aboutsummaryrefslogtreecommitdiff
path: root/engine/lib/metadata.php
blob: f2b1fd6423169a442a2a82b41e5e6c463d5e0c2c (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
<?php
/**
 * Elgg metadata
 * Functions to manage entity metadata.
 *
 * @package Elgg.Core
 * @subpackage DataModel.Metadata
 */

/**
 * Convert a database row to a new ElggMetadata
 *
 * @param stdClass $row An object from the database
 *
 * @return stdClass or ElggMetadata
 */
function row_to_elggmetadata($row) {
	if (!($row instanceof stdClass)) {
		return $row;
	}

	return new ElggMetadata($row);
}

/**
 * Get a specific metadata object.
 *
 * @param int $id The id of the metadata being retrieved.
 *
 * @return mixed False on failure or ElggMetadata
 */
function get_metadata($id) {
	global $CONFIG;

	$id = (int)$id;
	$access = get_access_sql_suffix("e");
	$md_access = get_access_sql_suffix("m");

	$query = "SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}metadata m"
		. " JOIN {$CONFIG->dbprefix}entities e on e.guid = m.entity_guid"
		. " JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id"
		. " JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id"
		. " where m.id=$id and $access and $md_access";


	return row_to_elggmetadata(get_data_row($query));
}

/**
 * Removes metadata on an entity with a particular name, optionally with a given value.
 *
 * @param int    $entity_guid The entity GUID
 * @param string $name        The name of the metadata
 * @param string $value       The value of the metadata (useful to remove a single item of a set)
 *
 * @return bool Depending on success
 */
function remove_metadata($entity_guid, $name, $value = "") {
	global $CONFIG;
	$entity_guid = (int) $entity_guid;
	$name = sanitise_string($name);
	$value = sanitise_string($value);
	
	$name = get_metastring_id($name);
	if ($name === FALSE) {
		// name doesn't exist
		return FALSE;
	}

	$query = "SELECT * from {$CONFIG->dbprefix}metadata WHERE entity_guid = '$entity_guid' and name_id = '$name'";
	if ($value != "") {
		$value = get_metastring_id($value);
		if ($value !== FALSE) {
			$query .= " AND value_id = '$value'";
		}
	}

	if ($existing = get_data($query)) {
		foreach ($existing as $ex) {
			delete_metadata($ex->id);
		}
		return true;
	}

	return false;
}

/**
 * Create a new metadata object, or update an existing one.
 *
 * Metadata can be an array by setting allow_multiple to TRUE, but it is an
 * indexed array with no control over the indexing.
 *
 * @param int    $entity_guid    The entity to attach the metadata to
 * @param string $name           Name of the metadata
 * @param string $value          Value of the metadata
 * @param string $value_type     'text', 'integer', or '' for automatic detection
 * @param int    $owner_guid     GUID of entity that owns the metadata
 * @param int    $access_id      Default is ACCESS_PRIVATE
 * @param bool   $allow_multiple Allow multiple values for one key. Default is FALSE
 *
 * @return int/bool id of metadata or FALSE if failure
 */
function create_metadata($entity_guid, $name, $value, $value_type, $owner_guid,
	$access_id = ACCESS_PRIVATE, $allow_multiple = false) {

	global $CONFIG;

	$entity_guid = (int)$entity_guid;
	// name and value are encoded in add_metastring()
	//$name = sanitise_string(trim($name));
	//$value = sanitise_string(trim($value));
	$value_type = detect_extender_valuetype($value, sanitise_string(trim($value_type)));
	$time = time();
	$owner_guid = (int)$owner_guid;
	$allow_multiple = (boolean)$allow_multiple;

	if (!isset($value)) {
		return FALSE;
	}

	if ($owner_guid == 0) {
		$owner_guid = get_loggedin_userid();
	}

	$access_id = (int)$access_id;

	$id = false;

	$query = "SELECT * from {$CONFIG->dbprefix}metadata"
		. " WHERE entity_guid = $entity_guid and name_id=" . add_metastring($name) . " limit 1";

	$existing = get_data_row($query);
	if ($existing && !$allow_multiple) {
		$id = (int)$existing->id;
		$result = update_metadata($id, $name, $value, $value_type, $owner_guid, $access_id);

		if (!$result) {
			return false;
		}
	} else {
		// Support boolean types
		if (is_bool($value)) {
			if ($value) {
				$value = 1;
			} else {
				$value = 0;
			}
		}

		// Add the metastrings
		$value = add_metastring($value);
		if (!$value) {
			return false;
		}

		$name = add_metastring($name);
		if (!$name) {
			return false;
		}

		// If ok then add it
		$query = "INSERT into {$CONFIG->dbprefix}metadata"
			. " (entity_guid, name_id, value_id, value_type, owner_guid, time_created, access_id)"
			. " VALUES ($entity_guid, '$name','$value','$value_type', $owner_guid, $time, $access_id)";

		$id = insert_data($query);

		if ($id !== false) {
			$obj = get_metadata($id);
			if (elgg_trigger_event('create', 'metadata', $obj)) {
				return $id;
			} else {
				delete_metadata($id);
			}
		}
	}

	return $id;
}

/**
 * Update a specific piece of metadata.
 *
 * @param int    $id         Metadata id
 * @param string $name       Metadata name
 * @param string $value      Metadata value
 * @param string $value_type Value type
 * @param int    $owner_guid Owner guid
 * @param int    $access_id  Access ID
 *
 * @return bool
 */
function update_metadata($id, $name, $value, $value_type, $owner_guid, $access_id) {
	global $CONFIG;

