summaryrefslogtreecommitdiff
path: root/includes/Title.php
blob: c4db4172f63bdadff7eca281226f0ca24edcf382 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
<?php
/**
 * See title.txt
 *
 */

/** */
if ( !class_exists( 'UtfNormal' ) ) {
	require_once( dirname(__FILE__) . '/normal/UtfNormal.php' );
}

define ( 'GAID_FOR_UPDATE', 1 );

# Title::newFromTitle maintains a cache to avoid
# expensive re-normalization of commonly used titles.
# On a batch operation this can become a memory leak
# if not bounded. After hitting this many titles,
# reset the cache.
define( 'MW_TITLECACHE_MAX', 1000 );

# Constants for pr_cascade bitfield
define( 'CASCADE', 1 );

/**
 * Title class
 * - Represents a title, which may contain an interwiki designation or namespace
 * - Can fetch various kinds of data from the database, albeit inefficiently.
 *
 */
class Title {
	/**
	 * Static cache variables
	 */
	static private $titleCache=array();
	static private $interwikiCache=array();
	
	
	/**
	 * All member variables should be considered private
	 * Please use the accessor functions
	 */

	/**#@+
	 * @private
	 */

	var $mTextform;           	# Text form (spaces not underscores) of the main part
	var $mUrlform;            	# URL-encoded form of the main part
	var $mDbkeyform;          	# Main part with underscores
	var $mUserCaseDBKey;        # DB key with the initial letter in the case specified by the user
	var $mNamespace;          	# Namespace index, i.e. one of the NS_xxxx constants
	var $mInterwiki;          	# Interwiki prefix (or null string)
	var $mFragment;           	# Title fragment (i.e. the bit after the #)
	var $mArticleID;          	# Article ID, fetched from the link cache on demand
	var $mLatestID;         	# ID of most recent revision
	var $mRestrictions;       	# Array of groups allowed to edit this article
	var $mCascadeRestriction;	# Cascade restrictions on this page to included templates and images?
	var $mRestrictionsExpiry;	# When do the restrictions on this page expire?
	var $mHasCascadingRestrictions;	# Are cascading restrictions in effect on this page?
	var $mCascadeRestrictionSources;# Where are the cascading restrictions coming from on this page?
	var $mRestrictionsLoaded; 	# Boolean for initialisation on demand
	var $mPrefixedText;       	# Text form including namespace/interwiki, initialised on demand
	var $mDefaultNamespace;   	# Namespace index when there is no namespace
	                    		# Zero except in {{transclusion}} tags
	var $mWatched;      		# Is $wgUser watching this page? NULL if unfilled, accessed through userIsWatching()
	/**#@-*/


	/**
	 * Constructor
	 * @private
	 */
	/* private */ function __construct() {
		$this->mInterwiki = $this->mUrlform =
		$this->mTextform = $this->mDbkeyform = '';
		$this->mArticleID = -1;
		$this->mNamespace = NS_MAIN;
		$this->mRestrictionsLoaded = false;
		$this->mRestrictions = array();
		# Dont change the following, NS_MAIN is hardcoded in several place
		# See bug #696
		$this->mDefaultNamespace = NS_MAIN;
		$this->mWatched = NULL;
		$this->mLatestID = false;
		$this->mOldRestrictions = false;
	}

	/**
	 * Create a new Title from a prefixed DB key
	 * @param string $key The database key, which has underscores
	 *	instead of spaces, possibly including namespace and
	 *	interwiki prefixes
	 * @return Title the new object, or NULL on an error
	 */
	public static function newFromDBkey( $key ) {
		$t = new Title();
		$t->mDbkeyform = $key;
		if( $t->secureAndSplit() )
			return $t;
		else
			return NULL;
	}

	/**
	 * Create a new Title from text, such as what one would
	 * find in a link. Decodes any HTML entities in the text.
	 *
	 * @param string $text the link text; spaces, prefixes,
	 *	and an initial ':' indicating the main namespace
	 *	are accepted
	 * @param int $defaultNamespace the namespace to use if
	 * 	none is specified by a prefix
	 * @return Title the new object, or NULL on an error
	 */
	public static function newFromText( $text, $defaultNamespace = NS_MAIN ) {
		if( is_object( $text ) ) {
			throw new MWException( 'Title::newFromText given an object' );
		}

		/**
		 * Wiki pages often contain multiple links to the same page.
		 * Title normalization and parsing can become expensive on
		 * pages with many links, so we can save a little time by
		 * caching them.
		 *
		 * In theory these are value objects and won't get changed...
		 */
		if( $defaultNamespace == NS_MAIN && isset( Title::$titleCache[$text] ) ) {
			return Title::$titleCache[$text];
		}

		/**
		 * Convert things like &eacute; &#257; or &#x3017; into real text...
		 */
		$filteredText = Sanitizer::decodeCharReferences( $text );

		$t = new Title();
		$t->mDbkeyform = str_replace( ' ', '_', $filteredText );
		$t->mDefaultNamespace = $defaultNamespace;

		static $cachedcount = 0 ;
		if( $t->secureAndSplit() ) {
			if( $defaultNamespace == NS_MAIN ) {
				if( $cachedcount >= MW_TITLECACHE_MAX ) {
					# Avoid memory leaks on mass operations...
					Title::$titleCache = array();
					$cachedcount=0;
				}
				$cachedcount++;
				Title::$titleCache[$text] =& $t;
			}
			return $t;
		} else {
			$ret = NULL;
			return $ret;
		}
	}

	/**
	 * Create a new Title from URL-encoded text. Ensures that
	 * the given title's length does not exceed the maximum.
	 * @param string $url the title, as might be taken from a URL
	 * @return Title the new object, or NULL on an error
	 */
	public static function newFromURL( $url ) {
		global $wgLegalTitleChars;
		$t = new Title();

		# For compatibility with old buggy URLs. "+" is usually not valid in titles,
		# but some URLs used it as a space replacement and they still come
		# from some external search tools.
		if ( strpos( $wgLegalTitleChars, '+' ) === false ) {
			$url = str_replace( '+', ' ', $url );
		}

		$t->mDbkeyform = str_replace( ' ', '_', $url );
		if( $t->secureAndSplit() ) {
			return $t;
		} else {
			return NULL;
		}
	}

	/**
	 * Create a new Title from an article ID
	 *
	 * @todo This is inefficiently implemented, the page row is requested
	 *       but not used for anything else
	 *
	 * @param int $id the page_id corresponding to the Title to create
	 * @return Title the new object, or NULL on an error
	 */
	public static function newFromID( $id ) {
		$fname = 'Title::newFromID';
		$dbr = wfGetDB( DB_SLAVE );
		$row = $dbr->selectRow( 'page', array( 'page_namespace', 'page_title' ),
			array( 'page_id' => $id ), $fname );
		if ( $row !== false ) {
			$title = Title::makeTitle( $row->page_namespace, $row->page_title );
		} else {
			$title = NULL;
		}
		return $title;
	}

	/**
	 * Make an array of titles from an array of IDs 
	 */
	public static function newFromIDs( $ids ) {
		$dbr = wfGetDB( DB_SLAVE );
		$res = $dbr->select( 'page', array( 'page_namespace', 'page_title' ),
			'page_id IN (' . $dbr->makeList( $ids ) . ')', __METHOD__ );

		$titles = array();
		while ( $row = $dbr->fetchObject( $res ) ) {
			$titles[] = Title::makeTitle( $row->page_namespace, $row->page_title );
		}
		return $titles;
	}

	/**
	 * Create a new Title from a namespace index and a DB key.
	 * It's assumed that $ns and $title are *valid*, for instance when
	 * they came directly from the database or a special page name.
	 * For convenience, spaces are converted to underscores so that
	 * eg user_text fields can be used directly.
	 *
	 * @param int $ns the namespace of the article
	 * @param string $title the unprefixed database key form
	 * @return Title the new object
	 */
	public static function &makeTitle( $ns, $title ) {
		$t = new Title();
		$t->mInterwiki = '';
		$t->mFragment = '';
		$t->mNamespace = $ns = intval( $ns );
		$t->mDbkeyform = str_replace( ' ', '_', $title );
		$t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
		$t->mUrlform = wfUrlencode( $t->mDbkeyform );
		$t->mTextform = str_replace( '_', ' ', $title );
		return $t;
	}

	/**
	 * Create a new Title from a namespace index and a DB key.
	 * The parameters will be checked for validity, which is a bit slower
	 * than makeTitle() but safer for user-provided data.
	 *
	 * @param int $ns the namespace of the article
	 * @param string $title the database key form
	 * @return Title the new object, or NULL on an error
	 */
	public static function makeTitleSafe( $ns, $title ) {
		$t = new Title();
		$t->mDbkeyform = Title::makeName( $ns, $title );
		if( $t->secureAndSplit() ) {
			return $t;
		} else {
			return NULL;
		}
 	}

	/**
	 * Create a new Title for the Main Page
	 * @return Title the new object
	 */
	public static function newMainPage() {
		return Title::newFromText( wfMsgForContent( 'mainpage' ) );
	}

	/**
	 * Extract a redirect destination from a string and return the
	 * Title, or null if the text doesn't contain a valid redirect
	 *
	 * @param string $text Text with possible redirect
	 * @return Title
	 */
	public static function newFromRedirect( $text ) {
		$redir = MagicWord::get( 'redirect' );
		if( $redir->matchStart( $text ) ) {
			// Extract the first link and see if it's usable
			$m = array();
			if( preg_match( '!\[{2}(.*?)(?:\||\]{2})!', $text, $m ) ) {
				// Strip preceding colon used to "escape" categories, etc.
				// and URL-decode links
				if( strpos( $m[1], '%' ) !== false ) {
					// Match behavior of inline link parsing here;
					// don't interpret + as " " most of the time!
					// It might be safe to just use rawurldecode instead, though.
					$m[1] = urldecode( ltrim( $m[1], ':' ) );
				}
				$title = Title::newFromText( $m[1] );
				// Redirects to Special:Userlogout are not permitted
				if( $title instanceof Title && !$title->isSpecial( 'Userlogout' ) )
					return $title;
			}
		}
		return null;
	}

#----------------------------------------------------------------------------
#	Static functions
#----------------------------------------------------------------------------

	/**
	 * Get the prefixed DB key associated with an ID
	 * @param int $id the page_id of the article
	 * @return Title an object representing the article, or NULL
	 * 	if no such article was found
	 * @static
	 * @access public
	 */
	function nameOf( $id ) {
		$fname = 'Title::nameOf';
		$dbr = wfGetDB( DB_SLAVE );

		$s = $dbr->selectRow( 'page', array( 'page_namespace','page_title' ),  array( 'page_id' => $id ), $fname );
		if ( $s === false ) { return NULL; }

		$n = Title::makeName( $s->page_namespace, $s->page_title );
		return $n;
	}

	/**
	 * Get a regex character class describing the legal characters in a link
	 * @return string the list of characters, not delimited
	 */
	public static function legalChars() {
		global $wgLegalTitleChars;
		return $wgLegalTitleChars;
	}

