aboutsummaryrefslogtreecommitdiff
path: root/engine/lib/elgglib.php
blob: 47d05327e748e9dd79b6bce1df87ed72107c7e38 (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
<?php
/**
 * Bootstrapping and helper procedural code available for use in Elgg core and plugins.
 *
 *
 * @package Elgg.Core
 * @todo These functions can't be subpackaged because they cover a wide mix of
 * puposes and subsystems.  Many of them should be moved to more relevant files.
 */

/**
 * Forward to $location.
 *
 * Sends a 'Location: $location' header and exists.  If headers have already been sent, returns FALSE.
 *
 * @param string $location URL to forward to browser to. Can be path relative to the network's URL.
 * @return False False if headers have been sent. Terminates execution if forwarding.
 */
function forward($location = "") {
	global $CONFIG;

	if (!headers_sent()) {
		if ($location === REFERER) {
			$location = $_SERVER['HTTP_REFERER'];
		}

		if ((substr_count($location, 'http://') == 0) && (substr_count($location, 'https://') == 0)) {
			$location = $CONFIG->url . $location;
		}

		// return new forward location or false to stop the forward or empty string to exit
		$current_page = current_page_url();
		$params = array('current_url' => $current_page, 'forward_url' => $location);
		$location = trigger_plugin_hook('forward', 'system', $params, $location);

		if ($location) {
			header("Location: {$location}");
			exit;
		} else if ($location === '') {
			exit;
		}
	}

	return false;
}

/**
 * Returns the current page's complete URL.
 *
 * The current URL is assembled using the network's wwwroot and the request URI
 * in $_SERVER as populated by the web server.  This function will include
 * any schemes, usernames and passwords, and ports.
 *
 * @return string The current page URL.
 */
function current_page_url() {
	global $CONFIG;

	$url = parse_url($CONFIG->wwwroot);

	$page = $url['scheme'] . "://";

	// user/pass
	if ((isset($url['user'])) && ($url['user'])) {
		$page .= $url['user'];
	}
	if ((isset($url['pass'])) && ($url['pass'])) {
		$page .= ":".$url['pass'];
	}
	if ((isset($url['user']) && $url['user']) ||
		(isset($url['pass']) && $url['pass'])) {
		$page .="@";
	}

	$page .= $url['host'];

	if ((isset($url['port'])) && ($url['port'])) {
		$page .= ":" . $url['port'];
	}

	$page = trim($page, "/");

	$page .= $_SERVER['REQUEST_URI'];

	return $page;
}

/**
 * Returns an ElggCache object suitable for caching view
 * file load paths to disk under $CONFIG->dataroot.
 *
 * @todo Can this be done in a cleaner way?
 * @todo Swap to memcache etc?
 *
 * @return ElggFileCache A cache object suitable for caching file load paths.
 */
function elgg_get_filepath_cache() {
	global $CONFIG;

	/**
	 * A default filestore cache using the dataroot.
	 */
	static $FILE_PATH_CACHE;

	if (!$FILE_PATH_CACHE) {
		$FILE_PATH_CACHE = new ElggFileCache($CONFIG->dataroot);
	}

	return $FILE_PATH_CACHE;
}

/**
 * Deletes the view file paths cache from disk.
 *
 * @return bool On success
 */
function elgg_filepath_cache_reset() {
	$cache = elgg_get_filepath_cache();
	return $cache->delete('view_paths');
}

/**
 * Saves $data to the views file paths disk cache as
 * 'view_paths'.
 *
 * @param mixed $data The data
 * @return bool On success
 */
function elgg_filepath_cache_save($data) {
	global $CONFIG;

	if ($CONFIG->viewpath_cache_enabled) {
		$cache = elgg_get_filepath_cache();
		return $cache->save('view_paths', $data);
	}

	return false;
}

/**
 * Returns the contents of the views file paths cache from disk.
 *
 * @return mixed Null if simplecache isn't enabled, the contents of the views file paths cache if it is.
 */
function elgg_filepath_cache_load() {
	global $CONFIG;

	if ($CONFIG->viewpath_cache_enabled) {
		$cache = elgg_get_filepath_cache();
		$cached_view_paths = $cache->load('view_paths');

		if ($cached_view_paths) {
			return $cached_view_paths;
		}
	}

	return NULL;
}

/**
 * Enables the views file paths disk cache.
 *
 * Uses the 'viewpath_cache_enabled' datalist with a boolean value.
 * Resets the views paths cache.
 *
 * @return null
 */
function elgg_enable_filepath_cache() {
	global $CONFIG;

	datalist_set('viewpath_cache_enabled', 1);
	$CONFIG->viewpath_cache_enabled = 1;
	elgg_filepath_cache_reset();
}

/**
 * Disables the views file paths disk cache.
 *
 * Uses the 'viewpath_cache_enabled' datalist with a boolean value.
 * Resets the views paths cache.
 *
 * @return null
 */
function elgg_disable_filepath_cache() {
	global $CONFIG;

	datalist_set('viewpath_cache_enabled', 0);
	$CONFIG->viewpath_cache_enabled = 0;
	elgg_filepath_cache_reset();
}

/**
 * Deprecated by elgg_add_submenu_item()
 *
 * @see elgg_add_submenu_item()
 * @deprecated 1.8
 */
function add_submenu_item($label, $link, $group = 'default', $onclick = false, $selected = NULL) {
	elgg_deprecated_notice('add_submenu_item was deprecated by elgg_add_submenu_item', 1.8);

	$item = array(
		'text' => $label,
		'href' => $link,
		'selected' => $selected
	);

	if (!$group) {
		$group = 'default';
	}

	if ($onclick) {
		$js = "onclick=\"javascript:return confirm('". elgg_echo('deleteconfirm') . "')\"";
		$item['vars'] = array('js' => $js);
	}
	// submenu items were added in the page setup hook usually by checking
	// the context.  We'll pass in the current context here, which will
	// emulate that effect.
	// if context == 'main' (default) it probably means they always wanted
	// the menu item to show up everywhere.
	$context = get_context();

	if ($context == 'main') {
		$context = 'all';
	}
	return elgg_add_submenu_item($item, $context, $group);
}

/**
 * Add an entry to the submenu.
 *
 * @param array $item The item as:
 * <code>
 * array(
 * 	'title' => 'Text to display',
 * 	'url' => 'URL of the link',
 * 	'id' => 'entry_unique_id' //used by children items to identify parents
 * 	'parent_id' => 'id_of_parent',
 * 	'selected' => BOOL // Is this item selected? (If NULL or unset will attempt to guess)
 * 	'vars' => array() // Array of vars to pass to the navigation/submenu_item view
 * )
 * </code>
 *
 * @param string $context Context in which to display this menu item.  'all' will make it show up all the time. Use sparingly.
 * @param string $group Group for the item. Each submenu group has its own <ul>
 * @return BOOL
 * @since 1.8
 * @see elgg_prepare_submenu
 */
function elgg_add_submenu_item(array $item, $context = 'all', $group = 'default') {
	global $CONFIG;

	if (!isset($CONFIG->submenu_items)) {
		$CONFIG->submenu_items = array();
	}

	if (!isset($CONFIG->submenu_items[$context])) {
		$CONFIG->submenu_items[$context] = array();
	}

	if (!isset($CONFIG->submenu_items[$context][$group])) {
		$CONFIG->submenu_items[$context][$group] = array();
	}

	if (!isset($item['text'])) {
		return FALSE;
	}

	// we use persistent object properties in the submenu
	// setup function, so normalize the array to an object.
	// we pass it in as an array because this would be the only
	// place in elgg that we ask for an object like this.
	// consistency ftw.
	$item_obj = new StdClass();

	foreach ($item as $k => $v) {
		switch ($k) {
			case 'parent_id':
			case 'id':
				// make sure '' and false make sense
				$v = (empty($v)) ? NULL : $v;

			default:
				$item_obj->$k = $v;
				break;
		}
	}

	$CONFIG->submenu_items[$context][$group][] = $item_obj;

	return TRUE;
}

/**
 * Properly nest all submenu entries for contexts $context and 'all'
 *
 * @param string $context
 * @param bool $sort Sort the menu items alphabetically
 * @since 1.8
 * @see elgg_add_submenu_item
 */
function elgg_prepare_submenu($context = 'main', $sort = FALSE) {
	global $CONFIG;

	if (!isset($CONFIG->submenu_items) || !($CONFIG->submenu_items)) {
		return FALSE;
	}

	$groups = array();

	if (isset($CONFIG->submenu_items['all'])) {
		$groups = $CONFIG->submenu_items['all'];
	}

	if (isset($CONFIG->submenu_items[$context])) {
		$groups = array_merge_recursive($groups, $CONFIG->submenu_items[$context]);
	}

	if (!$groups) {
		return FALSE;
	}

	foreach ($groups as $group => $items) {
		if ($sort) {
			usort($items, 'elgg_submenu_item_cmp');
		}

		$parsed_menu = array();
		// determin which children need to go in this item.
		foreach ($items as $i => $item) {
			// can only support children if there's an id
			if (isset($item->id)) {
				foreach ($items as $child_i => $child_item) {
					// don't check ourselves or used children.
					if ($child_i == $i || $child_item->used == TRUE) {
						continue;
					}

					if (isset($child_item->parent_id) && $child_item->parent_id == $item->id) {
						if (!isset($item->children)) {
							$item->children = array();
						}
						$item->children[] = $child_item;
						$child_item->parent = $item;
						// don't unset because we still need to check this item for children
						$child_item->used = TRUE;
					}
				}

				// if the parent doesn't have a url, make it the first child item.
				if (isset($item->children) && $item->children && !$item->href) {
					$child = $item->children[0];
					while ($child && !isset($child->href)) {
						if (isset($child->children) && isset($child->children[0])) {
							$child = $child->children[0];
						} else {
							$child = NULL;
						}
					}

					if ($child && isset($child->href)) {
						$item->href = $child->href;
					} else {
						// @todo There are no URLs anywhere in this tree.
						$item->href = $CONFIG->url;
					}
				}
			}

			// only add top-level elements to the menu.
			// the rest are children.
			if (!isset($item->parent_id)) {
				$parsed_menu[] = $item;
			}
		}

