summaryrefslogtreecommitdiffstats
path: root/system/core/Loader.php
blob: aea1d82ed57ee1f66d9ed355e5d649293cef587e (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
<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2019, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
 * @license	https://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * Loader Class
 *
 * Loads framework components.
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Loader
 * @author		EllisLab Dev Team
 * @link		https://codeigniter.com/userguide3/libraries/loader.html
 */
class CI_Loader {

	// All these are set automatically. Don't mess with them.
	/**
	 * Nesting level of the output buffering mechanism
	 *
	 * @var	int
	 */
	protected $_ci_ob_level;

	/**
	 * List of paths to load views from
	 *
	 * @var	array
	 */
	protected $_ci_view_paths =	array(VIEWPATH	=> TRUE);

	/**
	 * List of paths to load libraries from
	 *
	 * @var	array
	 */
	protected $_ci_library_paths =	array(APPPATH, BASEPATH);

	/**
	 * List of paths to load models from
	 *
	 * @var	array
	 */
	protected $_ci_model_paths =	array(APPPATH);

	/**
	 * List of paths to load helpers from
	 *
	 * @var	array
	 */
	protected $_ci_helper_paths =	array(APPPATH, BASEPATH);

	/**
	 * List of cached variables
	 *
	 * @var	array
	 */
	protected $_ci_cached_vars =	array();

	/**
	 * Stack of variable arrays to provide nested _ci_load calls with all variables from parent calls
	 *
	 * @var	array
	 */
	protected $_ci_load_vars_stack =	array();

	/**
	 * List of loaded classes
	 *
	 * @var	array
	 */
	protected $_ci_classes =	array();

	/**
	 * List of loaded models
	 *
	 * @var	array
	 */
	protected $_ci_models =	array();

	/**
	 * List of loaded helpers
	 *
	 * @var	array
	 */
	protected $_ci_helpers =	array();

	/**
	 * List of class name mappings
	 *
	 * @var	array
	 */
	protected $_ci_varmap =	array(
		'unit_test' => 'unit',
		'user_agent' => 'agent'
	);

	// --------------------------------------------------------------------

	/**
	 * Class constructor
	 *
	 * Sets component load paths, gets the initial output buffering level.
	 *
	 * @return	void
	 */
	public function __construct()
	{
		$this->_ci_ob_level = ob_get_level();
		$this->_ci_classes =& is_loaded();

		log_message('info', 'Loader Class Initialized');
	}

	// --------------------------------------------------------------------

	/**
	 * Initializer
	 *
	 * @todo	Figure out a way to move this to the constructor
	 *		without breaking *package_path*() methods.
	 * @uses	CI_Loader::_ci_autoloader()
	 * @used-by	CI_Controller::__construct()
	 * @return	void
	 */
	public function initialize()
	{
		$this->_ci_autoloader();
	}

	// --------------------------------------------------------------------

	/**
	 * Is Loaded
	 *
	 * A utility method to test if a class is in the self::$_ci_classes array.
	 *
	 * @used-by	Mainly used by Form Helper function _get_validation_object().
	 *
	 * @param 	string		$class	Class name to check for
	 * @return 	string|bool	Class object name if loaded or FALSE
	 */
	public function is_loaded($class)
	{
		return array_search(ucfirst($class), $this->_ci_classes, TRUE);
	}

	// --------------------------------------------------------------------

	/**
	 * Library Loader
	 *
	 * Loads and instantiates libraries.
	 * Designed to be called from application controllers.
	 *
	 * @param	mixed	$library	Library name
	 * @param	array	$params		Optional parameters to pass to the library class constructor
	 * @param	string	$object_name	An optional object name to assign to
	 * @return	object
	 */
	public function library($library, $params = NULL, $object_name = NULL)
	{
		if (empty($library))
		{
			return $this;
		}
		elseif (is_array($library))
		{
			foreach ($library as $key => $value)
			{
				if (is_int($key))
				{
					$this->library($value, $params);
				}
				else
				{
					$this->library($key, $params, $value);
				}
			}

			return $this;
		}

		if ($params !== NULL && ! is_array($params))
		{
			$params = NULL;
		}

		$this->_ci_load_library($library, $params, $object_name);
		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Model Loader
	 *
	 * Loads and instantiates models.
	 *
	 * @param	mixed	$model		Model name
	 * @param	string	$name		An optional object name to assign to
	 * @param	bool	$db_conn	An optional database connection configuration to initialize
	 * @return	object
	 */
	public function model($model, $name = '', $db_conn = FALSE)
	{
		if (empty($model))
		{
			return $this;
		}
		elseif (is_array($model))
		{
			foreach ($model as $key => $value)
			{
				is_int($key) ? $this->model($value, '', $db_conn) : $this->model($key, $value, $db_conn);
			}

			return $this;
		}

		$path = '';

