class-wp-theme.php 46.7 KB
Newer Older
imac's avatar
imac committed
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
<?php
/**
 * WP_Theme Class
 *
 * @package WordPress
 * @subpackage Theme
 * @since 3.4.0
 */
final class WP_Theme implements ArrayAccess {

	/**
	 * Whether the theme has been marked as updateable.
	 *
	 * @since 4.4.0
	 * @access public
	 * @var bool
	 *
	 * @see WP_MS_Themes_List_Table
	 */
	public $update = false;

	/**
	 * Headers for style.css files.
	 *
	 * @static
	 * @access private
	 * @var array
	 */
	private static $file_headers = array(
		'Name'        => 'Theme Name',
		'ThemeURI'    => 'Theme URI',
		'Description' => 'Description',
		'Author'      => 'Author',
		'AuthorURI'   => 'Author URI',
		'Version'     => 'Version',
		'Template'    => 'Template',
		'Status'      => 'Status',
		'Tags'        => 'Tags',
		'TextDomain'  => 'Text Domain',
		'DomainPath'  => 'Domain Path',
	);

	/**
	 * Default themes.
	 *
	 * @static
	 * @access private
	 * @var array
	 */
	private static $default_themes = array(
		'classic'         => 'WordPress Classic',
		'default'         => 'WordPress Default',
		'twentyten'       => 'Twenty Ten',
		'twentyeleven'    => 'Twenty Eleven',
		'twentytwelve'    => 'Twenty Twelve',
		'twentythirteen'  => 'Twenty Thirteen',
		'twentyfourteen'  => 'Twenty Fourteen',
		'twentyfifteen'   => 'Twenty Fifteen',
		'twentysixteen'   => 'Twenty Sixteen',
		'twentyseventeen' => 'Twenty Seventeen',
	);

	/**
	 * Renamed theme tags.
	 *
	 * @static
	 * @access private
	 * @var array
	 */
	private static $tag_map = array(
		'fixed-width'    => 'fixed-layout',
		'flexible-width' => 'fluid-layout',
	);

	/**
	 * Absolute path to the theme root, usually wp-content/themes
	 *
	 * @access private
	 * @var string
	 */
	private $theme_root;

	/**
	 * Header data from the theme's style.css file.
	 *
	 * @access private
	 * @var array
	 */
	private $headers = array();

	/**
	 * Header data from the theme's style.css file after being sanitized.
	 *
	 * @access private
	 * @var array
	 */
	private $headers_sanitized;

	/**
	 * Header name from the theme's style.css after being translated.
	 *
	 * Cached due to sorting functions running over the translated name.
	 *
	 * @access private
	 * @var string
	 */
	private $name_translated;

	/**
	 * Errors encountered when initializing the theme.
	 *
	 * @access private
	 * @var WP_Error
	 */
	private $errors;

	/**
	 * The directory name of the theme's files, inside the theme root.
	 *
	 * In the case of a child theme, this is directory name of the child theme.
	 * Otherwise, 'stylesheet' is the same as 'template'.
	 *
	 * @access private
	 * @var string
	 */
	private $stylesheet;

	/**
	 * The directory name of the theme's files, inside the theme root.
	 *
	 * In the case of a child theme, this is the directory name of the parent theme.
	 * Otherwise, 'template' is the same as 'stylesheet'.
	 *
	 * @access private
	 * @var string
	 */
	private $template;

	/**
	 * A reference to the parent theme, in the case of a child theme.
	 *
	 * @access private
	 * @var WP_Theme
	 */
	private $parent;

	/**
	 * URL to the theme root, usually an absolute URL to wp-content/themes
	 *
	 * @access private
	 * @var string
	 */
	private $theme_root_uri;

	/**
	 * Flag for whether the theme's textdomain is loaded.
	 *
	 * @access private
	 * @var bool
	 */
	private $textdomain_loaded;

	/**
	 * Stores an md5 hash of the theme root, to function as the cache key.
	 *
	 * @access private
	 * @var string
	 */
	private $cache_hash;

