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yap-6.3/packages/semweb/rdf_db.pl

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/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: wielemak@science.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2007, 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(rdf_db,
[ rdf_version/1, % -Version
rdf/3, % ?Subject, ?Predicate, ?Object
rdf/4, % ?Subject, ?Predicate, ?Object, ?DB
rdf_has/3, % ?Subject, +Pred, ?Obj
rdf_has/4, % ?Subject, +Pred, ?Obj, -RealPred
rdf_reachable/3, % ?Subject, +Pred, ?Object
rdf_reachable/5, % ?Subject, +Pred, ?Object, +MaxD, ?D
rdf_subject/1, % ?Subject
rdf_member_property/2, % ?Property, ?Index
rdf_assert/3, % +Subject, +Predicate, +Object
rdf_assert/4, % +Subject, +Predicate, +Object, +DB
rdf_retractall/3, % ?Subject, ?Predicate, ?Object
rdf_retractall/4, % ?Subject, ?Predicate, ?Object, +DB
rdf_update/4, % +Subject, +Predicate, +Object, +Act
rdf_update/5, % +Subject, +Predicate, +Object, +Src, +Act
rdf_set_predicate/2, % +Predicate, +Property
rdf_predicate_property/2, % +Predicate, ?Property
rdf_current_predicate/1, % -Predicate
rdf_current_literal/1, % -Literal
rdf_transaction/1, % :Goal
rdf_transaction/2, % :Goal, +Id
rdf_active_transaction/1, % ?Id
rdf_monitor/2, % :Goal, +Options
rdf_save_db/1, % +File
rdf_save_db/2, % +File, +DB
rdf_load_db/1, % +File
rdf_reset_db/0,
rdf_node/1, % -Id
rdf_bnode/1, % -Id
rdf_is_bnode/1, % +Id
rdf_is_resource/1, % +Term
rdf_is_literal/1, % +Term
rdf_load/1, % +File
rdf_load/2, % +File, +Options
rdf_save/1, % +File
rdf_save/2, % +File, +Options
rdf_unload/1, % +File
rdf_md5/2, % +DB, -MD5
rdf_atom_md5/3, % +Text, +Times, -MD5
rdf_graph/1, % ?DB
rdf_source/1, % ?File
rdf_source/2, % ?DB, ?SourceURL
rdf_make/0, % Reload modified databases
rdf_source_location/2, % +Subject, -Source
rdf_statistics/1, % -Key
rdf_generation/1, % -Generation
rdf_estimate_complexity/4, % +S,+P,+O,-Count
rdf_save_subject/3, % +Stream, +Subject, +DB
rdf_save_header/2, % +Out, +Options
rdf_save_footer/1, % +Out
rdf_equal/2, % ?Resource, ?Resource
rdf_current_ns/2, % ?Alias, ?URI
rdf_register_ns/2, % +Alias, +URI
rdf_register_ns/3, % +Alias, +URI, +Options
rdf_global_id/2, % ?NS:Name, ?Global
rdf_global_object/2, % ?Object, ?NSExpandedObject
rdf_global_term/2, % Term, WithExpandedNS
rdf_match_label/3, % +How, +String, +Label
rdf_split_url/3, % ?Base, ?Local, ?URL
rdf_url_namespace/2, % +URL, ?Base
rdf_quote_uri/2, % +URI, -Quoted
lang_matches/2, % +Lang, +Pattern
rdf_debug/1, % Set verbosity
rdf_new_literal_map/1, % -Handle
rdf_destroy_literal_map/1, % +Handle
rdf_reset_literal_map/1, % +Handle
rdf_insert_literal_map/3, % +Handle, +Key, +Literal
rdf_insert_literal_map/4, % +Handle, +Key, +Literal, -NewKeys
rdf_delete_literal_map/3, % +Handle, +Key, +Literal
rdf_delete_literal_map/2, % +Handle, +Key
rdf_find_literal_map/3, % +Handle, +KeyList, -Literals
rdf_keys_in_literal_map/3, % +Handle, +Spec, -Keys
rdf_statistics_literal_map/2, % +Handle, +Name(-Arg...)
rdf_graph_prefixes/2, % ?Graph, -Prefixes
rdf_graph_prefixes/3, % ?Graph, -Prefixes, :Filter
(rdf_meta)/1, % +Heads
op(1150, fx, (rdf_meta))
]).
:- use_module(library(rdf)).
:- use_module(library(lists)).
:- use_module(library(shlib)).
:- use_module(library(gensym)).
:- use_module(library(sgml)).
:- use_module(library(sgml_write)).
:- use_module(library(option)).
:- use_module(library(nb_set)).
:- use_module(library(error)).
:- use_module(library(uri)).
:- use_module(library(debug)).
:- use_module(rdf_cache).
:- use_foreign_library(foreign(rdf_db)).
:- multifile
ns/2,
rdf_meta_specification/3. % UnboundHead, Module, Head
:- dynamic
ns/2, % ID, URL
rdf_source/5. % DB, SourceURL, ModTimeAtLoad, Triples, MD5
:- volatile
rdf_source/5.
:- discontiguous
term_expansion/2.
/** <module> Core RDF database
@see Documentation for semweb package
*/
/*******************************
* NAMESPACES *
*******************************/
%% rdf_current_ns(?Alias, ?URI) is nondet.
%
% Query predefined namespaces and namespaces defined with
% rdf_register_ns/2.
rdf_current_ns(Alias, URI) :-
ns(Alias, URI).
%% ns(?Alias, ?URI) is nondet.
%
% Dynamic predicate that maintains the registered namespace
% aliases.
ns(rdf, 'http://www.w3.org/1999/02/22-rdf-syntax-ns#').
ns(rdfs, 'http://www.w3.org/2000/01/rdf-schema#').
ns(owl, 'http://www.w3.org/2002/07/owl#').
ns(xsd, 'http://www.w3.org/2001/XMLSchema#').
ns(dc, 'http://purl.org/dc/elements/1.1/').
ns(dcterms, 'http://purl.org/dc/terms/').
ns(eor, 'http://dublincore.org/2000/03/13/eor#').
ns(skos, 'http://www.w3.org/2004/02/skos/core#').
ns(serql, 'http://www.openrdf.org/schema/serql#').
%% rdf_register_ns(+Alias, +URI) is det.
%% rdf_register_ns(+Alias, +URI, +Options) is det.
%
% Register Alias as an abbreviateion for URI. Options:
%
% * force(Boolean)
% If =true=, Replace existing namespace alias. Please note
% that replacing a namespace is dangerous as namespaces
% affect preprocessing. Make sure all code that depends on
% a namespace is compiled after changing the registration.
%
% * keep(Boolean)
% If =true= and Alias is already defined, keep the
% original message and succeed silently.
%
% Without options, an attempt to redefine an alias raises a
% permission error.
rdf_register_ns(Alias, URI) :-
rdf_register_ns(Alias, URI, []).
rdf_register_ns(Alias, URI, _) :-
ns(Alias, URI), !.
rdf_register_ns(Alias, URI, Options) :-
ns(Alias, _),
( option(force(Force), Options, false),
Force == true
-> retractall(ns(Alias, _)),
assert(ns(Alias, URI))
; option(keep(Keep), Options, false),
Keep == true
-> true
; throw(error(permission_error(register, namespace, Alias),
context(_, 'Already defined')))
).
rdf_register_ns(Alias, URI, _) :-
assert(ns(Alias, URI)).
%% register_file_ns(+Map:list(pair)) is det.
%
% Register a namespace as encounted in the namespace list of an
% RDF document. We only register if both the abbreviation and URL
% are not already known. Is there a better way? This code could
% also do checks on the consistency of RDF and other well-known
% namespaces.
%
% @tbd Better error handling
register_file_ns([]) :- !.
register_file_ns([Decl|T]) :- !,
register_file_ns(Decl),
register_file_ns(T).
register_file_ns([]=_) :- !. % xmlns= (overall default)
register_file_ns(NS=URL) :- !, % compatibility
register_file_ns(NS-URL).
register_file_ns(NS-URL) :-
( ns(NS, URL)
-> true
; ns(NS, _)
-> true % redefined abbreviation
; ns(_, URL)
-> true % redefined URL
; rdf_register_ns(NS, URL)
).
%% rdf_global_id(?Id, ?GlobalId) is det.
%
% Convert between NS:Local and global atomic identifier.
% To be completed.
rdf_global_id(NS:Local, Global) :-
global(NS, Local, Global), !.
rdf_global_id(Global, Global).
%% rdf_global_object(+Object, -GlobalObject) is semidet.
%% rdf_global_object(-Object, +GlobalObject) is semidet.
%
% Same as rdf_global_id/2, but intended for dealing with the
% object part of a triple, in particular the type for typed
% literals.
