Wbase_doc_mgr.java

/*
XOWA: the XOWA Offline Wiki Application
Copyright (C) 2012-2017 gnosygnu@gmail.com

XOWA is licensed under the terms of the General Public License (GPL) Version 3,
or alternatively under the terms of the Apache License Version 2.0.

You may use XOWA according to either of these licenses as is most appropriate
for your project on a case-by-case basis.

The terms of each license can be found in the source code repository:

GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
*/
package gplx.xowa.xtns.wbases; import gplx.*; import gplx.xowa.*; import gplx.xowa.xtns.*;
import gplx.langs.jsons.*;
import gplx.xowa.wikis.pages.*;
public class Wbase_doc_mgr {
	private final    Xoae_app app;
	private final    Wdata_wiki_mgr wbase_mgr;
	private final    Wbase_qid_mgr qid_mgr;
	private final    gplx.xowa.apps.caches.Wdata_doc_cache hash;
	public Wbase_doc_mgr(Xoae_app app, Wdata_wiki_mgr wbase_mgr, Wbase_qid_mgr qid_mgr) {
		this.app = app; this.wbase_mgr = wbase_mgr; this.qid_mgr = qid_mgr;
		this.hash = app.Cache_mgr().Doc_cache();
	}
	public void Enabled_(boolean v) {this.enabled = v;} private boolean enabled;
	public void Clear() {
		synchronized (hash) {	// LOCK:app-level
			hash.Clear();
		}
	}
	public void Add(byte[] full_db, Wdata_doc page) {	// TEST:
		synchronized (hash) {	// LOCK:app-level
			if (hash.Get_or_null(full_db) == null)
				hash.Add(full_db, page);
		}
	}	
	public Wdata_doc Get_by_ttl_or_null(Xowe_wiki wiki, Xoa_ttl ttl) {
		byte[] qid_bry = qid_mgr.Get_or_null(wiki, ttl);	// EX: "enwiki","Earth" -> "Q2"
		return qid_bry == null ? null : this.Get_by_bry_or_null(qid_bry);
	}
	public Wdata_doc Get_by_xid_or_null(byte[] xid) {return Get_by_bry_or_null(Prepend_property_if_needed(xid));}// scribunto passes either p1 or q1; convert p1 to "Property:P1"
	public Wdata_doc Get_by_bry_or_null(byte[] ttl_bry) {// must be correct format; EX:"Q2" or "Property:P1"
		Wdata_doc rv = hash.Get_or_null(ttl_bry);
		if (rv == null) {
			synchronized (hash) {	// LOCK:app-level; hash;
				rv = Load_wdoc_or_null(ttl_bry); if (rv == null) return null;	// page not found
				Add(ttl_bry, rv);// NOTE: use ttl_bry, not rv.Qid; allows subsequent lookups to skip this redirect cycle
			}
		}
		return rv;
	}
	public Wdata_doc Load_wdoc_or_null(byte[] src_ttl_bry) {
		if (!enabled) return null;
		synchronized (hash) {	// LOCK:app-level; jdoc_parser; moved synchronized higher up; DATE:2016-09-03
			byte[] cur_ttl_bry = src_ttl_bry;
			int load_count = -1;
			while (load_count < 2) {	// limit to 2 tries (i.e.: 1 redirect)
				// parse ttl
				Xoa_ttl cur_ttl = wbase_mgr.Wdata_wiki().Ttl_parse(cur_ttl_bry);
				if (cur_ttl == null) {
					app.Usr_dlg().Warn_many("", "", "invalid wbase ttl: orig=~{0} cur=~{1}", src_ttl_bry, cur_ttl_bry);
					return null;
				}

				// get page
				Xoae_page page = wbase_mgr.Wdata_wiki().Data_mgr().Load_page_by_ttl(cur_ttl);
				if (!page.Db().Page().Exists()) return null;

				// parse jdoc
				byte[] jdoc_bry = page.Db().Text().Text_bry();
				Json_doc jdoc = null;
				jdoc = wbase_mgr.Jdoc_parser().Parse(jdoc_bry);
				if (jdoc == null) {
					app.Usr_dlg().Warn_many("", "", "invalid jdoc for ttl: orig=~{0} cur=~{1}", src_ttl_bry, cur_ttl_bry);
					return null;
				}

				// check for redirect; EX: {"entity":"Q22350516","redirect":"Q21006972"}; PAGE:fr.w:Tour_du_Táchira_2016; DATE:2016-08-13
				Json_nde jdoc_root = jdoc.Root_nde();
				byte[] redirect_ttl = jdoc_root.Get_as_bry_or(Bry__redirect, null);
				if (redirect_ttl != null) {
					cur_ttl_bry = redirect_ttl;
					continue;
				}

				// is json doc, and not a redirect; return
				return new Wdata_doc(cur_ttl_bry, wbase_mgr, jdoc);
			}
			app.Usr_dlg().Warn_many("", "", "too many redirects for ttl: orig=~{0} cur=~{1}", src_ttl_bry, cur_ttl_bry);
		}
		return null;
	}
	private static final    byte[] Bry__redirect = Bry_.new_a7("redirect");

	private static byte[] Prepend_property_if_needed(byte[] bry) {
		int len = bry == null ? 0 : bry.length;
		return	len > 1
			&&	Byte_ascii.Case_lower(bry[0]) == Byte_ascii.Ltr_p
			&&	Byte_ascii.Is_num(bry[1])
			?	Bry_.Add(Wdata_wiki_mgr.Ns_property_name_bry, Byte_ascii.Colon_bry, bry)	// if ttl starts with "p#", prepend "Property:" to get "Property:P#"; NOTE: do not ucase P b/c it breaks a test; DATE:2014-02-18
			:	bry;
	}
}