	$id = (int)$id;

	if (!$md = get_metadata($id)) {
		return false;
	}
	if (!$md->canEdit()) {
		return false;
	}

	// If memcached then we invalidate the cache for this entry
	static $metabyname_memcache;
	if ((!$metabyname_memcache) && (is_memcache_available())) {
		$metabyname_memcache = new ElggMemcache('metabyname_memcache');
	}

	if ($metabyname_memcache) {
		$metabyname_memcache->delete("{$md->entity_guid}:{$md->name_id}");
	}

	$value_type = detect_extender_valuetype($value, sanitise_string(trim($value_type)));

	$owner_guid = (int)$owner_guid;
	if ($owner_guid == 0) {
		$owner_guid = get_loggedin_userid();
	}

	$access_id = (int)$access_id;

	$access = get_access_sql_suffix();

	// Support boolean types (as integers)
	if (is_bool($value)) {
		if ($value) {
			$value = 1;
		} else {
			$value = 0;
		}
	}

	// Add the metastring
	$value = add_metastring($value);
	if (!$value) {
		return false;
	}

	$name = add_metastring($name);
	if (!$name) {
		return false;
	}

	// If ok then add it
	$query = "UPDATE {$CONFIG->dbprefix}metadata"
		. " set value_id='$value', value_type='$value_type', access_id=$access_id,"
		. " owner_guid=$owner_guid where id=$id and name_id='$name'";

	$result = update_data($query);
	if ($result !== false) {
		$obj = get_metadata($id);
		if (elgg_trigger_event('update', 'metadata', $obj)) {
			return true;
		} else {
			delete_metadata($id);
		}
	}

	return $result;
}

/**
 * This function creates metadata from an associative array of "key => value" pairs.
 *
 * To achieve an array for a single key, pass in the same key multiple times with
 * allow_multiple set to TRUE. This creates an indexed array. It does not support
 * associative arrays and there is no guarantee on the ordering in the array.
 *
 * @param int    $entity_guid     The entity to attach the metadata to
 * @param string $name_and_values Associative array - a value can be a string, number, bool
 * @param string $value_type      'text', 'integer', or '' for automatic detection
 * @param int    $owner_guid      GUID of entity that owns the metadata
 * @param int    $access_id       Default is ACCESS_PRIVATE
 * @param bool   $allow_multiple  Allow multiple values for one key. Default is FALSE
 *
 * @return bool
 */
function create_metadata_from_array($entity_guid, array $name_and_values, $value_type, $owner_guid,
$access_id = ACCESS_PRIVATE, $allow_multiple = false) {

	foreach ($name_and_values as $k => $v) {
		$result = create_metadata($entity_guid, $k, $v, $value_type, $owner_guid,
			$access_id, $allow_multiple);
		if (!$result) {
			return false;
		}
	}
	return true;
}

/**
 * Delete a piece of metadata, where the current user has access.
 *
 * @param int $id The id of metadata to delete.
 *
 * @return bool
 */
function delete_metadata($id) {
	global $CONFIG;

	$id = (int)$id;
	$metadata = get_metadata($id);

	if ($metadata) {
		// Tidy up if memcache is enabled.
		static $metabyname_memcache;
		if ((!$metabyname_memcache) && (is_memcache_available())) {
			$metabyname_memcache = new ElggMemcache('metabyname_memcache');
		}

		if ($metabyname_memcache) {
			$metabyname_memcache->delete("{$metadata->entity_guid}:{$metadata->name_id}");
		}

		if (($metadata->canEdit()) && (elgg_trigger_event('delete', 'metadata', $metadata))) {
			return delete_data("DELETE from {$CONFIG->dbprefix}metadata where id=$id");
		}
	}

	return false;
}

/**
 * Get metadata objects by name.
 *
 * @param int    $entity_guid Entity GUID
 * @param string $meta_name   Metadata name
 *
 * @return mixed ElggMetadata object, an array of ElggMetadata or false.
 */
function get_metadata_byname($entity_guid, $meta_name) {
	global $CONFIG;

	$meta_name = get_metastring_id($meta_name);

	if (empty($meta_name)) {
		return false;
	}

	$entity_guid = (int)$entity_guid;
	$access = get_access_sql_suffix("e");
	$md_access = get_access_sql_suffix("m");

	// If memcache is available then cache this (cache only by name for now
	// since this is the most common query)
	$meta = null;
	static $metabyname_memcache;
	if ((!$metabyname_memcache) && (is_memcache_available())) {
		$metabyname_memcache = new ElggMemcache('metabyname_memcache');
	}
	if ($metabyname_memcache) {
		$meta = $metabyname_memcache->load("{$entity_guid}:{$meta_name}");
	}
	if ($meta) {
		return $meta;
	}

	$query = "SELECT m.*, n.string as name, v.string as value"
		. " from {$CONFIG->dbprefix}metadata m"
		. " JOIN {$CONFIG->dbprefix}entities e ON e.guid = m.entity_guid"
		. " JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id"
		. " JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id"
		. " where m.entity_guid=$entity_guid and m.name_id='$meta_name'"
		. " and $access and $md_access ORDER BY m.id ASC" ;