%
% @error existence_error(rdf_namespace, NS)
rdf_global_object(NS:Local, Global) :-
global(NS, Local, Global), !.
rdf_global_object(literal(type(NS:Local, Value)),
literal(type(Global, Value))) :-
global(NS, Local, Global), !.
rdf_global_object(Global, Global).
global(NS, Local, Global) :-
( atom(Global)
-> ns(NS, Full),
atom_concat(Full, Local, Global)
; atom(NS), atom(Local)
-> ( ns(NS, Full)
*-> atom_concat(Full, Local, Global)
; existence_error(rdf_namespace, NS)
)
).
%% rdf_global_term(+TermIn, -GlobalTerm) is det.
%
% Does rdf_global_id/2 on all terms NS:Local by recursively analysing
% the term.
rdf_global_term(Var, Var) :-
var(Var), !.
rdf_global_term(NS:Local, Global) :-
atom(NS), atom(Local), ns(NS, Full), !,
atom_concat(Full, Local, Global).
rdf_global_term([H0|T0], [H|T]) :- !,
rdf_global_term(H0, H),
rdf_global_term(T0, T).
rdf_global_term(Term0, Term) :-
compound(Term0), !,
Term0 =.. [H|L0],
rdf_global_term(L0, L),
Term =.. [H|L].
rdf_global_term(Term, Term).
/*******************************
* EXPANSION *
*******************************/
:- multifile
system:term_expansion/2,
system:goal_expansion/2.
system:term_expansion((:- rdf_meta(Heads)), Clauses) :-
prolog_load_context(module, M),
mk_clauses(Heads, M, Clauses).
mk_clauses((A,B), M, [H|T]) :- !,
mk_clause(A, M, H),
mk_clauses(B, M, T).
mk_clauses(A, M, [C]) :-
mk_clause(A, M, C).
mk_clause(Head0, M0, rdf_db:rdf_meta_specification(Unbound, Module, Head)) :-
strip_module(M0:Head0, Module, Head),
valid_rdf_meta_head(Head),
functor(Head, Name, Arity),
functor(Unbound, Name, Arity).
valid_rdf_meta_head(Head) :-
callable(Head), !,
Head =.. [_|Args],
valid_args(Args).
valid_rdf_meta_head(Head) :-
throw(error(type_error(callable, Head), _)).
valid_args([]).
valid_args([H|T]) :-
valid_arg(H), !,
valid_args(T).
valid_arg(:). % meta argument
valid_arg(+). % non-var
valid_arg(-). % var
valid_arg(?). % either var or non-var
valid_arg(@). % not modified
valid_arg(r). % RDF resource
valid_arg(o). % RDF object
valid_arg(t). % term with RDF resources
valid_arg(A) :-
throw(error(type_error(rdf_meta_argument, A), _)).
%% rdf_meta(+Heads)
%
% This directive is expanded using term-expansion. The
% implementation just throws an error in case it is called with
% the wrong context.
rdf_meta(Heads) :-
throw(error(context_error(nodirective, rdf_meta(Heads)), _)).
system:goal_expansion(G, Expanded) :-
rdf_meta_specification(G, _, _), !,
prolog_load_context(module, LM),
( rdf_meta_specification(G, Module, Spec),
right_module(LM, G, Module)
-> rdf_expand(G, Spec, Expanded)
; debugging(rdf_meta),
sub_term(G, NS:Local),
atom(NS), atom(Local)
-> print_message(warning, rdf_meta(not_expanded(LM:G))),
fail
),
rdf_expand(G, Spec, Expanded).
system:term_expansion(Fact, Expanded) :-
rdf_meta_specification(Fact, Module, Spec),
prolog_load_context(module, Module), !,
rdf_expand(Fact, Spec, Expanded).
system:term_expansion((Head :- Body), (Expanded :- Body)) :-
rdf_meta_specification(Head, Module, Spec),
prolog_load_context(module, Module), !,
rdf_expand(Head, Spec, Expanded).
right_module(M, _, M) :- !.
right_module(LM, G, M) :-
predicate_property(LM:G, imported_from(M)).
rdf_expand(G, Spec, Expanded) :-
functor(G, Name, Arity),
functor(Expanded, Name, Arity),
rdf_expand_args(0, Arity, G, Spec, Expanded).
rdf_expand_args(Arity, Arity, _, _, _) :- !.
rdf_expand_args(I0, Arity, Goal, Spec, Expanded) :-
I is I0 + 1,
arg(I, Goal, GA),
arg(I, Spec, SA),
arg(I, Expanded, EA),
rdf_expand_arg(SA, GA, EA),
rdf_expand_args(I, Arity, Goal, Spec, Expanded).
rdf_expand_arg(r, A, E) :- !,
mk_global(A, E).
rdf_expand_arg(o, A, E) :- !,
rdf_global_object(A, E).
rdf_expand_arg(t, A, E) :- !,
rdf_global_term(A, E).
rdf_expand_arg(:, A, E) :- !,
expand_goal(A, E).
rdf_expand_arg(_, A, A).
%% mk_global(+Src, -Resource)
%
% Realised rdf_global_id(+, -), but adds compiletime checking,
% notably to see whether a namespace is not yet defined.
mk_global(X, X) :-
var(X), !.
mk_global(X, X) :-
atom(X), !.
mk_global(NS:Local, Global) :-
must_be(atom, NS),
must_be(atom, Local),
( ns(NS, Full)
-> atom_concat(Full, Local, Global)
; existence_error(namespace, NS)
).
:- rdf_meta
rdf(r,r,o),
rdf_has(r,r,o,r),
rdf_has(r,r,o),
rdf_assert(r,r,o),
rdf_retractall(r,r,o),
rdf(r,r,o,?),
rdf_assert(r,r,o,+),
rdf_retractall(r,r,o,?),
rdf_reachable(r,r,r),
rdf_reachable(r,r,r,+,?),
rdf_update(r,r,o,t),
rdf_update(r,r,o,+,t),
rdf_equal(r,r),
rdf_source_location(r,-),
rdf_subject(r),
rdf_set_predicate(r, +),
rdf_predicate_property(r, -),
rdf_estimate_complexity(r,r,r,-).
%% rdf_equal(?Resource1, ?Resource2)
%
% Simple equality test to exploit goal-expansion
rdf_equal(Resource, Resource).
%% rdf_has(?Subject, +Predicate, ?Object)
%
% Succeeds if the triple rdf(Subject, Predicate, Object) is true
% exploiting the rdfs:subPropertyOf predicate.
rdf_has(Subject, Predicate, Object) :-
rdf_has(Subject, Predicate, Object, _).
/*******************************
* COLLECTIONS *
*******************************/
%% rdf_member_property(?Prop, ?Index)
%
% Deal with the rdf:_1, ... properties.
term_expansion(member_prefix(x),
member_prefix(Prefix)) :-
rdf_db:ns(rdf, NS),
atom_concat(NS, '_', Prefix).
member_prefix(x).
rdf_member_property(P, N) :-
integer(N), !,
member_prefix(Prefix),
atom_concat(Prefix, N, P).
rdf_member_property(P, N) :-
member_prefix(Prefix),
atom_concat(Prefix, Sub, P),
atom_number(Sub, N).
/*******************************
* ANONYMOUS SUBJECTS *
*******************************/
%% rdf_node(-Id)
%
% Generate a unique blank node identifier for a subject.
%
% @deprecated New code should use rdf_bnode/1.
rdf_node(Resource) :-
rdf_bnode(Resource).
%% rdf_bnode(-Id)
%
% Generate a unique anonymous identifier for a subject.
rdf_bnode(Value) :-
repeat,
gensym('__bnode', Value),
\+ rdf_subject(Value),
\+ rdf(_, _, Value),
\+ rdf(_, Value, _), !.
/*******************************
* TYPES *
*******************************/
%% rdf_is_bnode(+Id)
%
% Tests if a resource is a blank node (i.e. is an anonymous
% resource).
%
% @see rdf_bnode/1.
rdf_is_bnode(Id) :-
atom(Id),
sub_atom(Id, 0, _, _, '__').
%% rdf_is_resource(@Term) is semidet.
%
% True if Term is an RDF resource. Note that this is merely a
% type-test; it does not mean this resource is involved in any
% triple. Blank nodes are also considered resources.
%
% @see rdf_is_bnode/1
rdf_is_resource(Term) :-
atom(Term).
%% rdf_is_literal(@Term) is semidet.
%
% True if Term is an RDF literal object. Currently only checks for
% groundness and the literal functor.
rdf_is_literal(literal(Value)) :-
ground(Value).
/*******************************
* SOURCE *
*******************************/
%% rdf_source_location(+Subject, -File:Line)
%
% Return the source-locations for triples for this subject.
rdf_source_location(Subject, Source) :-
findall(Source, rdf(Subject, _, _, Source), Sources),
sort(Sources, Unique),
member(Source, Unique).
/*******************************
* STATISTICS *
*******************************/
%% rdf_statistics(?KeyValue) is nondet.
%
% Obtain statistics on the RDF database.
