1/*  Part of XPCE --- The SWI-Prolog GUI toolkit
    2
    3    Author:        Jan Wielemaker and Anjo Anjewierden
    4    E-mail:        jan@swi-prolog.org
    5    WWW:           http://www.swi-prolog.nl/projects/xpce/
    6    Copyright (c)  2011-2025, University of Amsterdam
    7                              VU University Amsterdam
    8                              SWI-Prolog Solutions b.v.
    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(link_xpce, []).   38:- if(\+current_prolog_flag(xpce,false)).   39:- set_prolog_flag(generate_debug_info, true).   40
   41/** <module> Associate XPCE with SWI-Prolog
   42
   43This  file  initialises  XPCE,  the  SWI-Prolog   native  GUI.  XPCE  is
   44initialised if one of these conditions is true.
   45
   46  - The Prolog flag `xpce` is `true`
   47  - There is a GUI.  See has_display/0 below.  In this case, XPCE
   48    is loaded if the Prolog flag `xpce` is `true`.  Otherwise it is
   49    setup to be loaded lazily if one of the GUI IDE tools is invoked.
   50
   51The source-location of this file  is packages/xpce/swipl/swipl-rc. It is
   52installed as <plbase>/<exe-base>.rc, where   <exe-base> is ``swipl-win``
   53to  associate  with  the  SWI-Prolog  gui  application  on  Windows  and
   54``swipl`` on Unix/X11 platforms.
   55*/
   56
   57:- multifile
   58    user:file_search_path/2.   59:- dynamic
   60    pce_setup_done/1.   61
   62has_xpce_library :-
   63    pce_setup_done(How),
   64    How \== false.
   65
   66user:file_search_path(pce, swi(xpce)) :-
   67    has_xpce_library.
   68user:file_search_path(library, pce('prolog/lib')) :-
   69    has_xpce_library.
   70user:file_search_path(foreign, pce(ArchLib)) :-
   71    has_xpce_library,
   72    current_prolog_flag(arch, Arch),
   73    atom_concat('lib/', Arch, ArchLib).
   74
   75%!  gui_setup_
   76%
   77%   We have a GUI. Prepare it. This loads  hooks that may enable the gui
   78%   and set the editor to PceEmacs if it is still `default`.
   79
   80gui_setup_ :-
   81    current_prolog_flag(gui, true),
   82    !.
   83gui_setup_ :-
   84    create_prolog_flag(gui, true, []),
   85    editor_setup,
   86    use_module(user:library(swi_hooks)).
   87
   88editor_setup :-
   89    current_prolog_flag(editor, default),
   90    !,
   91    set_prolog_flag(editor, pce_emacs).
   92editor_setup.
   93
   94%!  has_display is semidet.
   95%
   96%   True when we can run graphics.  Graphics are always available on
   97%   Windows or MacOS (although they may   appear on the main console
   98%   when invoked from a  remote  login).   On  Linux,  we can detect
   99%   ``DISPLAY`` (X11) or  ``WAYLAND_DISPLAY``   (Wayland).  We  also
  100%   assume we can run graphics if the ``SDL_VIDEO_DRIVER`` is set to
  101%   `dummy`, implying we try to run _headless_.
  102
  103has_display :- current_prolog_flag(windows, true), !.
  104has_display :- current_prolog_flag(apple, true), !.
  105has_display :- getenv('WAYLAND_DISPLAY', D), D \== '', !.
  106has_display :- getenv('DISPLAY', D), D \== '', !.
  107has_display :- getenv('SDL_VIDEODRIVER', dummy).
  108has_display :- current_prolog_flag('SDL_VIDEODRIVER', dummy).
  109
  110%!  pce_setup_ is det.
  111%
  112%   Setup xpce.  There are these cases:
  113%
  114%     - The flag `xpce` is `false`: do not setup xpce.
  115%     - The flag `xpce` is `true`: load xpce and set it up.
  116%     - The flag `xpce` is not present.  Now
  117%       - If we seem to have a gui, prepare xpce to be loaded lazily
  118%       - If there is no gui, do not setup xpce.
  119
  120pce_setup_ :-
  121    pce_setup_done(_),
  122    !.
  123pce_setup_ :-
  124    (   current_prolog_flag(xpce, true)
  125    ->  Preload = true,
  126        How = true
  127    ;   has_display,                % no explicit xpce flag
  128        Preload = false,
  129        How = lazy
  130    ),
  131    !,
  132    set_prolog_flag(xpce, true),
  133    asserta(pce_setup_done(How)),
  134    reload_library_index,
  135    gui_setup_,
  136    (   Preload == true
  137    ->  ensure_loaded(user:library(pce))
  138    ;   true
  139    ).
  140pce_setup_ :-                       % Implicit and no display
  141    asserta(pce_setup_done(false)).
  142
  143:- initialization pce_setup_.  144:- endif. % \+ current_prolog_flag(xpce,false)