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    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)  1999-2017, 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(thread_util,
   37          [ thread_run_interactor/0,    % interactor main loop
   38            threads/0,                  % List available threads
   39            join_threads/0,             % Join all terminated threads
   40            interactor/0,               % Create a new interactor
   41            interactor/1,               % ?Title
   42            thread_has_console/0,       % True if thread has a console
   43            attach_console/0,           % Create a new console for thread.
   44            attach_console/1,           % ?Title
   45
   46            tspy/1,                     % :Spec
   47            tspy/2,                     % :Spec, +ThreadId
   48            tdebug/0,
   49            tdebug/1,                   % +ThreadId
   50            tnodebug/0,
   51            tnodebug/1,                 % +ThreadId
   52            tprofile/1,                 % +ThreadId
   53            tbacktrace/1,               % +ThreadId,
   54            tbacktrace/2                % +ThreadId, +Options
   55          ]).   56:- autoload(library(apply),[maplist/3]).   57:- autoload(library(backcomp),[thread_at_exit/1]).   58:- autoload(library(edinburgh),[nodebug/0]).   59:- autoload(library(lists),[max_list/2,append/2]).   60:- autoload(library(option),[merge_options/3,option/3]).   61:- autoload(library(prolog_stack),
   62	    [print_prolog_backtrace/2,get_prolog_backtrace/3]).   63:- autoload(library(statistics),[thread_statistics/2,show_profile/1]).   64:- autoload(library(thread),[call_in_thread/2]).   65
   66:- if(exists_source(library(pce))).   67:- autoload(library(gui_tracer),[gdebug/0]).   68:- autoload(library(pce),[send/2]).   69:- else.   70gdebug :-
   71    debug.
   72:- endif.   73
   74
   75:- set_prolog_flag(generate_debug_info, false).   76
   77:- module_transparent
   78    tspy/1,
   79    tspy/2.

Interactive thread utilities

This library provides utilities that are primarily intended for interactive usage in a threaded Prolog environment. It allows for inspecting threads, manage I/O of background threads (depending on the environment) and manipulating the debug status of threads. */