%
% @param KeyValue Term of the form Key(Value).
rdf_statistics(sources(Count)) :-
predicate_property(rdf_source(_,_,_,_,_), number_of_clauses(Count)).
rdf_statistics(subjects(Count)) :-
rdf_statistics_(subjects(Count)).
rdf_statistics(properties(Count)) :-
rdf_statistics_(predicates(Count)).
rdf_statistics(triples(Count)) :-
rdf_statistics_(triples(Count)).
rdf_statistics(gc(Count, Time)) :-
rdf_statistics_(gc(Count, Time)).
rdf_statistics(rehash(Count, Time)) :-
rdf_statistics_(rehash(Count, Time)).
rdf_statistics(core(Bytes)) :-
rdf_statistics_(core(Bytes)).
rdf_statistics(lookup(Index, Count)) :-
functor(Indexed, indexed, 8),
rdf_statistics_(Indexed),
index(Index, I),
Arg is I + 1,
arg(Arg, Indexed, Count),
Count \== 0.
rdf_statistics(searched_nodes(Count)) :-
rdf_statistics_(searched_nodes(Count)).
rdf_statistics(literals(Count)) :-
rdf_statistics_(literals(Count)).
rdf_statistics(triples_by_file(File, Count)) :-
( var(File)
-> rdf_graph(File),
rdf_statistics_(triples(File, Count))
; rdf_statistics_(triples(File, Count))
).
rdf_statistics(duplicates(Count)) :-
rdf_statistics_(duplicates(Count)).
index(rdf(-,-,-), 0).
index(rdf(+,-,-), 1).
index(rdf(-,+,-), 2).
index(rdf(+,+,-), 3).
index(rdf(-,-,+), 4).
index(rdf(+,-,+), 5).
index(rdf(-,+,+), 6).
index(rdf(+,+,+), 7).
/*******************************
* PREDICATES *
*******************************/
%% rdf_current_predicate(?Predicate)
%
% True if Predicate is a currently defined predicate.
rdf_current_predicate(P) :-
var(P), !,
rdf_current_predicates(All),
member(P, All),
rdf_predicate_property_(P, triples(N)),
N > 0.
rdf_current_predicate(P) :-
rdf_predicate_property_(P, triples(N)),
N > 0.
rdf_current_predicate(P, DB) :-
rdf_current_predicates(All),
member(P, All),
once(rdf(_,P,_,DB:_)).
%% rdf_predicate_property(?Predicate, ?Property)
%
% Enumerate predicates and their properties
rdf_predicate_property(P, Prop) :-
var(P), !,
rdf_current_predicates(All),
member(P, All),
rdf_predicate_property_(P, Prop).
rdf_predicate_property(P, Prop) :-
rdf_predicate_property_(P, Prop).
/*******************************
* TRANSACTION *
*******************************/
%% rdf_transaction(:Goal) is semidet.
%% rdf_transaction(:Goal, +Id) is semidet.
%
% Backward compatibility
rdf_transaction(Goal) :-
rdf_transaction_(Goal, user).
rdf_transaction(Goal, Id) :-
( nonvar(Id),
Id = log(_, DB)
-> must_be(atom, DB)
; true
),
rdf_transaction_(Goal, Id).
%% rdf_active_transaction(?Id) is nondet.
%
% True if Id is the identifier of a currently open transaction. If
% Id is not instantiated, backtracking yields transaction
% identifiers starting with the innermost nested transaction.
% Transaction identifier terms are not copied, need not be ground
% and can be instantiated during the transaction.
rdf_active_transaction(Id) :-
rdf_active_transactions_(List),
member(Id, List).
%% rdf_monitor(:Goal, +Options)
%
% Call Goal if specified actions occur on the database.
rdf_monitor(Goal, Options) :-
monitor_mask(Options, 0xffff, Mask),
rdf_monitor_(Goal, Mask).
monitor_mask([], Mask, Mask).
monitor_mask([H|T], Mask0, Mask) :-
update_mask(H, Mask0, Mask1),
monitor_mask(T, Mask1, Mask).
update_mask(-X, Mask0, Mask) :- !,
monitor_mask(X, M),
Mask is Mask0 /\ \M.
update_mask(+X, Mask0, Mask) :- !,
monitor_mask(X, M),
Mask is Mask0 \/ M.
update_mask(X, Mask0, Mask) :-
monitor_mask(X, M),
Mask is Mask0 \/ M.
%% monitor_mask(Name, Mask)
%
% Mask bit for the monitor events. Note that this must be kept
% consistent with the enum broadcast_id defined in rdf_db.c
% C-defined broadcasts
monitor_mask(assert, 0x0001).
monitor_mask(assert(load), 0x0002).
monitor_mask(retract, 0x0004).
monitor_mask(update, 0x0008).
monitor_mask(new_literal, 0x0010).
monitor_mask(old_literal, 0x0020).
monitor_mask(transaction, 0x0040).
monitor_mask(load, 0x0080).
monitor_mask(rehash, 0x0100).
% prolog defined broadcasts
monitor_mask(parse, 0x1000).
monitor_mask(reset, 0x2000).
monitor_mask(unload, 0x1000).
% mask for all
monitor_mask(all, 0xffff).
%rdf_broadcast(Term, MaskName) :-
%% monitor_mask(MaskName, Mask),
%% rdf_broadcast_(Term, Mask).
/*******************************
* QUICK BINARY LOAD/SAVE *
*******************************/
%% rdf_save_db(+File) is det.
%% rdf_save_db(+File, +DB) is det.
%
% Save triples into File in a quick-to-load binary format. If DB
% is supplied only triples flagged to originate from that database
% are added. Files created this way can be loaded using
% rdf_load_db/1.
rdf_save_db(File) :-
open(File, write, Out, [type(binary)]),
set_stream(Out, record_position(false)),
call_cleanup(rdf_save_db_(Out, _), close(Out)).
rdf_save_db(File, DB) :-
open(File, write, Out, [type(binary)]),
set_stream(Out, record_position(false)),
call_cleanup(rdf_save_db_(Out, DB), close(Out)).
%% rdf_load_db_no_admin(+File, +Id, -Graphs) is det.
%
% Load triples from a .trp file without updating the source
% administration. Id is handled to monitor action. Graphs is
% either an atom, indicating a single loaded graph or a list of
% graph-names encountered in File.
rdf_load_db_no_admin(File, Id, Graphs) :-
open(File, read, In, [type(binary)]),
set_stream(In, record_position(false)),
call_cleanup(rdf_load_db_(In, Id, Graphs), close(In)).
%% check_loaded_cache(+DB, +Graphs, +Modified) is det.
%
% Verify the loaded cache file and optionally fix the modification
% time (new versions save this along with the snapshot).
%
% @tbd What to do if there is a cache mismatch? Delete the loaded
% graphs and fail?
check_loaded_cache(DB, DB, _Modified) :- !.
check_loaded_cache(DB, Graphs, _) :-
print_message(warning, rdf(inconsistent_cache(DB, Graphs))).
%% rdf_load_db(+File) is det.
%
% Load triples from a file created using rdf_save_db/2 and update
% the file administration.
rdf_load_db(File) :-
uri_file_name(URL, File),
rdf_load_db_no_admin(File, URL, Graphs),
( ( is_list(Graphs)
-> member(DB, Graphs)
; DB = Graphs
),
rdf_md5(DB, MD5),
rdf_statistics_(triples(DB, Triples)),
rdf_graph_source_(DB, SourceURL, Modified),
retractall(rdf_source(DB, _, _, _, _)),
assert(rdf_source(DB, SourceURL, Modified, Triples, MD5)),
fail
; true
).
/*******************************
* LOADING RDF *
*******************************/
:- multifile
rdf_open_hook/8,
rdf_open_decode/4, % +Encoding, +File, -Stream, -Cleanup
rdf_load_stream/3, % +Format, +Stream, +Options
rdf_file_type/2, % ?Extension, ?Format
rdf_storage_encoding/2, % ?Extension, ?Encoding
url_protocol/1. % ?Protocol
%% rdf_load(+FileOrList) is det.
%% rdf_load(+FileOrList, +Options) is det.
%
% Load RDF file. Options provides additional processing options.
% Currently defined options are:
%
% * blank_nodes(+ShareMode)
% How to handle equivalent blank nodes. If =share= (default),
% equivalent blank nodes are shared in the same resource.
%
% * base_uri(+URI)
% URI that is used for rdf:about="" and other RDF constructs
% that are relative to the base uri. Default is the source
% URL.
%
% * graph(?Graph)
% Named graph in which to load the data. It is *not* allowed
% to load two sources into the same named graph. If Graph is
% unbound, it is unified to the graph into which the data is
% loaded.
%
% * db(?Graph)
% Deprecated. New code must use graph(Graph).
%
% * if(Condition)
% When to load the file. One of =true=, =changed= (default) or
% =not_loaded=.
%
% * modified(-Modified)
% Unify Modified with one of =not_modified=, cached(File),
% last_modified(Stamp) or =unknown=.
%
% * cache(Bool)
% If =false=, do not use or create a cache file.