	$result = get_data($query, "row_to_elggmetadata");

	if (!$result) {
		return false;
	}

	// Cache if memcache available
	if ($metabyname_memcache) {
		if (count($result) == 1) {
			$r = $result[0];
		} else {
			$r = $result;
		}
		// This is a bit of a hack - we shorten the expiry on object
		// metadata so that it'll be gone in an hour. This means that
		// deletions and more importantly updates will filter through eventually.
		$metabyname_memcache->setDefaultExpiry(3600);
		$metabyname_memcache->save("{$entity_guid}:{$meta_name}", $r);
	}
	if (count($result) == 1) {
		return $result[0];
	}

	return $result;
}

/**
 * Return all the metadata for a given GUID.
 *
 * @param int $entity_guid Entity GUID
 *
 * @return mixed
 */
function get_metadata_for_entity($entity_guid) {
	global $CONFIG;

	$entity_guid = (int)$entity_guid;
	$access = get_access_sql_suffix("e");
	$md_access = get_access_sql_suffix("m");

	$query = "SELECT m.*, n.string as name, v.string as value
		from {$CONFIG->dbprefix}metadata m
		JOIN {$CONFIG->dbprefix}entities e ON e.guid = m.entity_guid
		JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id
		JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id
		where m.entity_guid=$entity_guid and $access and $md_access";

	return get_data($query, "row_to_elggmetadata");
}

/**
 * Get the metadata where the entities they are referring to match a given criteria.
 *
 * @param mixed  $meta_name      Metadata name
 * @param mixed  $meta_value     Metadata value
 * @param string $entity_type    The type of entity to look for, eg 'site' or 'object'
 * @param string $entity_subtype The subtype of the entity.
 * @param int    $limit          Limit
 * @param int    $offset         Offset
 * @param string $order_by       Optional ordering.
 * @param int    $site_guid      Site GUID. 0 for current, -1 for any
 *
 * @return mixed
 */
function find_metadata($meta_name = "", $meta_value = "", $entity_type = "", $entity_subtype = "",
	$limit = 10, $offset = 0, $order_by = "", $site_guid = 0) {
	global $CONFIG;

	$meta_n = get_metastring_id($meta_name);
	$meta_v = get_metastring_id($meta_value);

	$entity_type = sanitise_string($entity_type);
	$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
	$limit = (int)$limit;
	$offset = (int)$offset;
	if ($order_by == "") {
		$order_by = "e.time_created desc";
	}

	$order_by = sanitise_string($order_by);
	$site_guid = (int) $site_guid;
	if ($site_guid == 0) {
		$site_guid = $CONFIG->site_guid;
	}

	$where = array();

	if ($entity_type != "") {
		$where[] = "e.type='$entity_type'";
	}

	if ($entity_subtype) {
		$where[] = "e.subtype=$entity_subtype";
	}

	if ($meta_name != "") {
		if (!$meta_v) {
			// The value is set, but we didn't get a value... so something went wrong.
			return false;
		}
		$where[] = "m.name_id='$meta_n'";
	}
	if ($meta_value != "") {
		// The value is set, but we didn't get a value... so something went wrong.
		if (!$meta_v) {
			return false;
		}
		$where[] = "m.value_id='$meta_v'";
	}
	if ($site_guid > 0) {
		$where[] = "e.site_guid = {$site_guid}";
	}

	$query = "SELECT m.*, n.string as name, v.string as value from {$CONFIG->dbprefix}entities e
		JOIN {$CONFIG->dbprefix}metadata m on e.guid = m.entity_guid
		JOIN {$CONFIG->dbprefix}metastrings v on m.value_id = v.id
		JOIN {$CONFIG->dbprefix}metastrings n on m.name_id = n.id where";

	foreach ($where as $w) {
		$query .= " $w and ";
	}
	$query .= get_access_sql_suffix("e"); // Add access controls
	$query .= ' and ' . get_access_sql_suffix("m"); // Add access controls
	$query .= " order by $order_by limit $offset, $limit"; // Add order and limit

	return get_data($query, "row_to_elggmetadata");
}

/**
 * Returns entities based upon metadata.  Also accepts all
 * options available to elgg_get_entities().  Supports
 * the singular option shortcut.
 *
 * NB: Using metadata_names and metadata_values results in a
 * "names IN (...) AND values IN (...)" clause.  This is subtly
 * differently than default multiple metadata_name_value_pairs, which use
 * "(name = value) AND (name = value)" clauses.
 *
 * When in doubt, use name_value_pairs.
 *
 * @see elgg_get_entities
 * @see elgg_get_entities_from_annotations
 *
 * @param array $options Array in format:
 *
 * 	metadata_names => NULL|ARR metadata names
 *
 * 	metadata_values => NULL|ARR metadata values
 *
 * 	metadata_name_value_pairs => NULL|ARR (
 *                                         name => 'name',
 *                                         value => 'value',
 *                                         'operand' => '=',
 *                                         'case_sensitive' => TRUE
 *                                        )
 * 	                             Currently if multiple values are sent via
 *                               an array (value => array('value1', 'value2')
 *                               the pair's operand will be forced to "IN".
 *
 * 	metadata_name_value_pairs_operator => NULL|STR The operator to use for combining
 *                                        (name = value) OPERATOR (name = value); default AND
 *
 * 	metadata_case_sensitive => BOOL Overall Case sensitive
 *
 *  order_by_metadata => NULL|ARR array(
 *                                      'name' => 'metadata_text1',
 *                                      'direction' => ASC|DESC,
 *                                      'as' => text|integer
 *                                     )
 *                                Also supports array('name' => 'metadata_text1')
 *
 *  metadata_owner_guids => NULL|ARR guids for metadata owners
 *
 * @return array
 * @since 1.7.0
 */
function elgg_get_entities_from_metadata(array $options = array()) {
	$defaults = array(
		'metadata_names'					=>	ELGG_ENTITIES_ANY_VALUE,
		'metadata_values'					=>	ELGG_ENTITIES_ANY_VALUE,
		'metadata_name_value_pairs'			=>	ELGG_ENTITIES_ANY_VALUE,