 threads
List currently known threads with their status.
   93threads :-
   94    threads(Threads),
   95    print_message(information, threads(Threads)).
   96
   97threads(Threads) :-
   98    findall(Thread, thread_statistics(_,Thread), Threads).
 join_threads
Join all terminated threads.
  104join_threads :-
  105    findall(Ripped, rip_thread(Ripped), AllRipped),
  106    (   AllRipped == []
  107    ->  true
  108    ;   print_message(informational, joined_threads(AllRipped))
  109    ).
  110
  111rip_thread(thread{id:id, status:Status}) :-
  112    thread_property(Id, status(Status)),
  113    Status \== running,
  114    \+ thread_self(Id),
  115    thread_join(Id, _).
 interactor is det
 interactor(?Title) is det
Run a Prolog toplevel in another thread with a new console window. If Title is given, this will be used as the window title.
  123interactor :-
  124    interactor(_).
  125
  126interactor(Title) :-
  127    thread_self(Me),
  128    thread_create(thread_run_interactor(Me, Title), _Id,
  129                  [ detached(true),
  130                    debug(false)
  131                  ]),
  132    thread_get_message(title(Title)).
  133
  134thread_run_interactor(Creator, Title) :-
  135    set_prolog_flag(query_debug_settings, debug(false, false)),
  136    attach_console(Title),
  137    thread_send_message(Creator, title(Title)),
  138    print_message(banner, thread_welcome),
  139    prolog.
 thread_run_interactor
Attach a console and run a Prolog toplevel in the current thread.
  145thread_run_interactor :-
  146    set_prolog_flag(query_debug_settings, debug(false, false)),
  147    attach_console(_Title),
  148    print_message(banner, thread_welcome),
  149    prolog.
 thread_has_console is semidet
True when the calling thread has an attached console.
See also
- attach_console/0
  157:- dynamic
  158    has_console/4.                  % Id, In, Out, Err
  159
  160thread_has_console(main) :- !.                  % we assume main has one.
  161thread_has_console(Id) :-
  162    has_console(Id, _, _, _).
  163
  164thread_has_console :-
  165    current_prolog_flag(break_level, _),
  166    !.
  167thread_has_console :-
  168    thread_self(Id),
  169    thread_has_console(Id),
  170    !.
 attach_console is det
 attach_console(?Title) is det
Create a new console and make the standard Prolog streams point to it. If not provided, the title is built using the thread id. Does nothing if the current thread already has a console attached.
  179attach_console :-
  180    attach_console(_).
  181
  182attach_console(_) :-
  183    thread_has_console,
  184    !.
  185attach_console(Title) :-
  186    thread_self(Id),
  187    (   var(Title)
  188    ->  console_title(Id, Title)
  189    ;   true
  190    ),
  191    open_console(Title, In, Out, Err),
  192    assert(has_console(Id, In, Out, Err)),
  193    set_stream(In,  alias(user_input)),
  194    set_stream(Out, alias(user_output)),
  195    set_stream(Err, alias(user_error)),
  196    set_stream(In,  alias(current_input)),
  197    set_stream(Out, alias(current_output)),
  198    enable_line_editing(In,Out,Err),
  199    thread_at_exit(detach_console(Id)).
  200
  201console_title(Thread, Title) :-         % uses tabbed consoles
  202    current_prolog_flag(console_menu_version, qt),
  203    !,
  204    human_thread_id(Thread, Id),
  205    format(atom(Title), 'Thread ~w', [Id]).
  206console_title(Thread, Title) :-
  207    current_prolog_flag(system_thread_id, SysId),
  208    human_thread_id(Thread, Id),
  209    format(atom(Title),
  210           'SWI-Prolog Thread ~w (~d) Interactor',
  211           [Id, SysId]).
  212
  213human_thread_id(Thread, Alias) :-
  214    thread_property(Thread, alias(Alias)),
  215    !.
  216human_thread_id(Thread, Id) :-
  217    thread_property(Thread, id(Id)).
 open_console(+Title, -In, -Out, -Err) is det
Open a new console window and unify In, Out and Err with the input, output and error streams for the new console.
  224:- multifile xterm_args/1.  225:- dynamic   xterm_args/1.  226
  227:- if(current_predicate(win_open_console/5)).  228
  229open_console(Title, In, Out, Err) :-
  230    thread_self(Id),
  231    regkey(Id, Key),
  232    win_open_console(Title, In, Out, Err,
  233                     [ registry_key(Key)
  234                     ]).
  235
  236regkey(Key, Key) :-
  237    atom(Key).
  238regkey(_, 'Anonymous').
  239
  240:- else.
 xterm_args(-List) is nondet
Multifile and dynamic hook that provides (additional) arguments for the xterm(1) process opened for additional thread consoles. Each solution must bind List to a list of atomic values. All solutions are concatenated using append/2 to form the final argument list.

The defaults set the colors to black-on-light-yellow, enable a scrollbar, set the font using Xft font pattern and prepares the back-arrow key.