		$CONFIG->submenu[$context][$group] = $parsed_menu;
	}

	return TRUE;
}

/**
 * Helper function used to sort submenu items by their display text.
 *
 * @param object $a
 * @param object $b
 * @since 1.8
 * @see elgg_prepare_submenu
 */
function elgg_submenu_item_cmp($a, $b) {
	$a = $a->text;
	$b = $b->text;

	return strnatcmp($a, $b);
}

/**
 * Use elgg_get_submenu().
 *
 * @see elgg_get_submenu()
 * @deprecated 1.8
 */
function get_submenu() {
	elgg_deprecated_notice("get_submenu() has been deprecated by elgg_get_submenu()", 1.8);
	return elgg_get_submenu();
}

/**
 * Return the HTML for a sidemenu.
 *
 * @param string $context The context of the submenu (defaults to main)
 * @param BOOL $sort Sort by display name?
 * @return string Formatted HTML.
 * @since 1.8
 * @todo Rename to a view function. See {@trac #2320}.
 */
function elgg_get_submenu($context = NULL, $sort = FALSE) {
	global $CONFIG;

	if (!$context) {
		$context = get_context();
	}

	if (!elgg_prepare_submenu($context, $sort)) {
		return '';
	}

	$groups = $CONFIG->submenu[$context];
	$submenu_html = '';

	foreach ($groups as $group => $items) {
		// how far down we are in children arrays
		$depth = 0;
		// push and pop parent items
		$temp_items = array();

		while ($item = current($items)) {
			// ignore parents created by a child but parent never defined properly
			if (!isset($item->text) || !($item->text)) {
				next($items);
				continue;
			}

			// try to guess if this should be selected if they don't specify
			if ((!isset($item->selected) || $item->selected === NULL) && isset($item->href)) {
				$item->selected = elgg_http_url_is_identical(full_url(), $item->href);
			}

			// traverse up the parent tree if matached to mark all parents as selected/expanded.
			if ($item->selected && isset($item->parent)) {
				$parent = $item->parent;
				while ($parent) {
					$parent->selected = TRUE;
					if (isset($parent->parent)) {
						$parent = $parent->parent;
					} else {
						$parent = NULL;
					}
				}
			}

			// get the next item
			if (isset($item->children) && $item->children) {
				$depth++;
				array_push($temp_items, $items);
				$items = $item->children;
			} elseif ($depth > 0) {
				// check if there are more children elements in the current items
				// pop back up to the parent(s) if not
				if ($item = next($items)) {
					continue;
				} else {
					while($depth > 0) {
						$depth--;
						$items = array_pop($temp_items);
						if ($item = next($items)) {
							break;
						}
					}
				}
			} else {
				next($items);
			}
		}

		$submenu_html .= elgg_view('navigation/submenu_group', array('group' => $group, 'items' => $items));
	}

	// include the JS for the expand menus too
	return elgg_view('navigation/submenu_js') . $submenu_html;
}

/**
 * Returns the HTML for "likes" and "like this" on entities.
 *
 * @param ElggEntity $entity The entity to like
 * @return string|false The HTML for the likes, or false on failure
 * @since 1.8
 * @see @elgg_view likes/forms/edit
 */
function elgg_view_likes($entity){
	if (!($entity instanceof ElggEntity)) {
		return false;
	}

	if ($likes = trigger_plugin_hook('likes', $entity->getType(), array('entity' => $entity), false)) {
		return $likes;
	} else {
		$likes = elgg_view('likes/forms/edit', array('entity' => $entity));
		return $likes;
	}
}

/**
 * Count the number of likes attached to an entity
 *
 * @param ElggEntity $entity
 * @return int Number of likes
 * @since 1.8
 */
function elgg_count_likes($entity) {
	if ($likeno = trigger_plugin_hook('likes:count', $entity->getType(),
		array('entity' => $entity), false)) {
		return $likeno;
	} else {
		return count_annotations($entity->getGUID(), "", "", "likes");
	}
}

/**
 * Count the number of comments attached to an entity
 *
 * @param ElggEntity $entity
 * @return int Number of comments
 */
function elgg_count_comments($entity) {
	if ($commentno = trigger_plugin_hook('comments:count', $entity->getType(),
		array('entity' => $entity), false)) {
		return $commentno;
	} else {
		return count_annotations($entity->getGUID(), "", "", "generic_comment");
	}
}

/**
 * @deprecated 1.7
 */
function get_library_files($directory, $exceptions = array(), $list = array()) {
	elgg_deprecated_notice('get_library_files() deprecated by elgg_get_file_list()', 1.7);
	return elgg_get_file_list($directory, $exceptions, $list, array('.php'));
}

/**
 * Returns a list of files in $directory.
 *
 * Only returns files.  Does not recurse into subdirs.
 *
 * @param string $directory
 * @param array $exceptions Array of filenames to ignore
 * @param array $list Array of files to append to
 * @param mixed $extensions Array of extensions to allow, NULL for all.  Use a dot: array('.php').
 * @return array Filenames in $directory, in the form $directory/filename.
 */
function elgg_get_file_list($directory, $exceptions = array(), $list = array(), $extensions = NULL) {
	$directory = sanitise_filepath($directory);
	if ($handle = opendir($directory)) {
		while (($file = readdir($handle)) !== FALSE) {
			if (!is_file($directory . $file) || in_array($file, $exceptions)) {
				continue;
			}

			if (is_array($extensions)) {
				if (in_array(strrchr($file, '.'), $extensions)) {
					$list[] = $directory . $file;
				}
			} else {
				$list[] = $directory . $file;
			}
		}
		closedir($handle);
	}

	return $list;
}

/**
 * Checks that Elgg has been installed and attempts to complete installation if not.
 *
 * This is called by {@link engine/start.php} immediately after Elgg libraries are loaded
 * to check the installation state.
 *
 * Elgg's installation state is determined by (1) the existence of the engine/settings.php
 * file, (2) a .htaccess file, and (3) a populated database.  This function checks
 * for 1 and 2, while 3 is checked by {@link is_installed()} and {@link is_db_installed()}.
 *
 * If settings.php doesn't exist and $_REQUEST['db_install_vars'] is present,
 * this function attempts to write the values from 'db_install_vars' to settings.php.
 *
 * If .htaccess doens't exist this function attempts to copy htaccess_dist to .htaccess.
 *
 * If there are any problems, this function calls {@link register_error()} and returns FALSE.
 * Since this function is called during bootstrapping, the viewtype is failsafe.
 * Returning FALSE results in an InstallationException, which halts execution.
 *
 * @return bool
 */
function sanitised() {
	$sanitised = true;

	if (!file_exists(dirname(dirname(__FILE__)) . "/settings.php")) {
		// See if we are being asked to save the file
		$save_vars = get_input('db_install_vars');
		$result = "";
		if ($save_vars) {
			$rtn = db_check_settings($save_vars['CONFIG_DBUSER'],
									$save_vars['CONFIG_DBPASS'],
									$save_vars['CONFIG_DBNAME'],
									$save_vars['CONFIG_DBHOST'] );
			if ($rtn == FALSE) {
				register_error(elgg_view("messages/sanitisation/dbsettings_error"));
				register_error(elgg_view("messages/sanitisation/settings",
								array(	'settings.php' => $result,
										'sticky' => $save_vars)));
				return FALSE;
			}

			$result = create_settings($save_vars, dirname(dirname(__FILE__)) . "/settings.example.php");


			if (file_put_contents(dirname(dirname(__FILE__)) . "/settings.php", $result)) {
				// blank result to stop it being displayed in textarea
				$result = "";
			}
		}

		// Recheck to see if the file is still missing
		if (!file_exists(dirname(dirname(__FILE__)) . "/settings.php")) {
			register_error(elgg_view("messages/sanitisation/settings", array('settings.php' => $result)));
			$sanitised = false;
		}
	}

	if (!file_exists(dirname(dirname(dirname(__FILE__))) . "/.htaccess")) {
		if (!@copy(dirname(dirname(dirname(__FILE__))) . "/htaccess_dist", dirname(dirname(dirname(__FILE__))) . "/.htaccess")) {
			register_error(elgg_view("messages/sanitisation/htaccess", array('.htaccess' => file_get_contents(dirname(dirname(dirname(__FILE__))) . "/htaccess_dist"))));
			$sanitised = false;
		}
	}

	return $sanitised;
}

/**
 * Adds an entry in $CONFIG[$register_name][$subregister_name].
 *
 * This is only used for the site-wide menu.  See {@link add_menu()}.
 *
 * @param string $register_name The name of the top-level register
 * @param string $subregister_name The name of the subregister
 * @param mixed $subregister_value The value of the subregister
 * @param array $children_array Optionally, an array of children
 * @return true|false Depending on success
 * @todo Can be deprecated when the new menu system is introduced.
 */
function add_to_register($register_name, $subregister_name, $subregister_value, $children_array = array()) {
	global $CONFIG;

	if (empty($register_name) || empty($subregister_name)) {
		return false;
	}

	if (!isset($CONFIG->registers)) {
		$CONFIG->registers = array();
	}

	if (!isset($CONFIG->registers[$register_name])) {
		$CONFIG->registers[$register_name]  = array();
	}

	$subregister = new stdClass;
	$subregister->name = $subregister_name;
	$subregister->value = $subregister_value;

	if (is_array($children_array)) {
		$subregister->children = $children_array;
	}

	$CONFIG->registers[$register_name][$subregister_name] = $subregister;
	return true;
}

/**
 * Removes a register entry from $CONFIG[register_name][subregister_name]
 *
 * This is used to by {@link remove_menu()} to remove site-wide menu items.
 *
 * @param string $register_name The name of the top-level register
 * @param string $subregister_name The name of the subregister
 * @return true|false Depending on success
 * @since 1.7.0
 * @todo Can be deprecated when the new menu system is introduced.
 */
function remove_from_register($register_name, $subregister_name) {
	global $CONFIG;

	if (empty($register_name) || empty($subregister_name)) {
		return false;
	}

	if (!isset($CONFIG->registers)) {
		return false;
	}

	if (!isset($CONFIG->registers[$register_name])) {
		return false;
	}

	if (isset($CONFIG->registers[$register_name][$subregister_name])) {
		unset($CONFIG->registers[$register_name][$subregister_name]);
		return true;
	}

	return false;
}

/**
 * Constructs and returns a register object.
 *
 * @param string $register_name The name of the register
 * @param mixed $register_value The value of the register
 * @param array $children_array Optionally, an array of children
 * @return false|stdClass Depending on success
 * @todo Can be deprecated when the new menu system is introduced.
 */
function make_register_object($register_name, $register_value, $children_array = array()) {
	elgg_deprecated_notice('make_register_object() is deprecated by add_submenu_item()', 1.7);
	if (empty($register_name) || empty($register_value)) {
		return false;
	}