		'metadata_name_value_pairs_operator'=>	'AND',
		'metadata_case_sensitive' 			=>	TRUE,
		'order_by_metadata'					=>	array(),

		'metadata_owner_guids'				=>	ELGG_ENTITIES_ANY_VALUE,
	);

	$options = array_merge($defaults, $options);

	$singulars = array('metadata_name', 'metadata_value',
		'metadata_name_value_pair', 'metadata_owner_guid');

	$options = elgg_normalise_plural_options_array($options, $singulars);

	if (!$options = elgg_entities_get_metastrings_options('metadata', $options)) {
		return FALSE;
	}

	return elgg_get_entities($options);
}

/**
 * Returns options to pass to elgg_get_entities() for metastrings operations.
 *
 * @param string $type    Metastring type: annotations or metadata
 * @param array  $options Options
 *
 * @return array
 * @since 1.7.0
 */
function elgg_entities_get_metastrings_options($type, $options) {
	$valid_types = array('metadata', 'annotation');
	if (!in_array($type, $valid_types)) {
		return FALSE;
	}

	// the options for annotations are singular (annotation_name) but the table
	// is plural (elgg_annotations) so rewrite for the table name.
	$n_table = ($type == 'annotation') ? 'annotations' : $type;

	$singulars = array("{$type}_name", "{$type}_value",
		"{$type}_name_value_pair", "{$type}_owner_guid");
	$options = elgg_normalise_plural_options_array($options, $singulars);

	$clauses = elgg_get_entity_metadata_where_sql('e', $n_table, $options["{$type}_names"],
		$options["{$type}_values"], $options["{$type}_name_value_pairs"],
		$options["{$type}_name_value_pairs_operator"], $options["{$type}_case_sensitive"],
		$options["order_by_{$type}"], $options["{$type}_owner_guids"]);

	if ($clauses) {
		// merge wheres to pass to get_entities()
		if (isset($options['wheres']) && !is_array($options['wheres'])) {
			$options['wheres'] = array($options['wheres']);
		} elseif (!isset($options['wheres'])) {
			$options['wheres'] = array();
		}

		$options['wheres'] = array_merge($options['wheres'], $clauses['wheres']);

		// merge joins to pass to get_entities()
		if (isset($options['joins']) && !is_array($options['joins'])) {
			$options['joins'] = array($options['joins']);
		} elseif (!isset($options['joins'])) {
			$options['joins'] = array();
		}

		$options['joins'] = array_merge($options['joins'], $clauses['joins']);

		if ($clauses['orders']) {
			$order_by_metadata = implode(", ", $clauses['orders']);
			if (isset($options['order_by']) && $options['order_by']) {
				$options['order_by'] = "$order_by_metadata, {$options['order_by']}";
			} else {
				$options['order_by'] = "$order_by_metadata, e.time_created DESC";
			}
		}
	}

	return $options;
}

/**
 * Returns metadata name and value SQL where for entities.
 * NB: $names and $values are not paired. Use $pairs for this.
 * Pairs default to '=' operand.
 *
 * This function is reused for annotations because the tables are
 * exactly the same.
 *
 * @param string   $e_table           Entities table name
 * @param string   $n_table           Normalized metastrings table name (Where entities,
 *                                    values, and names are joined. annotations / metadata)
 * @param arr|null $names             Array of names
 * @param arr|null $values            Array of values
 * @param arr|null $pairs             Array of names / values / operands
 * @param and|or   $pair_operator     Operator to use to join the where clauses for pairs
 * @param bool     $case_sensitive    Case sensitive metadata names?
 * @param arr|null $order_by_metadata Array of names / direction
 * @param arr|null $owner_guids       Array of owner GUIDs
 *
 * @return FALSE|array False on fail, array('joins', 'wheres')
 * @since 1.7.0
 */
function elgg_get_entity_metadata_where_sql($e_table, $n_table, $names = NULL, $values = NULL,
$pairs = NULL, $pair_operator = 'AND', $case_sensitive = TRUE, $order_by_metadata = NULL,
$owner_guids = NULL) {

	global $CONFIG;

	// short circuit if nothing requested
	// 0 is a valid (if not ill-conceived) metadata name.
	// 0 is also a valid metadata value for FALSE, NULL, or 0
	// 0 is also a valid(ish) owner_guid
	if ((!$names && $names !== 0)
		&& (!$values && $values !== 0)
		&& (!$pairs && $pairs !== 0)
		&& (!$owner_guids && $owner_guids !== 0)
		&& !$order_by_metadata) {
		return '';
	}

	// join counter for incremental joins.
	$i = 1;

	// binary forces byte-to-byte comparision of strings, making
	// it case- and diacritical-mark- sensitive.
	// only supported on values.
	$binary = ($case_sensitive) ? ' BINARY ' : '';