	/**
	 * Flag for whether the themes cache bucket should be persistently cached.
	 *
	 * Default is false. Can be set with the {@see 'wp_cache_themes_persistently'} filter.
	 *
	 * @static
	 * @access private
	 * @var bool
	 */
	private static $persistently_cache;

	/**
	 * Expiration time for the themes cache bucket.
	 *
	 * By default the bucket is not cached, so this value is useless.
	 *
	 * @static
	 * @access private
	 * @var bool
	 */
	private static $cache_expiration = 1800;

	/**
	 * Constructor for WP_Theme.
	 *
	 * @since  3.4.0
	 *
	 * @global array $wp_theme_directories
	 *
	 * @param string $theme_dir Directory of the theme within the theme_root.
	 * @param string $theme_root Theme root.
	 * @param WP_Error|void $_child If this theme is a parent theme, the child may be passed for validation purposes.
	 */
	public function __construct( $theme_dir, $theme_root, $_child = null ) {
		global $wp_theme_directories;

		// Initialize caching on first run.
		if ( ! isset( self::$persistently_cache ) ) {
			/** This action is documented in wp-includes/theme.php */
			self::$persistently_cache = apply_filters( 'wp_cache_themes_persistently', false, 'WP_Theme' );
			if ( self::$persistently_cache ) {
				wp_cache_add_global_groups( 'themes' );
				if ( is_int( self::$persistently_cache ) )
					self::$cache_expiration = self::$persistently_cache;
			} else {
				wp_cache_add_non_persistent_groups( 'themes' );
			}
		}

		$this->theme_root = $theme_root;
		$this->stylesheet = $theme_dir;

		// Correct a situation where the theme is 'some-directory/some-theme' but 'some-directory' was passed in as part of the theme root instead.
		if ( ! in_array( $theme_root, (array) $wp_theme_directories ) && in_array( dirname( $theme_root ), (array) $wp_theme_directories ) ) {
			$this->stylesheet = basename( $this->theme_root ) . '/' . $this->stylesheet;
			$this->theme_root = dirname( $theme_root );
		}

		$this->cache_hash = md5( $this->theme_root . '/' . $this->stylesheet );
		$theme_file = $this->stylesheet . '/style.css';

		$cache = $this->cache_get( 'theme' );

		if ( is_array( $cache ) ) {
			foreach ( array( 'errors', 'headers', 'template' ) as $key ) {
				if ( isset( $cache[ $key ] ) )
					$this->$key = $cache[ $key ];
			}
			if ( $this->errors )
				return;
			if ( isset( $cache['theme_root_template'] ) )
				$theme_root_template = $cache['theme_root_template'];
		} elseif ( ! file_exists( $this->theme_root . '/' . $theme_file ) ) {
			$this->headers['Name'] = $this->stylesheet;
			if ( ! file_exists( $this->theme_root . '/' . $this->stylesheet ) )
				$this->errors = new WP_Error( 'theme_not_found', sprintf( __( 'The theme directory "%s" does not exist.' ), esc_html( $this->stylesheet ) ) );
			else
				$this->errors = new WP_Error( 'theme_no_stylesheet', __( 'Stylesheet is missing.' ) );
			$this->template = $this->stylesheet;
			$this->cache_add( 'theme', array( 'headers' => $this->headers, 'errors' => $this->errors, 'stylesheet' => $this->stylesheet, 'template' => $this->template ) );
			if ( ! file_exists( $this->theme_root ) ) // Don't cache this one.
				$this->errors->add( 'theme_root_missing', __( 'ERROR: The themes directory is either empty or doesn&#8217;t exist. Please check your installation.' ) );
			return;
		} elseif ( ! is_readable( $this->theme_root . '/' . $theme_file ) ) {
			$this->headers['Name'] = $this->stylesheet;
			$this->errors = new WP_Error( 'theme_stylesheet_not_readable', __( 'Stylesheet is not readable.' ) );
			$this->template = $this->stylesheet;
			$this->cache_add( 'theme', array( 'headers' => $this->headers, 'errors' => $this->errors, 'stylesheet' => $this->stylesheet, 'template' => $this->template ) );
			return;
		} else {
			$this->headers = get_file_data( $this->theme_root . '/' . $theme_file, self::$file_headers, 'theme' );
			// Default themes always trump their pretenders.
			// Properly identify default themes that are inside a directory within wp-content/themes.
			if ( $default_theme_slug = array_search( $this->headers['Name'], self::$default_themes ) ) {
				if ( basename( $this->stylesheet ) != $default_theme_slug )
					$this->headers['Name'] .= '/' . $this->stylesheet;
			}
		}