	/**
	 * Get a string representation of a title suitable for
	 * including in a search index
	 *
	 * @param int $ns a namespace index
	 * @param string $title text-form main part
	 * @return string a stripped-down title string ready for the
	 * 	search index
	 */
	public static function indexTitle( $ns, $title ) {
		global $wgContLang;

		$lc = SearchEngine::legalSearchChars() . '&#;';
		$t = $wgContLang->stripForSearch( $title );
		$t = preg_replace( "/[^{$lc}]+/", ' ', $t );
		$t = $wgContLang->lc( $t );

		# Handle 's, s'
		$t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
		$t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );

		$t = preg_replace( "/\\s+/", ' ', $t );

		if ( $ns == NS_IMAGE ) {
			$t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
		}
		return trim( $t );
	}

	/*
	 * Make a prefixed DB key from a DB key and a namespace index
	 * @param int $ns numerical representation of the namespace
	 * @param string $title the DB key form the title
	 * @return string the prefixed form of the title
	 */
	public static function makeName( $ns, $title ) {
		global $wgContLang;

		$n = $wgContLang->getNsText( $ns );
		return $n == '' ? $title : "$n:$title";
	}

	/**
	 * Returns the URL associated with an interwiki prefix
	 * @param string $key the interwiki prefix (e.g. "MeatBall")
	 * @return the associated URL, containing "$1", which should be
	 * 	replaced by an article title
	 * @static (arguably)
	 */
	public function getInterwikiLink( $key )  {
		global $wgMemc, $wgInterwikiExpiry;
		global $wgInterwikiCache, $wgContLang;
		$fname = 'Title::getInterwikiLink';

		$key = $wgContLang->lc( $key );

		$k = wfMemcKey( 'interwiki', $key );
		if( array_key_exists( $k, Title::$interwikiCache ) ) {
			return Title::$interwikiCache[$k]->iw_url;
		}

		if ($wgInterwikiCache) {
			return Title::getInterwikiCached( $key );
		}

		$s = $wgMemc->get( $k );
		# Ignore old keys with no iw_local
		if( $s && isset( $s->iw_local ) && isset($s->iw_trans)) {
			Title::$interwikiCache[$k] = $s;
			return $s->iw_url;
		}

		$dbr = wfGetDB( DB_SLAVE );
		$res = $dbr->select( 'interwiki',
			array( 'iw_url', 'iw_local', 'iw_trans' ),
			array( 'iw_prefix' => $key ), $fname );
		if( !$res ) {
			return '';
		}

		$s = $dbr->fetchObject( $res );
		if( !$s ) {
			# Cache non-existence: create a blank object and save it to memcached
			$s = (object)false;
			$s->iw_url = '';
			$s->iw_local = 0;
			$s->iw_trans = 0;
		}
		$wgMemc->set( $k, $s, $wgInterwikiExpiry );
		Title::$interwikiCache[$k] = $s;

		return $s->iw_url;
	}
	
	/**
	 * Fetch interwiki prefix data from local cache in constant database
	 *
	 * More logic is explained in DefaultSettings
	 *
	 * @return string URL of interwiki site
	 */
	public static function getInterwikiCached( $key ) {
		global $wgInterwikiCache, $wgInterwikiScopes, $wgInterwikiFallbackSite;
		static $db, $site;

		if (!$db)
			$db=dba_open($wgInterwikiCache,'r','cdb');
		/* Resolve site name */
		if ($wgInterwikiScopes>=3 and !$site) {
			$site = dba_fetch('__sites:' . wfWikiID(), $db);
			if ($site=="")
				$site = $wgInterwikiFallbackSite;
		}
		$value = dba_fetch( wfMemcKey( $key ), $db);
		if ($value=='' and $wgInterwikiScopes>=3) {
			/* try site-level */
			$value = dba_fetch("_{$site}:{$key}", $db);
		}
		if ($value=='' and $wgInterwikiScopes>=2) {
			/* try globals */
			$value = dba_fetch("__global:{$key}", $db);
		}
		if ($value=='undef')
			$value='';
		$s = (object)false;
		$s->iw_url = '';
		$s->iw_local = 0;
		$s->iw_trans = 0;
		if ($value!='') {
			list($local,$url)=explode(' ',$value,2);
			$s->iw_url=$url;
			$s->iw_local=(int)$local;
		}
		Title::$interwikiCache[wfMemcKey( 'interwiki', $key )] = $s;
		return $s->iw_url;
	}
	/**
	 * Determine whether the object refers to a page within
	 * this project.
	 *
	 * @return bool TRUE if this is an in-project interwiki link
	 *	or a wikilink, FALSE otherwise
	 */
	public function isLocal() {
		if ( $this->mInterwiki != '' ) {
			# Make sure key is loaded into cache
			$this->getInterwikiLink( $this->mInterwiki );
			$k = wfMemcKey( 'interwiki', $this->mInterwiki );
			return (bool)(Title::$interwikiCache[$k]->iw_local);
		} else {
			return true;
		}
	}

	/**
	 * Determine whether the object refers to a page within
	 * this project and is transcludable.
	 *
	 * @return bool TRUE if this is transcludable
	 */
	public function isTrans() {
		if ($this->mInterwiki == '')
			return false;
		# Make sure key is loaded into cache
		$this->getInterwikiLink( $this->mInterwiki );
		$k = wfMemcKey( 'interwiki', $this->mInterwiki );
		return (bool)(Title::$interwikiCache[$k]->iw_trans);
	}

	/**
	 * Escape a text fragment, say from a link, for a URL
	 */
	static function escapeFragmentForURL( $fragment ) {
		$fragment = str_replace( ' ', '_', $fragment );
		$fragment = urlencode( Sanitizer::decodeCharReferences( $fragment ) );
		$replaceArray = array(
			'%3A' => ':',
			'%' => '.'
		);
		return strtr( $fragment, $replaceArray );
	}

#----------------------------------------------------------------------------
#	Other stuff
#----------------------------------------------------------------------------

	/** Simple accessors */
	/**
	 * Get the text form (spaces not underscores) of the main part
	 * @return string
	 */
	public function getText() { return $this->mTextform; }
	/**
	 * Get the URL-encoded form of the main part
	 * @return string
	 */
	public function getPartialURL() { return $this->mUrlform; }
	/**
	 * Get the main part with underscores
	 * @return string
	 */
	public function getDBkey() { return $this->mDbkeyform; }
	/**
	 * Get the namespace index, i.e. one of the NS_xxxx constants
	 * @return int
	 */
	public function getNamespace() { return $this->mNamespace; }
	/**
	 * Get the namespace text
	 * @return string
	 */
	public function getNsText() {
		global $wgContLang, $wgCanonicalNamespaceNames;

		if ( '' != $this->mInterwiki ) {
			// This probably shouldn't even happen. ohh man, oh yuck.
			// But for interwiki transclusion it sometimes does.
			// Shit. Shit shit shit.
			//
			// Use the canonical namespaces if possible to try to
			// resolve a foreign namespace.
			if( isset( $wgCanonicalNamespaceNames[$this->mNamespace] ) ) {
				return $wgCanonicalNamespaceNames[$this->mNamespace];
			}
		}
		return $wgContLang->getNsText( $this->mNamespace );
	}
	/**
	 * Get the DB key with the initial letter case as specified by the user
	 */
	function getUserCaseDBKey() {
		return $this->mUserCaseDBKey;
	}
	/**
	 * Get the namespace text of the subject (rather than talk) page
	 * @return string
	 */
	public function getSubjectNsText() {
		global $wgContLang;
		return $wgContLang->getNsText( Namespace::getSubject( $this->mNamespace ) );
	}

	/**
	 * Get the namespace text of the talk page
	 * @return string
	 */
	public function getTalkNsText() {
		global $wgContLang;
		return( $wgContLang->getNsText( Namespace::getTalk( $this->mNamespace ) ) );
	}

	/**
	 * Could this title have a corresponding talk page?
	 * @return bool
	 */
	public function canTalk() {
		return( Namespace::canTalk( $this->mNamespace ) );
	}

	/**
	 * Get the interwiki prefix (or null string)
	 * @return string
	 */
	public function getInterwiki() { return $this->mInterwiki; }
	/**
	 * Get the Title fragment (i.e. the bit after the #) in text form
	 * @return string
	 */
	public function getFragment() { return $this->mFragment; }
	/**
	 * Get the fragment in URL form, including the "#" character if there is one
	 * @return string
	 */
	public function getFragmentForURL() {
		if ( $this->mFragment == '' ) {
			return '';
		} else {
			return '#' . Title::escapeFragmentForURL( $this->mFragment );
		}
	}
	/**
	 * Get the default namespace index, for when there is no namespace
	 * @return int
	 */
	public function getDefaultNamespace() { return $this->mDefaultNamespace; }

	/**
	 * Get title for search index
	 * @return string a stripped-down title string ready for the
	 * 	search index
	 */
	public function getIndexTitle() {
		return Title::indexTitle( $this->mNamespace, $this->mTextform );
	}

	/**
	 * Get the prefixed database key form
	 * @return string the prefixed title, with underscores and
	 * 	any interwiki and namespace prefixes
	 */
	public function getPrefixedDBkey() {
		$s = $this->prefix( $this->mDbkeyform );
		$s = str_replace( ' ', '_', $s );
		return $s;
	}

	/**
	 * Get the prefixed title with spaces.
	 * This is the form usually used for display
	 * @return string the prefixed title, with spaces
	 */
	public function getPrefixedText() {
		if ( empty( $this->mPrefixedText ) ) { // FIXME: bad usage of empty() ?
			$s = $this->prefix( $this->mTextform );
			$s = str_replace( '_', ' ', $s );
			$this->mPrefixedText = $s;
		}
		return $this->mPrefixedText;
	}

	/**
	 * Get the prefixed title with spaces, plus any fragment
	 * (part beginning with '#')
	 * @return string the prefixed title, with spaces and
	 * 	the fragment, including '#'
	 */
	public function getFullText() {
		$text = $this->getPrefixedText();
		if( '' != $this->mFragment ) {
			$text .= '#' . $this->mFragment;
		}
		return $text;
	}

	/**
	 * Get the base name, i.e. the leftmost parts before the /
	 * @return string Base name
	 */
	public function getBaseText() {
		global $wgNamespacesWithSubpages;
		if( isset( $wgNamespacesWithSubpages[ $this->mNamespace ] ) && $wgNamespacesWithSubpages[ $this->mNamespace ] ) {
			$parts = explode( '/', $this->getText() );
			# Don't discard the real title if there's no subpage involved
			if( count( $parts ) > 1 )
				unset( $parts[ count( $parts ) - 1 ] );
			return implode( '/', $parts );
		} else {
			return $this->getText();
		}
	}

	/**
	 * Get the lowest-level subpage name, i.e. the rightmost part after /
	 * @return string Subpage name
	 */
	public function getSubpageText() {
		global $wgNamespacesWithSubpages;
		if( isset( $wgNamespacesWithSubpages[ $this->mNamespace ] ) && $wgNamespacesWithSubpages[ $this->mNamespace ] ) {
			$parts = explode( '/', $this->mTextform );
			return( $parts[ count( $parts ) - 1 ] );
		} else {
			return( $this->mTextform );
		}
	}

