1/*  Part of Extended Libraries for SWI-Prolog
    2
    3    Author:        Edison Mera
    4    E-mail:        efmera@gmail.com
    5    WWW:           https://github.com/edisonm/xlibrary
    6    Copyright (C): 2021, Process Design Center, Breda, The Netherlands.
    7    All rights reserved.
    8
    9    Redistribution and use in source and binary forms, with or without
   10    modification, are permitted provided that the following conditions
   11    are met:
   12
   13    1. Redistributions of source code must retain the above copyright
   14       notice, this list of conditions and the following disclaimer.
   15
   16    2. Redistributions in binary form must reproduce the above copyright
   17       notice, this list of conditions and the following disclaimer in
   18       the documentation and/or other materials provided with the
   19       distribution.
   20
   21    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   22    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   23    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   24    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   25    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   26    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   27    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   28    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   29    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   31    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   32    POSSIBILITY OF SUCH DAMAGE.
   33*/
   34
   35:- module(broker,
   36          [ add_server/2,
   37            del_server/1,
   38            module_server/2
   39          ]).   40
   41:- use_module(library(lists)).   42:- use_module(library(neck)).   43:- use_module(library(codegen)).   44:- reexport(library(compound_expand)).   45:- use_module(library(change_alias)).   46:- reexport(library(interface)).   47:- init_expansors.

fallback(local)
timeout
timereset

   63:- dynamic
   64    module_server/2.   65
   66:- multifile
   67    '$broker'/1.   68
   69alias_file(RelTo, Alias, File) :-
   70    absolute_file_name(Alias, File, [file_type(prolog), relative_to(RelTo)]).
   71
   72add_server(Module, URL) :-
   73    '$broker'(Module),
   74    assertz(module_server(Module, URL)).
   75
   76del_server(Module) :-
   77    '$broker'(Module),
   78    retractall(module_server(Module, _)).
   79
   80generate_broker(Target, File, Module, AliasTo) -->
   81    { prolog_load_context(source, RelTo),
   82      atom_concat(Module, '_intf', Interface),
   83      atom_concat(Module, '_remt', ImplRemote),
   84      atom_concat(Module, '_locl', ImplLocal)
   85    },
   86    [broker:'$broker'(Module)],
   87    generate_interface(     File, RelTo, Module, Interface,  AliasTo, AliasIntf),
   88    generate_local( Target, File, RelTo, Module, ImplLocal,  AliasTo, AliasIntf),
   89    generate_remote(Target, File, RelTo, Module, ImplRemote, AliasTo, AliasIntf),
   90    generate_server(Target, File, RelTo, Module, Interface,  AliasTo),
   91    {bind_implementation(Target, ImplLocal, ImplRemote, BindModule)},
   92    [(:- initialization(bind_interface(Interface, BindModule)))].
   93
   94bind_implementation(client, _, M, M).
   95bind_implementation(server, M, _, M).
   96bind_implementation(proxy,  _, M, M).
   97bind_implementation(A,B,C,D) :- writeln(user_error, bind_implementation(A,B,C,D)),fail.
   98
   99generate_interface(File, RelTo, Module, Interface, AliasTo, AliasIntf) -->
  100    {generate_file('_intf', File, RelTo, AliasTo, AliasIntf, dump_interface(Module, Interface))},
  101    [(:- use_module(AliasIntf))].
  102
  103generate_local(Target, _, _, _, _, _, _) -->
  104    {member(Target, [client, proxy])},
  105    neck.
  106generate_local(server, File, RelTo, Module, ImplLocal, AliasTo, AliasIntf) -->
  107    generate_file('_locl', File, RelTo, AliasTo, _, dump_local(Module, ImplLocal, AliasIntf)).
  108
  109generate_remote(server, _, _, _, _, _, _) --> [].
  110generate_remote(Target, File, RelTo, Module, ImplRemote, AliasTo, AliasIntf) -->
  111    {member(Target, [client, proxy])},
  112    neck,
  113    generate_file('_remt', File, RelTo, AliasTo, _, dump_remote(Module, ImplRemote, AliasIntf)).
  114
  115generate_server(client, _, _, _, _, _) --> [].
  116generate_server(Target, File, RelTo, Module, Interface, AliasTo) -->
  117    {member(Target, [server, proxy])},
  118    neck,
  119    generate_file('_serv', File, RelTo, AliasTo, _, dump_server(Module, Interface)).
  120
  121:- meta_predicate
  122    generate_file(+,+,+,+,+,2),
  123    generate_file(+,+,+,+,+,2,?,?).  124
  125generate_file(Suffix, File, RelTo, AliasIntf, AliasSuff, Dump) :-
  126    change_alias(add_suffix(Suffix), AliasIntf, AliasSuff),
  127    alias_file(RelTo, AliasSuff, FileSuff),
  128    ( is_newer(FileSuff, File)
  129    ->true
  130    ; save_to_file(FileSuff, Dump)
  131    ).
  132
  133generate_file(Suffix, File, RelTo, AliasIntf, AliasSuff, Dump) -->
  134    {generate_file(Suffix, File, RelTo, AliasIntf, AliasSuff, Dump)},
  135    [(:- use_module(AliasSuff, []))].
  136
  137dump_interface(Module, Interface) -->
  138    [(:- module(Interface, [])),
  139     (:- use_module(library(interface))),
  140     (:- interfaces_mod(Module))].
  141
  142dump_local(Module, ImplLocal, AliasIntf) -->
  143    [(:- module(ImplLocal, [])),
  144     (:- use_module(library(interface))),
  145     (:- implements(AliasIntf)),
  146     (:- module_property(Module, file(File)),
  147         reexport(File))].
  148
  149dump_remote(Module, ImplRemote, AliasIntf) -->
  150    [(:- module(ImplRemote, [])),
  151     (:- use_module(library(interface))),
  152     (:- use_module(library(broker_rt))),
  153     (:- implements(AliasIntf))
  154    ],
  155    findall((H :- remote_call(H, Module)),
  156            ( module_property(Module, exports(PIL)),
  157              member(F/A, PIL),
  158              functor(H, F, A)
  159            )).
  160
  161dump_server(Module, Interface) -->
  162    {atom_concat(Module, '_serv', ImplService)},
  163    [(:- module(ImplService, [])),
  164     (:- use_module(library(http/http_dispatch))),
  165     (:- use_module(library(http/websocket))),
  166     (:- use_module(library(interface))),
  167     (:- use_module(library(broker_ws))),
  168     (:- http_handler(root(broker/Module),
  169                      http_upgrade_to_websocket(broker_ws(Interface), []),
  170                      [spawn([])]))].
  171
  172term_expansion_broker(Target, Alias, AliasIntf) -->
  173    { use_module(Alias, []), % Ensure that the module is loaded
  174      absolute_file_name(Alias, File, [file_type(prolog), access(read)]),
  175      module_property(Module, file(File))
  176    },
  177    generate_broker(Target, File, Module, AliasIntf).
  178
  179term_expansion((:- broker_client(Alias, AliasIntf)), Clauses) :-
  180    phrase(term_expansion_broker(client, Alias, AliasIntf), Clauses).
  181term_expansion((:- broker_server(Alias, AliasIntf)), Clauses) :-
  182    phrase(term_expansion_broker(server, Alias, AliasIntf), Clauses).
  183term_expansion((:- broker_proxy( Alias, AliasIntf)), Clauses) :-
  184    phrase(term_expansion_broker(proxy,  Alias, AliasIntf), Clauses)