		// Is the model in a sub-folder? If so, parse out the filename and path.
		if (($last_slash = strrpos($model, '/')) !== FALSE)
		{
			// The path is in front of the last slash
			$path = substr($model, 0, ++$last_slash);

			// And the model name behind it
			$model = substr($model, $last_slash);
		}

		if (empty($name))
		{
			$name = $model;
		}

		if (in_array($name, $this->_ci_models, TRUE))
		{
			return $this;
		}

		$CI =& get_instance();
		if (isset($CI->$name))
		{
			throw new RuntimeException('The model name you are loading is the name of a resource that is already being used: '.$name);
		}

		if ($db_conn !== FALSE && ! class_exists('CI_DB', FALSE))
		{
			if ($db_conn === TRUE)
			{
				$db_conn = '';
			}

			$this->database($db_conn, FALSE, TRUE);
		}

		// Note: All of the code under this condition used to be just:
		//
		//       load_class('Model', 'core');
		//
		//       However, load_class() instantiates classes
		//       to cache them for later use and that prevents
		//       MY_Model from being an abstract class and is
		//       sub-optimal otherwise anyway.
		if ( ! class_exists('CI_Model', FALSE))
		{
			$app_path = APPPATH.'core'.DIRECTORY_SEPARATOR;
			if (file_exists($app_path.'Model.php'))
			{
				require_once($app_path.'Model.php');
				if ( ! class_exists('CI_Model', FALSE))
				{
					throw new RuntimeException($app_path."Model.php exists, but doesn't declare class CI_Model");
				}

				log_message('info', 'CI_Model class loaded');
			}
			elseif ( ! class_exists('CI_Model', FALSE))
			{
				require_once(BASEPATH.'core'.DIRECTORY_SEPARATOR.'Model.php');
			}

			$class = config_item('subclass_prefix').'Model';
			if (file_exists($app_path.$class.'.php'))
			{
				require_once($app_path.$class.'.php');
				if ( ! class_exists($class, FALSE))
				{
					throw new RuntimeException($app_path.$class.".php exists, but doesn't declare class ".$class);
				}

				log_message('info', config_item('subclass_prefix').'Model class loaded');
			}
		}

		$model = ucfirst($model);
		if ( ! class_exists($model, FALSE))
		{
			foreach ($this->_ci_model_paths as $mod_path)
			{
				if ( ! file_exists($mod_path.'models/'.$path.$model.'.php'))
				{
					continue;
				}

				require_once($mod_path.'models/'.$path.$model.'.php');
				if ( ! class_exists($model, FALSE))
				{
					throw new RuntimeException($mod_path."models/".$path.$model.".php exists, but doesn't declare class ".$model);
				}

				break;
			}

			if ( ! class_exists($model, FALSE))
			{
				throw new RuntimeException('Unable to locate the model you have specified: '.$model);
			}
		}

		if ( ! is_subclass_of($model, 'CI_Model'))
		{
			throw new RuntimeException("Class ".$model." doesn't extend CI_Model");
		}

		$this->_ci_models[] = $name;
		$model = new $model();
		$CI->$name = $model;
		log_message('info', 'Model "'.get_class($model).'" initialized');
		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Database Loader
	 *
	 * @param	mixed	$params		Database configuration options
	 * @param	bool	$return 	Whether to return the database object
	 * @return	object|bool	Database object if $return is set to TRUE,
	 *					FALSE on failure, CI_Loader instance in any other case
	 */
	public function database($params = '', $return = FALSE)
	{
		// Grab the super object
		$CI =& get_instance();

		// Do we even need to load the database class?
		if ($return === FALSE && isset($CI->db) && is_object($CI->db) && ! empty($CI->db->conn_id))
		{
			return FALSE;
		}

		require_once(BASEPATH.'database/DB.php');

		if ($return === TRUE)
		{
			return DB($params);
		}

		// Initialize the db variable. Needed to prevent
		// reference errors with some configurations
		$CI->db = '';