	/**
	 * Get a URL-encoded form of the subpage text
	 * @return string URL-encoded subpage name
	 */
	public function getSubpageUrlForm() {
		$text = $this->getSubpageText();
		$text = wfUrlencode( str_replace( ' ', '_', $text ) );
		$text = str_replace( '%28', '(', str_replace( '%29', ')', $text ) ); # Clean up the URL; per below, this might not be safe
		return( $text );
	}

	/**
	 * Get a URL-encoded title (not an actual URL) including interwiki
	 * @return string the URL-encoded form
	 */
	public function getPrefixedURL() {
		$s = $this->prefix( $this->mDbkeyform );
		$s = str_replace( ' ', '_', $s );

		$s = wfUrlencode ( $s ) ;

		# Cleaning up URL to make it look nice -- is this safe?
		$s = str_replace( '%28', '(', $s );
		$s = str_replace( '%29', ')', $s );

		return $s;
	}

	/**
	 * Get a real URL referring to this title, with interwiki link and
	 * fragment
	 *
	 * @param string $query an optional query string, not used
	 * 	for interwiki links
	 * @param string $variant language variant of url (for sr, zh..)
	 * @return string the URL
	 */
	public function getFullURL( $query = '', $variant = false ) {
		global $wgContLang, $wgServer, $wgRequest;

		if ( '' == $this->mInterwiki ) {
			$url = $this->getLocalUrl( $query, $variant );

			// Ugly quick hack to avoid duplicate prefixes (bug 4571 etc)
			// Correct fix would be to move the prepending elsewhere.
			if ($wgRequest->getVal('action') != 'render') {
				$url = $wgServer . $url;
			}
		} else {
			$baseUrl = $this->getInterwikiLink( $this->mInterwiki );

			$namespace = wfUrlencode( $this->getNsText() );
			if ( '' != $namespace ) {
				# Can this actually happen? Interwikis shouldn't be parsed.
				# Yes! It can in interwiki transclusion. But... it probably shouldn't.
				$namespace .= ':';
			}
			$url = str_replace( '$1', $namespace . $this->mUrlform, $baseUrl );
			$url = wfAppendQuery( $url, $query );
		}

		# Finally, add the fragment.
		$url .= $this->getFragmentForURL();

		wfRunHooks( 'GetFullURL', array( &$this, &$url, $query ) );
		return $url;
	}

	/**
	 * Get a URL with no fragment or server name.  If this page is generated
	 * with action=render, $wgServer is prepended.
	 * @param string $query an optional query string; if not specified,
	 * 	$wgArticlePath will be used.
	 * @param string $variant language variant of url (for sr, zh..)
	 * @return string the URL
	 */
	public function getLocalURL( $query = '', $variant = false ) {
		global $wgArticlePath, $wgScript, $wgServer, $wgRequest;
		global $wgVariantArticlePath, $wgContLang, $wgUser;

		// internal links should point to same variant as current page (only anonymous users)
		if($variant == false && $wgContLang->hasVariants() && !$wgUser->isLoggedIn()){
			$pref = $wgContLang->getPreferredVariant(false);
			if($pref != $wgContLang->getCode())
				$variant = $pref;
		}

		if ( $this->isExternal() ) {
			$url = $this->getFullURL();
			if ( $query ) {
				// This is currently only used for edit section links in the
				// context of interwiki transclusion. In theory we should
				// append the query to the end of any existing query string,
				// but interwiki transclusion is already broken in that case.
				$url .= "?$query";
			}
		} else {
			$dbkey = wfUrlencode( $this->getPrefixedDBkey() );
			if ( $query == '' ) {
				if($variant!=false && $wgContLang->hasVariants()){
					if($wgVariantArticlePath==false) {
						$variantArticlePath =  "$wgScript?title=$1&variant=$2"; // default
					} else {
						$variantArticlePath = $wgVariantArticlePath;
					}
					$url = str_replace( '$2', urlencode( $variant ), $variantArticlePath );
					$url = str_replace( '$1', $dbkey, $url  );
				}
				else {
					$url = str_replace( '$1', $dbkey, $wgArticlePath );
				}
			} else {
				global $wgActionPaths;
				$url = false;
				$matches = array();
				if( !empty( $wgActionPaths ) &&
					preg_match( '/^(.*&|)action=([^&]*)(&(.*)|)$/', $query, $matches ) )
				{
					$action = urldecode( $matches[2] );
					if( isset( $wgActionPaths[$action] ) ) {
						$query = $matches[1];
						if( isset( $matches[4] ) ) $query .= $matches[4];
						$url = str_replace( '$1', $dbkey, $wgActionPaths[$action] );
						if( $query != '' ) $url .= '?' . $query;
					}
				}
				if ( $url === false ) {
					if ( $query == '-' ) {
						$query = '';
					}
					$url = "{$wgScript}?title={$dbkey}&{$query}";
				}
			}
			
			// FIXME: this causes breakage in various places when we
			// actually expected a local URL and end up with dupe prefixes.
			if ($wgRequest->getVal('action') == 'render') {
				$url = $wgServer . $url;
			}
		}
		wfRunHooks( 'GetLocalURL', array( &$this, &$url, $query ) );
		return $url;
	}

	/**
	 * Get an HTML-escaped version of the URL form, suitable for
	 * using in a link, without a server name or fragment
	 * @param string $query an optional query string
	 * @return string the URL
	 */
	public function escapeLocalURL( $query = '' ) {
		return htmlspecialchars( $this->getLocalURL( $query ) );
	}

	/**
	 * Get an HTML-escaped version of the URL form, suitable for
	 * using in a link, including the server name and fragment
	 *
	 * @return string the URL
	 * @param string $query an optional query string
	 */
	public function escapeFullURL( $query = '' ) {
		return htmlspecialchars( $this->getFullURL( $query ) );
	}

	/**
	 * Get the URL form for an internal link.
	 * - Used in various Squid-related code, in case we have a different
	 * internal hostname for the server from the exposed one.
	 *
	 * @param string $query an optional query string
	 * @param string $variant language variant of url (for sr, zh..)
	 * @return string the URL
	 */
	public function getInternalURL( $query = '', $variant = false ) {
		global $wgInternalServer;
		$url = $wgInternalServer . $this->getLocalURL( $query, $variant );
		wfRunHooks( 'GetInternalURL', array( &$this, &$url, $query ) );
		return $url;
	}

	/**
	 * Get the edit URL for this Title
	 * @return string the URL, or a null string if this is an
	 * 	interwiki link
	 */
	public function getEditURL() {
		if ( '' != $this->mInterwiki ) { return ''; }
		$s = $this->getLocalURL( 'action=edit' );

		return $s;
	}

	/**
	 * Get the HTML-escaped displayable text form.
	 * Used for the title field in <a> tags.
	 * @return string the text, including any prefixes
	 */
	public function getEscapedText() {
		return htmlspecialchars( $this->getPrefixedText() );
	}

	/**
	 * Is this Title interwiki?
	 * @return boolean
	 */
	public function isExternal() { return ( '' != $this->mInterwiki ); }

	/**
	 * Is this page "semi-protected" - the *only* protection is autoconfirm?
	 *
	 * @param string Action to check (default: edit)
	 * @return bool
	 */
	public function isSemiProtected( $action = 'edit' ) {
		if( $this->exists() ) {
			$restrictions = $this->getRestrictions( $action );
			if( count( $restrictions ) > 0 ) {
				foreach( $restrictions as $restriction ) {
					if( strtolower( $restriction ) != 'autoconfirmed' )
						return false;
				}
			} else {
				# Not protected
				return false;
			}
			return true;
		} else {
			# If it doesn't exist, it can't be protected
			return false;
		}
	}

	/**
	 * Does the title correspond to a protected article?
	 * @param string $what the action the page is protected from,
	 *	by default checks move and edit
	 * @return boolean
	 */
	public function isProtected( $action = '' ) {
		global $wgRestrictionLevels;

		# Special pages have inherent protection
		if( $this->getNamespace() == NS_SPECIAL )
			return true;

		# Check regular protection levels				
		if( $action == 'edit' || $action == '' ) {
			$r = $this->getRestrictions( 'edit' );
			foreach( $wgRestrictionLevels as $level ) {
				if( in_array( $level, $r ) && $level != '' ) {
					return( true );
				}
			}
		}
		
		if( $action == 'move' || $action == '' ) {
			$r = $this->getRestrictions( 'move' );
			foreach( $wgRestrictionLevels as $level ) {
				if( in_array( $level, $r ) && $level != '' ) {
					return( true );
				}
			}
		}

		return false;
	}

	/**
	 * Is $wgUser is watching this page?
	 * @return boolean
	 */
	public function userIsWatching() {
		global $wgUser;

		if ( is_null( $this->mWatched ) ) {
			if ( NS_SPECIAL == $this->mNamespace || !$wgUser->isLoggedIn()) {
				$this->mWatched = false;
			} else {
				$this->mWatched = $wgUser->isWatched( $this );
			}
		}
		return $this->mWatched;
	}

 	/**
	 * Can $wgUser perform $action on this page?
	 * This skips potentially expensive cascading permission checks.
	 *
	 * Suitable for use for nonessential UI controls in common cases, but
	 * _not_ for functional access control.
	 *
	 * May provide false positives, but should never provide a false negative.
	 *
	 * @param string $action action that permission needs to be checked for
	 * @return boolean
 	 */
	public function quickUserCan( $action ) {
		return $this->userCan( $action, false );
	}

	/**
	 * Determines if $wgUser is unable to edit this page because it has been protected
	 * by $wgNamespaceProtection.
	 * 
	 * @return boolean
	 */
	public function isNamespaceProtected() {
		global $wgNamespaceProtection, $wgUser;
		if( isset( $wgNamespaceProtection[ $this->mNamespace ] ) ) {
			foreach( (array)$wgNamespaceProtection[ $this->mNamespace ] as $right ) {
				if( $right != '' && !$wgUser->isAllowed( $right ) )
					return true;
			}
		}
		return false;
	}

 	/**
	 * Can $wgUser perform $action on this page?
	 * @param string $action action that permission needs to be checked for
	 * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
	 * @return boolean
 	 */
	public function userCan( $action, $doExpensiveQueries = true ) {
		global $wgUser;
		return ( $this->getUserPermissionsErrorsInternal( $action, $wgUser, $doExpensiveQueries ) === array());
	}

        /**
	 * Can $user perform $action on this page?
	 * @param string $action action that permission needs to be checked for
	 * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
	 * @return array Array of arrays of the arguments to wfMsg to explain permissions problems.
	*/
	public function getUserPermissionsErrors( $action, $user, $doExpensiveQueries = true ) {
		$errors = $this->getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries );

		global $wgContLang;
		global $wgLang;

		if ( wfReadOnly() && $action != 'read' ) {
			global $wgReadOnly;
			$errors[] = array( 'readonlytext', $wgReadOnly );
		}

		global $wgEmailConfirmToEdit, $wgUser;

		if ( $wgEmailConfirmToEdit && !$wgUser->isEmailConfirmed() )
		{
			$errors[] = array( 'confirmedittext' );
		}

		if ( $user->isBlockedFrom( $this ) ) {
			$block = $user->mBlock;