  253xterm_args(['-xrm', '*backarrowKeyIsErase: false']).
  254xterm_args(['-xrm', '*backarrowKey: false']).
  255xterm_args(['-fa', 'Ubuntu Mono', '-fs', 12]).
  256xterm_args(['-fg', '#000000']).
  257xterm_args(['-bg', '#ffffdd']).
  258xterm_args(['-sb', '-sl', 1000, '-rightbar']).
  259
  260open_console(Title, In, Out, Err) :-
  261    findall(Arg, xterm_args(Arg), Args),
  262    append(Args, Argv),
  263    open_xterm(Title, In, Out, Err, Argv).
  264
  265:- endif.
 enable_line_editing(+In, +Out, +Err) is det
Enable line editing for the console. This is by built-in for the Windows console. We can also provide it for the X11 xterm(1) based console if we use the BSD libedit based command line editor.
  273:- if((current_prolog_flag(readline, editline),
  274       exists_source(library(editline)))).  275enable_line_editing(_In, _Out, _Err) :-
  276    current_prolog_flag(readline, editline),
  277    !,
  278    el_wrap.
  279:- endif.  280enable_line_editing(_In, _Out, _Err).
  281
  282:- if(current_predicate(el_unwrap/1)).  283disable_line_editing(_In, _Out, _Err) :-
  284    el_unwrap(user_input).
  285:- endif.  286disable_line_editing(_In, _Out, _Err).
 detach_console(+ThreadId) is det
Destroy the console for ThreadId.
  293detach_console(Id) :-
  294    (   retract(has_console(Id, In, Out, Err))
  295    ->  disable_line_editing(In, Out, Err),
  296        close(In, [force(true)]),
  297        close(Out, [force(true)]),
  298        close(Err, [force(true)])
  299    ;   true
  300    ).
  301
  302
  303                 /*******************************
  304                 *          DEBUGGING           *
  305                 *******************************/
 tspy(:Spec) is det
 tspy(:Spec, +ThreadId) is det
Trap the graphical debugger on reaching Spec in the specified or any thread.
  313tspy(Spec) :-
  314    spy(Spec),
  315    tdebug.
  316
  317tspy(Spec, ThreadID) :-
  318    spy(Spec),
  319    tdebug(ThreadID).
 tdebug is det
 tdebug(+Thread) is det
Enable debug-mode, trapping the graphical debugger on reaching spy-points or errors.
  328tdebug :-
  329    forall(debug_target(Id), thread_signal(Id, gdebug)).
  330
  331tdebug(ThreadID) :-
  332    thread_signal(ThreadID, gdebug).
 tnodebug is det
 tnodebug(+Thread) is det
Disable debug-mode in all threads or the specified Thread.
  339tnodebug :-
  340    forall(debug_target(Id), thread_signal(Id, nodebug)).
  341
  342tnodebug(ThreadID) :-
  343    thread_signal(ThreadID, nodebug).
  344
  345
  346debug_target(Thread) :-
  347    thread_property(Thread, status(running)),
  348    thread_property(Thread, debug(true)).
 tbacktrace(+Thread) is det
 tbacktrace(+Thread, +Options) is det
Print a backtrace for Thread to the stream user_error of the calling thread. This is achieved by inserting an interrupt into Thread using call_in_thread/2. Options:
depth(+MaxFrames)
Number of stack frames to show. Default is the current Prolog flag backtrace_depth or 20.

Other options are passed to get_prolog_backtrace/3.