%
% * register_namespaces(Bool)
% If =true= (default =false=), register xmlns= namespace
% declarations as ns/2 namespaces if there is no conflict.
%
% Other options are forwarded to process_rdf/3.
rdf_load(Spec) :-
rdf_load(Spec, []).
rdf_load([], _) :- !.
rdf_load([H|T], Options) :- !,
rdf_load(H, Options),
rdf_load(T, Options).
rdf_load(Spec, M:Options) :-
must_be(list, Options),
statistics(cputime, T0),
rdf_open_input(Spec, In, Cleanup, SourceURL, Graph, Modified,
Format, Options),
return_modified(Modified, Options),
( Modified == not_modified
-> Action = none
; Modified = cached(CacheFile)
-> do_unload(Graph),
catch(rdf_load_db_no_admin(CacheFile, cache(Graph), Graphs), _, fail),
check_loaded_cache(Graph, Graphs, Modified),
rdf_statistics_(triples(Graph, Triples)),
Action = load
; option(base_uri(BaseURI), Options, Graph),
( var(BaseURI)
-> BaseURI = SourceURL
; true
),
once(phrase(derived_options(Options, NSList), Extra)),
merge_options([ base_uri(BaseURI),
graph(Graph),
format(Format)
| Extra
], Options, RDFOptions),
do_unload(Graph),
graph_modified(Modified, ModifiedStamp),
rdf_set_graph_source(Graph, SourceURL, ModifiedStamp),
call_cleanup(rdf_load_stream(Format, In, M:RDFOptions),
Cleanup),
save_cache(Graph, SourceURL, Options),
register_file_ns(NSList),
rdf_statistics_(triples(Graph, Triples)),
rdf_md5(Graph, MD5),
assert(rdf_source(Graph, SourceURL, Modified, Triples, MD5)),
format_action(Format, Action)
),
report_loaded(Action, SourceURL, Graph, Triples, T0, Options).
format_action(triples, load) :- !.
format_action(_, parsed).
save_cache(Graph, SourceURL, Options) :-
option(cache(true), Options, true),
rdf_cache_file(SourceURL, write, CacheFile), !,
catch(save_cache(Graph, CacheFile), E,
print_message(warning, E)).
save_cache(_, _, _).
derived_options([], _) -->
[].
derived_options([H|T], NSList) -->
( { H == register_namespaces(true)
; H == (register_namespaces = true)
}
-> [ namespaces(NSList) ]
; []
),
derived_options(T, NSList).
graph_modified(last_modified(Stamp), Stamp).
graph_modified(unknown, Stamp) :-
get_time(Stamp).
return_modified(Modified, Options) :-
option(modified(M0), Options), !,
M0 = Modified.
return_modified(_, _).
/*******************************
* INPUT HANDLING *
*******************************/
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
This section deals with pluggable input sources. The task of the input
layer is
* Decide on the graph-name
* Decide on the source-location
* Decide whether loading is needed (if-modified)
* Decide on the serialization in the input
The protocol must ensure minimal overhead, in particular for network
protocols. E.g. for HTTP we want to make a single call on the server and
use If-modified-since to verify that we need not reloading this file.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
%% rdf_open_input(+Spec, -Stream, -Cleanup,
%% -Source, -Graph, -Modified, -Format,
%% +Options)
%
% Open an input source.
%
% Options processed:
%
% * graph(Graph)
% * db(Graph)
% * if(Condition)
% * cache(Cache)
% * format(Format)
%
% @param Modified is one of =not_modified=, last_modified(Time),
% cached(CacheFile) or =unknown=
rdf_open_input(Spec, Stream, Cleanup,
SourceURL, Graph, Modified, Format,
Options) :-
source_url(Spec, Protocol, SourceURL),
load_graph(SourceURL, Graph, Options),
option(if(If), Options, changed),
( If == true
-> true
; rdf_graph_source_(Graph, SourceURL, HaveModified)
-> true
; option(cache(true), Options, true),
rdf_cache_file(SourceURL, read, CacheFile)
-> time_file(CacheFile, HaveModified)
; true
),
option(format(Format), Options, _),
open_input_if_modified(Protocol, SourceURL, HaveModified,
Stream, Cleanup, Modified0, Format, Options),
( Modified0 == not_modified
-> ( nonvar(CacheFile)
-> Modified = cached(CacheFile)
; Modified = not_modified
)
; Modified = Modified0
).
%% source_url(+Spec, -Class, -SourceURL) is det.
%
% Determine class and url of the source. Class is one of
%
% * stream(Stream)
% * file
% * a url-protocol (e.g., =http=)
source_url(stream(In), stream(In), SourceURL) :- !,
( stream_property(In, file_name(File))
-> to_url(File, SourceURL)
; gensym('stream://', SourceURL)
).
source_url(Stream, Class, SourceURL) :-
is_stream(Stream), !,
source_url(stream(Stream), Class, SourceURL).
source_url(Spec, Protocol, SourceURL) :-
compound(Spec), !,
source_file(Spec, Protocol, SourceURL).
source_url(FileURL, Protocol, SourceURL) :- % or return FileURL?
uri_file_name(FileURL, File), !,
source_file(File, Protocol, SourceURL).
source_url(SourceURL, Protocol, SourceURL) :-
is_url(SourceURL, Protocol), !.
source_url(File, Protocol, SourceURL) :-
source_file(File, Protocol, SourceURL).
source_file(Spec, file(SExt), SourceURL) :-
findall(Ext, valid_extension(Ext), Exts),
absolute_file_name(Spec, File, [access(read), extensions(Exts)]),
storage_extension(Plain, SExt, File),
uri_file_name(SourceURL, Plain).
to_url(URL, URL) :-
is_url(URL, _Protocol), !.
to_url(File, URL) :-
absolute_file_name(File, Path),
uri_file_name(URL, Path).
storage_extension(Plain, SExt, File) :-
file_name_extension(Plain, SExt, File),
SExt \== '',
rdf_storage_encoding(SExt, _), !.
storage_extension(File, '', File).
%% rdf_input(URL, Source, _BaseURI) is semidet.
%
% @deprecated Only exists to make old ClioPatria rdf_library.pl
% work
rdf_input(Spec, Source, _BaseURI) :-
source_url(Spec, Class, SourceURL),
compat_input(Class, SourceURL, Source).
compat_input(file(Ext), SourceURL, file(Path)) :-
uri_file_name(SourceURL, File),
file_name_extension(File, Ext, Path).
compat_input(http, SourceURL, url(http, SourceURL)).
%% load_graph(+SourceURL, -Graph, +Options) is det.
%
% Graph is the graph into which we load the data. Processes
% the graph(?Graph) option.
load_graph(Source, Graph, Options) :-
( option(graph(Graph), Options)
-> true
; option(db(Graph), Options)
), !,
( ground(Graph)
-> true
; load_graph(Source, Graph)
).
load_graph(Source, Graph, _) :-
load_graph(Source, Graph).
load_graph(SourceURL, BaseURI) :-
file_name_extension(BaseURI, Ext, SourceURL),
rdf_storage_encoding(Ext, _), !.
load_graph(SourceURL, SourceURL).
open_input_if_modified(stream(In), SourceURL, _, In, true,
unknown, Format, _) :- !,
( var(Format)
-> guess_format(SourceURL, Format)
; true
).
open_input_if_modified(file(SExt), SourceURL, HaveModified, Stream, Cleanup,
Modified, Format, _) :- !,
uri_file_name(SourceURL, File0),
file_name_extension(File0, SExt, File),
time_file(File, LastModified),
( nonvar(HaveModified),
HaveModified >= LastModified
-> Modified = not_modified,
Cleanup = true
; storage_open(SExt, File, Stream, Cleanup),
Modified = last_modified(LastModified),
( var(Format)
-> guess_format(File0, Format)
; true
)
).
open_input_if_modified(file, SourceURL, HaveModified, Stream, Cleanup,
Modified, Format, Options) :- !,
open_input_if_modified(file(''), SourceURL, HaveModified,
Stream, Cleanup,
Modified, Format, Options).
open_input_if_modified(Protocol, SourceURL, HaveModified, Stream, Cleanup,
Modified, Format, Options) :-
rdf_open_hook(Protocol, SourceURL, HaveModified, Stream, Cleanup,
Modified, Format, Options).
guess_format(File, Format) :-
file_name_extension(_, Ext, File),
( rdf_file_type(Ext, Format)
-> true
; Format = xml,
print_message(warning, rdf(guess_format(Ext)))
).
storage_open('', File, Stream, close(Stream)) :- !,
open(File, read, Stream).
storage_open(Ext, File, Stream, Cleanup) :-
rdf_storage_encoding(Ext, Encoding),
rdf_open_decode(Encoding, File, Stream, Cleanup).
valid_extension(Ext) :-
rdf_file_type(Ext, _).
valid_extension(Ext) :-
rdf_storage_encoding(Ext, _).
%% is_url(+Term, -Protocol) is semidet.
