/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (c) 2008-2013, University of Amsterdam
VU University Amsterdam
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
:- module(prolog_hotfix,
[ load_hotfixes/1 % +Directory
]).
:- use_module(library(lists)).
:- use_module(library(option)).
:- use_module(library(readutil)).
:- use_module(library(apply)).
:- use_module(library(prolog_source)).
/** <module> Load hotfixes into executables
This library was developed to deal with hotfixing products that are
distributed as a Prolog saved state. It assumes the vendor is willing to
distribute hotfixes as Prolog source files. These files are placed into
a directory. The predicate load_hotfixes/1 replaces files that are
loaded into the saved state.
Resolution of the file to load is based on the module if the hotfix file
provides a module. If the hotfix file is not a module file and there are
multiple loaded source files with the same name from different
directories, the hotfix directory must create the minimal directory
structure to make the paths unique. If omitted, this library will prompt
the user for the file that must be replaced.
@tbd This could be extended in several ways:
* Load hotfixes from a (encrypted) zip file
* Use digital signatures and load over HTTP
* Replace individual predicates
@author Jan Wielemaker
*/
%! load_hotfixes(+Dir) is det.
%
% Load all hotfixes that have not yet been applied into the
% current state.
load_hotfixes(Dir) :-
absolute_file_name(Dir, DirPath,
[ file_type(directory),
access(read)
]),
phrase(prolog_source_files([DirPath]), Files),
ensure_dirsep(DirPath, Common),
maplist(apply_hotfix(Common), Files).
%! prolog_source_files(+Dirs)// is det.
%
% Find all Prolog source files in the given directory.
prolog_source_files([]) --> !.
prolog_source_files([H|T]) -->
!,
prolog_source_files(H),
prolog_source_files(T).
prolog_source_files(F) -->
{ exists_file(F),
file_name_extension(_, Ext, F),
user:prolog_file_type(Ext, prolog)
},
!,
[F].
prolog_source_files(Dir) -->
{ exists_directory(Dir),
!,
atom_concat(Dir, '/*', Pattern),
expand_file_name(Pattern, Members)
},
prolog_source_files(Members).
prolog_source_files(_) -->
[].
%! apply_hotfix(+HotfixDir, +File) is det.
%
% Locate the hotfix and load it if it is newer. First step to find
% the file we must replace is using the module name, as these are
% guaranteed to be unique in the Prolog process. If that fails, we
% use the filename, but now we can get multiple files with the
% same name loaded from different directories as candidates.
% Finally, if no file matches, we load the file into the =user=
% module.
apply_hotfix(_HotfixDir, File) :-
file_module(File, Module),
module_property(Module, file(Loaded)),
'$time_source_file'(Loaded, Time, _Type),
!,
time_file(File, HotfixTime),
( HotfixTime =\= Time
-> load_hotfix(File, Loaded)
; true
).
apply_hotfix(HotfixDir, File) :-
atom_concat(HotfixDir, Local, File),
atom_concat(/, Local, SlashLocal),
findall(Loaded-Time,
( '$time_source_file'(Loaded, Time, user),
sub_atom(Loaded, _, _, 0, SlashLocal)
),
Pairs),
Pairs \== [],
!,
( Pairs = [Loaded-Time]
-> true
; select_file_to_reload(Pairs, Local, Loaded-Time)
),
time_file(File, HotfixTime),
( HotfixTime =\= Time
-> load_hotfix(File, Loaded)
; true
).
apply_hotfix(_HotfixDir, File) :-
user:consult(File).
%! ensure_dirsep(+Dir, -DirSlash) is det.
ensure_dirsep(Dir0, Dir) :-
( sub_atom(Dir0, _, _, 0, /)
-> Dir = Dir0
; atom_concat(Dir0, /, Dir)
).
%! load_hotfix(+HotfixFile, +Loaded) is det.
%
% Reload the HotfixFile, pretending we are reloading Loaded.
%
% @see make:reload_file/1
load_hotfix(File, Loaded) :-
time_file(File, Modified),
setup_call_cleanup(
open(File, read, In),
load_hotfix_from_stream(Loaded, In, Modified),
close(In)).
load_hotfix_from_stream(Loaded, In, Modified) :-
FixOptions = [ stream(In),
modified(Modified),
register(false)
],
set_stream(In, file_name(Loaded)),
findall(M-Opts,
source_file_property(Loaded, load_context(M, _, Opts)),
Modules),
( Modules = [First-OptsFirst|Rest]
-> merge_options(FixOptions, OptsFirst, FirstOptions),
load_stream(First:Loaded, FirstOptions),
forall(member(Context-Opts, Rest),
( merge_options([if(not_loaded)|FirstOptions], Opts, ORest),
load_stream(Context:Loaded, ORest)
))
; load_stream(user:Loaded, FixOptions)
).
load_stream(Source, Options) :-
option(stream(In), Options),
setup_call_cleanup(
stream_property(In, position(Pos)),
load_files(Source, Options),
set_stream_position(In, Pos)).
%! select_file_to_reload(+Pairs, +Local, -Pair) is det.
select_file_to_reload(Pairs, Local, Pair) :-
format(user_error,
'Hotfix ~w matches multiple loaded files.~n~n',
[Local]),
forall(nth1(I, Pairs, File-_),
format(user_error, '~t~d~6| ~w~n', [I, File])),
repeat,
format(user_error, '~nPlease select (\'s\' skips hotfix)? ', []),
read_line_to_codes(user_input, Line),
( Line == end_of_file
-> halt(1)
; atom_codes(s, Line)
-> !, fail
; catch(number_codes(N, Line), _, fail)
),
nth1(N, Pairs, Pair),
!.
%! file_module(+File, -Module) is semidet.
%
% True if Module is the module defined in File.
file_module(File, Module) :-
catch(file_module_guarded(File, Module), _, fail).
file_module_guarded(File, Module) :-
setup_call_cleanup(
prolog_open_source(File, In),
prolog_read_source_term(In, _, Expanded, []),
prolog_close_source(In)),
Expanded = (:- module(Module, _)).