			// This is from OutputPage::blockedPage
			// Copied at r23888 by werdna

			$id = $user->blockedBy();
			$reason = $user->blockedFor();
			$ip = wfGetIP();

			if ( is_numeric( $id ) ) {
				$name = User::whoIs( $id );
			} else {
				$name = $id;
			}

			$link = '[[' . $wgContLang->getNsText( NS_USER ) . ":{$name}|{$name}]]";
			$blockid = $block->mId;
			$blockExpiry = $user->mBlock->mExpiry;
			$blockTimestamp = $wgLang->timeanddate( wfTimestamp( TS_MW, $wgUser->mBlock->mTimestamp ), true );

			if ( $blockExpiry == 'infinity' ) {
				// Entry in database (table ipblocks) is 'infinity' but 'ipboptions' uses 'infinite' or 'indefinite'
				$scBlockExpiryOptions = wfMsg( 'ipboptions' );

				foreach ( explode( ',', $scBlockExpiryOptions ) as $option ) {
					if ( strpos( $option, ':' ) == false )
						continue;

					list ($show, $value) = explode( ":", $option );

					if ( $value == 'infinite' || $value == 'indefinite' ) {
						$blockExpiry = $show;
						break;
					}
				}
			} else {
				$blockExpiry = $wgLang->timeanddate( wfTimestamp( TS_MW, $blockExpiry ), true );
			}

			$intended = $user->mBlock->mAddress;

			$errors[] = array ( ($block->mAuto ? 'autoblockedtext' : 'blockedtext'), $link, $reason, $ip, $name, $blockid, $blockExpiry, $intended, $blockTimestamp );
		}

		return $errors;
	}

	/**
	 * Can $user perform $action on this page?
	 * This is an internal function, which checks ONLY that previously checked by userCan (i.e. it leaves out checks on wfReadOnly() and blocks)
	 * @param string $action action that permission needs to be checked for
	 * @param bool $doExpensiveQueries Set this to false to avoid doing unnecessary queries.
	 * @return array Array of arrays of the arguments to wfMsg to explain permissions problems.
	 */
	private function getUserPermissionsErrorsInternal( $action, $user, $doExpensiveQueries = true ) {
		$fname = 'Title::userCan';
		wfProfileIn( $fname );

		$errors = array();

		if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, &$result ) ) ) {
			return $result ? array() : array( array( 'badaccess-group0' ) );
		}

		if( NS_SPECIAL == $this->mNamespace ) {
			$errors[] = array('ns-specialprotected');
		}
		
		if ( $this->isNamespaceProtected() ) {
			$ns = $this->getNamespace() == NS_MAIN
				? wfMsg( 'nstab-main' )
				: $this->getNsText();
			$errors[] = (NS_MEDIAWIKI == $this->mNamespace 
				? array('protectedinterface') 
				: array( 'namespaceprotected',  $ns ) );
		}

		if( $this->mDbkeyform == '_' ) {
			# FIXME: Is this necessary? Shouldn't be allowed anyway...
			$errors[] = array('badaccess-group0');
		}

		# protect css/js subpages of user pages
		# XXX: this might be better using restrictions
		# XXX: Find a way to work around the php bug that prevents using $this->userCanEditCssJsSubpage() from working
		if( $this->isCssJsSubpage()
			&& !$user->isAllowed('editinterface')
			&& !preg_match('/^'.preg_quote($user->getName(), '/').'\//', $this->mTextform) ) {
			$errors[] = array('customcssjsprotected');
		}
		
		if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
			# We /could/ use the protection level on the source page, but it's fairly ugly
			#  as we have to establish a precedence hierarchy for pages included by multiple
			#  cascade-protected pages. So just restrict it to people with 'protect' permission,
			#  as they could remove the protection anyway.
			list( $cascadingSources, $restrictions ) = $this->getCascadeProtectionSources();
			# Cascading protection depends on more than this page...
			# Several cascading protected pages may include this page...
			# Check each cascading level
			# This is only for protection restrictions, not for all actions
			if( $cascadingSources > 0 && isset($restrictions[$action]) ) {
				foreach( $restrictions[$action] as $right ) {
					$right = ( $right == 'sysop' ) ? 'protect' : $right;
					if( '' != $right && !$user->isAllowed( $right ) ) {
						$pages = '';
						foreach( $cascadingSources as $page )
							$pages .= '* [[:' . $page->getPrefixedText() . "]]\n";
						$errors[] = array( 'cascadeprotected', count( $cascadingSources ), $pages );
					}
				}
			}
		}
		
		foreach( $this->getRestrictions($action) as $right ) {
			// Backwards compatibility, rewrite sysop -> protect
			if ( $right == 'sysop' ) {
				$right = 'protect';
			}
			if( '' != $right && !$user->isAllowed( $right ) ) {
				$errors[] = array( 'protectedpagetext' );
			}
		}

		if( $action == 'create' ) {
			if( (  $this->isTalkPage() && !$user->isAllowed( 'createtalk' ) ) ||
				( !$this->isTalkPage() && !$user->isAllowed( 'createpage' ) ) ) {
				$errors[] = $user->isAnon() ? array ('nocreatetext') : array ('nocreate-loggedin');
			}
		} elseif( $action == 'move' && !( $this->isMovable() && $user->isAllowed( 'move' ) ) ) {
			$errors[] = $user->isAnon() ? array ( 'movenologintext' ) : array ('movenotallowed');
        } else if ( !$user->isAllowed( $action ) ) {
			$return = null;
		    $groups = array();
			global $wgGroupPermissions;
		        foreach( $wgGroupPermissions as $key => $value ) {
		            if( isset( $value[$action] ) && $value[$action] == true ) {
		                $groupName = User::getGroupName( $key );
		                $groupPage = User::getGroupPage( $key );
		                if( $groupPage ) {
		                    $skin = $user->getSkin();
		                    $groups[] = '[['.$groupPage->getPrefixedText().'|'.$groupName.']]';
		                } else {
		                    $groups[] = $groupName;
		                }
		            }
		        }
		        $n = count( $groups );
		        $groups = implode( ', ', $groups );
		        switch( $n ) {
		            case 0:
		            case 1:
		            case 2:
		                $return = array( "badaccess-group$n", $groups );
		                break;
		            default:
		                $return = array( 'badaccess-groups', $groups );
		        }
			$errors[] = $return;
		}

		wfProfileOut( $fname );
		return $errors;
	}

	/**
	 * Can $wgUser edit this page?
	 * @return boolean
	 * @deprecated use userCan('edit')
	 */
	public function userCanEdit( $doExpensiveQueries = true ) {
		return $this->userCan( 'edit', $doExpensiveQueries );
	}

	/**
	 * Can $wgUser create this page?
	 * @return boolean
	 * @deprecated use userCan('create')
	 */
	public function userCanCreate( $doExpensiveQueries = true ) {
		return $this->userCan( 'create', $doExpensiveQueries );
	}

	/**
	 * Can $wgUser move this page?
	 * @return boolean
	 * @deprecated use userCan('move')
	 */
	public function userCanMove( $doExpensiveQueries = true ) {
		return $this->userCan( 'move', $doExpensiveQueries );
	}

	/**
	 * Would anybody with sufficient privileges be able to move this page?
	 * Some pages just aren't movable.
	 *
	 * @return boolean
	 */
	public function isMovable() {
		return Namespace::isMovable( $this->getNamespace() )
			&& $this->getInterwiki() == '';
	}

	/**
	 * Can $wgUser read this page?
	 * @return boolean
	 * @todo fold these checks into userCan()
	 */
	public function userCanRead() {
		global $wgUser;

		$result = null;
		wfRunHooks( 'userCan', array( &$this, &$wgUser, 'read', &$result ) );
		if ( $result !== null ) {
			return $result;
		}

		if( $wgUser->isAllowed( 'read' ) ) {
			return true;
		} else {
			global $wgWhitelistRead;

			/** 
			 * Always grant access to the login page.
			 * Even anons need to be able to log in.
			*/
			if( $this->isSpecial( 'Userlogin' ) || $this->isSpecial( 'Resetpass' ) ) {
				return true;
			}
			
			/**
			 * Check for explicit whitelisting
			 */
			$name = $this->getPrefixedText();
			if( $wgWhitelistRead && in_array( $name, $wgWhitelistRead, true ) )
				return true;
			
			/**
			 * Old settings might have the title prefixed with
			 * a colon for main-namespace pages
			 */
			if( $wgWhitelistRead && $this->getNamespace() == NS_MAIN ) {
				if( in_array( ':' . $name, $wgWhitelistRead ) )
					return true;
			}
			
			/**
			 * If it's a special page, ditch the subpage bit
			 * and check again
			 */
			if( $this->getNamespace() == NS_SPECIAL ) {
				$name = $this->getText();
				list( $name, /* $subpage */) = SpecialPage::resolveAliasWithSubpage( $name );
				$pure = SpecialPage::getTitleFor( $name )->getPrefixedText();
				if( in_array( $pure, $wgWhitelistRead, true ) )
					return true;
			}

		}
		return false;
	}

	/**
	 * Is this a talk page of some sort?
	 * @return bool
	 */
	public function isTalkPage() {
		return Namespace::isTalk( $this->getNamespace() );
	}

	/**
	 * Is this a subpage?
	 * @return bool
	 */
	public function isSubpage() {
		global $wgNamespacesWithSubpages;
		
		if( isset( $wgNamespacesWithSubpages[ $this->mNamespace ] ) ) {
			return ( strpos( $this->getText(), '/' ) !== false && $wgNamespacesWithSubpages[ $this->mNamespace ] == true );
		} else {
			return false;
		}
	}
	
	/**
	 * Could this page contain custom CSS or JavaScript, based
	 * on the title?
	 *
	 * @return bool
	 */
	public function isCssOrJsPage() {
		return $this->mNamespace == NS_MEDIAWIKI
			&& preg_match( '!\.(?:css|js)$!u', $this->mTextform ) > 0;
	}

	/**
	 * Is this a .css or .js subpage of a user page?
	 * @return bool
	 */
	public function isCssJsSubpage() {
		return ( NS_USER == $this->mNamespace and preg_match("/\\/.*\\.(?:css|js)$/", $this->mTextform ) );
	}
	/**
	 * Is this a *valid* .css or .js subpage of a user page?
	 * Check that the corresponding skin exists
	 */
	public function isValidCssJsSubpage() {
		if ( $this->isCssJsSubpage() ) {
			$skinNames = Skin::getSkinNames();
			return array_key_exists( $this->getSkinFromCssJsSubpage(), $skinNames );
		} else {
			return false;
		}
	}
	/**
	 * Trim down a .css or .js subpage title to get the corresponding skin name
	 */
	public function getSkinFromCssJsSubpage() {
		$subpage = explode( '/', $this->mTextform );
		$subpage = $subpage[ count( $subpage ) - 1 ];
		return( str_replace( array( '.css', '.js' ), array( '', '' ), $subpage ) );
	}
	/**
	 * Is this a .css subpage of a user page?
	 * @return bool
	 */
	public function isCssSubpage() {
		return ( NS_USER == $this->mNamespace and preg_match("/\\/.*\\.css$/", $this->mTextform ) );
	}
	/**
	 * Is this a .js subpage of a user page?
	 * @return bool
	 */
	public function isJsSubpage() {
		return ( NS_USER == $this->mNamespace and preg_match("/\\/.*\\.js$/", $this->mTextform ) );
	}
	/**
	 * Protect css/js subpages of user pages: can $wgUser edit
	 * this page?
	 *
	 * @return boolean
	 * @todo XXX: this might be better using restrictions
	 */
	public function userCanEditCssJsSubpage() {
		global $wgUser;
		return ( $wgUser->isAllowed('editinterface') or preg_match('/^'.preg_quote($wgUser->getName(), '/').'\//', $this->mTextform) );
	}