		// Load the DB class
		$CI->db =& DB($params);
		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Load the Database Utilities Class
	 *
	 * @param	object	$db	Database object
	 * @param	bool	$return	Whether to return the DB Utilities class object or not
	 * @return	object
	 */
	public function dbutil($db = NULL, $return = FALSE)
	{
		$CI =& get_instance();

		if ( ! is_object($db) OR ! ($db instanceof CI_DB))
		{
			class_exists('CI_DB', FALSE) OR $this->database();
			$db =& $CI->db;
		}

		require_once(BASEPATH.'database/DB_utility.php');
		require_once(BASEPATH.'database/drivers/'.$db->dbdriver.'/'.$db->dbdriver.'_utility.php');
		$class = 'CI_DB_'.$db->dbdriver.'_utility';

		if ($return === TRUE)
		{
			return new $class($db);
		}

		$CI->dbutil = new $class($db);
		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Load the Database Forge Class
	 *
	 * @param	object	$db	Database object
	 * @param	bool	$return	Whether to return the DB Forge class object or not
	 * @return	object
	 */
	public function dbforge($db = NULL, $return = FALSE)
	{
		$CI =& get_instance();
		if ( ! is_object($db) OR ! ($db instanceof CI_DB))
		{
			class_exists('CI_DB', FALSE) OR $this->database();
			$db =& $CI->db;
		}

		require_once(BASEPATH.'database/DB_forge.php');
		require_once(BASEPATH.'database/drivers/'.$db->dbdriver.'/'.$db->dbdriver.'_forge.php');

		if ( ! empty($db->subdriver))
		{
			$driver_path = BASEPATH.'database/drivers/'.$db->dbdriver.'/subdrivers/'.$db->dbdriver.'_'.$db->subdriver.'_forge.php';
			if (file_exists($driver_path))
			{
				require_once($driver_path);
				$class = 'CI_DB_'.$db->dbdriver.'_'.$db->subdriver.'_forge';
			}
		}
		else
		{
			$class = 'CI_DB_'.$db->dbdriver.'_forge';
		}

		if ($return === TRUE)
		{
			return new $class($db);
		}

		$CI->dbforge = new $class($db);
		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * View Loader
	 *
	 * Loads "view" files.
	 *
	 * @param	string	$view	View name
	 * @param	array	$vars	An associative array of data
	 *				to be extracted for use in the view
	 * @param	bool	$return	Whether to return the view output
	 *				or leave it to the Output class
	 * @return	object|string
	 */
	public function view($view, $vars = array(), $return = FALSE)
	{
		return $this->_ci_load(array('_ci_view' => $view, '_ci_vars' => $this->_ci_prepare_view_vars($vars), '_ci_return' => $return));
	}

	// --------------------------------------------------------------------

	/**
	 * Generic File Loader
	 *
	 * @param	string	$path	File path
	 * @param	bool	$return	Whether to return the file output
	 * @return	object|string
	 */
	public function file($path, $return = FALSE)
	{
		return $this->_ci_load(array('_ci_path' => $path, '_ci_return' => $return));
	}

	// --------------------------------------------------------------------

	/**
	 * Set Variables
	 *
	 * Once variables are set they become available within
	 * the controller class and its "view" files.
	 *
	 * @param	array|object|string	$vars
	 *					An associative array or object containing values
	 *					to be set, or a value's name if string
	 * @param 	string	$val	Value to set, only used if $vars is a string
	 * @return	object
	 */
	public function vars($vars, $val = '')
	{
		$vars = is_string($vars)
			? array($vars => $val)
			: $this->_ci_prepare_view_vars($vars);

		foreach ($vars as $key => $val)
		{
			$this->_ci_cached_vars[$key] = $val;
		}

		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Clear Cached Variables
	 *
	 * Clears the cached variables.
	 *
	 * @return	CI_Loader
	 */
	public function clear_vars()
	{
		$this->_ci_cached_vars = array();
		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Get Variable
	 *
	 * Check if a variable is set and retrieve it.
	 *
	 * @param	string	$key	Variable name
	 * @return	mixed	The variable or NULL if not found
	 */
	public function get_var($key)
	{
		return isset($this->_ci_cached_vars[$key]) ? $this->_ci_cached_vars[$key] : NULL;
	}

	// --------------------------------------------------------------------

	/**
	 * Get Variables
	 *
	 * Retrieves all loaded variables.
	 *
	 * @return	array
	 */
	public function get_vars()
	{
		return $this->_ci_cached_vars;
	}

	// --------------------------------------------------------------------

	/**
	 * Helper Loader
	 *
	 * @param	string|string[]	$helpers	Helper name(s)
	 * @return	object
	 */
	public function helper($helpers = array())
	{
		is_array($helpers) OR $helpers = array($helpers);
		foreach ($helpers as &$helper)
		{
			$filename = basename($helper);
			$filepath = ($filename === $helper) ? '' : substr($helper, 0, strlen($helper) - strlen($filename));
			$filename = strtolower(preg_replace('#(_helper)?(\.php)?$#i', '', $filename)).'_helper';
			$helper   = $filepath.$filename;

			if (isset($this->_ci_helpers[$helper]))
			{
				continue;
			}

			// Is this a helper extension request?
			$ext_helper = config_item('subclass_prefix').$filename;
			$ext_loaded = FALSE;
			foreach ($this->_ci_helper_paths as $path)
			{
				if (file_exists($path.'helpers/'.$ext_helper.'.php'))
				{
					include_once($path.'helpers/'.$ext_helper.'.php');
					$ext_loaded = TRUE;
				}
			}

