public void Special_gen(Xowe_wiki wiki, Xoae_page page, Xoa_url url, Xoa_ttl ttl) {
   if (cfg == null)
     cfg =
         (Wdata_itemByTitle_cfg) wiki.Appe().Special_mgr().Get_or_null(Wdata_itemByTitle_cfg.Key);
   // Special:ItemByTitle/enwiki/Earth -> www.wikidata.org/wiki/Q2
   Gfo_usr_dlg usr_dlg = wiki.Appe().Usr_dlg();
   byte[] site_bry = cfg.Site_default();
   byte[] page_bry = Bry_.Empty;
   byte[] raw_bry = ttl.Full_txt_wo_qarg(); // EX: enwiki/Earth
   int args_len = url.Args().length;
   if (args_len > 0) {
     arg_hash.Load(url);
     site_bry = arg_hash.Get_val_bry_or(Arg_site, Bry_.Empty);
     page_bry = arg_hash.Get_val_bry_or(Arg_page, Bry_.Empty);
   }
   int site_bgn = Bry_finder.Find_fwd(raw_bry, Xoa_ttl.Subpage_spr);
   if (site_bgn != Bry_.NotFound) { // leaf arg is available
     int page_bgn = Bry_finder.Find_fwd(raw_bry, Xoa_ttl.Subpage_spr, site_bgn + 1);
     int raw_bry_len = raw_bry.length;
     if (page_bgn != Bry_.NotFound
         && page_bgn < raw_bry_len) { // pipe is found and not last char (EX: "enwiki/" is invalid
       site_bry = Bry_.Mid(raw_bry, site_bgn + 1, page_bgn);
       page_bry = Bry_.Mid(raw_bry, page_bgn + 1, raw_bry_len);
     }
   }
   Xoae_app app = wiki.Appe();
   if (Bry_.Len_gt_0(site_bry) && Bry_.Len_gt_0(page_bry))
     if (Navigate(usr_dlg, app, app.Wiki_mgr().Wdata_mgr(), page, site_bry, page_bry)) return;
   Bry_bfr tmp_bfr = wiki.Utl__bfr_mkr().Get_k004();
   html_fmtr.Bld_bfr_many(
       tmp_bfr,
       "Search for items by site and title",
       "Site",
       site_bry,
       "Page",
       page_bry,
       "Search");
   page.Data_raw_(tmp_bfr.To_bry_and_rls());
   page.Html_data().Html_restricted_n_(); // [[Special:]] pages allow all HTML
 }
	public static byte[] Write_wdata_links(List_adp slink_list, Xowe_wiki wiki, Xoa_ttl ttl, Wdata_external_lang_links_data external_links_mgr) {
		try {
			switch (wiki.Domain_tid()) {
				case Xow_domain_type_.Tid_home:		// home will never be in wikidata
				case Xow_domain_type_.Tid_wikidata:	// wikidata will never be in wikidata
					return Qid_null;
			}
			Wdata_wiki_mgr wdata_mgr = wiki.Appe().Wiki_mgr().Wdata_mgr();
			Wdata_doc doc = wdata_mgr.Pages_get(wiki, ttl); if (doc == null) return Qid_null;	// no links
			boolean external_links_mgr_enabled = external_links_mgr.Enabled();
			Ordered_hash links = doc.Slink_list();
			Bry_bfr tmp_bfr = wiki.Appe().Utl__bfr_mkr().Get_k004();
			Xow_wiki_abrv wiki_abrv = new Xow_wiki_abrv();
			int len = links.Count();
			for (int i = 0; i < len; i++) {
				Wdata_sitelink_itm slink = (Wdata_sitelink_itm)links.Get_at(i);
				byte[] xwiki_key = slink.Site();
				Xow_wiki_abrv_.parse_(wiki_abrv, xwiki_key, 0, xwiki_key.length);
				if (wiki_abrv.Domain_tid() == Xow_wiki_abrv_.Tid_null) {
					wiki.Appe().Usr_dlg().Warn_many("", "", "unknown wiki in wikidata: ttl=~{0} wiki=~{1}", ttl.Page_db_as_str(), String_.new_u8(xwiki_key));
					continue;
				}
				if (wiki_abrv.Domain_tid() != wiki.Domain_tid()) continue;	// ignore wikis in a different domain; EX: looking at enwiki:Earth, and wikidata has dewikiquote; ignore dewikiquote; DATE:2014-06-21
				byte[] lang_key = wiki_abrv.Lang_itm().Key();
				if (external_links_mgr_enabled && external_links_mgr.Langs_hide(lang_key, 0, lang_key.length)) continue;
				tmp_bfr.Add(lang_key);
				tmp_bfr.Add_byte(Byte_ascii.Colon);
				tmp_bfr.Add(slink.Name());
				Xoa_ttl slink_ttl = Xoa_ttl.parse_(wiki, tmp_bfr.Xto_bry_and_clear());
				if (slink_ttl == null) continue;								// invalid ttl
				Xow_xwiki_itm xwiki_itm = slink_ttl.Wik_itm();
				if (	xwiki_itm == null									// not a known xwiki; EX: [[zzz:abc]]
					||	Bry_.Eq(xwiki_itm.Domain_bry(), wiki.Domain_bry())	// skip if same as self; i.e.: do not include links to enwiki if already in enwiki
					) continue;
				slink.Page_ttl_(slink_ttl);
				slink_list.Add(slink);
			}
			tmp_bfr.Mkr_rls();
			if (external_links_mgr_enabled && external_links_mgr.Sort())
				slink_list.Sort_by(Xoa_ttl_sorter._);
			return doc.Qid();
		} catch (Exception e) {Err_.Noop(e); return Qid_null;}
	}