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)  2011-2025, VU University Amsterdam
    7                              CWI, 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(prolog_history,
   38          [ prolog_history/1
   39          ]).   40:- autoload(library(base32),[base32/2]).   41
   42:- multifile
   43    prolog:history/2.   44
   45/** <module> Per-directory persistent commandline history
   46
   47This module implements  persistency  of   the  commandline  history over
   48Prolog sessions on Prolog  installations  that   are  based  on  the GNU
   49readline library (default for the development version on Unix systems).
   50
   51The history is stored  in   the  directory ``<config>/dir-history``. For
   52each directory for which it keeps the  history, there is file whose name
   53is the base32 encoding of the directory path.
   54
   55This file is normally loaded when Prolog is started if =user_input= is a
   56terminal and the system supports history.
   57*/
   58
   59:- create_prolog_flag(save_history, true, [type(boolean)]).   60
   61%!  history_directory(-Dir) is semidet.
   62%
   63%   Dir is the directory where   the per-directory history databases
   64%   are stored.
   65
   66history_directory(Dir) :-
   67    absolute_file_name(user_app_config('dir-history'),
   68                       Dir,
   69                       [ access(write),
   70                         file_type(directory),
   71                         file_errors(fail)
   72                       ]),
   73    !.
   74history_directory(Dir) :-
   75    absolute_file_name(user_app_config('.'),
   76                       ConfigDir,
   77                       [ access(write),
   78                         file_type(directory),
   79                         file_errors(fail)
   80                       ]),
   81    atom_concat(ConfigDir, '/dir-history', Dir),
   82    (   exists_directory(Dir)
   83    ->  '$my_file'(Dir)
   84    ;   file_directory_name(Dir, Parent),
   85        '$my_file'(Parent),
   86        make_directory(Dir)
   87    ).
   88
   89%!  dir_history_file(+Dir, -File) is det.
   90%!  dir_history_file(?Dir, ?File) is nondet.
   91%
   92%   File is the history file for a Prolog session running in Dir.
   93
   94dir_history_file(Dir, File) :-
   95    nonvar(Dir),
   96    !,
   97    history_directory(Base),
   98    absolute_file_name(Dir, Path),
   99    base32(Path, Encoded),
  100    atomic_list_concat([Base, Encoded], /, File).
  101dir_history_file(Dir, File) :-
  102    history_directory(HDir),
  103    directory_files(HDir, Files),
  104    '$member'(Base32, Files),
  105    base32(Dir, Base32),
  106    !,
  107    atomic_list_concat([Dir, Base32], /, File).
  108
  109write_history(File) :-
  110    current_prolog_flag(save_history, true),
  111    catch(prolog:history(user_input, save(File)), _, true), !.
  112write_history(_).
  113
  114
  115%!  prolog_history(+Action) is det.
  116%
  117%   Execute Action on  the  history.   Action is one of
  118%
  119%     - enable
  120%       Enable history. First loads history for the current directory.
  121%       Loading the history is done at most once.
  122%     - disable
  123%       Sets the Prolog flag `save_history` to `false`, such that the
  124%       history is not saved on halt.
  125%     - save
  126%       If there is a history loaded from a file, save the current
  127%       history back into that file if `save_history` is `true`
  128
  129:- thread_local history_loaded/1.  130
  131load_dir_history(File) :-
  132    (   exists_file(File),
  133        prolog:history(user_input, load(File))
  134    ->  assertz(history_loaded(File))
  135    ;   true
  136    ).
  137
  138prolog_history(enable) =>
  139    (   history_loaded(_)
  140    ->  true
  141    ;   catch(dir_history_file('.', File), E,
  142              (print_message(warning, E),fail)),
  143        catch(load_dir_history(File), E,
  144              print_message(warning, E)),
  145        (   thread_self(main)
  146        ->  at_halt(write_history(File))
  147        ;   true
  148        ),
  149        set_prolog_flag(save_history, true)
  150    ).
  151prolog_history(disable) =>
  152    set_prolog_flag(save_history, false).
  153prolog_history(save) =>
  154    (   history_loaded(File)
  155    ->  write_history(File)
  156    ;   true
  157    )