prolog_flag(verbose_autoload, true), 648 !, 649 set_prolog_flag(verbose_autoload, false), 650 print_message(informational, autoload(PI, Library)), 651 set_prolog_flag(verbose_autoload, true). 652verbose_autoload(PI, Library) :- 653 print_message(silent, autoload(PI, Library)).
autoload(File). The module muse be
instantiated.662:- public % used from predicate_property/2 663 autoloadable/2. 664 665autoloadable(M:Head, FullFile) :- 666 atom(M), 667 current_module(M), 668 autoload_in(M, explicit), 669 ( callable(Head) 670 -> goal_name_arity(Head, Name, Arity), 671 autoload_from(M:Name/Arity, _, FullFile) 672 ; findall((M:H)-F, autoloadable_2(M:H, F), Pairs), 673 ( '$member'(M:Head-FullFile, Pairs) 674 ; current_autoload(M:File, Ctx, all), 675 library_info(File, Ctx, FullFile, _, Exports), 676 '$member'(PI, Exports), 677 '$pi_head'(PI, Head), 678 \+ memberchk(M:Head-_, Pairs) 679 ) 680 ). 681autoloadable(M:Head, FullFile) :- 682 ( var(M) 683 -> autoload_in(any, general) 684 ; autoload_in(M, general) 685 ), 686 ( callable(Head) 687 -> goal_name_arity(Head, Name, Arity), 688 ( '$find_library'(_, Name, Arity, _, FullFile) 689 -> true 690 ) 691 ; '$in_library'(Name, Arity, autoload), 692 functor(Head, Name, Arity) 693 ). 694 695 696autoloadable_2(M:Head, FullFile) :- 697 current_autoload(M:File, Ctx, import(Imports)), 698 library_info(File, Ctx, FullFile, _LoadModule, _Exports), 699 '$member'(PI, Imports), 700 '$pi_head'(PI, Head). 701 702goal_name_arity(Head, Name, Arity) :- 703 compound(Head), 704 !, 705 compound_name_arity(Head, Name, Arity). 706goal_name_arity(Head, Head, 0).
712library_info(Spec, _, FullFile, Module, Exports) :- 713 '$resolved_source_path'(Spec, FullFile, []), 714 !, 715 ( \+ '$loading_file'(FullFile, _Queue, _LoadThread) 716 -> '$current_module'(Module, FullFile), 717 '$module_property'(Module, exports(Exports)) 718 ; library_info_from_file(FullFile, Module, Exports) 719 ). 720library_info(Spec, Context, FullFile, Module, Exports) :- 721 ( Context = (Path:_Line) 722 -> Extra = [relative_to(Path)] 723 ; Extra = [] 724 ), 725 ( absolute_file_name(Spec, FullFile, 726 [ file_type(prolog), 727 access(read), 728 file_errors(fail) 729 | Extra 730 ]) 731 -> '$register_resolved_source_path'(Spec, FullFile), 732 library_info_from_file(FullFile, Module, Exports) 733 ; autoload_error(Context, no_file(Spec)), 734 fail 735 ). 736 737library_info_from_file(FullFile, Module, Exports) :- 738 setup_call_cleanup( 739 '$set_source_module'(OldModule, system), 740 setup_call_cleanup( 741 '$open_source'(FullFile, In, State, [], []), 742 '$term_in_file'(In, _Read, _RLayout, Term, _TLayout, _Stream, 743 [FullFile], []), 744 '$close_source'(State, true)), 745 '$set_source_module'(OldModule)), 746 ( Term = (:- module(Module, Exports)) 747 -> ! 748 ; nonvar(Term), 749 skip_header(Term) 750 -> fail 751 ; '$domain_error'(module_header, Term) 752 ). 753 754skip_header(begin_of_file). 755 756 757:- dynamic printed/3. 758:- volatile printed/3. 759 760autoload_error(Context, Error) :- 761 suppress(Context, Error), 762 !. 763autoload_error(Context, Error) :- 764 get_time(Now), 765 assertz(printed(Context, Error, Now)), 766 print_message(warning, error(autoload(Error), autoload(Context))). 767 768suppress(Context, Error) :- 769 printed(Context, Error, Printed), 770 get_time(Now), 771 ( Now - Printed < 1 772 -> true 773 ; retractall(printed(Context, Error, _)), 774 fail 775 ). 776 777 778 /******************************* 779 * CALLBACK * 780 *******************************/ 781 782:- public 783 set_autoload/1.