	$register = new stdClass;
	$register->name = $register_name;
	$register->value = $register_value;
	$register->children = $children_array;

	return $register;
}

/**
 * If it exists, returns a particular register as an array
 *
 * @param string $register_name The name of the register
 * @return array|false Depending on success
 * @todo Can be deprecated when the new menu system is introduced.
 */
function get_register($register_name) {
	global $CONFIG;

	if (isset($CONFIG->registers[$register_name])) {
		return $CONFIG->registers[$register_name];
	}

	return false;
}

/**
 * Adds an item to the site-wide menu.
 *
 * You can obtain the menu array by calling {@link get_register('menu')}
 *
 * @param string $menu_name The name of the menu item
 * @param string $menu_url The URL of the page
 * @param array $menu_children Optionally, an array of submenu items (not currently used)
 * @param string $context
 * @return true|false Depending on success
 * @todo Can be deprecated when the new menu system is introduced.
 */
function add_menu($menu_name, $menu_url, $menu_children = array(), $context = "") {
	global $CONFIG;

	if (!isset($CONFIG->menucontexts)) {
		$CONFIG->menucontexts = array();
	}

	if (empty($context)) {
		$context = get_plugin_name();
	}

	$value = new stdClass();
	$value->url = $menu_url;
	$value->context = $context;

	$CONFIG->menucontexts[] = $context;
	return add_to_register('menu', $menu_name, $value, $menu_children);
}

/**
 * Removes an item from the menu register
 *
 * @param string $menu_name The name of the menu item
 * @return true|false Depending on success
 */
function remove_menu($menu_name) {
	return remove_from_register('menu', $menu_name);
}

/**
 * Returns a menu item for use in the children section of add_menu()
 * This is not currently used in the Elgg core.
 *
 * @param string $menu_name The name of the menu item
 * @param string $menu_url Its URL
 * @return stdClass|false Depending on success
 * @todo Can be deprecated when the new menu system is introduced.
 */
function menu_item($menu_name, $menu_url) {
	elgg_deprecated_notice('menu_item() is deprecated by add_submenu_item', 1.7);
	return make_register_object($menu_name, $menu_url);
}

/**
 * Queues a message to be displayed.
 *
 * Messages will not be displayed immediately, but are stored in
 * for later display, usually upon next page load.
 *
 * The method of displaying these messages differs depending upon plugins and
 * viewtypes.  The core default viewtype retrieves messages in {@link views/default/page_shells/default.php}
 * and displays messages as javascript popups.
 *
 * @internal Messages are stored as strings in the $_SESSION['msg'][$register] array.
 *
 * @warning This function is used to both add to and clear the message
 * stack.  If $messages is null, $register will be returned and cleared.
 * If $messages is null and $register is empty, all messages will be
 * returned and removed.
 *
 * @important This function handles the standard {@link system_message()} ($register =
 * 'messages') as well as {@link register_error()} messages ($register = 'errors').
 *
 * @param string|array $message Optionally, a single message or array of messages to add, (default: null)
 * @param string $register This allows for different types of messages: "errors", "messages" (default: messages)
 * @param bool $count Count the number of messages (default: false)
 * @return true|false|array Either the array of messages, or a response regarding whether the message addition was successful
 * @todo Clean up. Separate registering messages and retrieving them.
 */
function system_messages($message = null, $register = "messages", $count = false) {
	if (!isset($_SESSION['msg'])) {
		$_SESSION['msg'] = array();
	}
	if (!isset($_SESSION['msg'][$register]) && !empty($register)) {
		$_SESSION['msg'][$register] = array();
	}
	if (!$count) {
		if (!empty($message) && is_array($message)) {
			$_SESSION['msg'][$register] = array_merge($_SESSION['msg'][$register], $message);
			return true;
		} else if (!empty($message) && is_string($message)) {
			$_SESSION['msg'][$register][] = $message;
			return true;
		} else if (is_null($message)) {
			if ($register != "") {
				$returnarray = array();
				$returnarray[$register] = $_SESSION['msg'][$register];
				$_SESSION['msg'][$register] = array();
			} else {
				$returnarray = $_SESSION['msg'];
				$_SESSION['msg'] = array();
			}
			return $returnarray;
		}
	} else {
		if (!empty($register)) {
			return sizeof($_SESSION['msg'][$register]);
		} else {
			$count = 0;
			foreach($_SESSION['msg'] as $register => $submessages) {
				$count += sizeof($submessages);
			}
			return $count;
		}
	}
	return false;
}

/**
 * Counts the number of messages, either globally or in a particular register
 *
 * @param string $register Optionally, the register
 * @return integer The number of messages
 */
function count_messages($register = "") {
	return system_messages(null, $register, true);
}

/**
 * Display a system message on next page load.
 *
 * @see system_messages()
 * @param string|array $message Message or messages to add
 * @return Bool
 */
function system_message($message) {
	return system_messages($message, "messages");
}

/**
 * Display an error on next page load.
 *
 * @see system_messages()
 * @param string|array $message Error or errors to add
 * @return true|false Success response
 */
function register_error($error) {
	return system_messages($error, "errors");
}

/**
 * Register a callback function as a handler or trigger registered handlers for an event.
 *
 * Elgg emits an event when certain core actions occur, like creating an entity.
 * Functions registered to these events can respond to the event, prevent the
 * event from completing, or ignore the event.
 *
 * Callback functions are registered with {@link register_elgg_event_handler()}
 *
 * When an event is triggered ({@link trigger_elgg_event()}, each callback function is
 * run in order of priority.  Any callback that returns false will halt execution
 * and control will be passed back to the caller.
 *
 * @internal Events are stored in $CONFIG->events as:
 * <code>
 * $CONFIG->events[$event][$type][$priority] = 'callback_function'
 * </code>
 *
 * @note You cannot generally alter the event, only halt it.
 * @tip Plugin authors should use {@link register_elgg_event_handler()} to register events.
 *
 * @param string $event The type of event (eg 'init', 'update', 'delete')
 * @param string $object_type The type of object (eg 'system', 'blog', 'user')
 * @param string $function The name of the function that will handle the event
 * @param int $priority A priority to add new event handlers at. Lower numbers will be called first (default 500)
 * @param boolean $call Set to true to call the event rather than add to it (default false)
 * @param mixed $object Optionally, the object the event is being performed on (eg a user)
 * @return true|false Depending on success
 *
 * @todo Separate registering and calling events. {@trac #2466}
 * @example events/basic.php Register and respond to an Elgg event
 * @example events/advanced.php Register for an Elgg event and optionally halt it.
 * @internal @example events/emit.php Basic emitting of an Elgg event.
 * @link http://docs.elgg.org/Tutorials/Core/Events
 */
function events($event = "", $object_type = "", $function = "", $priority = 500, $call = false, $object = null) {
	global $CONFIG;

	if (!isset($CONFIG->events)) {
		$CONFIG->events = array();
	} else if (!isset($CONFIG->events[$event]) && !empty($event)) {
		$CONFIG->events[$event] = array();
	} else if (!isset($CONFIG->events[$event][$object_type]) && !empty($event) && !empty($object_type)) {
		$CONFIG->events[$event][$object_type] = array();
	}

	if (!$call) {
		if (!empty($event) && !empty($object_type) && is_callable($function)) {
			$priority = (int) $priority;
			if ($priority < 0) {
				$priority = 0;
			}
			while (isset($CONFIG->events[$event][$object_type][$priority])) {
				$priority++;
			}
			$CONFIG->events[$event][$object_type][$priority] = $function;
			ksort($CONFIG->events[$event][$object_type]);
			return true;
		} else {
			return false;
		}
	} else {
		$return = true;
		if (!empty($CONFIG->events[$event][$object_type]) && is_array($CONFIG->events[$event][$object_type])) {
			foreach($CONFIG->events[$event][$object_type] as $eventfunction) {
				if ($eventfunction($event, $object_type, $object) === false) {
					return false;
				}
			}
		}

		if (!empty($CONFIG->events['all'][$object_type]) && is_array($CONFIG->events['all'][$object_type])) {
			foreach($CONFIG->events['all'][$object_type] as $eventfunction) {
				if ($eventfunction($event, $object_type, $object) === false) {
					return false;
				}
			}
		}

		if (!empty($CONFIG->events[$event]['all']) && is_array($CONFIG->events[$event]['all'])) {
			foreach($CONFIG->events[$event]['all'] as $eventfunction) {
				if ($eventfunction($event, $object_type, $object) === false) {
					return false;
				}
			}
		}

		if (!empty($CONFIG->events['all']['all']) && is_array($CONFIG->events['all']['all'])) {
			foreach($CONFIG->events['all']['all'] as $eventfunction) {
				if ($eventfunction($event, $object_type, $object) === false) {
					return false;
				}
			}
		}

		return $return;