%
% True if Term is an atom denoting a URL of the given Protocol.
% We only support a limited set of protocols as defined by the
% extensible predicate url_protocol/1.
is_url(URL, Protocol) :-
atom(URL),
sub_atom(URL, B, _, _, :), !,
sub_atom(URL, 0, B, _, RawProtocol),
downcase_atom(RawProtocol, Protocol),
url_protocol(Protocol).
url_protocol(file). % built-in
%% rdf_file_type(+Extension, -Format) is semidet.
%
% True if Format is the format belonging to the given file
% extension. This predicate is multifile and can thus be extended
% by plugins.
rdf_file_type(xml, xml).
rdf_file_type(rdf, xml).
rdf_file_type(rdfs, xml).
rdf_file_type(owl, xml).
rdf_file_type(htm, xhtml).
rdf_file_type(html, xhtml).
rdf_file_type(xhtml, xhtml).
rdf_file_type(trp, triples).
%% rdf_file_encoding(+Extension, -Format) is semidet.
%
% True if Format describes the storage encoding of file.
rdf_storage_encoding('', plain).
%% rdf_load_stream(+Format, +Stream, :Options)
%
% Load RDF data from Stream.
%
% @tbd Handle mime-types?
rdf_load_stream(xml, Stream, Options) :- !,
graph(Options, Graph),
rdf_transaction(process_rdf(Stream, assert_triples, Options),
parse(Graph)).
rdf_load_stream(xhtml, Stream, M:Options) :- !,
graph(Options, Graph),
rdf_transaction(process_rdf(Stream, assert_triples,
M:[embedded(true)|Options]),
parse(Graph)).
rdf_load_stream(triples, Stream, Options) :- !,
graph(Options, Graph),
rdf_load_db_(Stream, Graph, _Graphs).
%% report_loaded(+Action, +Source, +DB, +Triples, +StartCPU, +Options)
report_loaded(none, _, _, _, _, _) :- !.
report_loaded(Action, Source, DB, Triples, T0, Options) :-
statistics(cputime, T1),
Time is T1 - T0,
( option(silent(true), Options)
-> Level = silent
; Level = informational
),
print_message(Level,
rdf(loaded(Action, Source, DB, Triples, Time))).
%% rdf_unload(+Spec) is det.
%
% Remove the triples loaded from the specified source and remove
% the source from the database.
rdf_unload(Graph) :-
atom(Graph),
rdf_statistics_(triples(Graph, Triples)),
Triples > 0, !,
do_unload(Graph).
rdf_unload(Spec) :-
source_url(Spec, _Protocol, SourceURL),
rdf_graph_source_(Graph, SourceURL, _), !,
do_unload(Graph).
rdf_unload(_).
do_unload(DB) :-
rdf_transaction(rdf_retractall(_,_,_,DB),
unload(DB)),
retractall(rdf_source(DB, _, _, _, _)),
rdf_unset_graph_source(DB).
%% rdf_graph(+DB) is semidet.
%% rdf_graph(-DB) is nondet.
%
% True if DB is a current named graph with at least one triple.
rdf_graph(DB) :-
atom(DB), !,
rdf_statistics_(triples(DB, Triples)),
Triples > 0.
rdf_graph(DB) :-
rdf_graphs_(Sources),
member(DB, Sources),
rdf_statistics_(triples(DB, Triples)),
Triples > 0.
%% rdf_source(?Graph, ?SourceURL) is nondet.
%
% True if named Graph is loaded from SourceURL.
rdf_source(Graph, SourceURL) :-
rdf_graph(Graph),
rdf_graph_source_(Graph, SourceURL, _Modified).
%% rdf_source(?Source)
%
% True if Source is a loaded source.
%
% @deprecated Use rdf_graph/1 or rdf_source/2.
rdf_source(SourceURL) :-
rdf_source(_Graph, SourceURL).
%% rdf_make
%
% Reload all loaded files that have been modified since the last
% time they were loaded.
rdf_make :-
findall(Source-Graph, modified_graph(Source, Graph), Modified),
forall(member(Source-Graph, Modified),
catch(rdf_load(Source, [graph(Graph), if(changed)]), E,
print_message(error, E))).
modified_graph(SourceURL, Graph) :-
rdf_graph(Graph),
rdf_graph_source_(Graph, SourceURL, Modified),
Modified > 0.
%% save_cache(+DB, +Cache) is det.
%
% Save triples belonging to DB in the file Cache.
save_cache(DB, Cache) :-
catch(open(Cache, write, CacheStream, [type(binary)]), _, fail), !,
call_cleanup(rdf_save_db_(CacheStream, DB),
close(CacheStream)).
%% assert_triples(+Triples, +Source)
%
% Assert a list of triples into the database. Foir security
% reasons we check we aren't inserting anything but nice RDF
% triples.
assert_triples([], _).
assert_triples([rdf(S,P,O)|T], DB) :- !,
rdf_assert(S, P, O, DB),
assert_triples(T, DB).
assert_triples([H|_], _) :-
throw(error(type_error(rdf_triple, H), _)).
/*******************************
* RESET *
*******************************/
%% rdf_reset_db
%
% Remove all triples from the RDF database and reset all its
% statistics.
rdf_reset_db :-
retractall(rdf_source(_,_,_,_,_)),
rdf_transaction(rdf_reset_db_, reset).
/*******************************
* SAVE RDF *
*******************************/
%% rdf_save(+Out) is det.
%% rdf_save(+Out, :Options) is det.
%
% Write RDF data as RDF/XML. Options is a list of one or more of
% the following options:
%
% * graph(+Graph)
% Save only triples associated to the given named Graph.
%
% * db(+DB)
% Deprecated synonym for graph(DB).
%
% * anon(Bool)
% If false (default true) do not save blank nodes that do
% not appear (indirectly) as object of a named resource.
%
% * base_uri(URI)
% BaseURI used. If present, all URIs that can be
% represented relative to this base are written using
% their shorthand. See also =write_xml_base= option
%
% * write_xml_base(Bool)
% If =false=, do _not_ include the =|xml:base|=
% declaration that is written normally when using the
% =base_uri= option.
%
% * convert_typed_literal(:Convertor)
% Call Convertor(-Type, -Content, +RDFObject), providing
% the opposite for the convert_typed_literal option of
% the RDF parser.
%
% * encoding(Encoding)
% Encoding for the output. Either utf8 or iso_latin_1
%
% * document_language(+Lang)
% Initial xml:lang saved with rdf:RDF element
%
% * sorted(+Boolean)
% If =true= (default =false=), emit subjects sorted on
% the full URI. Useful to make file comparison easier.
%
% @param Out Location to save the data. This can also be a
% file-url (=|file://path|=) or a stream wrapped
% in a term stream(Out).
:- meta_predicate
rdf_transaction(0),
rdf_transaction(0, +),
rdf_monitor(1, +),
rdf_save(+, :),
rdf_load(+, :).
:- thread_local
named_anon/2. % +Resource, -Id
rdf_save(File) :-
rdf_save2(File, []).
rdf_save(Spec, M:Options0) :-
is_list(Options0), !,
meta_options(save_meta_option, M:Options0, Options),
to_file(Spec, File),
rdf_save2(File, Options).
rdf_save(Spec, _:DB) :-
atom(DB), !, % backward compatibility
to_file(Spec, File),
rdf_save2(File, [graph(DB)]).
save_meta_option(convert_typed_literal).
to_file(URL, File) :-
atom(URL),
uri_file_name(URL, File), !.
to_file(File, File).
rdf_save2(File, Options) :-
option(encoding(Encoding), Options, utf8),
valid_encoding(Encoding),
open_output(File, Encoding, Out, Close),
flag(rdf_db_saved_subjects, OSavedSubjects, 0),
flag(rdf_db_saved_triples, OSavedTriples, 0),
call_cleanup(rdf_do_save(Out, Options),
Reason,
cleanup_save(Reason,
File,
OSavedSubjects,
OSavedTriples,
Close)).
open_output(stream(Out), Encoding, Out,
set_stream(Out, encoding(Old))) :- !,
stream_property(Out, encoding(Old)),
set_stream(Out, encoding(Encoding)).
open_output(File, Encoding, Out,
close(Out)) :-
open(File, write, Out, [encoding(Encoding)]).
valid_encoding(Enc) :-
( xml_encoding_name(Enc, _)
-> true
; throw(error(domain_error(encoding, Enc), _))
).
cleanup_save(Reason,
File,
OSavedSubjects,
OSavedTriples,
Close) :-
call(Close),
flag(rdf_db_saved_subjects, SavedSubjects, OSavedSubjects),
flag(rdf_db_saved_triples, SavedTriples, OSavedTriples),
retractall(named_anon(_, _)),
( Reason == exit
-> print_message(informational,
rdf(saved(File, SavedSubjects, SavedTriples)))
; format(user_error, 'Reason = ~w~n', [Reason])
).
rdf_do_save(Out, Options0) :-
rdf_save_header(Out, Options0, Options),
( option(sorted(true), Options, false)
-> setof(Subject, rdf_subject(Subject, Options), Subjects),
forall(member(Subject, Subjects),
rdf_save_non_anon_subject(Out, Subject, Options))
; forall(rdf_subject(Subject, Options),
rdf_save_non_anon_subject(Out, Subject, Options))
),
rdf_save_footer(Out), !. % dubious cut; without the
% cleanup handlers isn't called!?
rdf_subject(Subject, Options) :-
graph(Options, DB),
var(DB), !,
rdf_subject(Subject).
rdf_subject(Subject, Options) :-
graph(Options, DB),
rdf_subject(Subject),
( rdf(Subject, _, _, DB:_)
-> true
).
graph(Options0, DB) :-
strip_module(Options0, _, Options),
( memberchk(graph(DB0), Options)
-> DB = DB0
; memberchk(db(DB0), Options)
-> DB = DB0
; true % leave unbound
).