		// (If template is set from cache [and there are no errors], we know it's good.)
		if ( ! $this->template && ! ( $this->template = $this->headers['Template'] ) ) {
			$this->template = $this->stylesheet;
			if ( ! file_exists( $this->theme_root . '/' . $this->stylesheet . '/index.php' ) ) {
				$error_message = sprintf(
					/* translators: 1: index.php, 2: Codex URL, 3: style.css */
					__( 'Template is missing. Standalone themes need to have a %1$s template file. <a href="%2$s">Child themes</a> need to have a Template header in the %3$s stylesheet.' ),
					'<code>index.php</code>',
					__( 'https://codex.wordpress.org/Child_Themes' ),
					'<code>style.css</code>'
				);
				$this->errors = new WP_Error( 'theme_no_index', $error_message );
				$this->cache_add( 'theme', array( 'headers' => $this->headers, 'errors' => $this->errors, 'stylesheet' => $this->stylesheet, 'template' => $this->template ) );
				return;
			}
		}

		// If we got our data from cache, we can assume that 'template' is pointing to the right place.
		if ( ! is_array( $cache ) && $this->template != $this->stylesheet && ! file_exists( $this->theme_root . '/' . $this->template . '/index.php' ) ) {
			// If we're in a directory of themes inside /themes, look for the parent nearby.
			// wp-content/themes/directory-of-themes/*
			$parent_dir = dirname( $this->stylesheet );
			if ( '.' != $parent_dir && file_exists( $this->theme_root . '/' . $parent_dir . '/' . $this->template . '/index.php' ) ) {
				$this->template = $parent_dir . '/' . $this->template;
			} elseif ( ( $directories = search_theme_directories() ) && isset( $directories[ $this->template ] ) ) {
				// Look for the template in the search_theme_directories() results, in case it is in another theme root.
				// We don't look into directories of themes, just the theme root.
				$theme_root_template = $directories[ $this->template ]['theme_root'];
			} else {
				// Parent theme is missing.
				$this->errors = new WP_Error( 'theme_no_parent', sprintf( __( 'The parent theme is missing. Please install the "%s" parent theme.' ), esc_html( $this->template ) ) );
				$this->cache_add( 'theme', array( 'headers' => $this->headers, 'errors' => $this->errors, 'stylesheet' => $this->stylesheet, 'template' => $this->template ) );
				$this->parent = new WP_Theme( $this->template, $this->theme_root, $this );
				return;
			}
		}

		// Set the parent, if we're a child theme.
		if ( $this->template != $this->stylesheet ) {
			// If we are a parent, then there is a problem. Only two generations allowed! Cancel things out.
			if ( $_child instanceof WP_Theme && $_child->template == $this->stylesheet ) {
				$_child->parent = null;
				$_child->errors = new WP_Error( 'theme_parent_invalid', sprintf( __( 'The "%s" theme is not a valid parent theme.' ), esc_html( $_child->template ) ) );
				$_child->cache_add( 'theme', array( 'headers' => $_child->headers, 'errors' => $_child->errors, 'stylesheet' => $_child->stylesheet, 'template' => $_child->template ) );
				// The two themes actually reference each other with the Template header.
				if ( $_child->stylesheet == $this->template ) {
					$this->errors = new WP_Error( 'theme_parent_invalid', sprintf( __( 'The "%s" theme is not a valid parent theme.' ), esc_html( $this->template ) ) );
					$this->cache_add( 'theme', array( 'headers' => $this->headers, 'errors' => $this->errors, 'stylesheet' => $this->stylesheet, 'template' => $this->template ) );
				}
				return;
			}
			// Set the parent. Pass the current instance so we can do the crazy checks above and assess errors.
			$this->parent = new WP_Theme( $this->template, isset( $theme_root_template ) ? $theme_root_template : $this->theme_root, $this );
		}