	/**
	 * Cascading protection: Return true if cascading restrictions apply to this page, false if not.
	 *
	 * @return bool If the page is subject to cascading restrictions.
	 */
	public function isCascadeProtected() {
		list( $sources, /* $restrictions */ ) = $this->getCascadeProtectionSources( false );
		return ( $sources > 0 );
	}

	/**
	 * Cascading protection: Get the source of any cascading restrictions on this page.
	 *
	 * @param $get_pages bool Whether or not to retrieve the actual pages that the restrictions have come from.
	 * @return array( mixed title array, restriction array)
	 * Array of the Title objects of the pages from which cascading restrictions have come, false for none, or true if such restrictions exist, but $get_pages was not set.
	 * The restriction array is an array of each type, each of which contains an array of unique groups
	 */
	public function getCascadeProtectionSources( $get_pages = true ) {
		global $wgEnableCascadingProtection, $wgRestrictionTypes;

		# Define our dimension of restrictions types
		$pagerestrictions = array();
		foreach( $wgRestrictionTypes as $action )
			$pagerestrictions[$action] = array();

		if (!$wgEnableCascadingProtection)
			return array( false, $pagerestrictions );

		if ( isset( $this->mCascadeSources ) && $get_pages ) {
			return array( $this->mCascadeSources, $this->mCascadingRestrictions );
		} else if ( isset( $this->mHasCascadingRestrictions ) && !$get_pages ) {
			return array( $this->mHasCascadingRestrictions, $pagerestrictions );
		}

		wfProfileIn( __METHOD__ );

		$dbr = wfGetDb( DB_SLAVE );

		if ( $this->getNamespace() == NS_IMAGE ) {
			$tables = array ('imagelinks', 'page_restrictions');
			$where_clauses = array(
				'il_to' => $this->getDBkey(),
				'il_from=pr_page',
				'pr_cascade' => 1 );
		} else {
			$tables = array ('templatelinks', 'page_restrictions');
			$where_clauses = array(
				'tl_namespace' => $this->getNamespace(),
				'tl_title' => $this->getDBkey(),
				'tl_from=pr_page',
				'pr_cascade' => 1 );
		}

		if ( $get_pages ) {
			$cols = array('pr_page', 'page_namespace', 'page_title', 'pr_expiry', 'pr_type', 'pr_level' );
			$where_clauses[] = 'page_id=pr_page';
			$tables[] = 'page';
		} else {
			$cols = array( 'pr_expiry' );
		}

		$res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ );

		$sources = $get_pages ? array() : false;
		$now = wfTimestampNow();
		$purgeExpired = false;
		
		while( $row = $dbr->fetchObject( $res ) ) {
			$expiry = Block::decodeExpiry( $row->pr_expiry );
			if( $expiry > $now ) {
				if ($get_pages) {
					$page_id = $row->pr_page;
					$page_ns = $row->page_namespace;
					$page_title = $row->page_title;
					$sources[$page_id] = Title::makeTitle($page_ns, $page_title);
					# Add groups needed for each restriction type if its not already there
					# Make sure this restriction type still exists
					if ( isset($pagerestrictions[$row->pr_type]) && !in_array($row->pr_level, $pagerestrictions[$row->pr_type]) ) {
						$pagerestrictions[$row->pr_type][]=$row->pr_level;
					}
				} else {
					$sources = true;
				}
			} else {
				// Trigger lazy purge of expired restrictions from the db
				$purgeExpired = true;
			}
		}
		if( $purgeExpired ) {
			Title::purgeExpiredRestrictions();
		}

		wfProfileOut( __METHOD__ );

		if ( $get_pages ) {
			$this->mCascadeSources = $sources;
			$this->mCascadingRestrictions = $pagerestrictions;
		} else {
			$this->mHasCascadingRestrictions = $sources;
		}

		return array( $sources, $pagerestrictions );
	}

	function areRestrictionsCascading() {
		if (!$this->mRestrictionsLoaded) {
			$this->loadRestrictions();
		}

		return $this->mCascadeRestriction;
	}

	/**
	 * Loads a string into mRestrictions array
	 * @param resource $res restrictions as an SQL result.
	 */
	private function loadRestrictionsFromRow( $res, $oldFashionedRestrictions = NULL ) {
		$dbr = wfGetDb( DB_SLAVE );

		$this->mRestrictions['edit'] = array();
		$this->mRestrictions['move'] = array();

		# Backwards-compatibility: also load the restrictions from the page record (old format).

		if ( $oldFashionedRestrictions == NULL ) {
			$oldFashionedRestrictions = $dbr->selectField( 'page', 'page_restrictions', array( 'page_id' => $this->getArticleId() ), __METHOD__ );
		}

		if ($oldFashionedRestrictions != '') {

			foreach( explode( ':', trim( $oldFashionedRestrictions ) ) as $restrict ) {
				$temp = explode( '=', trim( $restrict ) );
				if(count($temp) == 1) {
					// old old format should be treated as edit/move restriction
					$this->mRestrictions["edit"] = explode( ',', trim( $temp[0] ) );
					$this->mRestrictions["move"] = explode( ',', trim( $temp[0] ) );
				} else {
					$this->mRestrictions[$temp[0]] = explode( ',', trim( $temp[1] ) );
				}
			}

			$this->mOldRestrictions = true;
			$this->mCascadeRestriction = false;
			$this->mRestrictionsExpiry = Block::decodeExpiry('');

		}

		if( $dbr->numRows( $res ) ) {
			# Current system - load second to make them override.
			$now = wfTimestampNow();
			$purgeExpired = false;

			while ($row = $dbr->fetchObject( $res ) ) {
				# Cycle through all the restrictions.

				// This code should be refactored, now that it's being used more generally,
				// But I don't really see any harm in leaving it in Block for now -werdna
				$expiry = Block::decodeExpiry( $row->pr_expiry );

				// Only apply the restrictions if they haven't expired!
				if ( !$expiry || $expiry > $now ) {
					$this->mRestrictionsExpiry = $expiry;
					$this->mRestrictions[$row->pr_type] = explode( ',', trim( $row->pr_level ) );

					$this->mCascadeRestriction |= $row->pr_cascade;
				} else {
					// Trigger a lazy purge of expired restrictions
					$purgeExpired = true;
				}
			}

			if( $purgeExpired ) {
				Title::purgeExpiredRestrictions();
			}
		}

		$this->mRestrictionsLoaded = true;
	}

	public function loadRestrictions( $oldFashionedRestrictions = NULL ) {
		if( !$this->mRestrictionsLoaded ) {
			$dbr = wfGetDB( DB_SLAVE );

			$res = $dbr->select( 'page_restrictions', '*',
				array ( 'pr_page' => $this->getArticleId() ), __METHOD__ );

			$this->loadRestrictionsFromRow( $res, $oldFashionedRestrictions );
		}
	}

	/**
	 * Purge expired restrictions from the page_restrictions table
	 */
	static function purgeExpiredRestrictions() {
		$dbw = wfGetDB( DB_MASTER );
		$dbw->delete( 'page_restrictions',
			array( 'pr_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ),
			__METHOD__ );
	}

	/**
	 * Accessor/initialisation for mRestrictions
	 *
	 * @param string $action action that permission needs to be checked for
	 * @return array the array of groups allowed to edit this article
	 */
	public function getRestrictions( $action ) {
		if( $this->exists() ) {
			if( !$this->mRestrictionsLoaded ) {
				$this->loadRestrictions();
			}
			return isset( $this->mRestrictions[$action] )
					? $this->mRestrictions[$action]
					: array();
		} else {
			return array();
		}
	}

	/**
	 * Is there a version of this page in the deletion archive?
	 * @return int the number of archived revisions
	 */
	public function isDeleted() {
		$fname = 'Title::isDeleted';
		if ( $this->getNamespace() < 0 ) {
			$n = 0;
		} else {
			$dbr = wfGetDB( DB_SLAVE );
			$n = $dbr->selectField( 'archive', 'COUNT(*)', array( 'ar_namespace' => $this->getNamespace(),
				'ar_title' => $this->getDBkey() ), $fname );
			if( $this->getNamespace() == NS_IMAGE ) {
				$n += $dbr->selectField( 'filearchive', 'COUNT(*)',
					array( 'fa_name' => $this->getDBkey() ), $fname );
			}
		}
		return (int)$n;
	}

	/**
	 * Get the article ID for this Title from the link cache,
	 * adding it if necessary
	 * @param int $flags a bit field; may be GAID_FOR_UPDATE to select
	 * 	for update
	 * @return int the ID
	 */
	public function getArticleID( $flags = 0 ) {
		$linkCache =& LinkCache::singleton();
		if ( $flags & GAID_FOR_UPDATE ) {
			$oldUpdate = $linkCache->forUpdate( true );
			$this->mArticleID = $linkCache->addLinkObj( $this );
			$linkCache->forUpdate( $oldUpdate );
		} else {
			if ( -1 == $this->mArticleID ) {
				$this->mArticleID = $linkCache->addLinkObj( $this );
			}
		}
		return $this->mArticleID;
	}

	public function getLatestRevID() {
		if ($this->mLatestID !== false)
			return $this->mLatestID;

		$db = wfGetDB(DB_SLAVE);
		return $this->mLatestID = $db->selectField( 'revision',
			"max(rev_id)",
			array('rev_page' => $this->getArticleID()),
			'Title::getLatestRevID' );
	}

	/**
	 * This clears some fields in this object, and clears any associated
	 * keys in the "bad links" section of the link cache.
	 *
	 * - This is called from Article::insertNewArticle() to allow
	 * loading of the new page_id. It's also called from
	 * Article::doDeleteArticle()
	 *
	 * @param int $newid the new Article ID
	 */
	public function resetArticleID( $newid ) {
		$linkCache =& LinkCache::singleton();
		$linkCache->clearBadLink( $this->getPrefixedDBkey() );

		if ( 0 == $newid ) { $this->mArticleID = -1; }
		else { $this->mArticleID = $newid; }
		$this->mRestrictionsLoaded = false;
		$this->mRestrictions = array();
	}