%% rdf_save_header(+Fd, +Options)
%
% Save XML document header, doctype and open the RDF environment.
% This predicate also sets up the namespace notation.
rdf_save_header(Out, Options) :-
rdf_save_header(Out, Options, _).
rdf_save_header(Out, Options, OptionsOut) :-
is_list(Options), !,
stream_property(Out, encoding(Enc)),
xml_encoding(Enc, Encoding),
format(Out, '<?xml version=\'1.0\' encoding=\'~w\'?>~n', [Encoding]),
format(Out, '<!DOCTYPE rdf:RDF [', []),
header_namespaces(Options, NSIdList),
nsmap(NSIdList, NsMap),
append(Options, [nsmap(NsMap)], OptionsOut),
forall(member(Id=URI, NsMap),
( rdf_quote_uri(URI, QURI),
xml_quote_attribute(QURI, NSText0, Enc),
xml_escape_parameter_entity(NSText0, NSText),
format(Out, '~N <!ENTITY ~w \'~w\'>', [Id, NSText])
)),
format(Out, '~N]>~n~n', []),
format(Out, '<rdf:RDF', []),
( member(Id, NSIdList),
format(Out, '~N xmlns:~w="&~w;"~n', [Id, Id]),
fail
; true
),
( option(base_uri(Base), Options),
option(write_xml_base(true), Options, true)
-> rdf_quote_uri(Base, QBase),
xml_quote_attribute(QBase, BaseText, Enc),
format(Out, '~N xml:base="~w"~n', [BaseText])
; true
),
( memberchk(document_language(Lang), Options)
-> format(Out, '~N xml:lang="~w"', [Lang])
; true
),
format(Out, '>~n', []).
rdf_save_header(Out, FileRef, OptionsOut) :- % compatibility
atom(FileRef),
rdf_save_header(Out, [graph(FileRef)], OptionsOut).
xml_encoding(Enc, Encoding) :-
( xml_encoding_name(Enc, Encoding)
-> true
; throw(error(domain_error(rdf_encoding, Enc), _))
).
xml_encoding_name(ascii, 'US-ASCII').
xml_encoding_name(iso_latin_1, 'ISO-8859-1').
xml_encoding_name(utf8, 'UTF-8').
%% nsmap(+NSIds, -Map:list(id=uri)) is det.
%
% Create a namespace-map that is compatible to xml_write/2
% for dealing with XML-Literals
nsmap([], []).
nsmap([Id|T0], [Id=URI|T]) :-
ns(Id, URI),
nsmap(T0, T).
%% xml_escape_parameter_entity(+In, -Out) is det.
%
% Escape % as &#37; for entity declarations.
xml_escape_parameter_entity(In, Out) :-
sub_atom(In, _, _, _, '%'), !,
atom_codes(In, Codes),
phrase(escape_parent(Codes), OutCodes),
atom_codes(Out, OutCodes).
xml_escape_parameter_entity(In, In).
escape_parent([]) --> [].
escape_parent([H|T]) -->
( { H == 37 }
-> "&#37;"
; [H]
),
escape_parent(T).
%% header_namespaces(Options, -List)
%
% Get namespaces we will define as entities
header_namespaces(Options, List) :-
memberchk(namespaces(NSL0), Options), !,
sort([rdf,rdfs|NSL0], List).
header_namespaces(Options, List) :-
graph(Options, DB),
used_namespace_entities(List, DB).
%% rdf_graph_prefixes(?Graph, -List:ord_set) is det.
%% rdf_graph_prefixes(?Graph, -List:ord_set, :Filter) is det.
%
% List is a sorted list of prefixes (namepaces) in Graph. The
% optional Filter argument is used to filter the results. It is
% called with 3 additional arguments:
%
% ==
% call(Filter, Where, Prefix, URI)
% ==
%
% The Where argument gives the location of the prefix ans is one
% of =subject=, =predicate=, =object= or =type=. The Prefix
% argument is the potentionally new prefix and URI is the full URI
% that is being processed.
:- thread_local
graph_prefix/1.
:- meta_predicate
rdf_graph_prefixes(?, -, 3).
rdf_graph_prefixes(Graph, List) :-
rdf_graph_prefixes(Graph, List, true).
rdf_graph_prefixes(Graph, List, Filter) :-
call_cleanup(prefixes(Graph, Prefixes, Filter),
retractall(graph_prefix(_))),
sort(Prefixes, List).
prefixes(Graph, Prefixes, Filter) :-
( rdf_db(S, P, O, Graph),
add_ns(subject, Filter, S),
add_ns(predicate, Filter, P),
add_ns_obj(Filter, O),
fail
; true
),
findall(Prefix, graph_prefix(Prefix), Prefixes).
add_ns(Where, Filter, S) :-
\+ rdf_is_bnode(S),
iri_xml_namespace(S, Full),
Full \== '', !,
( graph_prefix(Full)
-> true
; Filter = _:true
-> assert(graph_prefix(Full))
; call(Filter, Where, Full, S)
-> assert(graph_prefix(Full))
; true
).
add_ns(_, _, _).
add_ns_obj(Filter, O) :-
atom(O), !,
add_ns(object, Filter, O).
add_ns_obj(Filter, literal(type(Type, _))) :-
atom(Type), !,
add_ns(type, Filter, Type).
add_ns_obj(_, _).
%% used_namespace_entities(-List, ?Graph) is det.
%
% Return the namespace aliases that are actually used in Graph. In
% addition, this predicate creates ns<N> aliases for namespaces
% used in predicates because RDF/XML cannot write predicates other
% than as an XML name.
used_namespace_entities(List, Graph) :-
decl_used_predicate_ns(Graph),
used_namespaces(List, Graph).
used_namespaces(List, DB) :-
rdf_graph_prefixes(DB, FullList),
ns_abbreviations(FullList, List0),
sort([rdf|List0], List).
ns_abbreviations([], []).
ns_abbreviations([H0|T0], [H|T]) :-
ns(H, H0), !,
ns_abbreviations(T0, T).
ns_abbreviations([_|T0], T) :-
ns_abbreviations(T0, T).
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
For every URL used as a predicate we *MUST* define a namespace as we
cannot use names holding /, :, etc. as XML identifiers.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
:- thread_local
predicate_ns/2.
decl_used_predicate_ns(DB) :-
retractall(predicate_ns(_,_)),
( rdf_current_predicate(P, DB),
decl_predicate_ns(P),
fail
; true
).
decl_predicate_ns(Pred) :-
predicate_ns(Pred, _), !.
decl_predicate_ns(Pred) :-
rdf_global_id(NS:Local, Pred),
xml_name(Local), !,
assert(predicate_ns(Pred, NS)).
decl_predicate_ns(Pred) :-
atom_codes(Pred, Codes),
append(NSCodes, LocalCodes, Codes),
xml_codes(LocalCodes), !,
( NSCodes \== []
-> atom_codes(NS, NSCodes),
( ns(Id, NS)
-> assert(predicate_ns(Pred, Id))
; between(1, infinite, N),
atom_concat(ns, N, Id),
\+ ns(Id, _)
-> rdf_register_ns(Id, NS),
print_message(informational,
rdf(using_namespace(Id, NS)))
),
assert(predicate_ns(Pred, Id))
; assert(predicate_ns(Pred, -)) % no namespace used
).
xml_codes([]).
xml_codes([H|T]) :-
xml_code(H),
xml_codes(T).
xml_code(X) :-
code_type(X, csym), !.
xml_code(0'-). % Match 0'-
%% rdf_save_footer(Out:stream) is det.
%
% Finish XML generation and write the document footer.
rdf_save_footer(Out) :-
retractall(named_anon(_, _)),
format(Out, '</rdf:RDF>~n', []).
%% rdf_save_non_anon_subject(+Out, +Subject, +Options)
%
% Save an object. Anonymous objects not saved if anon(false)
% is present in the Options list.
rdf_save_non_anon_subject(_Out, Subject, Options) :-
rdf_is_bnode(Subject),
( memberchk(anon(false), Options)
; graph(Options, DB),
rdf_db(_, _, Subject, DB)
), !.
rdf_save_non_anon_subject(Out, Subject, Options) :-
rdf_save_subject(Out, Subject, Options),
flag(rdf_db_saved_subjects, X, X+1).
