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yap-6.3/LGPL/shlib.pl
2010-06-17 00:33:20 +01:00

410 lines
12 KiB
Prolog

/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@cs.vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2009, University of Amsterdam
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
:- module(shlib,
[ load_foreign_library/1, % :LibFile
load_foreign_library/2, % :LibFile, +InstallFunc
unload_foreign_library/1, % +LibFile
unload_foreign_library/2, % +LibFile, +UninstallFunc
current_foreign_library/2, % ?LibFile, ?Public
reload_foreign_libraries/0,
% Directives
use_foreign_library/1, % :LibFile
use_foreign_library/2 % :LibFile, +InstallFunc
]).
:- use_module(library(lists), [reverse/2]).
:- set_prolog_flag(generate_debug_info, false).
/** <module> Utility library for loading foreign objects (DLLs, shared objects)
This section discusses the functionality of the (autoload)
library(shlib), providing an interface to manage shared libraries. We
describe the procedure for using a foreign resource (DLL in Windows and
shared object in Unix) called =mylib=.
First, one must assemble the resource and make it compatible to
SWI-Prolog. The details for this vary between platforms. The plld(1)
utility can be used to deal with this in a portable manner. The typical
commandline is:
==
plld -o mylib file.{c,o,cc,C} ...
==
Make sure that one of the files provides a global function
=|install_mylib()|= that initialises the module using calls to
PL_register_foreign(). Here is a simple example file mylib.c, which
creates a Windows MessageBox:
==
#include <windows.h>
#include <SWI-Prolog.h>
static foreign_t
pl_say_hello(term_t to)
{ char *a;
if ( PL_get_atom_chars(to, &a) )
{ MessageBox(NULL, a, "DLL test", MB_OK|MB_TASKMODAL);
PL_succeed;
}
PL_fail;
}
install_t
install_mylib()
{ PL_register_foreign("say_hello", 1, pl_say_hello, 0);
}
==
Now write a file mylib.pl:
==
:- module(mylib, [ say_hello/1 ]).
:- use_foreign_library(foreign(mylib)).
==
The file mylib.pl can be loaded as a normal Prolog file and provides the
predicate defined in C.
*/
:- meta_predicate
load_foreign_library(:),
load_foreign_library(:, +),
use_foreign_library(:),
use_foreign_library(:, +).
:- dynamic
loading/1, % Lib
error/2, % File, Error
foreign_predicate/2, % Lib, Pred
current_library/5. % Lib, Entry, Path, Module, Handle
:- volatile % Do not store in state
loading/1,
error/2,
foreign_predicate/2,
current_library/5.
:- ( current_prolog_flag(open_shared_object, true)
-> true
; print_message(warning, shlib(not_supported)) % error?
).
/*******************************
* DISPATCHING *
*******************************/
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Windows: If libpl.dll is compiled for debugging, prefer loading <lib>D.dll
to allow for debugging.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
find_library(Spec, Lib) :-
current_prolog_flag(windows, true),
false,
current_prolog_flag(kernel_compile_mode, debug),
libd_spec(Spec, SpecD),
catch(find_library2(SpecD, Lib), _, fail).
find_library(Spec, Lib) :-
find_library2(Spec, Lib).
find_library2(Spec, Lib) :-
absolute_file_name(Spec,
[ file_type(executable),
access(read),
file_errors(fail)
], Lib), !.
find_library2(Spec, Spec) :-
atom(Spec), !. % use machines finding schema
find_library2(foreign(Spec), Spec) :-
atom(Spec), !. % use machines finding schema
find_library2(Spec, _) :-
throw(error(existence_error(source_sink, Spec), _)).
libd_spec(Name, NameD) :-
atomic(Name),
file_name_extension(Base, Ext, Name),
atom_concat(Base, 'D', BaseD),
file_name_extension(BaseD, Ext, NameD).
libd_spec(Spec, SpecD) :-
compound(Spec),
Spec =.. [Alias,Name],
libd_spec(Name, NameD),
SpecD =.. [Alias,NameD].
libd_spec(Spec, Spec). % delay errors
base(Path, Base) :-
atomic(Path), !,
file_base_name(Path, File),
file_name_extension(Base, _Ext, File).
base(Path, Base) :-
Path =.. [_,Arg],
base(Arg, Base).
entry(_, Function, Function) :-
Function \= default(_), !.
entry(Spec, default(FuncBase), Function) :-
base(Spec, Base),
atomic_list_concat([FuncBase, Base], '_', Function).
entry(_, default(Function), Function).
/*******************************
* (UN)LOADING *
*******************************/
%% load_foreign_library(:FileSpec) is det.
%% load_foreign_library(:FileSpec, +Entry:atom) is det.
%
% Load a _|shared object|_ or _DLL_. After loading the Entry
% function is called without arguments. The default entry function
% is composed from =install_=, followed by the file base-name.
% E.g., the load-call below calls the function
% =|install_mylib()|=. If the platform prefixes extern functions
% with =_=, this prefix is added before calling.
%
% ==
% ...
% load_foreign_library(foreign(mylib)),
% ...
% ==
%
% @param FileSpec is a specification for absolute_file_name/3. If searching
% the file fails, the plain name is passed to the OS to try the default
% method of the OS for locating foreign objects. The default definition
% of file_search_path/2 searches <prolog home>/lib/<arch> on Unix and
% <prolog home>/bin on Windows.