	}

	return false;
}

/**
 * Register a callback function as an Elgg event handler.
 *
 * Events are emitted by Elgg when certain actions occur.  Plugins
 * can respond to these events or halt them completely by registering a handler
 * as a callback function to an event.  Multiple handlers can be registered for
 * the same event and will be executed in order of $priority.  Any handler
 * returning false will halt the execution chain.
 *
 * This function is called with the event name, event type, and handler function name.
 * Setting the optional $priority allows plugin authors to specify when the
 * function should be run.  Priorities for plugins should be 1-1000.
 *
 * The callback function is passed 3 arguments when called: $event, $type, and optional $params.
 *
 * $event is the name of event being emitted.
 * $type is the type of event or object concerned.
 * $params is an optional parameter passed that can include a related object.  See
 * specific event documentation for details on which events pass what parameteres.
 *
 * @tip If a priority isn't specified it is determined by the order the handler was
 * registered relative to the event and type.  For plugins, this generally means
 * the earlier the plugin is in the load order, the earlier the priorities are for
 * any event handlers.
 *
 * @tip $event and $object_type can use the special keyword 'all'.  Handler functions registered
 * with $event = all will be called for all events of type $object_type.  Similarly,
 * functions registered with $object_type = all will be called for all events of type
 * $event, regardless of $object_type.  If $event and $object_type both are 'all', the
 * handler function will be called for all events.
 *
 * @tip Event handler functions are considered in the follow order:
 *  - Specific registration where 'all' isn't used.
 *  - Registration where 'all' is used for $event only.
 *  - Registration where 'all' is used for $type only.
 *  - Registration where 'all' is used for both.
 *
 * @warning If you use the 'all' keyword, you must have logic in the handler function to
 * test the passed parameters before taking an action.
 *
 * @tip When referring to events, the preferred syntax is "event:type".
 *
 * @param string $event The event type
 * @param string $object_type The object type
 * @param string $function The handler callback function name
 * @param int $priority The priority of the event
 * @return bool
 * @link http://docs.elgg.org/Tutorials/Plugins/Events
 * @example events/basic.php Basic example of registering an event handler callback function.
 * @example events/advanced.php Advanced example of registering an event handler callback function and halting execution.
 * @example events/all.php Example of how to use the 'all' keyword.
 */
function register_elgg_event_handler($event, $object_type, $function, $priority = 500) {
	return events($event, $object_type, $function, $priority);
}

/**
 * Unregisters a callback function from an event.
 *
 * @param string $event The event type
 * @param string $object_type The object type
 * @param string $function The function name
 * @since 1.7.0
 */
function unregister_elgg_event_handler($event, $object_type, $function) {
	global $CONFIG;
	foreach($CONFIG->events[$event][$object_type] as $key => $event_function) {
		if ($event_function == $function) {
			unset($CONFIG->events[$event][$object_type][$key]);
		}
	}
}

/**
 * Trigger an Elgg Event and run all handler functions registered to that event:type.
 *
 * This function runs all handlers regsitered to $event:$object_type or
 * the special keyword 'all' for either or both.
 *
 * $event is usually a verb: create, update, delete, annotation.
 *
 * $object_type is usually a noun: object, group, user, annotation, relationship, metadata.
 *
 * $object is usually an Elgg* object assciated with the event.
 *
 * @warning Elgg events should only be called by core.  Plugin authors should use
 * {@link trigger_elgg_plugin_hook()} instead.
 *
 * @tip When referring to events, the preferred syntax is "event:type".
 *
 * @internal Only rarely should events be changed, added, or removed in core.
 * When making changes to events, be sure to first create a ticket in trac.
 *
 * @internal @tip Think of $object_type as the primary namespace element, and
 * $event as the secondary namespace.
 *
 * @param string $event The event type
 * @param string $object_type The object type
 * @param string $function The function name
 * @return bool The result of running all handler functions.
 * @link http://docs.elgg.org/Tutorials/Core/Events
 */
function trigger_elgg_event($event, $object_type, $object = null) {
	$return = true;
	$return1 = events($event, $object_type, "", null, true, $object);
	if (!is_null($return1)) {
		$return = $return1;
	}
	return $return;
}

/**
 * Register a callback function as a plugin hook handler.
 *
 * Plugin hooks allow developers to losely couple plugins and features by
 * repsonding to and emitting {@link trigger_plugin_hook()} customizable hooks.
 * Handler functions can respond to the hook, change the details of the hook, or ignore it.
 *
 * Multiple handlers can be registered for a plugin hook, and each callback
 * function is called in order of priority.  If the return value of a handler
 * function is not null, that value is passed to the next function in the
 * call stack.  When all functions have been run, the final value is passed
 * back to the caller via {@link trigger_plugin_hook()}.
 *
 * Similar to Elgg Events, plugin hook handler functions are registered by passing
 * a hook, a type, and a priority.
 *
 * The callback function is passed 4 arguments when called: $hook, $type
 * $value, and $params.
 *
 *  - str $hook The name of the hook.
 *  - str $type The type of hook.
 *  - mixed $value The return value of the last handler or the default
 *  value if no other handlers have been called.
 *  - mixed $params An optional array of parameters.  Used to provide additional information
 *  to plugins.
 *
 * @internal Plugin hooks are stored in $CONFIG->hooks as:
 * <code>
 * $CONFIG->hooks[$hook][$type][$priority] = 'callback_function'
 * </code>
 *
 * @tip Plugin hooks are similar to Elgg Events in that Elgg emits
 * a plugin hook when certain actions occur, but a plugin hook allows you to alter the
 * parameters, as well as halt execution.
 *
 * @tip If a priority isn't specified it is determined by the order the handler was
 * registered relative to the event and type.  For plugins, this generally means
 * the earlier the plugin is in the load order, the earlier the priorities are for
 * any event handlers.
 *
 * @tip Like Elgg Events, $hook and $type can use the special keyword 'all'.
 * Handler functions registered with $hook = all will be called for all hooks
 * of type $type.  Similarly, handlers registered with $type = all will be
 * called for all hooks of type $event, regardless of $object_type.  If $hook
 * and $type both are 'all', the handler will be called for all hooks.
 *
 * @tip Plugin hooks are sometimes used to gather lists from plugins.  This is
 * usually done by pushing elements into an array passed in $params.  Be sure
 * to append to and then return $value so you don't overwrite other plugin's
 * values.
 *
 * @warning Unlike Elgg Events, a handler that returns false will NOT halt the
 * execution chain.
 *
 * @param string $hook The name of the hook
 * @param string $type The type of the hook
 * @param string $function The name of a valid function to be run
 * @param string $priority The priority - 0 is first, 1000 last, default is 500
 * @return bool
 *
 * @example hooks/register/basic.php Registering for a plugin hook and examining the variables.
 * @example hooks/register/advanced.php Registering for a plugin hook and changing the params.
 * @link http://docs.elgg.org/Tutorials/Plugins/Hooks
 */
function register_plugin_hook($hook, $type, $function, $priority = 500) {
	global $CONFIG;

	if (!isset($CONFIG->hooks)) {
		$CONFIG->hooks = array();
	} else if (!isset($CONFIG->hooks[$hook]) && !empty($hook)) {
		$CONFIG->hooks[$hook] = array();
	} else if (!isset($CONFIG->hooks[$hook][$type]) && !empty($type)) {
		$CONFIG->hooks[$hook][$type] = array();
	}

	if (!empty($hook) && !empty($type) && is_callable($function)) {
		$priority = (int) $priority;
		if ($priority < 0) {
			$priority = 0;
		}
		while (isset($CONFIG->hooks[$hook][$type][$priority])) {
			$priority++;
		}
		$CONFIG->hooks[$hook][$type][$priority] = $function;
		ksort($CONFIG->hooks[$hook][$type]);
		return true;
	} else {
		return false;
	}
}

/**
 * Unregister a callback function as a plugin hook.
 *
 * @param string $hook The name of the hook
 * @param string $entity_type The name of the type of entity (eg "user", "object" etc)
 * @param string $function The name of a valid function to be run
 * @since 1.7.0
 */
function unregister_plugin_hook($hook, $entity_type, $function) {
	global $CONFIG;
	foreach($CONFIG->hooks[$hook][$entity_type] as $key => $hook_function) {
		if ($hook_function == $function) {
			unset($CONFIG->hooks[$hook][$entity_type][$key]);
		}
	}
}

/**
 * Trigger a Plugin Hook and run all handler functions registered to that hook:type.
 *
 * This function runs all handlers regsitered to $hook:$type or
 * the special keyword 'all' for either or both.
 *
 * Use $params to send additional information to the handler functions.
 *
 * $returnvalue Is the initial value to pass to the handlers, which can
 * then change it.  It is useful to use $returnvalue to set defaults.
 * If no handlers are registered, $returnvalue is immediately returned.
 *
 * $hook is usually a verb: import, get_views, output.
 *
 * $type is usually a noun: user, ecml, page.
 *
 * @tip Like Elgg Events, $hook and $type can use the special keyword 'all'.
 * Handler functions registered with $hook = all will be called for all hooks
 * of type $type.  Similarly, handlers registered with $type = all will be
 * called for all hooks of type $event, regardless of $object_type.  If $hook
 * and $type both are 'all', the handler will be called for all hooks.
 *
 * @see register_plugin_hook()
 * @param string $hook The name of the hook to trigger (NB: "all" will trigger for all $types regardless of $hook value)
 * @param string $type The type of the hook to trigger (NB: "all" will trigger for all $hooks regardless of $type value)
 * @param mixed $params Additional parameters to pass to the handlers
 * @param mixed $returnvalue An initial return value
 * @return mixed|null The return value of the last handler function called
 *
 * @example hooks/trigger/basic.php Trigger a hook that determins if execution should continue.
 * @example hooks/trigger/advanced.php Trigger a hook with a default value and use the results to populate a menu.
 * @example hooks/basic.php Trigger and respond to a basic plugin hook.
 * @link http://docs.elgg.org/Tutorials/Plugins/Hooks
 */
function trigger_plugin_hook($hook, $type, $params = null, $returnvalue = null) {
	global $CONFIG;

	if (!empty($CONFIG->hooks[$hook][$type]) && is_array($CONFIG->hooks[$hook][$type])) {
		foreach($CONFIG->hooks[$hook][$type] as $hookfunction) {
			$temp_return_value = $hookfunction($hook, $type, $returnvalue, $params);
			if (!is_null($temp_return_value)) {
				$returnvalue = $temp_return_value;
			}
		}
	}

	if (!empty($CONFIG->hooks['all'][$type]) && is_array($CONFIG->hooks['all'][$type])) {
		foreach($CONFIG->hooks['all'][$type] as $hookfunction) {
			$temp_return_value = $hookfunction($hook, $type, $returnvalue, $params);
			if (!is_null($temp_return_value)) {
				$returnvalue = $temp_return_value;
			}
		}
	}