%% rdf_save_subject(+Out, +Subject:resource, +Options) is det.
%
% Save the triples associated to Subject to Out.
rdf_save_subject(Out, Subject, Options) :-
is_list(Options), !,
option(base_uri(BaseURI), Options, '-'),
( rdf_save_subject(Out, Subject, BaseURI, 0, Options)
-> format(Out, '~n', [])
; throw(error(rdf_save_failed(Subject), 'Internal error'))
).
rdf_save_subject(Out, Subject, DB) :-
( var(DB)
-> rdf_save_subject(Out, Subject, [])
; rdf_save_subject(Out, Subject, [graph(DB)])
).
%% rdf_save_subject(+Out:stream, +Subject:resource, +BaseURI,
%% +Indent:int, +Options) is det.
%
% Save properties of Subject.
%
% @param Indent Current indentation
rdf_save_subject(Out, Subject, BaseURI, Indent, Options) :-
graph(Options, DB),
findall(Pred=Object, rdf_db(Subject, Pred, Object, DB), Atts0),
sort(Atts0, Atts), % remove duplicates
length(Atts, L),
( length(Atts0, L0),
Del is L0-L,
Del > 0
-> print_message(informational,
rdf(save_removed_duplicates(Del, Subject)))
; true
),
rdf_save_subject(Out, Subject, BaseURI, Atts, Indent, Options),
flag(rdf_db_saved_triples, X, X+L).
rdf_db(Subject, Pred, Object, DB) :-
var(DB), !,
rdf(Subject, Pred, Object).
rdf_db(Subject, Pred, Object, DB) :-
rdf(Subject, Pred, Object, DB:_).
%% rdf_save_subject(+Out:stream, +Subject:resource, +BaseURI,
%% +Atts:list(Pred=Obj), +Indent:int, +Options) is det.
%
% Save triples defined by Atts on Subject.
rdf_save_subject(Out, Subject, BaseURI, Atts, Indent, Options) :-
rdf_equal(rdf:type, RdfType),
select(RdfType=Type, Atts, Atts1),
\+ rdf_is_bnode(Type),
rdf_id(Type, BaseURI, TypeId),
xml_is_name(TypeId), !,
format(Out, '~*|<', [Indent]),
rdf_write_id(Out, TypeId),
save_about(Out, BaseURI, Subject),
save_attributes(Atts1, BaseURI, Out, TypeId, Indent, Options).
rdf_save_subject(Out, Subject, BaseURI, Atts, Indent, Options) :-
format(Out, '~*|<rdf:Description', [Indent]),
save_about(Out, BaseURI, Subject),
save_attributes(Atts, BaseURI, Out, rdf:'Description', Indent, Options).
xml_is_name(_NS:Atom) :- !,
xml_name(Atom).
xml_is_name(Atom) :-
xml_name(Atom).
%% save_about(+Out, +BaseURI, +Subject) is det.
%
% Save the rdf:about. If Subject is a blank node, save the nodeID
% if any.
save_about(Out, _, Subject) :-
rdf_is_bnode(Subject), !,
( named_anon(Subject, NodeID)
-> format(Out, ' rdf:nodeID="~w"', [NodeID])
; true
).
save_about(Out, BaseURI, Subject) :-
stream_property(Out, encoding(Encoding)),
rdf_value(Subject, BaseURI, QSubject, Encoding),
format(Out, ' rdf:about="~w"', [QSubject]).
%% save_attributes(+List, +BaseURI, +Stream, Element)
%
% Save the attributes. Short literal attributes are saved in the
% tag. Others as the content of the description element. The
% begin tag has already been filled.
save_attributes(Atts, BaseURI, Out, Element, Indent, Options) :-
split_attributes(Atts, InTag, InBody),
SubIndent is Indent + 2,
save_attributes2(InTag, BaseURI, tag, Out, SubIndent, Options),
( InBody == []
-> format(Out, '/>~n', [])
; format(Out, '>~n', []),
save_attributes2(InBody, BaseURI, body, Out, SubIndent, Options),
format(Out, '~N~*|</', [Indent]),
rdf_write_id(Out, Element),
format(Out, '>~n', [])
).
%% split_attributes(+Attributes, -HeadAttrs, -BodyAttr)
%
% Split attribute (Name=Value) list into attributes for the head
% and body. Attributes can only be in the head if they are literal
% and appear only one time in the attribute list.
split_attributes(Atts, HeadAttr, BodyAttr) :-
duplicate_attributes(Atts, Dupls, Singles),
simple_literal_attributes(Singles, HeadAttr, Rest),
append(Dupls, Rest, BodyAttr).
%% duplicate_attributes(+Attrs, -Duplicates, -Singles)
%
% Extract attributes that appear more than onces as we cannot
% dublicate an attribute in the head according to the XML rules.
duplicate_attributes([], [], []).
duplicate_attributes([H|T], Dupls, Singles) :-
H = (Name=_),
named_attributes(Name, T, D, R),
D \== [],
append([H|D], Dupls2, Dupls), !,
duplicate_attributes(R, Dupls2, Singles).
duplicate_attributes([H|T], Dupls2, [H|Singles]) :-
duplicate_attributes(T, Dupls2, Singles).
named_attributes(_, [], [], []) :- !.
named_attributes(Name, [H|T], D, R) :-
( H = (Name=_)
-> D = [H|DT],
named_attributes(Name, T, DT, R)
; R = [H|RT],
named_attributes(Name, T, D, RT)
).
%% simple_literal_attributes(+Attributes, -Inline, -Body)
%
% Split attributes for (literal) attributes to be used in the
% begin-tag and ones that have to go into the body of the description.
simple_literal_attributes([], [], []).
simple_literal_attributes([H|TA], [H|TI], B) :-
in_tag_attribute(H), !,
simple_literal_attributes(TA, TI, B).
simple_literal_attributes([H|TA], I, [H|TB]) :-
simple_literal_attributes(TA, I, TB).
in_tag_attribute(_=literal(Text)) :-
atom(Text), % may not have lang qualifier
atom_length(Text, Len),
Len < 60.
%% save_attributes(+List, +BaseURI, +TagOrBody, +Stream)
%
% Save a list of attributes.
save_attributes2([], _, _, _, _, _).
save_attributes2([H|T], BaseURI, Where, Out, Indent, Options) :-
save_attribute(Where, H, BaseURI, Out, Indent, Options),
save_attributes2(T, BaseURI, Where, Out, Indent, Options).
save_attribute(tag, Name=literal(Value), BaseURI, Out, Indent, _DB) :-
AttIndent is Indent + 2,
rdf_id(Name, BaseURI, NameText),
stream_property(Out, encoding(Encoding)),
xml_quote_attribute(Value, QVal, Encoding),
format(Out, '~N~*|', [AttIndent]),
rdf_write_id(Out, NameText),
format(Out, '="~w"', [QVal]).
save_attribute(body, Name=literal(Literal0), BaseURI, Out, Indent, Options) :- !,
rdf_id(Name, BaseURI, NameText),
( memberchk(convert_typed_literal(Converter), Options),
call(Converter, Type, Content, Literal0)
-> Literal = type(Type, Content)
; Literal = Literal0
),
save_body_literal(Literal, NameText, BaseURI, Out, Indent, Options).
save_attribute(body, Name=Value, BaseURI, Out, Indent, Options) :-
rdf_is_bnode(Value), !,
rdf_id(Name, BaseURI, NameText),
format(Out, '~N~*|<', [Indent]),
rdf_write_id(Out, NameText),
( named_anon(Value, NodeID)
-> format(Out, ' rdf:nodeID="~w"/>', [NodeID])
; ( rdf(S1, Name, Value),
rdf(S2, P2, Value),
(S1 \== S2 ; Name \== P2)
-> predicate_property(named_anon(_,_), number_of_clauses(N)),
atom_concat('bn', N, NodeID),
assert(named_anon(Value, NodeID))
; true
),
SubIndent is Indent + 2,
( rdf(Value, rdf:type, rdf:'List')
-> save_about(Out, BaseURI, Value),
format(Out, ' rdf:parseType="Collection">~n', []),
rdf_save_list(Out, Value, BaseURI, SubIndent, Options)
; format(Out, '>~n', []),
rdf_save_subject(Out, Value, BaseURI, SubIndent, Options)
),
format(Out, '~N~*|</', [Indent]),
rdf_write_id(Out, NameText),
format(Out, '>~n', [])
).
save_attribute(body, Name=Value, BaseURI, Out, Indent, _DB) :-
stream_property(Out, encoding(Encoding)),
rdf_value(Value, BaseURI, QVal, Encoding),
rdf_id(Name, BaseURI, NameText),
format(Out, '~N~*|<', [Indent]),
rdf_write_id(Out, NameText),
format(Out, ' rdf:resource="~w"/>', [QVal]).