	/**
	 * Updates page_touched for this page; called from LinksUpdate.php
	 * @return bool true if the update succeded
	 */
	public function invalidateCache() {
		global $wgUseFileCache;

		if ( wfReadOnly() ) {
			return;
		}

		$dbw = wfGetDB( DB_MASTER );
		$success = $dbw->update( 'page',
			array( /* SET */
				'page_touched' => $dbw->timestamp()
			), array( /* WHERE */
				'page_namespace' => $this->getNamespace() ,
				'page_title' => $this->getDBkey()
			), 'Title::invalidateCache'
		);

		if ($wgUseFileCache) {
			$cache = new HTMLFileCache($this);
			@unlink($cache->fileCacheName());
		}

		return $success;
	}

	/**
	 * Prefix some arbitrary text with the namespace or interwiki prefix
	 * of this object
	 *
	 * @param string $name the text
	 * @return string the prefixed text
	 * @private
	 */
	/* private */ function prefix( $name ) {
		$p = '';
		if ( '' != $this->mInterwiki ) {
			$p = $this->mInterwiki . ':';
		}
		if ( 0 != $this->mNamespace ) {
			$p .= $this->getNsText() . ':';
		}
		return $p . $name;
	}

	/**
	 * Secure and split - main initialisation function for this object
	 *
	 * Assumes that mDbkeyform has been set, and is urldecoded
	 * and uses underscores, but not otherwise munged.  This function
	 * removes illegal characters, splits off the interwiki and
	 * namespace prefixes, sets the other forms, and canonicalizes
	 * everything.
	 * @return bool true on success
	 */
	private function secureAndSplit() {
		global $wgContLang, $wgLocalInterwiki, $wgCapitalLinks;

		# Initialisation
		static $rxTc = false;
		if( !$rxTc ) {
			# % is needed as well
			$rxTc = '/[^' . Title::legalChars() . ']|%[0-9A-Fa-f]{2}/S';
		}

		$this->mInterwiki = $this->mFragment = '';
		$this->mNamespace = $this->mDefaultNamespace; # Usually NS_MAIN
		
		$dbkey = $this->mDbkeyform;

		# Strip Unicode bidi override characters.
		# Sometimes they slip into cut-n-pasted page titles, where the
		# override chars get included in list displays.
		$dbkey = str_replace( "\xE2\x80\x8E", '', $dbkey ); // 200E LEFT-TO-RIGHT MARK
		$dbkey = str_replace( "\xE2\x80\x8F", '', $dbkey ); // 200F RIGHT-TO-LEFT MARK
		
		# Clean up whitespace
		#
		$dbkey = preg_replace( '/[ _]+/', '_', $dbkey );
		$dbkey = trim( $dbkey, '_' );

		if ( '' == $dbkey ) {
			return false;
		}

		if( false !== strpos( $dbkey, UTF8_REPLACEMENT ) ) {
			# Contained illegal UTF-8 sequences or forbidden Unicode chars.
			return false;
		}

		$this->mDbkeyform = $dbkey;

		# Initial colon indicates main namespace rather than specified default
		# but should not create invalid {ns,title} pairs such as {0,Project:Foo}
		if ( ':' == $dbkey{0} ) {
			$this->mNamespace = NS_MAIN;
			$dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
			$dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
		}

		# Namespace or interwiki prefix
		$firstPass = true;
		do {
			$m = array();
			if ( preg_match( "/^(.+?)_*:_*(.*)$/S", $dbkey, $m ) ) {
				$p = $m[1];
				if ( $ns = $wgContLang->getNsIndex( $p )) {
					# Ordinary namespace
					$dbkey = $m[2];
					$this->mNamespace = $ns;
				} elseif( $this->getInterwikiLink( $p ) ) {
					if( !$firstPass ) {
						# Can't make a local interwiki link to an interwiki link.
						# That's just crazy!
						return false;
					}

					# Interwiki link
					$dbkey = $m[2];
					$this->mInterwiki = $wgContLang->lc( $p );

					# Redundant interwiki prefix to the local wiki
					if ( 0 == strcasecmp( $this->mInterwiki, $wgLocalInterwiki ) ) {
						if( $dbkey == '' ) {
							# Can't have an empty self-link
							return false;
						}
						$this->mInterwiki = '';
						$firstPass = false;
						# Do another namespace split...
						continue;
					}

					# If there's an initial colon after the interwiki, that also
					# resets the default namespace
					if ( $dbkey !== '' && $dbkey[0] == ':' ) {
						$this->mNamespace = NS_MAIN;
						$dbkey = substr( $dbkey, 1 );
					}
				}
				# If there's no recognized interwiki or namespace,
				# then let the colon expression be part of the title.
			}
			break;
		} while( true );

		# We already know that some pages won't be in the database!
		#
		if ( '' != $this->mInterwiki || NS_SPECIAL == $this->mNamespace ) {
			$this->mArticleID = 0;
		}
		$fragment = strstr( $dbkey, '#' );
		if ( false !== $fragment ) {
			$this->setFragment( $fragment );
			$dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
			# remove whitespace again: prevents "Foo_bar_#"
			# becoming "Foo_bar_"
			$dbkey = preg_replace( '/_*$/', '', $dbkey );
		}

		# Reject illegal characters.
		#
		if( preg_match( $rxTc, $dbkey ) ) {
			return false;
		}

		/**
		 * Pages with "/./" or "/../" appearing in the URLs will
		 * often be unreachable due to the way web browsers deal
		 * with 'relative' URLs. Forbid them explicitly.
		 */
		if ( strpos( $dbkey, '.' ) !== false &&
		     ( $dbkey === '.' || $dbkey === '..' ||
		       strpos( $dbkey, './' ) === 0  ||
		       strpos( $dbkey, '../' ) === 0 ||
		       strpos( $dbkey, '/./' ) !== false ||
		       strpos( $dbkey, '/../' ) !== false ) )
		{
			return false;
		}
		
		/**
		 * Magic tilde sequences? Nu-uh!
		 */
		if( strpos( $dbkey, '~~~' ) !== false ) {
			return false;
		}

		/**
		 * Limit the size of titles to 255 bytes.
		 * This is typically the size of the underlying database field.
		 * We make an exception for special pages, which don't need to be stored
		 * in the database, and may edge over 255 bytes due to subpage syntax 
		 * for long titles, e.g. [[Special:Block/Long name]]
		 */
		if ( ( $this->mNamespace != NS_SPECIAL && strlen( $dbkey ) > 255 ) ||
		  strlen( $dbkey ) > 512 ) 
		{
			return false;
		}

		/**
		 * Normally, all wiki links are forced to have
		 * an initial capital letter so [[foo]] and [[Foo]]
		 * point to the same place.
		 *
		 * Don't force it for interwikis, since the other
		 * site might be case-sensitive.
		 */
		$this->mUserCaseDBKey = $dbkey;
		if( $wgCapitalLinks && $this->mInterwiki == '') {
			$dbkey = $wgContLang->ucfirst( $dbkey );
		}

		/**
		 * Can't make a link to a namespace alone...
		 * "empty" local links can only be self-links
		 * with a fragment identifier.
		 */
		if( $dbkey == '' &&
			$this->mInterwiki == '' &&
			$this->mNamespace != NS_MAIN ) {
			return false;
		}
		// Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
		// IP names are not allowed for accounts, and can only be referring to 
		// edits from the IP. Given '::' abbreviations and caps/lowercaps, 
		// there are numerous ways to present the same IP. Having sp:contribs scan 
		// them all is silly and having some show the edits and others not is 
		// inconsistent. Same for talk/userpages. Keep them normalized instead.
		$dbkey = ($this->mNamespace == NS_USER || $this->mNamespace == NS_USER_TALK) ? 
			IP::sanitizeIP( $dbkey ) : $dbkey;
		// Any remaining initial :s are illegal.
		if ( $dbkey !== '' && ':' == $dbkey{0} ) {
			return false;
		}
		
		# Fill fields
		$this->mDbkeyform = $dbkey;
		$this->mUrlform = wfUrlencode( $dbkey );

		$this->mTextform = str_replace( '_', ' ', $dbkey );

		return true;
	}

	/**
	 * Set the fragment for this title
	 * This is kind of bad, since except for this rarely-used function, Title objects
	 * are immutable. The reason this is here is because it's better than setting the 
	 * members directly, which is what Linker::formatComment was doing previously.
	 *
	 * @param string $fragment text
	 * @todo clarify whether access is supposed to be public (was marked as "kind of public")
	 */
	public function setFragment( $fragment ) {
		$this->mFragment = str_replace( '_', ' ', substr( $fragment, 1 ) );
	}

	/**
	 * Get a Title object associated with the talk page of this article
	 * @return Title the object for the talk page
	 */
	public function getTalkPage() {
		return Title::makeTitle( Namespace::getTalk( $this->getNamespace() ), $this->getDBkey() );
	}

	/**
	 * Get a title object associated with the subject page of this
	 * talk page
	 *
	 * @return Title the object for the subject page
	 */
	public function getSubjectPage() {
		return Title::makeTitle( Namespace::getSubject( $this->getNamespace() ), $this->getDBkey() );
	}

	/**
	 * Get an array of Title objects linking to this Title
	 * Also stores the IDs in the link cache.
	 *
	 * WARNING: do not use this function on arbitrary user-supplied titles!
	 * On heavily-used templates it will max out the memory.
	 *
	 * @param string $options may be FOR UPDATE
	 * @return array the Title objects linking here
	 */
	public function getLinksTo( $options = '', $table = 'pagelinks', $prefix = 'pl' ) {
		$linkCache =& LinkCache::singleton();

		if ( $options ) {
			$db = wfGetDB( DB_MASTER );
		} else {
			$db = wfGetDB( DB_SLAVE );
		}

		$res = $db->select( array( 'page', $table ),
			array( 'page_namespace', 'page_title', 'page_id' ),
			array(
				"{$prefix}_from=page_id",
				"{$prefix}_namespace" => $this->getNamespace(),
				"{$prefix}_title"     => $this->getDbKey() ),
			'Title::getLinksTo',
			$options );

		$retVal = array();
		if ( $db->numRows( $res ) ) {
			while ( $row = $db->fetchObject( $res ) ) {
				if ( $titleObj = Title::makeTitle( $row->page_namespace, $row->page_title ) ) {
					$linkCache->addGoodLinkObj( $row->page_id, $titleObj );
					$retVal[] = $titleObj;
				}
			}
		}
		$db->freeResult( $res );
		return $retVal;
	}

	/**
	 * Get an array of Title objects using this Title as a template
	 * Also stores the IDs in the link cache.
	 *
	 * WARNING: do not use this function on arbitrary user-supplied titles!
	 * On heavily-used templates it will max out the memory.
	 *
	 * @param string $options may be FOR UPDATE
	 * @return array the Title objects linking here
	 */
	public function getTemplateLinksTo( $options = '' ) {
		return $this->getLinksTo( $options, 'templatelinks', 'tl' );
	}

	/**
	 * Get an array of Title objects referring to non-existent articles linked from this page
	 *
	 * @param string $options may be FOR UPDATE
	 * @return array the Title objects
	 */
	public function getBrokenLinksFrom( $options = '' ) {
		if ( $options ) {
			$db = wfGetDB( DB_MASTER );
		} else {
			$db = wfGetDB( DB_SLAVE );
		}

		$res = $db->safeQuery(
			  "SELECT pl_namespace, pl_title
			     FROM !
			LEFT JOIN !
			       ON pl_namespace=page_namespace
			      AND pl_title=page_title
			    WHERE pl_from=?
			      AND page_namespace IS NULL
				  !",
			$db->tableName( 'pagelinks' ),
			$db->tableName( 'page' ),
			$this->getArticleId(),
			$options );

