/* Part of SWI-Prolog Author: Jan Wielemaker and Matt Lilley E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 2016, CWI 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(c14n2, [ xml_write_canonical/3 % +Stream, +Term, +Options ]). :- use_module(library(error)). :- use_module(library(option)). :- use_module(library(sgml_write)). :- use_module(library(dicts)). :- use_module(library(ordsets)). :- use_module(library(apply)). :- use_module(library(lists)). /** C14n2 canonical XML documents C14n2 specifies a _canonical_ XML document. This library writes such a document from an XML DOM as returned by the XML (or SGML) parser. The process takes two steps: - Normalise the DOM - Call xml_write/3 with appropriate flags */ %! xml_write_canonical(+Stream, +DOM, +Options) is det. % % Write an XML DOM using the canonical conventions as defined by % C14n2. Namespace declarations in the canonical document depend % on the original namespace declarations. For this reason the % input document must be parsed (see load_structure/3) using the % dialect `xmlns` and the option keep_prefix(true). xml_write_canonical(Stream, DOM, Options) :- option(method(Method), Options, 'http://www.w3.org/TR/2001/REC-xml-c14n-20010315'), xml_canonical_dom(DOM, CDOM, xml{in_ns:ns{}, out_ns:ns{}, is_root:true, method:Method}), xml_write(Stream, CDOM, [ header(false), layout(false), net(false) ]). xml_canonical_dom(Var, _, _) :- var(Var), !, instantiation_error(Var). xml_canonical_dom(DOM, CDOM, Options) :- is_list(DOM), !, xml_canonical_list(DOM, CDOM, Options). xml_canonical_dom(element( Name, Attrs, Content), element(CName, CAttrs, CContent), Options) :- !, InNS0 = Options.in_ns, OutNS0 = Options.out_ns, Method = Options.method, take_ns(Attrs, Method, Name, Attrs1, InNS0, InNS), partition(has_ns, Attrs1, AttrsWithNS0, AttrsSans0), sort(1, @<, AttrsWithNS0, AttrsWithNS1), sort(1, @<, AttrsSans0, AttrsSans), put_elemns(Name, CName, InNS, OutNS0, OutNS1, KillDefault), put_ns_attrs(AttrsWithNS1, AttrsWithNS, InNS, OutNS1, OutNS), ns_attrs(OutNS0, OutNS, NSAttrs), ( Options.is_root == true -> ( select(xmlns=DefaultNamespace, NSAttrs, NSAttrs0) % If there is a default namespace, it must come first, and I dont think sort/4 can sort on two keys at once -> findall(xmlns:NS=URI, member(xmlns:NS=URI, Attrs), RootNSAttrs, NSAttrs0), sort(2, @=<, RootNSAttrs, RootNSAttrs0), RootNSAttrs1 = [xmlns=DefaultNamespace|RootNSAttrs0] ; Method == 'http://www.w3.org/2001/10/xml-exc-c14n#' -> RootNSAttrs1 = NSAttrs ; findall(xmlns:NS=URI, member(xmlns:NS=URI, Attrs), RootNSAttrs, NSAttrs), sort(2, @<, RootNSAttrs, RootNSAttrs1) ), append([KillDefault, RootNSAttrs1, AttrsSans, AttrsWithNS], CAttrs) ; append([KillDefault, NSAttrs, AttrsSans, AttrsWithNS], CAttrs) ), must_be(list, Content), xml_canonical_list(Content, CContent, Options.put(_{in_ns:InNS, out_ns:OutNS, is_root:false})). xml_canonical_dom(CDATA, CDATA, _) :- atomic(CDATA). has_ns(_NS:_Name=_Value). xml_canonical_list([], [], _). xml_canonical_list([H0|T0], [H|T], Options) :- xml_canonical_dom(H0, H, Options), xml_canonical_list(T0, T, Options). take_ns([], _, _, [], NSList, NSList). take_ns([H|T0], Method, Name, T, NSList0, NSList) :- xml_ns(H, NS, URL), !, ( include_ns(Name, Method, NS, URL) -> take_ns(T0, Method, Name, T, NSList0.put(NS, URL), NSList) ; take_ns(T0, Method, Name, T, NSList0, NSList) ). take_ns([H|T0], Method, Name, [H|T], NSList0, NSList) :- take_ns(T0, Method, Name, T, NSList0, NSList). include_ns(ns(Prefix, URI):_, 'http://www.w3.org/2001/10/xml-exc-c14n#', Prefix, URI):- !. include_ns(_, 'http://www.w3.org/TR/2001/REC-xml-c14n-20010315', _, _):- !. put_ns_attrs([], [], _, OutNS, OutNS). put_ns_attrs([Name=Value|T0], [CName=Value|T], InNS, OutNS0, OutNS) :- put_ns(Name, CName, InNS, OutNS0, OutNS1), put_ns_attrs(T0, T, InNS, OutNS1, OutNS). put_elemns(Name, Name, _InNS, OutNS0, OutNS1, [xmlns='']) :- atom(Name), dict_pairs(OutNS0, _, Pairs), memberchk(URL-'', Pairs), !, del_dict(URL, OutNS0, '', OutNS1). put_elemns(Name, CName, InNS, OutNS0, OutNS, []) :- put_ns(Name, CName, InNS, OutNS0, OutNS). put_ns(ns(NS, URL):Name, CName, _InNS, OutNS, OutNS) :- get_dict(URL, OutNS, NS), !, make_cname(NS:Name, CName). put_ns(ns(NS, URL):Name, CName, _InNS, OutNS0, OutNS) :- !, make_cname(NS:Name, CName), OutNS = OutNS0.put(URL, NS). put_ns(URL:Name, CName, _InNS, OutNS, OutNS) :- get_dict(URL, OutNS, NS), !, make_cname(NS:Name, CName). put_ns(URL:Name, CName, InNS, OutNS0, OutNS) :- dict_pairs(InNS, _, Pairs), memberchk(NS-URL, Pairs), !, make_cname(NS:Name, CName), OutNS = OutNS0.put(URL, NS). put_ns(Name, Name, _, OutNS, OutNS). ns_attrs(OutNS, OutNS, []) :- !. ns_attrs(OutNS0, OutNS, NSAttrs) :- !, dict_keys(OutNS, URLs), dict_keys(OutNS0, URLs0), ord_subtract(URLs, URLs0, NewURLs), maplist(ns_attr(OutNS), NewURLs, NSAttrs0), sort(NSAttrs0, NSAttrs). ns_attr(Dict, URL, NSAttr) :- ns_simplify(xmlns:Dict.URL=URL, NSAttr). ns_simplify(xmlns:''=URL, xmlns=URL) :- !. ns_simplify(xmlns:NS=URL, XMLNS=URL) :- make_cname(xmlns:NS, XMLNS). xml_ns(xmlns=URL, '', URL) :- !. xml_ns(xmlns:NS=URL, NS, URL) :- !. xml_ns(Name=URL, NS, URL) :- atom(Name), atom_concat('xmlns:', NS, Name). make_cname('':Name, Name) :- !. make_cname(NS:Name, CName) :- atomic_list_concat([NS,Name], :, CName).