			// If we have loaded extensions - check if the base one is here
			if ($ext_loaded === TRUE)
			{
				$base_helper = BASEPATH.'helpers/'.$helper.'.php';
				if ( ! file_exists($base_helper))
				{
					show_error('Unable to load the requested file: helpers/'.$helper.'.php');
				}

				include_once($base_helper);
				$this->_ci_helpers[$helper] = TRUE;
				log_message('info', 'Helper loaded: '.$helper);
				continue;
			}

			// No extensions found ... try loading regular helpers and/or overrides
			foreach ($this->_ci_helper_paths as $path)
			{
				if (file_exists($path.'helpers/'.$helper.'.php'))
				{
					include_once($path.'helpers/'.$helper.'.php');

					$this->_ci_helpers[$helper] = TRUE;
					log_message('info', 'Helper loaded: '.$helper);
					break;
				}
			}

			// unable to load the helper
			if ( ! isset($this->_ci_helpers[$helper]))
			{
				show_error('Unable to load the requested file: helpers/'.$helper.'.php');
			}
		}

		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Load Helpers
	 *
	 * An alias for the helper() method in case the developer has
	 * written the plural form of it.
	 *
	 * @uses	CI_Loader::helper()
	 * @param	string|string[]	$helpers	Helper name(s)
	 * @return	object
	 */
	public function helpers($helpers = array())
	{
		return $this->helper($helpers);
	}

	// --------------------------------------------------------------------

	/**
	 * Language Loader
	 *
	 * Loads language files.
	 *
	 * @param	string|string[]	$files	List of language file names to load
	 * @param	string		Language name
	 * @return	object
	 */
	public function language($files, $lang = '')
	{
		get_instance()->lang->load($files, $lang);
		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Config Loader
	 *
	 * Loads a config file (an alias for CI_Config::load()).
	 *
	 * @uses	CI_Config::load()
	 * @param	string	$file			Configuration file name
	 * @param	bool	$use_sections		Whether configuration values should be loaded into their own section
	 * @param	bool	$fail_gracefully	Whether to just return FALSE or display an error message
	 * @return	bool	TRUE if the file was loaded correctly or FALSE on failure
	 */
	public function config($file, $use_sections = FALSE, $fail_gracefully = FALSE)
	{
		return get_instance()->config->load($file, $use_sections, $fail_gracefully);
	}

	// --------------------------------------------------------------------

	/**
	 * Driver Loader
	 *
	 * Loads a driver library.
	 *
	 * @param	string|string[]	$library	Driver name(s)
	 * @param	array		$params		Optional parameters to pass to the driver
	 * @param	string		$object_name	An optional object name to assign to
	 *
	 * @return	object|bool	Object or FALSE on failure if $library is a string
	 *				and $object_name is set. CI_Loader instance otherwise.
	 */
	public function driver($library, $params = NULL, $object_name = NULL)
	{
		if (is_array($library))
		{
			foreach ($library as $key => $value)
			{
				if (is_int($key))
				{
					$this->driver($value, $params);
				}
				else
				{
					$this->driver($key, $params, $value);
				}
			}

			return $this;
		}
		elseif (empty($library))
		{
			return FALSE;
		}

		if ( ! class_exists('CI_Driver_Library', FALSE))
		{
			// We aren't instantiating an object here, just making the base class available
			require BASEPATH.'libraries/Driver.php';
		}

		// We can save the loader some time since Drivers will *always* be in a subfolder,
		// and typically identically named to the library
		if ( ! strpos($library, '/'))
		{
			$library = ucfirst($library).'/'.$library;
		}

		return $this->library($library, $params, $object_name);
	}

	// --------------------------------------------------------------------

	/**
	 * Add Package Path
	 *
	 * Prepends a parent path to the library, model, helper and config
	 * path arrays.
	 *
	 * @see	CI_Loader::$_ci_library_paths
	 * @see	CI_Loader::$_ci_model_paths
	 * @see CI_Loader::$_ci_helper_paths
	 * @see CI_Config::$_config_paths
	 *
	 * @param	string	$path		Path to add
	 * @param 	bool	$view_cascade	(default: TRUE)
	 * @return	object
	 */
	public function add_package_path($path, $view_cascade = TRUE)
	{
		$path = rtrim($path, '/').'/';

		array_unshift($this->_ci_library_paths, $path);
		array_unshift($this->_ci_model_paths, $path);
		array_unshift($this->_ci_helper_paths, $path);