	if (!empty($CONFIG->hooks[$hook]['all']) && is_array($CONFIG->hooks[$hook]['all'])) {
		foreach($CONFIG->hooks[$hook]['all'] as $hookfunction) {
			$temp_return_value = $hookfunction($hook, $type, $returnvalue, $params);
			if (!is_null($temp_return_value)) {
				$returnvalue = $temp_return_value;
			}
		}
	}

	if (!empty($CONFIG->hooks['all']['all']) && is_array($CONFIG->hooks['all']['all'])) {
		foreach($CONFIG->hooks['all']['all'] as $hookfunction) {
			$temp_return_value = $hookfunction($hook, $type, $returnvalue, $params);
			if (!is_null($temp_return_value)) {
				$returnvalue = $temp_return_value;
			}
		}
	}

	return $returnvalue;
}

/**
 * Intercepts catchable PHP errors.
 *
 * @warning This function should never be called directly.
 *
 * @internal
 * For catchable fatal errors, throws an Exception with the error.
 *
 * For non-fatal errors, depending upon the debug settings, either
 * log the error or ignore it.
 *
 * @see http://www.php.net/set-error-handler
 * @param int $errno The level of the error raised
 * @param string $errmsg The error message
 * @param string $filename The filename the error was raised in
 * @param int $linenum The line number the error was raised at
 * @param array $vars An array that points to the active symbol table at the point that the error occurred
 */
function __elgg_php_error_handler($errno, $errmsg, $filename, $linenum, $vars) {
	$error = date("Y-m-d H:i:s (T)") . ": \"$errmsg\" in file $filename (line $linenum)";

	switch ($errno) {
		case E_USER_ERROR:
			error_log("PHP ERROR: $error");
			register_error("ERROR: $error");

			// Since this is a fatal error, we want to stop any further execution but do so gracefully.
			throw new Exception($error);
			break;

		case E_WARNING :
		case E_USER_WARNING :
			error_log("PHP WARNING: $error");
			break;

		default:
			global $CONFIG;
			if (isset($CONFIG->debug) && $CONFIG->debug === 'NOTICE') {
				error_log("PHP NOTICE: $error");
			}
	}

	return true;
}

/**
 * Display or log a message.
 *
 * If $level is >= to the debug setting in {@link $CONFIG->debug}, the
 * message will be sent to {@link elgg_dump()}.  Messages with lower
 * priority than {@link $CONFIG->debug} are ignored.
 *
 * {@link elgg_dump()} outputs all levels but NOTICE to screen by default.
 *
 * @note No messages will be displayed unless debugging has been enabled.
 *
 * @param str $message User message
 * @param str $level NOTICE | WARNING | ERROR | DEBUG
 * @return bool
 * @since 1.7.0
 * @todo This is complicated and confusing.  Using int constants for debug levels will make things easier.
 */
function elgg_log($message, $level='NOTICE') {
	global $CONFIG;

	// only log when debugging is enabled
	if (isset($CONFIG->debug)) {
		// debug to screen or log?
		$to_screen = !($CONFIG->debug == 'NOTICE');

		switch ($level) {
			case 'ERROR':
				// always report
				elgg_dump("$level: $message", $to_screen, $level);
				break;
			case 'WARNING':
			case 'DEBUG':
				// report except if user wants only errors
				if ($CONFIG->debug != 'ERROR') {
					elgg_dump("$level: $message", $to_screen, $level);
				}
				break;
			case 'NOTICE':
			default:
				// only report when lowest level is desired
				if ($CONFIG->debug == 'NOTICE') {
					elgg_dump("$level: $message", FALSE, $level);
				}
				break;
		}

		return TRUE;
	}

	return FALSE;
}

/**
 * Logs or displays $value.
 *
 * If $to_screen is true, $value is displayed to screen.  Else,
 * it is handled by PHP's {@link error_log()} function.
 *
 * A {@elgg_plugin_hook debug:log} is called.  If a handler returns
 * false, it will stop the default logging method.
 *
 * @param mixed $value
 * @param bool $to_screen
 * @param string $level
 * @return void
 * @since 1.7.0
 */
function elgg_dump($value, $to_screen = TRUE, $level = 'NOTICE') {
	global $CONFIG;

	// plugin can return false to stop the default logging method
	$params = array('level' => $level,
					'msg' => $value,
					'to_screen' => $to_screen);
	if (!trigger_plugin_hook('debug', 'log', $params, true)) {
		return;
	}

	// Do not want to write to screen before page creation has started.
	// This is not fool-proof but probably fixes 95% of the cases when logging
	// results in data sent to the browser before the page is begun.
	if (!isset($CONFIG->pagesetupdone)) {
		$to_screen = FALSE;
	}

	if ($to_screen == TRUE) {
		echo '<pre>';
		print_r($value);
		echo '</pre>';
	} else {
		error_log(print_r($value, TRUE));
	}
}

/**
 * Intercepts, logs, and display uncaught exceptions.
 *
 * @warning This function should never be called directly.
 *
 * @see http://www.php.net/set-exception-handler
 * @param Exception $exception The exception being handled
 */
function __elgg_php_exception_handler($exception) {
	error_log("*** FATAL EXCEPTION *** : " . $exception);

	// Wipe any existing output buffer
	ob_end_clean();

	// make sure the error isn't cached
	header("Cache-Control: no-cache, must-revalidate", true);
	header('Expires: Fri, 05 Feb 1982 00:00:00 -0500', true);
	// @todo Why don't we send a 500 header?
	//header("Internal Server Error", true, 500);

	$body = elgg_view("messages/exceptions/exception", array('object' => $exception));
	page_draw(elgg_echo('exception:title'), $body);
}

/**
 * An array of key value pairs from the datalists table.
 *
 * Used as a cache in datalist functions.
 *
 * @global array $DATALIST_CACHE
 */
$DATALIST_CACHE = array();

/**
 * Get the value of a datalist element.
 *
 * @internal Datalists are stored in the datalist table.
 *
 * @tip Use datalists to store information common to a full installation.
 *
 * @param string $name The name of the datalist element
 * @return string|false The datalist value or false if it doesn't exist.
 */
function datalist_get($name) {
	global $CONFIG, $DATALIST_CACHE;

	// We need this, because sometimes datalists are attempted
	// to be retrieved before the database is created
	if (!is_db_installed()) {
		return false;
	}

	$name = sanitise_string($name);
	if (isset($DATALIST_CACHE[$name])) {
		return $DATALIST_CACHE[$name];
	}

	// If memcache enabled then cache value in memcache
	$value = null;
	static $datalist_memcache;
	if ((!$datalist_memcache) && (is_memcache_available())) {
		$datalist_memcache = new ElggMemcache('datalist_memcache');
	}
	if ($datalist_memcache) {
		$value = $datalist_memcache->load($name);
	}
	if ($value) {
		return $value;
	}

	// [Marcus Povey 20090217 : Now retrieving all datalist values on first load as this saves about 9 queries per page]
	$result = get_data("SELECT * from {$CONFIG->dbprefix}datalists");
	if ($result) {
		foreach ($result as $row) {
			$DATALIST_CACHE[$row->name] = $row->value;

			// Cache it if memcache is available
			if ($datalist_memcache) {
				$datalist_memcache->save($row->name, $row->value);
			}
		}

		if (isset($DATALIST_CACHE[$name])) {
			return $DATALIST_CACHE[$name];
		}
	}

	return false;
}

/**
 * Set the value for a datalist element.
 *
 * @param string $name The name of the datalist
 * @param string $value The new value
 * @return true
 */
function datalist_set($name, $value) {
	global $CONFIG, $DATALIST_CACHE;

	$name = sanitise_string($name);
	$value = sanitise_string($value);

	// If memcache is available then invalidate the cached copy
	static $datalist_memcache;
	if ((!$datalist_memcache) && (is_memcache_available())) {
		$datalist_memcache = new ElggMemcache('datalist_memcache');
	}

	if ($datalist_memcache) {
		$datalist_memcache->delete($name);
	}

	insert_data("INSERT into {$CONFIG->dbprefix}datalists set name = '{$name}', value = '{$value}' ON DUPLICATE KEY UPDATE value='{$value}'");

	$DATALIST_CACHE[$name] = $value;

	return true;
}

/**
 * Run a function one time per installation.
 *
 * If you pass a timestamp as the second argument, it will run the function
 * only if (i) it has never been run before or (ii) the timestamp is >=
 * the last time it was run.
 *
 * @warning Functions are determined by their name.  If you change the name of a function
 * it will be run again.
 *
 * @tip Use $timelastupdatedcheck in your plugins init function to perform automated
 * upgrades.  Schedule a function to run once and pass the timestamp of the new release.
 * This will cause the run once function to be run on all installations.  To perform
 * additional upgrades, create new functions for each release.
 *
 * @internal A datalist entry $functioname is created with the value of time().
 *
 * @param string $functionname The name of the function you want to run.
 * @param int $timelastupdatedcheck A UNIX timestamp. If time() is > than this, this function will be run again.
 * @return bool
 */
function run_function_once($functionname, $timelastupdatedcheck = 0) {
	if ($lastupdated = datalist_get($functionname)) {
		$lastupdated = (int) $lastupdated;
	} else {
		$lastupdated = 0;
	}
	if (is_callable($functionname) && $lastupdated <= $timelastupdatedcheck) {
		$functionname();
		datalist_set($functionname, time());
		return true;
	} else {
		return false;
	}
}

/**
 * Sends a notice about deprecated use of a function, view, etc.
 *
 * This function either displays or logs the deprecation message,
 * depending upon the deprecation policies in {@link CODING.txt}.
 * Logged messages are sent with the level of 'WARNING'.
 *
 * A user-visual message will be displayed if $dep_version is greater
 * than 1 minor releases lower than the current Elgg version, or at all
 * lower than the current Elgg major version.
 *
 * @note This will always at least log a warning.  Don't use to pre-deprecate things.
 * This assumes we are releasing in order and deprecating according to policy.
 *
 * @see CODING.txt
 * @param str $msg Message to log / display.
 * @param str $version human-readable *release* version: 1.7, 1.7.3
 * @return bool
 * @since 1.7.0
 */
function elgg_deprecated_notice($msg, $dep_version) {
	// if it's a major release behind, visual and logged
	// if it's a 2 minor releases behind, visual and logged
	// if it's 1 minor release behind, logged.
	// bugfixes don't matter because you're not deprecating between them, RIGHT?
	if (!$dep_version) {
		return FALSE;
	}