false we should materialize all registered
requests for autoloading. We must do so before disabling autoloading
as loading the files may require autoloading.792set_autoload(FlagValue) :- 793 current_prolog_flag(autoload, FlagValue), 794 !. 795set_autoload(FlagValue) :- 796 \+ autoload_in(FlagValue, explicit, any), 797 !, 798 setup_call_cleanup( 799 nb_setval('$autoload_disabling', true), 800 materialize_autoload(Count), 801 nb_delete('$autoload_disabling')), 802 print_message(informational, autoload(disabled(Count))). 803set_autoload(_). 804 805materialize_autoload(Count) :- 806 State = state(0), 807 forall(current_predicate(M:'$autoload'/3), 808 materialize_autoload(M, State)), 809 arg(1, State, Count). 810 811materialize_autoload(M, State) :- 812 ( current_autoload(M:File, Context, Import), 813 library_info(File, Context, FullFile, _LoadModule, _Exports), 814 arg(1, State, N0), 815 N is N0+1, 816 nb_setarg(1, State, N), 817 ( Import == all 818 -> verbose_autoload(M:all, FullFile), 819 use_module(M:FullFile) 820 ; Import = import(Preds) 821 -> verbose_autoload(M:Preds, FullFile), 822 use_module(M:FullFile, Preds) 823 ), 824 fail 825 ; true 826 ), 827 abolish(M:'$autoload'/3). 828 829 830 /******************************* 831 * AUTOLOAD/2 * 832 *******************************/ 833 834autoload(M:File) :- 835 ( \+ autoload_in(M, explicit) 836 ; nb_current('$autoload_disabling', true) 837 ), 838 !, 839 use_module(M:File). 840autoload(M:File) :- 841 '$must_be'(filespec, File), 842 source_context(Context), 843 ( current_autoload(M:File, _, import(all)) 844 -> true 845 ; assert_autoload(M:'$autoload'(File, Context, all)) 846 ). 847 848autoload(M:File, Imports) :- 849 ( \+ autoload_in(M, explicit) 850 ; nb_current('$autoload_disabling', true) 851 ), 852 !, 853 use_module(M:File, Imports). 854autoload(M:File, Imports0) :- 855 '$must_be'(filespec, File), 856 valid_imports(Imports0, Imports), 857 source_context(Context), 858 register_autoloads(Imports, M, File, Context), 859 ( current_autoload(M:File, _, import(Imports)) 860 -> true 861 ; assert_autoload(M:'$autoload'(File, Context, import(Imports))) 862 ). 863 864source_context(Path:Line) :- 865 source_location(Path, Line), 866 !. 867source_context(-). 868 869assert_autoload(Clause) :- 870 '$initialization_context'(Source, Ctx), 871 '$store_admin_clause2'(Clause, _Layout, Source, Ctx). 872 873valid_imports(Imports0, Imports) :- 874 '$must_be'(list, Imports0), 875 valid_import_list(Imports0, Imports). 876 877valid_import_list([], []). 878valid_import_list([H0|T0], [H|T]) :- 879 '$pi_head'(H0, Head), 880 '$pi_head'(H, Head), 881 valid_import_list(T0, T).