		$this->_ci_view_paths = array($path.'views/' => $view_cascade) + $this->_ci_view_paths;

		// Add config file path
		$config =& $this->_ci_get_component('config');
		$config->_config_paths[] = $path;

		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Get Package Paths
	 *
	 * Return a list of all package paths.
	 *
	 * @param	bool	$include_base	Whether to include BASEPATH (default: FALSE)
	 * @return	array
	 */
	public function get_package_paths($include_base = FALSE)
	{
		return ($include_base === TRUE) ? $this->_ci_library_paths : $this->_ci_model_paths;
	}

	// --------------------------------------------------------------------

	/**
	 * Remove Package Path
	 *
	 * Remove a path from the library, model, helper and/or config
	 * path arrays if it exists. If no path is provided, the most recently
	 * added path will be removed removed.
	 *
	 * @param	string	$path	Path to remove
	 * @return	object
	 */
	public function remove_package_path($path = '')
	{
		$config =& $this->_ci_get_component('config');

		if ($path === '')
		{
			array_shift($this->_ci_library_paths);
			array_shift($this->_ci_model_paths);
			array_shift($this->_ci_helper_paths);
			array_shift($this->_ci_view_paths);
			array_pop($config->_config_paths);
		}
		else
		{
			$path = rtrim($path, '/').'/';
			foreach (array('_ci_library_paths', '_ci_model_paths', '_ci_helper_paths') as $var)
			{
				if (($key = array_search($path, $this->{$var})) !== FALSE)
				{
					unset($this->{$var}[$key]);
				}
			}

			if (isset($this->_ci_view_paths[$path.'views/']))
			{
				unset($this->_ci_view_paths[$path.'views/']);
			}

			if (($key = array_search($path, $config->_config_paths)) !== FALSE)
			{
				unset($config->_config_paths[$key]);
			}
		}

		// make sure the application default paths are still in the array
		$this->_ci_library_paths = array_unique(array_merge($this->_ci_library_paths, array(APPPATH, BASEPATH)));
		$this->_ci_helper_paths = array_unique(array_merge($this->_ci_helper_paths, array(APPPATH, BASEPATH)));
		$this->_ci_model_paths = array_unique(array_merge($this->_ci_model_paths, array(APPPATH)));
		$this->_ci_view_paths = array_merge($this->_ci_view_paths, array(APPPATH.'views/' => TRUE));
		$config->_config_paths = array_unique(array_merge($config->_config_paths, array(APPPATH)));

		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Internal CI Data Loader
	 *
	 * Used to load views and files.
	 *
	 * Variables are prefixed with _ci_ to avoid symbol collision with
	 * variables made available to view files.
	 *
	 * @used-by	CI_Loader::view()
	 * @used-by	CI_Loader::file()
	 * @param	array	$_ci_data	Data to load
	 * @return	object
	 */
	protected function _ci_load($_ci_data)
	{
		// Set the default data variables
		foreach (array('_ci_view', '_ci_vars', '_ci_path', '_ci_return') as $_ci_val)
		{
			$$_ci_val = isset($_ci_data[$_ci_val]) ? $_ci_data[$_ci_val] : FALSE;
		}

		$file_exists = FALSE;

		// Set the path to the requested file
		if (is_string($_ci_path) && $_ci_path !== '')
		{
			$_ci_x = explode('/', $_ci_path);
			$_ci_file = end($_ci_x);
		}
		else
		{
			$_ci_ext = pathinfo($_ci_view, PATHINFO_EXTENSION);
			$_ci_file = ($_ci_ext === '') ? $_ci_view.'.php' : $_ci_view;

			foreach ($this->_ci_view_paths as $_ci_view_file => $cascade)
			{
				if (file_exists($_ci_view_file.$_ci_file))
				{
					$_ci_path = $_ci_view_file.$_ci_file;
					$file_exists = TRUE;
					break;
				}

				if ( ! $cascade)
				{
					break;
				}
			}
		}

		if ( ! $file_exists && ! file_exists($_ci_path))
		{
			show_error('Unable to load the requested file: '.$_ci_file);
		}

		// This allows anything loaded using $this->load (views, files, etc.)
		// to become accessible from within the Controller and Model functions.
		$_ci_CI =& get_instance();
		foreach (get_object_vars($_ci_CI) as $_ci_key => $_ci_var)
		{
			if ( ! isset($this->$_ci_key))
			{
				$this->$_ci_key =& $_ci_CI->$_ci_key;
			}
		}