	$elgg_version = get_version(TRUE);
	$elgg_version_arr = explode('.', $elgg_version);
	$elgg_major_version = $elgg_version_arr[0];
	$elgg_minor_version = $elgg_version_arr[1];

	$dep_version_arr = explode('.', $dep_version);
	$dep_major_version = $dep_version_arr[0];
	$dep_minor_version = $dep_version_arr[1];

	$last_working_version = $dep_minor_version - 1;

	$visual = FALSE;

	// use version_compare to account for 1.7a < 1.7
	if (($dep_major_version < $elgg_major_version)
	|| (($elgg_minor_version - $last_working_version) > 1)) {
		$visual = TRUE;
	}

	$msg = "Deprecated in $dep_version: $msg";

	if ($visual) {
		register_error($msg);
	}

	// Get a file and line number for the log. Never show this in the UI.
	// Skip over the function that sent this notice and see who called the deprecated
	// function itself.
	$backtrace = debug_backtrace();
	$caller = $backtrace[1];
	$msg .= " (Called from {$caller['file']}:{$caller['line']})";

	elgg_log($msg, 'WARNING');

	return TRUE;
}


/**
 * Checks if code is being called from a certain function.
 *
 * To use, call this function with the function name (and optional file location) that it has to be called
 * from, it will either return true or false.
 *
 * e.g.
 *
 * function my_secure_function()
 * {
 * 		if (!call_gatekeeper("my_call_function"))
 * 			return false;
 *
 * 		... do secure stuff ...
 * }
 *
 * function my_call_function()
 * {
 * 		// will work
 * 		my_secure_function();
 * }
 *
 * function bad_function()
 * {
 * 		// Will not work
 * 		my_secure_function();
 * }
 *
 * @param mixed $function The function that this function must have in its call stack,
 * 		to test against a method pass an array containing a class and method name.
 * @param string $file Optional file that the function must reside in.
 * @todo This is neat but is it necessary?
 */
function call_gatekeeper($function, $file = "") {
	// Sanity check
	if (!$function) {
		return false;
	}

	// Check against call stack to see if this is being called from the correct location
	$callstack = debug_backtrace();
	$stack_element = false;

	foreach ($callstack as $call) {
		if (is_array($function)) {
			if (
				(strcmp($call['class'], $function[0]) == 0) &&
				(strcmp($call['function'], $function[1]) == 0)
			) {
				$stack_element = $call;
			}
		} else {
			if (strcmp($call['function'], $function) == 0) {
				$stack_element = $call;
			}
		}
	}

	if (!$stack_element) {
		return false;
	}

	// If file then check that this it is being called from this function
	if ($file) {
		$mirror = null;

		if (is_array($function)) {
			$mirror = new ReflectionMethod($function[0], $function[1]);
		} else {
			$mirror = new ReflectionFunction($function);
		}

		if ((!$mirror) || (strcmp($file,$mirror->getFileName())!=0)) {
			return false;
		}
	}

	return true;
}

/**
 * This function checks to see if it is being called at somepoint by a function defined somewhere
 * on a given path (optionally including subdirectories).
 *
 * This function is similar to call_gatekeeper() but returns true if it is being called by a method or function which has been defined on a given path or by a specified file.
 *
 * @param string $path The full path and filename that this function must have in its call stack If a partial path is given and $include_subdirs is true, then the function will return true if called by any function in or below the specified path.
 * @param bool $include_subdirs Are subdirectories of the path ok, or must you specify an absolute path and filename.
 * @param bool $strict_mode If true then the calling method or function must be directly called by something on $path, if false the whole call stack is searched.
 * @todo Again, very neat, but is it necessary?
 */
function callpath_gatekeeper($path, $include_subdirs = true, $strict_mode = false) {
	global $CONFIG;

	$path = sanitise_string($path);

	if ($path) {
		$callstack = debug_backtrace();

		foreach ($callstack as $call) {
			$call['file'] = str_replace("\\","/",$call['file']);

			if ($include_subdirs) {
				if (strpos($call['file'], $path) === 0) {

					if ($strict_mode) {
						$callstack[1]['file'] = str_replace("\\","/",$callstack[1]['file']);
						if ($callstack[1] === $call) { return true; }
					} else {
						return true;
					}
				}
			} else {
				if (strcmp($path, $call['file'])==0) {
					if ($strict_mode) {
						if ($callstack[1] === $call) {
							return true;
						}
					} else {
						return true;
					}
				}
			}

		}
		return false;
	}

	if (isset($CONFIG->debug)) {
		system_message("Gatekeeper'd function called from {$callstack[1]['file']}:{$callstack[1]['line']}\n\nStack trace:\n\n" . print_r($callstack, true));
	}

	return false;
}

/**
 * Return the state of a php.ini setting.
 *
 * Normalizes the setting to bool.
 *
 * @param string $ini_get_arg The INI setting
 * @return true|false Depending on whether it's on or off
 */
function ini_get_bool($ini_get_arg) {
	$temp = ini_get($ini_get_arg);

	if ($temp == '1' or strtolower($temp) == 'on') {
		return true;
	}
	return false;
}

/**
 * Returns true is string is not empty, false, or null.
 *
 * Function to be used in array_filter which returns true if $string is not null.
 *
 * @param string $string
 * @return bool
 * @todo This is used once in metadata.php.  Use a lambda function instead.
 */
function is_not_null($string) {
	if (($string==='') || ($string===false) || ($string===null)) {
		return false;
	}

	return true;
}


/**
 * Normalise the singular keys in an options array to plural keys.
 *
 * Used in elgg_get_entities*() functions to support shortcutting plural
 * names by singular names.
 *
 * @param array $options The options array. $options['keys'] = 'values';
 * @param array $singulars A list of sinular words to pluralize by adding 's'.
 * @return array
 * @since 1.7.0
 */
function elgg_normalise_plural_options_array($options, $singulars) {
	foreach ($singulars as $singular) {
		$plural = $singular . 's';

		if (array_key_exists($singular, $options)) {
			if ($options[$singular] === ELGG_ENTITIES_ANY_VALUE) {
				$options[$plural] = $options[$singular];
			} else {
				$options[$plural] = array($options[$singular]);
			}
		}

		unset($options[$singular]);
	}

	return $options;
}

/**
 * Return the full URL of the current page.
 *
 * @return string The URL
 * @todo Combine / replace with current_page_url()
 */
function full_url() {
	$s = empty($_SERVER["HTTPS"]) ? '' : ($_SERVER["HTTPS"] == "on") ? "s" : "";
	$protocol = substr(strtolower($_SERVER["SERVER_PROTOCOL"]), 0, strpos(strtolower($_SERVER["SERVER_PROTOCOL"]), "/")) . $s;
	$port = ($_SERVER["SERVER_PORT"] == "80" || $_SERVER["SERVER_PORT"] == "443") ? "" : (":".$_SERVER["SERVER_PORT"]);

	// This is here to prevent XSS in poorly written browsers used by 80% of the population.
	// {@trac [5813]}
	$quotes = array('\'', '"');
	$encoded = array('%27', '%22');

	return $protocol . "://" . $_SERVER['SERVER_NAME'] . $port . str_replace($quotes, $encoded, $_SERVER['REQUEST_URI']);
}

/**
 * Useful function found in the comments on the PHP man page for ip2long.
 * Returns 1 if an IP matches a given range.
 *
 * @todo Check licence... assuming this is PD since it was found several places on the interwebs..
 * please check or rewrite.
 *
 * Matches:
 *  xxx.xxx.xxx.xxx        (exact)
 *  xxx.xxx.xxx.[yyy-zzz]  (range)
 *  xxx.xxx.xxx.xxx/nn    (nn = # bits, cisco style -- i.e. /24 = class C)
 * Does not match:
 * xxx.xxx.xxx.xx[yyy-zzz]  (range, partial octets not supported)
 *
 * @todo not used at all.
 */
function test_ip($range, $ip) {
	$result = 1;

	# IP Pattern Matcher
	# J.Adams <jna@retina.net>
	#
	# Matches:
	#
	# xxx.xxx.xxx.xxx        (exact)
	# xxx.xxx.xxx.[yyy-zzz]  (range)
	# xxx.xxx.xxx.xxx/nn    (nn = # bits, cisco style -- i.e. /24 = class C)
	#
	# Does not match:
	# xxx.xxx.xxx.xx[yyy-zzz]  (range, partial octets not supported)

	if (ereg("([0-9]+)\.([0-9]+)\.([0-9]+)\.([0-9]+)/([0-9]+)",$range,$regs)) {
		# perform a mask match
		$ipl = ip2long($ip);
		$rangel = ip2long($regs[1] . "." . $regs[2] . "." . $regs[3] . "." . $regs[4]);

		$maskl = 0;

		for ($i = 0; $i< 31; $i++) {
			if ($i < $regs[5]-1) {
				$maskl = $maskl + pow(2,(30-$i));
			}
		}

		if (($maskl & $rangel) == ($maskl & $ipl)) {
			return 1;
		} else {
			return 0;
		}
	} else {
		# range based
		$maskocts = split("\.",$range);
		$ipocts = split("\.",$ip);

		# perform a range match
		for ($i=0; $i<4; $i++) {
			if (ereg("\[([0-9]+)\-([0-9]+)\]",$maskocts[$i],$regs)) {
				if ( ($ipocts[$i] > $regs[2]) || ($ipocts[$i] < $regs[1])) {
					$result = 0;
				}
			} else {
				if ($maskocts[$i] <> $ipocts[$i]) {
					$result = 0;
				}
			}
		}
	}

	return $result;
}

/**
 * Match an IP address against a number of ip addresses or ranges, returning true if found.
 *
 * @param array $networks
 * @param string $ip
 * @return bool
 * @todo not used at all in core.
 */
function is_ip_in_array(array $networks, $ip) {
	foreach ($networks as $network) {
		if (test_ip(trim($network), $ip)) {
			return true;
		}
	}

	return false;
}

require_once dirname(dirname(__FILE__)).'/classes/Friendable.php';