		$retVal = array();
		if ( $db->numRows( $res ) ) {
			while ( $row = $db->fetchObject( $res ) ) {
				$retVal[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
			}
		}
		$db->freeResult( $res );
		return $retVal;
	}


	/**
	 * Get a list of URLs to purge from the Squid cache when this
	 * page changes
	 *
	 * @return array the URLs
	 */
	public function getSquidURLs() {
		global $wgContLang;

		$urls = array(
			$this->getInternalURL(),
			$this->getInternalURL( 'action=history' )
		);

		// purge variant urls as well
		if($wgContLang->hasVariants()){
			$variants = $wgContLang->getVariants();
			foreach($variants as $vCode){
				if($vCode==$wgContLang->getCode()) continue; // we don't want default variant
				$urls[] = $this->getInternalURL('',$vCode);
			}
		}

		return $urls;
	}

	public function purgeSquid() {
		global $wgUseSquid;
		if ( $wgUseSquid ) {
			$urls = $this->getSquidURLs();
			$u = new SquidUpdate( $urls );
			$u->doUpdate();
		}
	}

	/**
	 * Move this page without authentication
	 * @param Title &$nt the new page Title
	 */
	public function moveNoAuth( &$nt ) {
		return $this->moveTo( $nt, false );
	}

	/**
	 * Check whether a given move operation would be valid.
	 * Returns true if ok, or a message key string for an error message
	 * if invalid. (Scarrrrry ugly interface this.)
	 * @param Title &$nt the new title
	 * @param bool $auth indicates whether $wgUser's permissions
	 * 	should be checked
	 * @return mixed true on success, message name on failure
	 */
	public function isValidMoveOperation( &$nt, $auth = true ) {
		if( !$this or !$nt ) {
			return 'badtitletext';
		}
		if( $this->equals( $nt ) ) {
			return 'selfmove';
		}
		if( !$this->isMovable() || !$nt->isMovable() ) {
			return 'immobile_namespace';
		}

		$oldid = $this->getArticleID();
		$newid = $nt->getArticleID();

		if ( strlen( $nt->getDBkey() ) < 1 ) {
			return 'articleexists';
		}
		if ( ( '' == $this->getDBkey() ) ||
			 ( !$oldid ) ||
		     ( '' == $nt->getDBkey() ) ) {
			return 'badarticleerror';
		}

		if ( $auth && (
				!$this->userCan( 'edit' ) || !$nt->userCan( 'edit' ) ||
				!$this->userCan( 'move' ) || !$nt->userCan( 'move' ) ) ) {
			return 'protectedpage';
		}

		# The move is allowed only if (1) the target doesn't exist, or
		# (2) the target is a redirect to the source, and has no history
		# (so we can undo bad moves right after they're done).

		if ( 0 != $newid ) { # Target exists; check for validity
			if ( ! $this->isValidMoveTarget( $nt ) ) {
				return 'articleexists';
			}
		}
		return true;
	}

	/**
	 * Move a title to a new location
	 * @param Title &$nt the new title
	 * @param bool $auth indicates whether $wgUser's permissions
	 * 	should be checked
	 * @return mixed true on success, message name on failure
	 */
	public function moveTo( &$nt, $auth = true, $reason = '' ) {
		$err = $this->isValidMoveOperation( $nt, $auth );
		if( is_string( $err ) ) {
			return $err;
		}

		$pageid = $this->getArticleID();
		if( $nt->exists() ) {
			$this->moveOverExistingRedirect( $nt, $reason );
			$pageCountChange = 0;
		} else { # Target didn't exist, do normal move.
			$this->moveToNewTitle( $nt, $reason );
			$pageCountChange = 1;
		}
		$redirid = $this->getArticleID();

		# Fixing category links (those without piped 'alternate' names) to be sorted under the new title
		$dbw = wfGetDB( DB_MASTER );
		$categorylinks = $dbw->tableName( 'categorylinks' );
		$sql = "UPDATE $categorylinks SET cl_sortkey=" . $dbw->addQuotes( $nt->getPrefixedText() ) .
			" WHERE cl_from=" . $dbw->addQuotes( $pageid ) .
			" AND cl_sortkey=" . $dbw->addQuotes( $this->getPrefixedText() );
		$dbw->query( $sql, 'SpecialMovepage::doSubmit' );

		# Update watchlists

		$oldnamespace = $this->getNamespace() & ~1;
		$newnamespace = $nt->getNamespace() & ~1;
		$oldtitle = $this->getDBkey();
		$newtitle = $nt->getDBkey();

		if( $oldnamespace != $newnamespace || $oldtitle != $newtitle ) {
			WatchedItem::duplicateEntries( $this, $nt );
		}

		# Update search engine
		$u = new SearchUpdate( $pageid, $nt->getPrefixedDBkey() );
		$u->doUpdate();
		$u = new SearchUpdate( $redirid, $this->getPrefixedDBkey(), '' );
		$u->doUpdate();

		# Update site_stats
		if( $this->isContentPage() && !$nt->isContentPage() ) {
			# No longer a content page
			# Not viewed, edited, removing
			$u = new SiteStatsUpdate( 0, 1, -1, $pageCountChange );
		} elseif( !$this->isContentPage() && $nt->isContentPage() ) {
			# Now a content page
			# Not viewed, edited, adding
			$u = new SiteStatsUpdate( 0, 1, +1, $pageCountChange );
		} elseif( $pageCountChange ) {
			# Redirect added
			$u = new SiteStatsUpdate( 0, 0, 0, 1 );
		} else {
			# Nothing special
			$u = false;
		}
		if( $u )
			$u->doUpdate();
		
		global $wgUser;
		wfRunHooks( 'TitleMoveComplete', array( &$this, &$nt, &$wgUser, $pageid, $redirid ) );
		return true;
	}

	/**
	 * Move page to a title which is at present a redirect to the
	 * source page
	 *
	 * @param Title &$nt the page to move to, which should currently
	 * 	be a redirect
	 */
	private function moveOverExistingRedirect( &$nt, $reason = '' ) {
		global $wgUseSquid;
		$fname = 'Title::moveOverExistingRedirect';
		$comment = wfMsgForContent( '1movedto2_redir', $this->getPrefixedText(), $nt->getPrefixedText() );

		if ( $reason ) {
			$comment .= ": $reason";
		}

		$now = wfTimestampNow();
		$newid = $nt->getArticleID();
		$oldid = $this->getArticleID();
		$dbw = wfGetDB( DB_MASTER );
		$linkCache =& LinkCache::singleton();

		# Delete the old redirect. We don't save it to history since
		# by definition if we've got here it's rather uninteresting.
		# We have to remove it so that the next step doesn't trigger
		# a conflict on the unique namespace+title index...
		$dbw->delete( 'page', array( 'page_id' => $newid ), $fname );

		# Save a null revision in the page's history notifying of the move
		$nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
		$nullRevId = $nullRevision->insertOn( $dbw );

		# Change the name of the target page:
		$dbw->update( 'page',
			/* SET */ array(
				'page_touched'   => $dbw->timestamp($now),
				'page_namespace' => $nt->getNamespace(),
				'page_title'     => $nt->getDBkey(),
				'page_latest'    => $nullRevId,
			),
			/* WHERE */ array( 'page_id' => $oldid ),
			$fname
		);
		$linkCache->clearLink( $nt->getPrefixedDBkey() );

		# Recreate the redirect, this time in the other direction.
		$mwRedir = MagicWord::get( 'redirect' );
		$redirectText = $mwRedir->getSynonym( 0 ) . ' [[' . $nt->getPrefixedText() . "]]\n";
		$redirectArticle = new Article( $this );
		$newid = $redirectArticle->insertOn( $dbw );
		$redirectRevision = new Revision( array(
			'page'    => $newid,
			'comment' => $comment,
			'text'    => $redirectText ) );
		$redirectRevision->insertOn( $dbw );
		$redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
		$linkCache->clearLink( $this->getPrefixedDBkey() );

		# Log the move
		$log = new LogPage( 'move' );
		$log->addEntry( 'move_redir', $this, $reason, array( 1 => $nt->getPrefixedText() ) );

		# Now, we record the link from the redirect to the new title.
		# It should have no other outgoing links...
		$dbw->delete( 'pagelinks', array( 'pl_from' => $newid ), $fname );
		$dbw->insert( 'pagelinks',
			array(
				'pl_from'      => $newid,
				'pl_namespace' => $nt->getNamespace(),
				'pl_title'     => $nt->getDbKey() ),
			$fname );

		# Purge squid
		if ( $wgUseSquid ) {
			$urls = array_merge( $nt->getSquidURLs(), $this->getSquidURLs() );
			$u = new SquidUpdate( $urls );
			$u->doUpdate();
		}
	}

	/**
	 * Move page to non-existing title.
	 * @param Title &$nt the new Title
	 */
	private function moveToNewTitle( &$nt, $reason = '' ) {
		global $wgUseSquid;
		$fname = 'MovePageForm::moveToNewTitle';
		$comment = wfMsgForContent( '1movedto2', $this->getPrefixedText(), $nt->getPrefixedText() );
		if ( $reason ) {
			$comment .= ": $reason";
		}

		$newid = $nt->getArticleID();
		$oldid = $this->getArticleID();
		$dbw = wfGetDB( DB_MASTER );
		$now = $dbw->timestamp();
		$linkCache =& LinkCache::singleton();

		# Save a null revision in the page's history notifying of the move
		$nullRevision = Revision::newNullRevision( $dbw, $oldid, $comment, true );
		$nullRevId = $nullRevision->insertOn( $dbw );

		# Rename cur entry
		$dbw->update( 'page',
			/* SET */ array(
				'page_touched'   => $now,
				'page_namespace' => $nt->getNamespace(),
				'page_title'     => $nt->getDBkey(),
				'page_latest'    => $nullRevId,
			),
			/* WHERE */ array( 'page_id' => $oldid ),
			$fname
		);

		$linkCache->clearLink( $nt->getPrefixedDBkey() );

		# Insert redirect
		$mwRedir = MagicWord::get( 'redirect' );
		$redirectText = $mwRedir->getSynonym( 0 ) . ' [[' . $nt->getPrefixedText() . "]]\n";
		$redirectArticle = new Article( $this );
		$newid = $redirectArticle->insertOn( $dbw );
		$redirectRevision = new Revision( array(
			'page'    => $newid,
			'comment' => $comment,
			'text'    => $redirectText ) );
		$redirectRevision->insertOn( $dbw );
		$redirectArticle->updateRevisionOn( $dbw, $redirectRevision, 0 );
		$linkCache->clearLink( $this->getPrefixedDBkey() );

		# Log the move
		$log = new LogPage( 'move' );
		$log->addEntry( 'move', $this, $reason, array( 1 => $nt->getPrefixedText()) );

		# Purge caches as per article creation
		Article::onArticleCreate( $nt );

		# Record the just-created redirect's linking to the page
		$dbw->insert( 'pagelinks',
			array(
				'pl_from'      => $newid,
				'pl_namespace' => $nt->getNamespace(),
				'pl_title'     => $nt->getDBkey() ),
			$fname );