		/*
		 * Extract and stack variables
		 *
		 * You can either set variables using the dedicated $this->load->vars()
		 * function or via the second parameter of this function. We'll merge
		 * the two types so that loaded views and files have access to these
		 * variables.
		 * Additionally we want all subsequent nested _ci_load() calls embedded
		 * within the current file to 'inherit' all variables that are
		 * accessible to the current file. For this purpose we push the current
		 * variable configuration (_ci_vars) to the stack and remove it again
		 * after the file or view is completely loaded. Nested _ci_load() calls
		 * within the current file extend the stack with their variable
		 * configuration.
		 */

		is_array($_ci_vars) && $_ci_vars = array();

		// Include the global cached vars into the current _ci_vars if needed
		empty($this->_ci_cached_vars) OR $_ci_vars = array_merge($this->_ci_cached_vars, $_ci_vars);

		// Merge the last variable configuration from a parent _ci_load()
		// call into the current _ci_vars
		if ( ! empty($this->_ci_load_vars_stack))
		{
			$previous_variable_configuration = end($this->_ci_load_vars_stack);
			$_ci_vars = array_merge($previous_variable_configuration, $_ci_vars);
		}

		array_push($this->_ci_load_vars_stack, $_ci_vars);
		extract($_ci_vars);

		/**
		 * Buffer the output
		 *
		 * We buffer the output for two reasons:
		 * 1. Speed. You get a significant speed boost.
		 * 2. So that the final rendered template can be post-processed by
		 *	the output class. Why do we need post processing? For one thing,
		 *	in order to show the elapsed page load time. Unless we can
		 *	intercept the content right before it's sent to the browser and
		 *	then stop the timer it won't be accurate.
		 */
		ob_start();

		include($_ci_path); // include() vs include_once() allows for multiple views with the same name
		log_message('info', 'File loaded: '.$_ci_path);

		// Remove current _ci_vars from stack
		array_pop($this->_ci_load_vars_stack);

		// Return the file data if requested
		if ($_ci_return === TRUE)
		{
			$buffer = ob_get_contents();
			@ob_end_clean();
			return $buffer;
		}

		/*
		 * Flush the buffer... or buff the flusher?
		 *
		 * In order to permit views to be nested within
		 * other views, we need to flush the content back out whenever
		 * we are beyond the first level of output buffering so that
		 * it can be seen and included properly by the first included
		 * template and any subsequent ones. Oy!
		 */
		if (ob_get_level() > $this->_ci_ob_level + 1)
		{
			ob_end_flush();
		}
		else
		{
			$_ci_CI->output->append_output(ob_get_contents());
			@ob_end_clean();
		}

		return $this;
	}

	// --------------------------------------------------------------------

	/**
	 * Internal CI Library Loader
	 *
	 * @used-by	CI_Loader::library()
	 * @uses	CI_Loader::_ci_init_library()
	 *
	 * @param	string	$class		Class name to load
	 * @param	mixed	$params		Optional parameters to pass to the class constructor
	 * @param	string	$object_name	Optional object name to assign to
	 * @return	void
	 */
	protected function _ci_load_library($class, $params = NULL, $object_name = NULL)
	{
		// Get the class name, and while we're at it trim any slashes.
		// The directory path can be included as part of the class name,
		// but we don't want a leading slash
		$class = str_replace('.php', '', trim($class, '/'));

		// Was the path included with the class name?
		// We look for a slash to determine this
		if (($last_slash = strrpos($class, '/')) !== FALSE)
		{
			// Extract the path
			$subdir = substr($class, 0, ++$last_slash);

			// Get the filename from the path
			$class = substr($class, $last_slash);
		}
		else
		{
			$subdir = '';
		}

		$class = ucfirst($class);

		// Is this a stock library? There are a few special conditions if so ...
		if (file_exists(BASEPATH.'libraries/'.$subdir.$class.'.php'))
		{
			return $this->_ci_load_stock_library($class, $subdir, $params, $object_name);
		}

		// Safety: Was the class already loaded by a previous call?
		if (class_exists($class, FALSE))
		{
			$property = $object_name;
			if (empty($property))
			{
				$property = strtolower($class);
				isset($this->_ci_varmap[$property]) && $property = $this->_ci_varmap[$property];
			}

			$CI =& get_instance();
			if (isset($CI->$property))
			{
				log_message('debug', $class.' class already loaded. Second attempt ignored.');
				return;
			}

			return $this->_ci_init_library($class, '', $params, $object_name);
		}

		// Let's search for the requested library file and load it.
		foreach ($this->_ci_library_paths as $path)
		{
			// BASEPATH has already been checked for
			if ($path === BASEPATH)
			{
				continue;
			}