/**
 * Builds a URL from the a parts array like one returned by {@link parse_url()}.
 *
 * @note If only partial information is passed, a partial URL will be returned.
 *
 * @param array $parts Associative array of URL components like parse_url() returns
 * @param bool $htmlencode HTML Encode the url?
 * @return str Full URL
 * @since 1.7.0
 */
function elgg_http_build_url(array $parts, $html_encode = TRUE) {
	// build only what's given to us.
	$scheme = isset($parts['scheme']) ? "{$parts['scheme']}://" : '';
	$host = isset($parts['host']) ? "{$parts['host']}" : '';
	$port = isset($parts['port']) ? ":{$parts['port']}" : '';
	$path = isset($parts['path']) ? "{$parts['path']}" : '';
	$query = isset($parts['query']) ? "?{$parts['query']}" : '';

	$string = $scheme . $host . $port . $path . $query;

	if ($html_encode) {
		return elgg_format_url($string);
	} else {
		return $string;
	}
}

/**
 * Adds action tokens to URL
 *
 * As of 1.7.0 action tokens are required on all actions.
 * Use this function to append action tokens to a URL's GET parameters.
 * This will preserve any existing GET parameters.
 *
 * @note If you are using {@elgg_view input/form} you don't need to
 * add tokens to the action.  The form view automatically handles
 * tokens.
 *
 * @param str $link Full action URL
 * @param bool $htmlencode html encode the url?
 * @return str URL with action tokens
 * @since 1.7.0
 * @link http://docs.elgg.org/Tutorials/Actions
 */
function elgg_add_action_tokens_to_url($url, $html_encode = TRUE) {
	$components = parse_url($url);

	if (isset($components['query'])) {
		$query = elgg_parse_str($components['query']);
	} else {
		$query = array();
	}

	if (isset($query['__elgg_ts']) && isset($query['__elgg_token'])) {
		return $url;
	}

	// append action tokens to the existing query
	$query['__elgg_ts'] = time();
	$query['__elgg_token'] = generate_action_token($query['__elgg_ts']);
	$components['query'] = http_build_query($query);

	// rebuild the full url
	return elgg_http_build_url($components, $html_encode);
}


/**
 * Add action tokens to URL.
 *
 * @deprecated 1.7 final
 */
function elgg_validate_action_url($url) {
	elgg_deprecated_notice('elgg_validate_action_url had a short life. Use elgg_add_action_tokens_to_url() instead.', '1.7b');

	return elgg_add_action_tokens_to_url($url);
}


/**
 * Removes an element from a URL's query string.
 *
 * @note You can send a partial URL string.
 *
 * @param string $url
 * @param string $element
 * @return string The new URL with the query element removed.
 * @since 1.7.0
 */
function elgg_http_remove_url_query_element($url, $element) {
	$url_array = parse_url($url);

	if (isset($url_array['query'])) {
		$query = elgg_parse_str($url_array['query']);
	} else {
		// nothing to remove. Return original URL.
		return $url;
	}

	if (array_key_exists($element, $query)) {
		unset($query[$element]);
	}

	$url_array['query'] = http_build_query($query);
	$string = elgg_http_build_url($url_array);
	return $string;
}

/**
 * Adds an element or elements to a URL's query string.
 *
 * @param str $url The URL
 * @param array $elements key/value pairs to add to the URL
 * @return str The new URL with the query strings added
 * @since 1.7.0
 */
function elgg_http_add_url_query_elements($url, array $elements) {
	$url_array = parse_url($url);

	if (isset($url_array['query'])) {
		$query = elgg_parse_str($url_array['query']);
	} else {
		$query = array();
	}

	foreach ($elements as $k => $v) {
		$query[$k] = $v;
	}

	$url_array['query'] = http_build_query($query);
	$string = elgg_http_build_url($url_array);

	return $string;
}

/**
 * Adds a breadcrumb to the breadcrumbs stack.
 *
 * @param string $title The title to display
 * @param string $link Optional. The link for the title.
 * @link http://docs.elgg.org/Tutorials/UI/Breadcrumbs
 */
function elgg_push_breadcrumb($title, $link = NULL) {
	global $CONFIG;
	if (!is_array($CONFIG->breadcrumbs)) {
		$CONFIG->breadcrumbs = array();
	}

	// avoid key collisions.
	$CONFIG->breadcrumbs[] = array('title' => $title, 'link' => $link);
}

/**
 * Removes last breadcrumb entry.
 *
 * @return array popped item.
 * @link http://docs.elgg.org/Tutorials/UI/Breadcrumbs
 */
function elgg_pop_breadcrumb() {
	global $CONFIG;

	if (is_array($CONFIG->breadcrumbs)) {
		array_pop($CONFIG->breadcrumbs);
	}

	return FALSE;
}

/**
 * Returns all breadcrumbs as an array of array('title' => 'Readable Title', 'link' => 'URL')
 *
 * @return array Breadcrumbs
 * @link http://docs.elgg.org/Tutorials/UI/Breadcrumbs
 */
function elgg_get_breadcrumbs() {
	global $CONFIG;

	return (is_array($CONFIG->breadcrumbs)) ? $CONFIG->breadcrumbs : array();
}

/**
 * Load all the REQUEST variables into the sticky form cache
 *
 * Call this from an action when you want all your submitted variables
 * available if the submission fails validation and is sent back to the form
 *
 * @link http://docs.elgg.org/Tutorials/UI/StickyForms
 */
function elgg_make_sticky_form($form_name) {
	global $CONFIG;

	$CONFIG->active_sticky_form = $form_name;
	elgg_clear_sticky_form($form_name);

	if (!isset($_SESSION['sticky_forms'])) {
		$_SESSION['sticky_forms'] = array();
	}
	$_SESSION['sticky_forms'][$form_name] = array();

	foreach($_REQUEST as $key => $var) {
		// will go through XSS filtering on the get function
		$_SESSION['sticky_forms'][$form_name][$key] = $var;
	}
}

/**
 * Clear the sticky form cache
 *
 * Call this if validation is successful in the action handler or
 * when they sticky values have been used to repopulate the form
 * after a validation error.
 *
 * @param string $name Form namespace
 * @link http://docs.elgg.org/Tutorials/UI/StickyForms
 */
function elgg_clear_sticky_form($form_name) {
	unset($_SESSION['sticky_forms'][$form_name]);
}

/**
 * Has this form been made sticky?
 *
 * @param string $name Form namespace
 * @return boolean
 * @link http://docs.elgg.org/Tutorials/UI/StickyForms
 */
function elgg_is_sticky_form($form_name) {
	return isset($_SESSION['sticky_forms'][$form_name]);
}

/**
 * Get a specific sticky variable
 *
 * @param string $variable The name of the variable
 * @param mixed $default Default value if the variable does not exist in sticky cache
 * @param boolean $filter_result Filter for bad input if true
 * @return mixed
 *
 * @todo should this filter the default value?
 * @link http://docs.elgg.org/Tutorials/UI/StickyForms
 */
function elgg_get_sticky_value($form_name, $variable, $default = NULL, $filter_result = true) {
	if (isset($_SESSION['sticky_forms'][$form_name][$variable])) {
		$value = $_SESSION['sticky_forms'][$form_name][$variable];
		if ($filter_result) {
			// XSS filter result
			$value = filter_tags($value);
		}
		return $value;
	}
	return $default;
}

/**
 * Clear a specific sticky variable
 *
 * @param string $variable The name of the variable to clear
 * @link http://docs.elgg.org/Tutorials/UI/StickyForms
 */
function elgg_clear_sticky_value($form_name, $variable) {
	unset($_SESSION['sticky_forms'][$form_name][$variable]);
}

/**
 * Returns the current active sticky form.
 * @return mixed Str | FALSE
 * @link http://docs.elgg.org/Tutorials/UI/StickyForms
 */
function elgg_get_active_sticky_form() {
	global $CONFIG;

	if (isset($CONFIG->active_sticky_form)) {
		$form_name = $CONFIG->active_sticky_form;
	} else {
		return FALSE;
	}

	return (elgg_is_sticky_form($form_name)) ? $form_name : FALSE;
}

/**
 * Sets the active sticky form.
 *
 * @param string $form_name
 * @link http://docs.elgg.org/Tutorials/UI/StickyForms
 */
function elgg_set_active_sticky_form($form_name) {
	global $CONFIG;

	$CONFIG->active_sticky_form = $form_name;
}

/**
 * Returns a PHP INI setting in bytes.
 *
 * @tip Use this for arithmetic when determining if a file can be uploaded.
 *
 * @param str $setting
 * @return int
 * @since 1.7.0
 * @link http://www.php.net/manual/en/function.ini-get.php
 */
function elgg_get_ini_setting_in_bytes($setting) {
	// retrieve INI setting
	$val = ini_get($setting);

	// convert INI setting when shorthand notation is used
	$last = strtolower($val[strlen($val)-1]);
	switch($last) {
		case 'g':
			$val *= 1024;
		case 'm':
			$val *= 1024;
		case 'k':
			$val *= 1024;
	}

	// return byte value
	return $val;
}

/**
 * Serve javascript pages.
 *
 * Searches for views under js/ and outputs them with special
 * headers for caching control.
 *
 * @param $page
 * @return unknown_type
 * @elgg_pagehandler js
 */
function js_page_handler($page) {
	if (is_array($page) && sizeof($page)) {
		$js = str_replace('.js','',$page[0]);
		$return = elgg_view('js/' . $js);

		header('Content-type: text/javascript');
		header('Expires: ' . date('r',time() + 864000));
		header("Pragma: public");
		header("Cache-Control: public");
		header("Content-Length: " . strlen($return));

		echo $return;
		exit;
	}
}

/**
 * Emits a shutdown:system event upon PHP shutdown, but before database connections are dropped.
 *
 * @tip Register for the shutdown:system event to perform functions at the end of page loads.
 *
 * @warning Using this event to perform long-running functions is not very useful.  Servers will hold pages until processing is done
 * before sending them out to the browser.
 *
 * @see register_shutdown_hook()
 */
function __elgg_shutdown_hook() {
	global $START_MICROTIME;

	trigger_elgg_event('shutdown', 'system');