	$access = get_access_sql_suffix('n_table');

	$return = array (
		'joins' => array (),
		'wheres' => array(),
		'orders' => array()
	);

	// will always want to join these tables if pulling metastrings.
	$return['joins'][] = "JOIN {$CONFIG->dbprefix}{$n_table} n_table on
		{$e_table}.guid = n_table.entity_guid";

	$wheres = array();

	// get names wheres and joins
	$names_where = '';
	if ($names !== NULL) {
		if (!is_array($names)) {
			$names = array($names);
		}

		$sanitised_names = array();
		foreach ($names as $name) {
			// normalise to 0.
			if (!$name) {
				$name = '0';
			}
			$sanitised_names[] = '\'' . sanitise_string($name) . '\'';
		}

		if ($names_str = implode(',', $sanitised_names)) {
			$return['joins'][] = "JOIN {$CONFIG->dbprefix}metastrings msn on n_table.name_id = msn.id";
			$names_where = "(msn.string IN ($names_str))";
		}
	}

	// get values wheres and joins
	$values_where = '';
	if ($values !== NULL) {
		if (!is_array($values)) {
			$values = array($values);
		}

		$sanitised_values = array();
		foreach ($values as $value) {
			// normalize to 0
			if (!$value) {
				$value = 0;
			}
			$sanitised_values[] = '\'' . sanitise_string($value) . '\'';
		}

		if ($values_str = implode(',', $sanitised_values)) {
			$return['joins'][] = "JOIN {$CONFIG->dbprefix}metastrings msv on n_table.value_id = msv.id";
			$values_where = "({$binary}msv.string IN ($values_str))";
		}
	}

	if ($names_where && $values_where) {
		$wheres[] = "($names_where AND $values_where AND $access)";
	} elseif ($names_where) {
		$wheres[] = "($names_where AND $access)";
	} elseif ($values_where) {
		$wheres[] = "($values_where AND $access)";
	}

	// add pairs
	// pairs must be in arrays.
	if (is_array($pairs)) {
		// check if this is an array of pairs or just a single pair.
		if (isset($pairs['name']) || isset($pairs['value'])) {
			$pairs = array($pairs);
		}

		$pair_wheres = array();

		// @todo when the pairs are > 3 should probably split the query up to
		// denormalize the strings table.

		foreach ($pairs as $index => $pair) {
			// @todo move this elsewhere?
			// support shortcut 'n' => 'v' method.
			if (!is_array($pair)) {
				$pair = array(
					'name' => $index,
					'value' => $pair
				);
			}

			// must have at least a name and value
			if (!isset($pair['name']) || !isset($pair['value'])) {
				// @todo should probably return false.
				continue;
			}

			// case sensitivity can be specified per pair.
			// default to higher level setting.
			if (isset($pair['case_sensitive'])) {
				$pair_binary = ($pair['case_sensitive']) ? ' BINARY ' : '';
			} else {
				$pair_binary = $binary;
			}

			if (isset($pair['operand'])) {
				$operand = sanitise_string($pair['operand']);
			} else {
				$operand = ' = ';
			}

			// for comparing
			$trimmed_operand = trim(strtolower($operand));

			$access = get_access_sql_suffix("n_table{$i}");
			// if the value is an int, don't quote it because str '15' < str '5'
			// if the operand is IN don't quote it because quoting should be done already.
			if (is_numeric($pair['value'])) {
				$value = sanitise_string($pair['value']);
			} else if (is_array($pair['value'])) {
				$values_array = array();

				foreach ($pair['value'] as $pair_value) {
					if (is_numeric($pair_value)) {
						$values_array[] = sanitise_string($pair_value);
					} else {
						$values_array[] = "'" . sanitise_string($pair_value) . "'";
					}
				}

				if ($values_array) {
					$value = '(' . implode(', ', $values_array) . ')';
				}

				// @todo allow support for non IN operands with array of values.
				// will have to do more silly joins.
				$operand = 'IN';
			} else if ($trimmed_operand == 'in') {
				$value = "({$pair['value']})";
			} else {
				$value = "'" . sanitise_string($pair['value']) . "'";
			}

			$name = sanitise_string($pair['name']);

			// @todo The multiple joins are only needed when the operator is AND
			$return['joins'][] = "JOIN {$CONFIG->dbprefix}{$n_table} n_table{$i}
				on {$e_table}.guid = n_table{$i}.entity_guid";
			$return['joins'][] = "JOIN {$CONFIG->dbprefix}metastrings msn{$i}
				on n_table{$i}.name_id = msn{$i}.id";
			$return['joins'][] = "JOIN {$CONFIG->dbprefix}metastrings msv{$i}
				on n_table{$i}.value_id = msv{$i}.id";

			$pair_wheres[] = "(msn{$i}.string = '$name' AND {$pair_binary}msv{$i}.string
				$operand $value AND $access)";

			$i++;
		}

		if ($where = implode (" $pair_operator ", $pair_wheres)) {
			$wheres[] = "($where)";
		}
	}

	// add owner_guids
	if ($owner_guids) {
		if (is_array($owner_guids)) {
			$sanitised = array_map('sanitise_int', $owner_guids);
			$owner_str = implode(',', $sanitised);
		} else {
			$owner_str = sanitise_int($owner_guids);
		}