			$filepath = $path.'libraries/'.$subdir.$class.'.php';
			// Does the file exist? No? Bummer...
			if ( ! file_exists($filepath))
			{
				continue;
			}

			include_once($filepath);
			return $this->_ci_init_library($class, '', $params, $object_name);
		}

		// One last attempt. Maybe the library is in a subdirectory, but it wasn't specified?
		if ($subdir === '')
		{
			return $this->_ci_load_library($class.'/'.$class, $params, $object_name);
		}

		// If we got this far we were unable to find the requested class.
		log_message('error', 'Unable to load the requested class: '.$class);
		show_error('Unable to load the requested class: '.$class);
	}

	// --------------------------------------------------------------------

	/**
	 * Internal CI Stock Library Loader
	 *
	 * @used-by	CI_Loader::_ci_load_library()
	 * @uses	CI_Loader::_ci_init_library()
	 *
	 * @param	string	$library_name	Library name to load
	 * @param	string	$file_path	Path to the library filename, relative to libraries/
	 * @param	mixed	$params		Optional parameters to pass to the class constructor
	 * @param	string	$object_name	Optional object name to assign to
	 * @return	void
	 */
	protected function _ci_load_stock_library($library_name, $file_path, $params, $object_name)
	{
		$prefix = 'CI_';

		if (class_exists($prefix.$library_name, FALSE))
		{
			if (class_exists(config_item('subclass_prefix').$library_name, FALSE))
			{
				$prefix = config_item('subclass_prefix');
			}

			$property = $object_name;
			if (empty($property))
			{
				$property = strtolower($library_name);
				isset($this->_ci_varmap[$property]) && $property = $this->_ci_varmap[$property];
			}

			$CI =& get_instance();
			if ( ! isset($CI->$property))
			{
				return $this->_ci_init_library($library_name, $prefix, $params, $object_name);
			}

			log_message('debug', $library_name.' class already loaded. Second attempt ignored.');
			return;
		}

		$paths = $this->_ci_library_paths;
		array_pop($paths); // BASEPATH
		array_pop($paths); // APPPATH (needs to be the first path checked)
		array_unshift($paths, APPPATH);

		foreach ($paths as $path)
		{
			if (file_exists($path = $path.'libraries/'.$file_path.$library_name.'.php'))
			{
				// Override
				include_once($path);
				if (class_exists($prefix.$library_name, FALSE))
				{
					return $this->_ci_init_library($library_name, $prefix, $params, $object_name);
				}

				log_message('debug', $path.' exists, but does not declare '.$prefix.$library_name);
			}
		}

		include_once(BASEPATH.'libraries/'.$file_path.$library_name.'.php');

		// Check for extensions
		$subclass = config_item('subclass_prefix').$library_name;
		foreach ($paths as $path)
		{
			if (file_exists($path = $path.'libraries/'.$file_path.$subclass.'.php'))
			{
				include_once($path);
				if (class_exists($subclass, FALSE))
				{
					$prefix = config_item('subclass_prefix');
					break;
				}

				log_message('debug', $path.' exists, but does not declare '.$subclass);
			}
		}

		return $this->_ci_init_library($library_name, $prefix, $params, $object_name);
	}

	// --------------------------------------------------------------------

	/**
	 * Internal CI Library Instantiator
	 *
	 * @used-by	CI_Loader::_ci_load_stock_library()
	 * @used-by	CI_Loader::_ci_load_library()
	 *
	 * @param	string		$class		Class name
	 * @param	string		$prefix		Class name prefix
	 * @param	array|null|bool	$config		Optional configuration to pass to the class constructor:
	 *						FALSE to skip;
	 *						NULL to search in config paths;
	 *						array containing configuration data
	 * @param	string		$object_name	Optional object name to assign to
	 * @return	void
	 */
	protected function _ci_init_library($class, $prefix, $config = FALSE, $object_name = NULL)
	{
		// Is there an associated config file for this class? Note: these should always be lowercase
		if ($config === NULL)
		{
			// Fetch the config paths containing any package paths
			$config_component = $this->_ci_get_component('config');

			if (is_array($config_component->_config_paths))
			{
				$found = FALSE;
				foreach ($config_component->_config_paths as $path)
				{
					// We test for both uppercase and lowercase, for servers that
					// are case-sensitive with regard to file names. Load global first,
					// override with environment next
					if (file_exists($path.'config/'.strtolower($class).'.php'))
					{
						include($path.'config/'.strtolower($class).'.php');
						$found = TRUE;
					}
					elseif (file_exists($path.'config/'.ucfirst(strtolower($class)).'.php'))
					{
						include($path.'config/'.ucfirst(strtolower($class)).'.php');
						$found = TRUE;
					}

					if (file_exists($path.'config/'.ENVIRONMENT.'/'.strtolower($class).'.php'))
					{
						include($path.'config/'.ENVIRONMENT.'/'.strtolower($class).'.php');
						$found = TRUE;
					}
					elseif (file_exists($path.'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php'))
					{
						include($path.'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php');
						$found = TRUE;
					}