autoload flag on all predicates declared using autoload/2
to prevent duplicates or the user defining the same predicate.888register_autoloads([], _, _, _). 889register_autoloads([PI|T], Module, File, Context) :- 890 PI = Name/Arity, 891 functor(Head, Name, Arity), 892 ( '$get_predicate_attribute'(Module:Head, autoload, 1) 893 -> ( current_autoload(Module:_File0, _Ctx0, import(Imports)), 894 memberchk(PI, Imports) 895 -> '$permission_error'(redefine, imported_procedure, PI), 896 fail 897 ; Done = true 898 ) 899 ; '$c_current_predicate'(_, Module:Head), % no auto-import 900 '$get_predicate_attribute'(Module:Head, imported, From) 901 -> ( ( '$resolved_source_path'(File, FullFile) 902 -> true 903 ; '$resolve_source_path'(File, FullFile, []) 904 ), 905 module_property(From, file(FullFile)) 906 -> Done = true 907 ; print_message(warning, 908 autoload(already_defined(Module:PI, From))), 909 Done = true 910 ) 911 ; true 912 ), 913 ( Done == true 914 -> true 915 ; '$set_predicate_attribute'(Module:Head, autoload, 1) 916 ), 917 register_autoloads(T, Module, File, Context). 918 919pi_in_exports(PI, Exports) :- 920 '$member'(E, Exports), 921 canonical_pi(E, PI), 922 !. 923 924current_autoload(M:File, Context, Term) :- 925 '$get_predicate_attribute'(M:'$autoload'(_,_,_), defined, 1), 926 M:'$autoload'(File, Context, Term). 927 928 /******************************* 929 * REQUIRE * 930 *******************************/
937require(M:Spec) :- 938 ( is_list(Spec) 939 -> List = Spec 940 ; phrase(comma_list(Spec), List) 941 ), !, 942 require(List, M, FromLib), 943 keysort(FromLib, Sorted), 944 by_file(Sorted, Autoload), 945 forall('$member'(File-Import, Autoload), 946 autoload(M:File, Import)). 947require(_:Spec) :- 948 '$type_error'(list, Spec). 949 950require([],_, []). 951require([H|T], M, Needed) :- 952 '$pi_head'(H, Head), 953 ( '$get_predicate_attribute'(system:Head, defined, 1) 954 -> require(T, M, Needed) 955 ; '$pi_head'(Module:Name/Arity, M:Head), 956 ( '$find_library'(Module, Name, Arity, LoadModule, Library) 957 -> ( current_predicate(LoadModule:Name/Arity) 958 -> Module:import(LoadModule:Name/Arity), 959 require(T, M, Needed) 960 ; Needed = [Library-H|More], 961 require(T, M, More) 962 ) 963 ; print_message(error, error(existence_error(procedure, Name/Arity), _)), 964 require(T, M, Needed) 965 ) 966 ). 967 968by_file([], []). 969by_file([File-PI|T0], [Spec-[PI|PIs]|T]) :- 970 on_path(File, Spec), 971 same_file(T0, File, PIs, T1), 972 by_file(T1, T). 973 974on_path(Library, library(Base)) :- 975 file_base_name(Library, Base), 976 findall(Path, plain_source(library(Base), Path), [Library]), 977 !. 978on_path(Library, Library). 979 980plain_source(Spec, Path) :- 981 absolute_file_name(Spec, PathExt, 982 [ file_type(prolog), 983 access(read), 984 file_errors(fail), 985 solutions(all) 986 ]), 987 file_name_extension(Path, _, PathExt). 988 989same_file([File-PI|T0], File, [PI|PIs], T) :- 990 !, 991 same_file(T0, File, PIs, T). 992same_file(List, _, [], List). 993 994comma_list(Var) --> 995 { var(Var), 996 !, 997 '$instantiation_error'(Var) 998 }. 999comma_list((A,B)) --> 1000 !, 1001 comma_list(A), 1002 comma_list(B). 1003comma_list(A) --> 1004 [A]