		$wheres[] = "(n_table.owner_guid IN ($owner_str))";
	}

	if ($where = implode(' AND ', $wheres)) {
		$return['wheres'][] = "($where)";
	}

	if (is_array($order_by_metadata)) {
		if ((count($order_by_metadata) > 0) && !is_array($order_by_metadata[0])) {
			// singleton, so fix
			$order_by_metadata = array($order_by_metadata);
		}
		foreach ($order_by_metadata as $order_by) {
			if (is_array($order_by) && isset($order_by['name'])) {
				$name = sanitise_string($order_by['name']);
				if (isset($order_by['direction'])) {
					$direction = sanitise_string($order_by['direction']);
				} else {
					$direction = 'ASC';
				}
				$return['joins'][] = "JOIN {$CONFIG->dbprefix}{$n_table} n_table{$i}
					on {$e_table}.guid = n_table{$i}.entity_guid";
				$return['joins'][] = "JOIN {$CONFIG->dbprefix}metastrings msn{$i}
					on n_table{$i}.name_id = msn{$i}.id";
				$return['joins'][] = "JOIN {$CONFIG->dbprefix}metastrings msv{$i}
					on n_table{$i}.value_id = msv{$i}.id";

				$access = get_access_sql_suffix("n_table{$i}");

				$return['wheres'][] = "(msn{$i}.string = '$name' AND $access)";
				if (isset($order_by['as']) && $order_by['as'] == 'integer') {
					$return['orders'][] = "CAST(msv{$i}.string AS SIGNED) $direction";
				} else {
					$return['orders'][] = "msv{$i}.string $direction";
				}
				$i++;
			}
		}
	}

	return $return;
}

/**
 * Return a list of entities based on the given search criteria.
 *
 * @deprecated 1.7 use elgg_get_entities_from_metadata().
 *
 * @param mixed  $meta_name      Metadat name
 * @param mixed  $meta_value     Metadata value
 * @param string $entity_type    The type of entity to look for, eg 'site' or 'object'
 * @param string $entity_subtype The subtype of the entity.
 * @param int    $owner_guid     Owner GUID
 * @param int    $limit          Limit
 * @param int    $offset         Offset
 * @param string $order_by       Optional ordering.
 * @param int    $site_guid      Site GUID. 0 for current, -1 for any.
 * @param bool   $count          Return a count instead of entities
 * @param bool   $case_sensitive Metadata names case sensitivity
 *
 * @return int|array A list of entities, or a count if $count is set to true
 */
function get_entities_from_metadata($meta_name, $meta_value = "", $entity_type = "",
$entity_subtype = "", $owner_guid = 0, $limit = 10, $offset = 0, $order_by = "",
$site_guid = 0, $count = FALSE, $case_sensitive = TRUE) {

	elgg_deprecated_notice('get_entities_from_metadata() was deprecated by elgg_get_entities_from_metadata()!', 1.7);

	$options = array();

	$options['metadata_names'] = $meta_name;

	if ($meta_value) {
		$options['metadata_values'] = $meta_value;
	}

	if ($entity_type) {
		$options['types'] = $entity_type;
	}

	if ($entity_subtype) {
		$options['subtypes'] = $entity_subtype;
	}

	if ($owner_guid) {
		if (is_array($owner_guid)) {
			$options['owner_guids'] = $owner_guid;
		} else {
			$options['owner_guid'] = $owner_guid;
		}
	}

	if ($limit) {
		$options['limit'] = $limit;
	}

	if ($offset) {
		$options['offset'] = $offset;
	}

	if ($order_by) {
		$options['order_by'];
	}

	if ($site_guid) {
		$options['site_guid'];
	}

	if ($count) {
		$options['count'] = $count;
	}

	// need to be able to pass false
	$options['metadata_case_sensitive'] = $case_sensitive;

	return elgg_get_entities_from_metadata($options);
}

/**
 * Return a list of entities suitable for display based on the given search criteria.
 *
 * @see elgg_view_entity_list
 *
 * @deprecated 1.8 Use elgg_list_entities_from_metadata
 *
 * @param mixed  $meta_name      Metadata name to search on
 * @param mixed  $meta_value     The value to match, optionally
 * @param string $entity_type    The type of entity to look for, eg 'site' or 'object'
 * @param string $entity_subtype The subtype of the entity
 * @param int    $owner_guid     Owner GUID
 * @param int    $limit          Number of entities to display per page
 * @param bool   $fullview       WDisplay the full view (default: true)
 * @param bool   $listtypetoggle Allow users to toggle to the gallery view. Default: true
 * @param bool   $pagination     Display pagination? Default: true
 * @param bool   $case_sensitive Case sensitive metadata names?
 *
 * @return string
 *
 * @return string A list of entities suitable for display
 */
function list_entities_from_metadata($meta_name, $meta_value = "",
$entity_type = ELGG_ENTITIES_ANY_VALUE, $entity_subtype = ELGG_ENTITIES_ANY_VALUE,
$owner_guid = 0, $limit = 10, $fullview = true, $listtypetoggle = true,
$pagination = true, $case_sensitive = true) {

	elgg_deprecated_notice('list_entities_from_metadata() was deprecated by elgg_list_entities_from_metadata()!', 1.8);

	$offset = (int) get_input('offset');
	$limit = (int) $limit;
	$options = array(
		'metadata_name' => $meta_name,
		'metadata_value' => $meta_value,
		'types' => $entity_type,
		'subtypes' => $entity_subtype,
		'owner_guid' => $owner_guid,
		'limit' => $limit,
		'offset' => $offset,
		'count' => TRUE,
		'metadata_case_sensitive' => $case_sensitive
	);
	$count = elgg_get_entities_from_metadata($options);