bug
- call_in_thread/2 may not process the event.
  365tbacktrace(Thread) :-
  366    tbacktrace(Thread, []).
  367
  368tbacktrace(Thread, Options) :-
  369    merge_options(Options, [clause_references(false)], Options1),
  370    (   current_prolog_flag(backtrace_depth, Default)
  371    ->  true
  372    ;   Default = 20
  373    ),
  374    option(depth(Depth), Options1, Default),
  375    call_in_thread(Thread, thread_get_prolog_backtrace(Depth, Stack, Options1)),
  376    print_prolog_backtrace(user_error, Stack).
 thread_get_prolog_backtrace(+Depth, -Stack, +Options)
As get_prolog_backtrace/3, but starts above the C callback, hiding the overhead inside call_in_thread/2.
  383thread_get_prolog_backtrace(Depth, Stack, Options) :-
  384    prolog_current_frame(Frame),
  385    signal_frame(Frame, SigFrame),
  386    get_prolog_backtrace(Depth, Stack, [frame(SigFrame)|Options]).
  387
  388signal_frame(Frame, SigFrame) :-
  389    prolog_frame_attribute(Frame, clause, _),
  390    !,
  391    (   prolog_frame_attribute(Frame, parent, Parent)
  392    ->  signal_frame(Parent, SigFrame)
  393    ;   SigFrame = Frame
  394    ).
  395signal_frame(Frame, SigFrame) :-
  396    (   prolog_frame_attribute(Frame, parent, Parent)
  397    ->  SigFrame = Parent
  398    ;   SigFrame = Frame
  399    ).
  400
  401
  402
  403                 /*******************************
  404                 *       REMOTE PROFILING       *
  405                 *******************************/
 tprofile(+Thread) is det
Profile the operation of Thread until the user hits a key.
  411tprofile(Thread) :-
  412    init_pce,
  413    thread_signal(Thread,
  414                  (   reset_profiler,
  415                      profiler(_, true)
  416                  )),
  417    format('Running profiler in thread ~w (press RET to show results) ...',
  418           [Thread]),
  419    flush_output,
  420    get_code(_),
  421    thread_signal(Thread,
  422                  (   profiler(_, false),
  423                      show_profile([])
  424                  )).
 init_pce
Make sure XPCE is running if it is attached, so we can use the graphical display using in_pce_thread/1.
  432:- if(exists_source(library(pce))).  433init_pce :-
  434    current_prolog_flag(gui, true),
  435    !,
  436    call(send(@(display), open)).   % avoid autoloading
  437:- endif.  438init_pce.
  439
  440
  441                 /*******************************
  442                 *             HOOKS            *
  443                 *******************************/
  444
  445:- multifile
  446    user:message_hook/3.  447
  448user:message_hook(trace_mode(on), _, Lines) :-
  449    \+ thread_has_console,
  450    \+ current_prolog_flag(gui_tracer, true),
  451    catch(attach_console, _, fail),
  452    print_message_lines(user_error, '% ', Lines).
  453
  454:- multifile
  455    prolog:message/3.  456
  457prolog:message(thread_welcome) -->
  458    { thread_self(Self),
  459      human_thread_id(Self, Id)
  460    },
  461    [ 'SWI-Prolog console for thread ~w'-[Id],
  462      nl, nl
  463    ].
  464prolog:message(joined_threads(Threads)) -->
  465    [ 'Joined the following threads'-[], nl ],
  466    thread_list(Threads).
  467prolog:message(threads(Threads)) -->
  468    thread_list(Threads).
  469
  470thread_list(Threads) -->
  471    { maplist(th_id_len, Threads, Lens),
  472      max_list(Lens, MaxWidth),
  473      LeftColWidth is max(6, MaxWidth),
  474      Threads = [H|_]
  475    },
  476    thread_list_header(H, LeftColWidth),
  477    thread_list(Threads, LeftColWidth).
  478
  479th_id_len(Thread, IdLen) :-
  480    write_length(Thread.id, IdLen, [quoted(true)]).
  481
  482thread_list([], _) --> [].
  483thread_list([H|T], CW) -->
  484    thread_info(H, CW),
  485    (   {T == []}
  486    ->  []
  487    ;   [nl],
  488        thread_list(T, CW)
  489    ).
  490
  491thread_list_header(Thread, CW) -->
  492    { _{id:_, status:_, time:_, stacks:_} :< Thread,
  493      !,
  494      HrWidth is CW+18+13+13
  495    },
  496    [ '~|~tThread~*+ Status~tTime~18+~tStack use~13+~tallocated~13+'-[CW], nl ],
  497    [ '~|~`-t~*+'-[HrWidth], nl ].
  498thread_list_header(Thread, CW) -->
  499    { _{id:_, status:_} :< Thread,
  500      !,
  501      HrWidth is CW+7
  502    },
  503    [ '~|~tThread~*+ Status'-[CW], nl ],
  504    [ '~|~`-t~*+'-[HrWidth], nl ].
  505
  506thread_info(Thread, CW) -->
  507    { _{id:Id, status:Status, time:Time, stacks:Stacks} :< Thread },
  508    !,
  509    [ '~|~t~q~*+ ~w~t~3f~18+~t~D~13+~t~D~13+'-
  510      [ Id, CW, Status, Time.cpu, Stacks.total.usage, Stacks.total.allocated
  511      ]
  512    ].
  513thread_info(Thread, CW) -->
  514    { _{id:Id, status:Status} :< Thread },
  515    !,
  516    [ '~|~t~q~*+ ~w'-
  517      [ Id, CW, Status
  518      ]
  519    ]