%% save_body_literal(+Literal, +NameText, +BaseURI,
%% +Out, +Indent, +Options).
save_body_literal(lang(Lang, Value),
NameText, BaseURI, Out, Indent, Options) :- !,
format(Out, '~N~*|<', [Indent]),
rdf_write_id(Out, NameText),
( memberchk(document_language(Lang), Options)
-> write(Out, '>')
; rdf_id(Lang, BaseURI, LangText),
format(Out, ' xml:lang="~w">', [LangText])
),
save_attribute_value(Value, Out, Indent),
write(Out, '</'), rdf_write_id(Out, NameText), write(Out, '>').
save_body_literal(type(Type, DOM),
NameText, _BaseURI, Out, Indent, Options) :-
rdf_equal(Type, rdf:'XMLLiteral'), !,
save_xml_literal(DOM, NameText, Out, Indent, Options).
save_body_literal(type(Type, Value),
NameText, BaseURI, Out, Indent, _) :- !,
format(Out, '~N~*|<', [Indent]),
rdf_write_id(Out, NameText),
stream_property(Out, encoding(Encoding)),
rdf_value(Type, BaseURI, QVal, Encoding),
format(Out, ' rdf:datatype="~w">', [QVal]),
save_attribute_value(Value, Out, Indent),
write(Out, '</'), rdf_write_id(Out, NameText), write(Out, '>').
save_body_literal(Literal,
NameText, _, Out, Indent, _) :-
atomic(Literal), !,
format(Out, '~N~*|<', [Indent]),
rdf_write_id(Out, NameText),
write(Out, '>'),
save_attribute_value(Literal, Out, Indent),
write(Out, '</'), rdf_write_id(Out, NameText), write(Out, '>').
save_body_literal(DOM,
NameText, BaseURI, Out, Indent, Options) :-
rdf_equal(Type, rdf:'XMLLiteral'),
save_body_literal(type(Type, DOM),
NameText, BaseURI, Out, Indent, Options).
save_attribute_value(Value, Out, _) :- % strings
atom(Value), !,
stream_property(Out, encoding(Encoding)),
xml_quote_cdata(Value, QVal, Encoding),
write(Out, QVal).
save_attribute_value(Value, Out, _) :- % numbers
number(Value), !,
writeq(Out, Value). % quoted: preserve floats
save_attribute_value(Value, _Out, _) :-
throw(error(save_attribute_value(Value), _)).
%% save_xml_literal(+DOM, +Attr, +Out, +Indent, +Options) is det.
%
% Save an XMLLiteral value. We already emitted
%
% ==
% <prop parseType="literal"
% ==
%
% but not the terminating =|>|=. We need to establish the
% namespaces used in the DOM. The namespaces in the rdf document
% are in the nsmap-option of Options.
save_xml_literal(DOM, Attr, Out, Indent, Options) :-
xml_is_dom(DOM), !,
memberchk(nsmap(NsMap), Options),
id_to_atom(Attr, Atom),
xml_write(Out,
element(Atom, ['rdf:parseType'='Literal'], DOM),
[ header(false),
indent(Indent),
nsmap(NsMap)
]).
save_xml_literal(NoDOM, _, _, _, _) :-
must_be(xml_dom, NoDOM).
id_to_atom(NS:Local, Atom) :- !,
atomic_list_concat([NS,Local], :, Atom).
id_to_atom(ID, ID).
%% rdf_save_list(+Out, +List, +BaseURI, +Indent, +Options)
rdf_save_list(_, List, _, _, _) :-
rdf_equal(List, rdf:nil), !.
rdf_save_list(Out, List, BaseURI, Indent, Options) :-
rdf_has(List, rdf:first, First),
( rdf_is_bnode(First)
-> nl(Out),
rdf_save_subject(Out, First, BaseURI, Indent, Options)
; stream_property(Out, encoding(Encoding)),
rdf_value(First, BaseURI, QVal, Encoding),
format(Out, '~N~*|<rdf:Description rdf:about="~w"/>',
[Indent, QVal])
),
flag(rdf_db_saved_triples, X, X+3),
( rdf_has(List, rdf:rest, List2),
\+ rdf_equal(List2, rdf:nil)
-> rdf_save_list(Out, List2, BaseURI, Indent, Options)
; true
).
%% rdf_id(+Resource, +BaseURI, -NSLocal)
%
% Generate a NS:Local name for Resource given the indicated
% default namespace. This call is used for elements.
rdf_id(Id, BaseURI, Local) :-
assertion(atom(BaseURI)),
atom_concat(BaseURI, Local, Id),
sub_atom(Local, 0, 1, _, #), !.
rdf_id(Id, _, NS:Local) :-
iri_xml_namespace(Id, Full, Local),
ns(NS, Full), !.
rdf_id(Id, _, NS:Local) :-
ns(NS, Full),
Full \== '',
atom_concat(Full, Local, Id), !.
rdf_id(Id, _, Id).
%% rdf_write_id(+Out, +NSLocal) is det.
%
% Write an identifier. We cannot use native write on it as both NS
% and Local can be operators.
rdf_write_id(Out, NS:Local) :- !,
format(Out, '~w:~w', [NS, Local]).
rdf_write_id(Out, Atom) :-
write(Out, Atom).
%% rdf_value(+Resource, +BaseURI, -Text, +Encoding)
%
% According to "6.4 RDF URI References" of the RDF Syntax
% specification, a URI reference is UNICODE string not containing
% control sequences, represented as UTF-8 and then as escaped
% US-ASCII.
rdf_value(Base, Base, '', _) :- !.
rdf_value(V, Base, Text, Encoding) :-
atom_concat(Base, Local, V),
sub_atom(Local, 0, _, _, #), !,
rdf_quote_uri(Local, Q0),
xml_quote_attribute(Q0, Text, Encoding).
rdf_value(V, _, Text, Encoding) :-
ns(NS, Full),
atom_concat(Full, Local, V), !,
rdf_quote_uri(Local, QLocal0),
xml_quote_attribute(QLocal0, QLocal, Encoding),
atomic_list_concat(['&', NS, (';'), QLocal], Text).
rdf_value(V, _, Q, Encoding) :-
rdf_quote_uri(V, Q0),
xml_quote_attribute(Q0, Q, Encoding).
/*******************************
* DEPRECATED MATERIAL *
*******************************/
%% rdf_split_url(+Prefix, +Local, -URL) is det.
%% rdf_split_url(-Prefix, -Local, +URL) is det.
%
% Split/join a URL. This functionality is moved to library(sgml).
%
% @deprecated Use iri_xml_namespace/3. Note that the argument
% order is iri_xml_namespace(+IRI, -Namespace, -Localname).
rdf_split_url(Prefix, Local, URL) :-
atomic(URL), !,
iri_xml_namespace(URL, Prefix, Local).
rdf_split_url(Prefix, Local, URL) :-
atom_concat(Prefix, Local, URL).
%% rdf_url_namespace(+URL, -Namespace)
%
% Namespace is the namespace of URL.
%
% @deprecated Use iri_xml_namespace/2
rdf_url_namespace(URL, Prefix) :-
iri_xml_namespace(URL, Prefix).
/*******************************
* MESSAGES *
*******************************/
:- multifile
prolog:message/3.
prolog:message(rdf(loaded(How, What, BaseURI, Triples, Time))) -->
how(How),
source(What),
into(What, BaseURI),
in_time(Triples, Time).
prolog:message(rdf(save_removed_duplicates(N, Subject))) -->
[ 'Removed ~d duplicate triples about "~p"'-[N,Subject] ].
prolog:message(rdf(saved(File, SavedSubjects, SavedTriples))) -->
[ 'Saved ~D triples about ~D subjects into ~p'-
[SavedTriples, SavedSubjects, File]
].
prolog:message(rdf(using_namespace(Id, NS))) -->
[ 'Using namespace id ~w for ~w'-[Id, NS] ].
prolog:message(rdf(inconsistent_cache(DB, Graphs))) -->
[ 'RDF cache file for ~w contains the following graphs'-[DB], nl,
'~t~8|~p'-[Graphs]
].
prolog:message(rdf(guess_format(Ext))) -->
[ 'Unknown file-extension: ~w. Assuming RDF/XML'-[Ext] ].
prolog:message(rdf_meta(not_expanded(G))) -->
[ 'rdf_meta: ~p is not expanded'-[G] ].
how(load) --> [ 'Loaded' ].
how(parsed) --> [ 'Parsed' ].
source(SourceURL) -->
{ uri_file_name(SourceURL, File), !,
file_base_name(File, Base) % TBD: relative file?
},
[ ' "~p"'-[Base] ].
source(SourceURL) -->
[ ' "~p"'-[SourceURL] ].
into(_, _) --> []. % TBD
in_time(Triples, ParseTime) -->
[ ' in ~2f sec; ~D triples'-[ParseTime, Triples]
].
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