		# Purge old title from squid
		# The new title, and links to the new title, are purged in Article::onArticleCreate()
		$this->purgeSquid();
	}

	/**
	 * Checks if $this can be moved to a given Title
	 * - Selects for update, so don't call it unless you mean business
	 *
	 * @param Title &$nt the new title to check
	 */
	public function isValidMoveTarget( $nt ) {

		$fname = 'Title::isValidMoveTarget';
		$dbw = wfGetDB( DB_MASTER );

		# Is it a redirect?
		$id  = $nt->getArticleID();
		$obj = $dbw->selectRow( array( 'page', 'revision', 'text'),
			array( 'page_is_redirect','old_text','old_flags' ),
			array( 'page_id' => $id, 'page_latest=rev_id', 'rev_text_id=old_id' ),
			$fname, 'FOR UPDATE' );

		if ( !$obj || 0 == $obj->page_is_redirect ) {
			# Not a redirect
			wfDebug( __METHOD__ . ": not a redirect\n" );
			return false;
		}
		$text = Revision::getRevisionText( $obj );

		# Does the redirect point to the source?
		# Or is it a broken self-redirect, usually caused by namespace collisions?
		$m = array();
		if ( preg_match( "/\\[\\[\\s*([^\\]\\|]*)]]/", $text, $m ) ) {
			$redirTitle = Title::newFromText( $m[1] );
			if( !is_object( $redirTitle ) ||
				( $redirTitle->getPrefixedDBkey() != $this->getPrefixedDBkey() &&
				$redirTitle->getPrefixedDBkey() != $nt->getPrefixedDBkey() ) ) {
				wfDebug( __METHOD__ . ": redirect points to other page\n" );
				return false;
			}
		} else {
			# Fail safe
			wfDebug( __METHOD__ . ": failsafe\n" );
			return false;
		}

		# Does the article have a history?
		$row = $dbw->selectRow( array( 'page', 'revision'),
			array( 'rev_id' ),
			array( 'page_namespace' => $nt->getNamespace(),
				'page_title' => $nt->getDBkey(),
				'page_id=rev_page AND page_latest != rev_id'
			), $fname, 'FOR UPDATE'
		);

		# Return true if there was no history
		return $row === false;
	}
	
	/**
	 * Can this title be added to a user's watchlist?
	 *
	 * @return bool
	 */
	public function isWatchable() {
		return !$this->isExternal()
			&& Namespace::isWatchable( $this->getNamespace() );
	}

	/**
	 * Get categories to which this Title belongs and return an array of
	 * categories' names.
	 *
	 * @return array an array of parents in the form:
	 *	$parent => $currentarticle
	 */
	public function getParentCategories() {
		global $wgContLang;

		$titlekey = $this->getArticleId();
		$dbr = wfGetDB( DB_SLAVE );
		$categorylinks = $dbr->tableName( 'categorylinks' );

		# NEW SQL
		$sql = "SELECT * FROM $categorylinks"
		     ." WHERE cl_from='$titlekey'"
			 ." AND cl_from <> '0'"
			 ." ORDER BY cl_sortkey";

		$res = $dbr->query ( $sql ) ;

		if($dbr->numRows($res) > 0) {
			while ( $x = $dbr->fetchObject ( $res ) )
				//$data[] = Title::newFromText($wgContLang->getNSText ( NS_CATEGORY ).':'.$x->cl_to);
				$data[$wgContLang->getNSText ( NS_CATEGORY ).':'.$x->cl_to] = $this->getFullText();
			$dbr->freeResult ( $res ) ;
		} else {
			$data = '';
		}
		return $data;
	}

	/**
	 * Get a tree of parent categories
	 * @param array $children an array with the children in the keys, to check for circular refs
	 * @return array
	 */
	public function getParentCategoryTree( $children = array() ) {
		$parents = $this->getParentCategories();

		if($parents != '') {
			foreach($parents as $parent => $current) {
				if ( array_key_exists( $parent, $children ) ) {
					# Circular reference
					$stack[$parent] = array();
				} else {
					$nt = Title::newFromText($parent);
					if ( $nt ) {
						$stack[$parent] = $nt->getParentCategoryTree( $children + array($parent => 1) );
					}
				}
			}
			return $stack;
		} else {
			return array();
		}
	}


	/**
	 * Get an associative array for selecting this title from
	 * the "page" table
	 *
	 * @return array
	 */
	public function pageCond() {
		return array( 'page_namespace' => $this->mNamespace, 'page_title' => $this->mDbkeyform );
	}

	/**
	 * Get the revision ID of the previous revision
	 *
	 * @param integer $revision  Revision ID. Get the revision that was before this one.
	 * @return integer $oldrevision|false
	 */
	public function getPreviousRevisionID( $revision ) {
		$dbr = wfGetDB( DB_SLAVE );
		return $dbr->selectField( 'revision', 'rev_id',
			'rev_page=' . intval( $this->getArticleId() ) .
			' AND rev_id<' . intval( $revision ) . ' ORDER BY rev_id DESC' );
	}

	/**
	 * Get the revision ID of the next revision
	 *
	 * @param integer $revision  Revision ID. Get the revision that was after this one.
	 * @return integer $oldrevision|false
	 */
	public function getNextRevisionID( $revision ) {
		$dbr = wfGetDB( DB_SLAVE );
		return $dbr->selectField( 'revision', 'rev_id',
			'rev_page=' . intval( $this->getArticleId() ) .
			' AND rev_id>' . intval( $revision ) . ' ORDER BY rev_id' );
	}

	/**
	 * Get the number of revisions between the given revision IDs.
	 *
	 * @param integer $old  Revision ID.
	 * @param integer $new  Revision ID.
	 * @return integer  Number of revisions between these IDs.
	 */
	public function countRevisionsBetween( $old, $new ) {
		$dbr = wfGetDB( DB_SLAVE );
		return $dbr->selectField( 'revision', 'count(*)',
			'rev_page = ' . intval( $this->getArticleId() ) .
			' AND rev_id > ' . intval( $old ) .
			' AND rev_id < ' . intval( $new ) );
	}

	/**
	 * Compare with another title.
	 *
	 * @param Title $title
	 * @return bool
	 */
	public function equals( $title ) {
		// Note: === is necessary for proper matching of number-like titles.
		return $this->getInterwiki() === $title->getInterwiki()
			&& $this->getNamespace() == $title->getNamespace()
			&& $this->getDbkey() === $title->getDbkey();
	}
	
	/**
	 * Return a string representation of this title
	 *
	 * @return string
	 */
	public function __toString() {
		return $this->getPrefixedText();
	}

	/**
	 * Check if page exists
	 * @return bool
	 */
	public function exists() {
		return $this->getArticleId() != 0;
	}

	/**
	 * Do we know that this title definitely exists, or should we otherwise
	 * consider that it exists?
	 *
	 * @return bool
	 */
	public function isAlwaysKnown() {
		return $this->isExternal()
			|| ( $this->mNamespace == NS_MAIN && $this->mDbkeyform == '' )
			|| ( $this->mNamespace == NS_MEDIAWIKI && wfMsgWeirdKey( $this->mDbkeyform ) );
	}

	/**
	 * Update page_touched timestamps and send squid purge messages for
	 * pages linking to this title.	May be sent to the job queue depending 
	 * on the number of links. Typically called on create and delete.
	 */
	public function touchLinks() {
		$u = new HTMLCacheUpdate( $this, 'pagelinks' );
		$u->doUpdate();

		if ( $this->getNamespace() == NS_CATEGORY ) {
			$u = new HTMLCacheUpdate( $this, 'categorylinks' );
			$u->doUpdate();
		}
	}

	/**
	 * Get the last touched timestamp
	 */
	public function getTouched() {
		$dbr = wfGetDB( DB_SLAVE );
		$touched = $dbr->selectField( 'page', 'page_touched',
			array( 
				'page_namespace' => $this->getNamespace(),
				'page_title' => $this->getDBkey()
			), __METHOD__
		);
		return $touched;
	}

	public function trackbackURL() {
		global $wgTitle, $wgScriptPath, $wgServer;

		return "$wgServer$wgScriptPath/trackback.php?article="
			. htmlspecialchars(urlencode($wgTitle->getPrefixedDBkey()));
	}

	public function trackbackRDF() {
		$url = htmlspecialchars($this->getFullURL());
		$title = htmlspecialchars($this->getText());
		$tburl = $this->trackbackURL();

		return "
<rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
         xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
         xmlns:trackback=\"http://madskills.com/public/xml/rss/module/trackback/\">
<rdf:Description
   rdf:about=\"$url\"
   dc:identifier=\"$url\"
   dc:title=\"$title\"
   trackback:ping=\"$tburl\" />
</rdf:RDF>";
	}

	/**
	 * Generate strings used for xml 'id' names in monobook tabs
	 * @return string
	 */
	public function getNamespaceKey() {
		global $wgContLang;
		switch ($this->getNamespace()) {
			case NS_MAIN:
			case NS_TALK:
				return 'nstab-main';
			case NS_USER:
			case NS_USER_TALK:
				return 'nstab-user';
			case NS_MEDIA:
				return 'nstab-media';
			case NS_SPECIAL:
				return 'nstab-special';
			case NS_PROJECT:
			case NS_PROJECT_TALK:
				return 'nstab-project';
			case NS_IMAGE:
			case NS_IMAGE_TALK:
				return 'nstab-image';
			case NS_MEDIAWIKI:
			case NS_MEDIAWIKI_TALK:
				return 'nstab-mediawiki';
			case NS_TEMPLATE:
			case NS_TEMPLATE_TALK:
				return 'nstab-template';
			case NS_HELP:
			case NS_HELP_TALK:
				return 'nstab-help';
			case NS_CATEGORY:
			case NS_CATEGORY_TALK:
				return 'nstab-category';
			default:
				return 'nstab-' . $wgContLang->lc( $this->getSubjectNsText() );
		}
	}

	/**
	 * Returns true if this title resolves to the named special page
	 * @param string $name The special page name
	 */
	public function isSpecial( $name ) {
		if ( $this->getNamespace() == NS_SPECIAL ) {
			list( $thisName, /* $subpage */ ) = SpecialPage::resolveAliasWithSubpage( $this->getDBkey() );
			if ( $name == $thisName ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * If the Title refers to a special page alias which is not the local default, 
	 * returns a new Title which points to the local default. Otherwise, returns $this.
	 */
	public function fixSpecialName() {
		if ( $this->getNamespace() == NS_SPECIAL ) {
			$canonicalName = SpecialPage::resolveAlias( $this->mDbkeyform );
			if ( $canonicalName ) {
				$localName = SpecialPage::getLocalNameFor( $canonicalName );
				if ( $localName != $this->mDbkeyform ) {
					return Title::makeTitle( NS_SPECIAL, $localName );
				}
			}
		}
		return $this;
	}

	/**
	 * Is this Title in a namespace which contains content?
	 * In other words, is this a content page, for the purposes of calculating
	 * statistics, etc?
	 *
	 * @return bool
	 */
	public function isContentPage() {
		return Namespace::isContent( $this->getNamespace() );
	}
	
}