	$time = (float)(microtime(TRUE) - $START_MICROTIME);
	// demoted to NOTICE from DEBUG so javascript is not corrupted
	elgg_log("Page {$_SERVER['REQUEST_URI']} generated in $time seconds", 'NOTICE');
}

/**
 * Elgg's main init.
 *
 * Handles core actions for comments and likes, the JS pagehandler, and the shutdown function.
 *
 * @elgg_event_handler init system
 */
function elgg_init() {
	global $CONFIG;

	register_action('comments/add');
	register_action('comments/delete');
	register_action('likes/add');
	register_action('likes/delete');

	register_page_handler('js', 'js_page_handler');

	// Trigger the shutdown:system event upon PHP shutdown.
	register_shutdown_function('__elgg_shutdown_hook');
}

/**
 * Intercepts the index page when Walled Garden mode is enabled.
 *
 * @link http://docs.elgg.org/Tutorials/WalledGarden
 * @elgg_plugin_hook index system
 */
function elgg_walled_garden_index() {
	$login = elgg_view('account/forms/login_walled_garden');

	page_draw('', $login, 'page_shells/walled_garden');

	// @hack Index must exit to keep plugins from continuing to extend
	exit;
}

/**
 * Adds unit tests for the general API.
 *
 * @elgg_plugin_hook unit_tests system
 */
function elgg_api_test($hook, $type, $value, $params) {
	global $CONFIG;
	$value[] = $CONFIG->path . 'engine/tests/api/entity_getter_functions.php';
	$value[] = $CONFIG->path . 'engine/tests/api/helpers.php';
	$value[] = $CONFIG->path . 'engine/tests/regression/trac_bugs.php';
	return $value;
}

/**
 * Returns the main site menu.
 *
 * @note The main site menu is split into "featured" links and
 * "more" links.
 *
 * @return array ('featured_urls' and 'more')
 * @since 1.8
 * @link http://docs.elgg.org/Tutorials/UI/SiteMenu
 */
function elgg_get_nav_items() {
	$menu_items = get_register('menu');
	$featured_urls_info = get_config('menu_items_featured_urls');

	$more = array();
	$featured_urls = array();
	$featured_urls_sanitised = array();

	// easier to compare with in_array() than embedded foreach()es
	$valid_urls = array();
	foreach ($menu_items as $info) {
		$valid_urls[] = $info->value->url;
	}

	// make sure the url is a valid link.
	// this prevents disabled plugins leaving behind
	// valid links when not using a pagehandler.
	foreach ($featured_urls_info as $info) {
		if (in_array($info->value->url, $valid_urls)) {
			$featured_urls[] = $info->value->url;
			$featured_urls_sanitised[] = $info;
		}
	}

	// add toolbar entries if not hiding dupes.
	foreach ($menu_items as $name => $info) {
		if (!in_array($info->value->url, $featured_urls)) {
			$more[] = $info;
		}
	}

	return array(
		'featured' => $featured_urls_sanitised,
		'more' => $more
	);
}

/**
 * Registers any custom menu items with the main Site Menu.
 *
 * @note Custom menu items are added through the admin interface.  Plugins
 * can add standard menu items by using {@link add_menu()}.
 *
 * @since 1.8
 * @link http://docs.elgg.org/Tutorials/UI/SiteMenu
 * @elgg_event_handler init system
 */
function add_custom_menu_items() {
	if ($custom_items = get_config('menu_items_custom_items')) {
		foreach ($custom_items as $url => $name) {
			add_menu($name, $url);
		}
	}
}

/**
 * Test if two URLs are functionally identical.
 *
 * @tip If $ignore_params is used, neither the name nor its value will be considered when comparing.
 *
 * @tip The order of GET params doesn't matter.
 *
 * @param string $url1
 * @param string $url2
 * @param array $ignore_params - GET params to ignore in the comparison
 * @return BOOL
 * @since 1.8
 */
function elgg_http_url_is_identical($url1, $url2, $ignore_params = array('offset', 'limit')) {
	global $CONFIG;

	// if the server portion is missing but it starts with / then add the url in.
	if (elgg_substr($url1, 0, 1) == '/') {
		$url1 = $CONFIG->url . ltrim($url1, '/');
	}

	if (elgg_substr($url1, 0, 1) == '/') {
		$url2 = $CONFIG->url . ltrim($url2, '/');
	}

	// @todo - should probably do something with relative URLs

	if ($url1 == $url2) {
		return TRUE;
	}

	$url1_info = parse_url($url1);
	$url2_info = parse_url($url2);

	$url1_info['path'] = trim($url1_info['path'], '/');
	$url2_info['path'] = trim($url2_info['path'], '/');

	// compare basic bits
	$parts = array('scheme', 'host', 'path');

	foreach ($parts as $part) {
		if ((isset($url1_info[$part]) && isset($url2_info[$part])) && $url1_info[$part] != $url2_info[$part]) {
			return FALSE;
		} elseif (isset($url1_info[$part]) && !isset($url2_info[$part])) {
			return FALSE;
		} elseif (!isset($url1_info[$part]) && isset($url2_info[$part])) {
			return FALSE;
		}
	}

	// quick compare of get params
	if (isset($url1_info['query']) && isset($url2_info['query']) && $url1_info['query'] == $url2_info['query']) {
		return TRUE;
	}

	// compare get params that might be out of order
	$url1_params = array();
	$url2_params = array();

	if (isset($url1_info['query'])) {
		if ($url1_info['query'] = html_entity_decode($url1_info['query'])) {
			$url1_params = elgg_parse_str($url1_info['query']);
		}
	}

	if (isset($url2_info['query'])) {
		if ($url2_info['query'] = html_entity_decode($url2_info['query'])) {
			$url2_params = elgg_parse_str($url2_info['query']);
		}
	}

	// drop ignored params
	foreach ($ignore_params as $param) {
		if (isset($url1_params[$param])) {
			unset($url1_params[$param]);
		}
		if (isset($url2_params[$param])) {
			unset($url2_params[$param]);
		}
	}

	// array_diff_assoc only returns the items in arr1 that aren't in arrN
	// but not the items that ARE in arrN but NOT in arr1
	// if arr1 is an empty array, this function will return 0 no matter what.
	// since we only care if they're different and not how different,
	// add the results together to get a non-zero (ie, different) result
	$diff_count = count(array_diff_assoc($url1_params, $url2_params));
	$diff_count += count(array_diff_assoc($url2_params, $url1_params));
	if ($diff_count > 0) {
		return FALSE;
	}

	return TRUE;
}

/**
 * Checks the status of the Walled Garden and forwards to a login page
 * if required.
 *
 * If the site is in Walled Garden mode, all page except those registered as
 * plugin pages by {@elgg_hook public_pages walled_garden} will redirect to
 * a login page.
 *
 * @since 1.8
 * @elgg_event_handler init system
 * @link http://docs.elgg.org/Tutorials/WalledGarden
 */
function elgg_walled_garden() {
	global $CONFIG;

	// check for external page view
	if (isset($CONFIG->site) && $CONFIG->site instanceof ElggSite) {
		$CONFIG->site->check_walled_garden();
	}
}

/**
 * Checks for $array[$key] and returns its value if it exists, else
 * returns $default.
 *
 * Shorthand for $value = (isset($array['key'])) ? $array['key'] : 'default';
 *
 * @param string $key The key to check.
 * @param array $array The array to check against.
 * @param mixed $default Default value to return if nothing is found.
 * @since 1.8
 */
function elgg_get_array_value($key, array $array, $default = NULL) {
	return (isset($array[$key])) ? $array[$key] : $default;
}

/**
 * Sorts a 3d array by specific element.
 *
 * @warning Will re-index numeric indexes.
 *
 * @note This operates the same as the built-in sort functions.
 * ie, sorts the array and returns a bool for success.
 *
 * Do this: elgg_sort_3d_array_by_value($my_array);
 * Not this: $my_array = elgg_sort_3d_array_by_value($my_array);
 *
 * @param array $array Array to sort
 * @param string $element Element to sort by
 * @param $sort_order
 * @param $sort_type
 * @return bool
 */
function elgg_sort_3d_array_by_value(&$array, $element, $sort_order = SORT_ASC, $sort_type = SORT_LOCALE_STRING) {
	$sort = array();

	foreach ($array as $k => $v) {
		if (isset($v[$element])) {
			$sort[] = strtolower($v[$element]);
		} else {
			$sort[] = NULL;
		}
	};

	return array_multisort($sort, $sort_order, $sort_type, $array);
}


/**#@+
 * Controlls access levels on ElggEntity entities, metadata, and annotations.
 *
 * @var int
 */
define('ACCESS_DEFAULT', -1);
define('ACCESS_PRIVATE', 0);
define('ACCESS_LOGGED_IN', 1);
define('ACCESS_PUBLIC', 2);
define('ACCESS_FRIENDS', -2);
/**#@-*/

/**
 * Constant to request the value of a parameter be ignored in elgg_get_*() functions
 *
 * @see elgg_get_entities()
 * @var NULL
 * @since 1.7
 */
define('ELGG_ENTITIES_ANY_VALUE', NULL);

/**
 * Constant to request the value of a parameter be nothing in elgg_get_*() functions.
 *
 * @see elgg_get_entities()
 * @var int 0
 * @since 1.7
 */
define('ELGG_ENTITIES_NO_VALUE', 0);

/**
 * Used in calls to forward() to specify the browser should be redirected to the
 * referring page.
 *
 * @see forward
 * @var unknown_type
 */
define('REFERRER', -1);

/**
 * Alternate spelling for REFERRER.  Included because of some bad documentation
 * in the original HTTP spec.
 *
 * @see forward()
 * @link http://en.wikipedia.org/wiki/HTTP_referrer#Origin_of_the_term_referer
 * @var int -1
 */
define('REFERER', -1);

register_elgg_event_handler('init', 'system', 'elgg_init');
register_plugin_hook('unit_test', 'system', 'elgg_api_test');

register_elgg_event_handler('init', 'system', 'add_custom_menu_items', 1000);
register_elgg_event_handler('init', 'system', 'elgg_walled_garden', 1000);