%
% @see use_foreign_library/1,2 are intended for use in directives.
load_foreign_library(Library) :-
load_foreign_library(Library, default(install)).
load_foreign_library(Module:LibFile, Entry) :-
with_mutex('$foreign',
load_foreign_library(LibFile, Module, Entry)).
load_foreign_library(LibFile, _Module, _) :-
current_library(LibFile, _, _, _, _), !.
load_foreign_library(LibFile, Module, DefEntry) :-
retractall(error(_, _)),
find_library(LibFile, Path),
asserta(loading(LibFile)),
catch(Module:open_shared_object(Path, Handle), E, true),
( nonvar(E)
-> assert(error(Path, E)),
fail
; true
), !,
( ( entry(LibFile, DefEntry, Entry),
Module:call_shared_object_function(Handle, Entry)
-> true
; DefEntry == default(install)
)
-> retractall(loading(LibFile)),
assert_shlib(LibFile, Entry, Path, Module, Handle)
; retractall(loading(LibFile)),
close_shared_object(Handle),
print_message(error, shlib(LibFile, call_entry(DefEntry))),
fail
).
load_foreign_library(LibFile, _, _) :-
retractall(loading(LibFile)),
( error(_Path, E)
-> retractall(error(_, _)),
throw(E)
; throw(error(existence_error(foreign_library, LibFile), _))
).
%% use_foreign_library(+FileSpec) is det.
%% use_foreign_library(+FileSpec, +Entry:atom) is det.
%
% Load and install a foreign library as load_foreign_library/1,2
% and register the installation using initialization/2 with the
% option =now=. This is similar to using:
%
% ==
% :- initialization(load_foreign_library(foreign(mylib))).
% ==
%
% but using the initialization/1 wrapper causes the library to be
% loaded _after_ loading of the file in which it appears is
% completed, while use_foreign_library/1 loads the library
% _immediately_. I.e. the difference is only relevant if the
% remainder of the file uses functionality of the C-library.
use_foreign_library(FileSpec) :-
initialization(load_foreign_library(FileSpec), now).
use_foreign_library(FileSpec, Entry) :-
initialization(load_foreign_library(FileSpec, Entry), now).
%% unload_foreign_library(+FileSpec) is det.
%% unload_foreign_library(+FileSpec, +Exit:atom) is det.
%
% Unload a _|shared object|_ or _DLL_. After calling the Exit
% function, the shared object is removed from the process. The
% default exit function is composed from =uninstall_=, followed by
% the file base-name.
unload_foreign_library(LibFile) :-
unload_foreign_library(LibFile, default(uninstall)).
unload_foreign_library(LibFile, DefUninstall) :-
with_mutex('$foreign', do_unload(LibFile, DefUninstall)).
do_unload(LibFile, DefUninstall) :-
current_library(LibFile, _, _, Module, Handle),
retractall(current_library(LibFile, _, _, _, _)),
( entry(LibFile, DefUninstall, Uninstall),
Module:call_shared_object_function(Handle, Uninstall)
-> true
; true
),
abolish_foreign(LibFile),
close_shared_object(Handle).
abolish_foreign(LibFile) :-
( retract(foreign_predicate(LibFile, Module:Head)),
functor(Head, Name, Arity),
abolish(Module:Name, Arity),
fail
; true
).
system:'$foreign_registered'(M, H) :-
( loading(Lib)
-> true
; Lib = '<spontaneous>'
),
assert(foreign_predicate(Lib, M:H)).
assert_shlib(File, Entry, Path, Module, Handle) :-
retractall(current_library(File, _, _, _, _)),
asserta(current_library(File, Entry, Path, Module, Handle)).
/*******************************
* ADMINISTRATION *
*******************************/
%% current_foreign_library(?File, ?Public)
%
% Query currently loaded shared libraries.
current_foreign_library(File, Public) :-
current_library(File, _Entry, _Path, _Module, _Handle),
findall(Pred, foreign_predicate(File, Pred), Public).
/*******************************
* RELOAD *
*******************************/
%% reload_foreign_libraries
%
% Reload all foreign libraries loaded (after restore of a state
% created using qsave_program/2.
reload_foreign_libraries :-
findall(lib(File, Entry, Module),
( retract(current_library(File, Entry, _, Module, _)),
File \== -
),
Libs),
reverse(Libs, Reversed),
reload_libraries(Reversed).
reload_libraries([]).
reload_libraries([lib(File, Entry, Module)|T]) :-
( load_foreign_library(File, Module, Entry)
-> true
; print_message(error, shlib(File, load_failed))
),
reload_libraries(T).
/*******************************
* CLEANUP (WINDOWS ...) *
*******************************/
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Called from Halt() in pl-os.c (if it is defined), *after* all at_halt/1
hooks have been executed, and after dieIO(), closing and flushing all
files has been called.
On Unix, this is not very useful, and can only lead to conflicts.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
unload_all_foreign_libraries :-
current_prolog_flag(unix, true), !.
unload_all_foreign_libraries :-
forall(current_library(File, _, _, _, _),
unload_foreign(File)).
%% unload_foreign(+File)
%
% Unload the given foreign file and all `spontaneous' foreign
% predicates created afterwards. Handling these spontaneous
% predicates is a bit hard, as we do not know who created them and
% on which library they depend.
unload_foreign(File) :-
unload_foreign_library(File),
( clause(foreign_predicate(Lib, M:H), true, Ref),
( Lib == '<spontaneous>'
-> functor(H, Name, Arity),
abolish(M:Name, Arity),
erase(Ref),
fail
; !
)
-> true
; true
).
/*******************************
* MESSAGES *
*******************************/
:- multifile
prolog:message/3.
prolog:message(shlib(LibFile, call_entry(DefEntry))) -->
[ '~w: Failed to call entry-point ~w'-[LibFile, DefEntry] ].
prolog:message(shlib(LibFile, load_failed)) -->
[ '~w: Failed to load file'-[LibFile] ].
prolog:message(shlib(not_supported)) -->
[ 'Emulator does not support foreign libraries' ].