	$options['count'] = FALSE;
	$entities = elgg_get_entities_from_metadata($options);

	return elgg_view_entity_list($entities, $count, $offset, $limit,
		$fullview, $listtypetoggle, $pagination);
}

/**
 * Returns a list of entities filtered by provided metadata.
 *
 * @see elgg_get_entities_from_metadata
 *
 * @param array $options Options array
 *
 * @return array
 * @since 1.7.0
 */
function elgg_list_entities_from_metadata($options) {
	return elgg_list_entities($options, 'elgg_get_entities_from_metadata');
}

/**
 * Return entities from metadata
 *
 * @deprecated 1.7.  Use elgg_get_entities_from_metadata().
 *
 * @param mixed  $meta_array          Metadata name
 * @param string $entity_type         The type of entity to look for, eg 'site' or 'object'
 * @param string $entity_subtype      The subtype of the entity.
 * @param int    $owner_guid          Owner GUID
 * @param int    $limit               Limit
 * @param int    $offset              Offset
 * @param string $order_by            Optional ordering.
 * @param int    $site_guid           Site GUID. 0 for current, -1 for any.
 * @param bool   $count               Return a count instead of entities
 * @param bool   $meta_array_operator Operator for metadata values
 *
 * @return int|array A list of entities, or a count if $count is set to true
 */
function get_entities_from_metadata_multi($meta_array, $entity_type = "", $entity_subtype = "",
$owner_guid = 0, $limit = 10, $offset = 0, $order_by = "", $site_guid = 0,
$count = false, $meta_array_operator = 'and') {

	elgg_deprecated_notice('get_entities_from_metadata_multi() was deprecated by elgg_get_entities_from_metadata()!', 1.7);

	if (!is_array($meta_array) || sizeof($meta_array) == 0) {
		return false;
	}

	$options = array();

	$options['metadata_name_value_pairs'] = $meta_array;

	if ($entity_type) {
		$options['types'] = $entity_type;
	}

	if ($entity_subtype) {
		$options['subtypes'] = $entity_subtype;
	}

	if ($owner_guid) {
		if (is_array($owner_guid)) {
			$options['owner_guids'] = $owner_guid;
		} else {
			$options['owner_guid'] = $owner_guid;
		}
	}

	if ($limit) {
		$options['limit'] = $limit;
	}

	if ($offset) {
		$options['offset'] = $offset;
	}

	if ($order_by) {
		$options['order_by'];
	}

	if ($site_guid) {
		$options['site_guid'];
	}

	if ($count) {
		$options['count'] = $count;
	}

	$options['metadata_name_value_pairs_operator'] = $meta_array_operator;

	return elgg_get_entities_from_metadata($options);
}

/**
 * Returns a viewable list of entities based on the given search criteria.
 *
 * @see elgg_view_entity_list
 *
 * @param array  $meta_array     Array of 'name' => 'value' pairs
 * @param string $entity_type    The type of entity to look for, eg 'site' or 'object'
 * @param string $entity_subtype The subtype of the entity.
 * @param int    $owner_guid     Owner GUID
 * @param int    $limit          Limit
 * @param bool   $fullview       WDisplay the full view (default: true)
 * @param bool   $listtypetoggle Allow users to toggle to the gallery view. Default: true
 * @param bool   $pagination     Display pagination? Default: true
 *
 * @return string List of ElggEntities suitable for display
 * 
 * @deprecated Use elgg_list_entities_from_metadata() instead
 */
function list_entities_from_metadata_multi($meta_array, $entity_type = "", $entity_subtype = "",
$owner_guid = 0, $limit = 10, $fullview = true, $listtypetoggle = true, $pagination = true) {
	elgg_deprecated_notice(elgg_echo('deprecated:function', array(
		'list_entities_from_metadata_multi', 
		'elgg_get_entities_from_metadata'
	)), 1.8);
	

	$offset = (int) get_input('offset');
	$limit = (int) $limit;
	$count = get_entities_from_metadata_multi($meta_array, $entity_type, $entity_subtype,
		$owner_guid, $limit, $offset, "", $site_guid, true);
	$entities = get_entities_from_metadata_multi($meta_array, $entity_type, $entity_subtype,
		$owner_guid, $limit, $offset, "", $site_guid, false);

	return elgg_view_entity_list($entities, $count, $offset, $limit, $fullview,
		$listtypetoggle, $pagination);
}

/**
 * Clear all the metadata for a given entity, assuming you have access to that metadata.
 *
 * @param int $entity_guid Entity GUID
 *
 * @return bool
 */
function clear_metadata($entity_guid) {
	global $CONFIG;

	$entity_guid = (int)$entity_guid;
	if ($entity = get_entity($entity_guid)) {
		if ($entity->canEdit()) {
			return delete_data("DELETE from {$CONFIG->dbprefix}metadata where entity_guid={$entity_guid}");
		}
	}
	return false;
}

/**
 * Clear all annotations belonging to a given owner_guid
 *
 * @param int $owner_guid The owner
 *
 * @return bool
 */
function clear_metadata_by_owner($owner_guid) {
	global $CONFIG;

	$owner_guid = (int)$owner_guid;