					// Break on the first found configuration, thus package
					// files are not overridden by default paths
					if ($found === TRUE)
					{
						break;
					}
				}
			}
		}

		$class_name = $prefix.$class;

		// Is the class name valid?
		if ( ! class_exists($class_name, FALSE))
		{
			log_message('error', 'Non-existent class: '.$class_name);
			show_error('Non-existent class: '.$class_name);
		}

		// Set the variable name we will assign the class to
		// Was a custom class name supplied? If so we'll use it
		if (empty($object_name))
		{
			$object_name = strtolower($class);
			if (isset($this->_ci_varmap[$object_name]))
			{
				$object_name = $this->_ci_varmap[$object_name];
			}
		}

		// Don't overwrite existing properties
		$CI =& get_instance();
		if (isset($CI->$object_name))
		{
			if ($CI->$object_name instanceof $class_name)
			{
				log_message('debug', $class_name." has already been instantiated as '".$object_name."'. Second attempt aborted.");
				return;
			}

			show_error("Resource '".$object_name."' already exists and is not a ".$class_name." instance.");
		}

		// Save the class name and object name
		$this->_ci_classes[$object_name] = $class;

		// Instantiate the class
		$CI->$object_name = isset($config)
			? new $class_name($config)
			: new $class_name();
	}

	// --------------------------------------------------------------------

	/**
	 * CI Autoloader
	 *
	 * Loads component listed in the config/autoload.php file.
	 *
	 * @used-by	CI_Loader::initialize()
	 * @return	void
	 */
	protected function _ci_autoloader()
	{
		if (file_exists(APPPATH.'config/autoload.php'))
		{
			include(APPPATH.'config/autoload.php');
		}

		if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/autoload.php'))
		{
			include(APPPATH.'config/'.ENVIRONMENT.'/autoload.php');
		}

		if ( ! isset($autoload))
		{
			return;
		}

		// Autoload packages
		if (isset($autoload['packages']))
		{
			foreach ($autoload['packages'] as $package_path)
			{
				$this->add_package_path($package_path);
			}
		}

		// Load any custom config file
		if (count($autoload['config']) > 0)
		{
			foreach ($autoload['config'] as $val)
			{
				$this->config($val);
			}
		}

		// Autoload helpers and languages
		foreach (array('helper', 'language') as $type)
		{
			if (isset($autoload[$type]) && count($autoload[$type]) > 0)
			{
				$this->$type($autoload[$type]);
			}
		}

		// Autoload drivers
		if (isset($autoload['drivers']))
		{
			$this->driver($autoload['drivers']);
		}

		// Load libraries
		if (isset($autoload['libraries']) && count($autoload['libraries']) > 0)
		{
			// Load the database driver.
			if (in_array('database', $autoload['libraries']))
			{
				$this->database();
				$autoload['libraries'] = array_diff($autoload['libraries'], array('database'));
			}

			// Load all other libraries
			$this->library($autoload['libraries']);
		}

		// Autoload models
		if (isset($autoload['model']))
		{
			$this->model($autoload['model']);
		}
	}

	// --------------------------------------------------------------------

	/**
	 * Prepare variables for _ci_vars, to be later extract()-ed inside views
	 *
	 * Converts objects to associative arrays and filters-out internal
	 * variable names (i.e. keys prefixed with '_ci_').
	 *
	 * @param	mixed	$vars
	 * @return	array
	 */
	protected function _ci_prepare_view_vars($vars)
	{
		if ( ! is_array($vars))
		{
			$vars = is_object($vars)
				? get_object_vars($vars)
				: array();
		}

		foreach (array_keys($vars) as $key)
		{
			if (strncmp($key, '_ci_', 4) === 0)
			{
				unset($vars[$key]);
			}
		}

		return $vars;
	}

	// --------------------------------------------------------------------

	/**
	 * CI Component getter
	 *
	 * Get a reference to a specific library or model.
	 *
	 * @param 	string	$component	Component name
	 * @return	bool
	 */
	protected function &_ci_get_component($component)
	{
		$CI =& get_instance();
		return $CI->$component;
	}
}