	$metas = get_data("SELECT id from {$CONFIG->dbprefix}metadata WHERE owner_guid=$owner_guid");
	$deleted = 0;

	if (is_array($metas)) {
		foreach ($metas as $id) {
			// Is this the best way?
			if (delete_metadata($id->id)) {
				$deleted++;
			}
		}
	}

	return $deleted;
}

/**
 * Handler called by trigger_plugin_hook on the "export" event.
 *
 * @param string $hook        export
 * @param string $entity_type all
 * @param mixed  $returnvalue Value returned from previous hook
 * @param mixed  $params      Params
 *
 * @return array
 */
function export_metadata_plugin_hook($hook, $entity_type, $returnvalue, $params) {
	// Sanity check values
	if ((!is_array($params)) && (!isset($params['guid']))) {
		throw new InvalidParameterException(elgg_echo('InvalidParameterException:GUIDNotForExport'));
	}

	if (!is_array($returnvalue)) {
		throw new InvalidParameterException(elgg_echo('InvalidParameterException:NonArrayReturnValue'));
	}

	$guid = (int)$params['guid'];
	$name = $params['name'];

	$result = get_metadata_for_entity($guid);

	if ($result) {
		foreach ($result as $r) {
			$returnvalue[] = $r->export();
		}
	}

	return $returnvalue;
}

/**
 * Takes in a comma-separated string and returns an array of tags
 * which have been trimmed and set to lower case
 *
 * @param string $string Comma-separated tag string
 *
 * @return array|false An array of strings, or false on failure
 */
function string_to_tag_array($string) {
	if (is_string($string)) {
		$ar = explode(",", $string);
		// trim blank spaces
		$ar = array_map('trim', $ar);
		// make lower case : [Marcus Povey 20090605 - Using mb wrapper function
		// using UTF8 safe function where available]
		$ar = array_map('elgg_strtolower', $ar);
		// Remove null values
		$ar = array_filter($ar, 'is_not_null');
		return $ar;
	}
	return false;

}

/**
 * Takes a metadata array (which has all kinds of properties)
 * and turns it into a simple array of strings
 *
 * @param array $array Metadata array
 *
 * @return array Array of strings
 */
function metadata_array_to_values($array) {
	$valuearray = array();

	if (is_array($array)) {
		foreach ($array as $element) {
			$valuearray[] = $element->value;
		}
	}

	return $valuearray;
}

/**
 * Get the URL for this metadata
 *
 * By default this links to the export handler in the current view.
 *
 * @param int $id Metadata ID
 *
 * @return mixed
 */
function get_metadata_url($id) {
	$id = (int)$id;

	if ($extender = get_metadata($id)) {
		return get_extender_url($extender);
	}
	return false;
}

/**
 * Mark entities with a particular type and subtype as having access permissions
 * that can be changed independently from their parent entity
 *
 * @param string $type    The type - object, user, etc
 * @param string $subtype The subtype; all subtypes by default
 *
 * @return void
 */
function register_metadata_as_independent($type, $subtype = '*') {
	global $CONFIG;
	if (!isset($CONFIG->independents)) {
		$CONFIG->independents = array();
	}
	$CONFIG->independents[$type][$subtype] = true;
}

/**
 * Determines whether entities of a given type and subtype should not change
 * their metadata in line with their parent entity
 *
 * @param string $type    The type - object, user, etc
 * @param string $subtype The entity subtype
 *
 * @return bool
 */
function is_metadata_independent($type, $subtype) {
	global $CONFIG;
	if (empty($CONFIG->independents)) {
		return false;
	}
	if (!empty($CONFIG->independents[$type][$subtype])
		|| !empty($CONFIG->independents[$type]['*'])) {
			return true;
		}
	return false;
}

/**
 * When an entity is updated, resets the access ID on all of its child metadata
 *
 * @param string     $event       The name of the event
 * @param string     $object_type The type of object
 * @param ElggEntity $object      The entity itself
 *
 * @return true
 */
function metadata_update($event, $object_type, $object) {
	if ($object instanceof ElggEntity) {
		if (!is_metadata_independent($object->getType(), $object->getSubtype())) {
			global $CONFIG;
			$access_id = (int) $object->access_id;
			$guid = (int) $object->getGUID();
			$query = "update {$CONFIG->dbprefix}metadata set access_id = {$access_id} where entity_guid = {$guid}";
			update_data($query);
		}
	}
	return true;
}

/**
 * Register a metadata url handler.
 *
 * @param string $function_name The function.
 * @param string $extender_name The name, default 'all'.
 *
 * @return bool
 */
function register_metadata_url_handler($function_name, $extender_name = "all") {
	return register_extender_url_handler($function_name, 'metadata', $extender_name);
}

/** Register the hook */
elgg_register_plugin_hook_handler("export", "all", "export_metadata_plugin_hook", 2);

/** Call a function whenever an entity is updated **/
elgg_register_event_handler('update', 'all', 'metadata_update');

// unit testing
elgg_register_plugin_hook_handler('unit_test', 'system', 'metadata_test');

/**
 * Metadata unit test
 *
 * @param string $hook   unit_test
 * @param string $type   system
 * @param mixed  $value  Array of other tests
 * @param mixed  $params Params
 *
 * @return array
 */
function metadata_test($hook, $type, $value, $params) {
	global $CONFIG;
	$value[] = $CONFIG->path . 'engine/tests/objects/metadata.php';
	return $value;
}