		// We're good. If we didn't retrieve from cache, set it.
		if ( ! is_array( $cache ) ) {
			$cache = array( 'headers' => $this->headers, 'errors' => $this->errors, 'stylesheet' => $this->stylesheet, 'template' => $this->template );
			// If the parent theme is in another root, we'll want to cache this. Avoids an entire branch of filesystem calls above.
			if ( isset( $theme_root_template ) )
				$cache['theme_root_template'] = $theme_root_template;
			$this->cache_add( 'theme', $cache );
		}
	}

	/**
	 * When converting the object to a string, the theme name is returned.
	 *
	 * @since  3.4.0
	 *
	 * @return string Theme name, ready for display (translated)
	 */
	public function __toString() {
		return (string) $this->display('Name');
	}

	/**
	 * __isset() magic method for properties formerly returned by current_theme_info()
	 *
	 * @staticvar array $properties
	 *
	 * @since  3.4.0
	 *
	 * @param string $offset Property to check if set.
	 * @return bool Whether the given property is set.
	 */
	public function __isset( $offset ) {
		static $properties = array(
			'name', 'title', 'version', 'parent_theme', 'template_dir', 'stylesheet_dir', 'template', 'stylesheet',
			'screenshot', 'description', 'author', 'tags', 'theme_root', 'theme_root_uri',
		);

		return in_array( $offset, $properties );
	}

	/**
	 * __get() magic method for properties formerly returned by current_theme_info()
	 *
	 * @since  3.4.0
	 *
	 * @param string $offset Property to get.
	 * @return mixed Property value.
	 */
	public function __get( $offset ) {
		switch ( $offset ) {
			case 'name' :
			case 'title' :
				return $this->get('Name');
			case 'version' :
				return $this->get('Version');
			case 'parent_theme' :
				return $this->parent() ? $this->parent()->get('Name') : '';
			case 'template_dir' :
				return $this->get_template_directory();
			case 'stylesheet_dir' :
				return $this->get_stylesheet_directory();
			case 'template' :
				return $this->get_template();
			case 'stylesheet' :
				return $this->get_stylesheet();
			case 'screenshot' :
				return $this->get_screenshot( 'relative' );
			// 'author' and 'description' did not previously return translated data.
			case 'description' :
				return $this->display('Description');
			case 'author' :
				return $this->display('Author');
			case 'tags' :
				return $this->get( 'Tags' );
			case 'theme_root' :
				return $this->get_theme_root();
			case 'theme_root_uri' :
				return $this->get_theme_root_uri();
			// For cases where the array was converted to an object.
			default :
				return $this->offsetGet( $offset );
		}
	}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes()
	 *
	 * @since  3.4.0
	 *
	 * @param mixed $offset
	 * @param mixed $value
	 */
	public function offsetSet( $offset, $value ) {}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes()
	 *
	 * @since  3.4.0
	 *
	 * @param mixed $offset
	 */
	public function offsetUnset( $offset ) {}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes()
	 *
	 * @staticvar array $keys
	 *
	 * @since  3.4.0
	 *
	 * @param mixed $offset
	 * @return bool
	 */
	public function offsetExists( $offset ) {
		static $keys = array(
			'Name', 'Version', 'Status', 'Title', 'Author', 'Author Name', 'Author URI', 'Description',
			'Template', 'Stylesheet', 'Template Files', 'Stylesheet Files', 'Template Dir', 'Stylesheet Dir',
			'Screenshot', 'Tags', 'Theme Root', 'Theme Root URI', 'Parent Theme',
		);

		return in_array( $offset, $keys );
	}

	/**
	 * Method to implement ArrayAccess for keys formerly returned by get_themes().
	 *
	 * Author, Author Name, Author URI, and Description did not previously return
	 * translated data. We are doing so now as it is safe to do. However, as
	 * Name and Title could have been used as the key for get_themes(), both remain
	 * untranslated for back compatibility. This means that ['Name'] is not ideal,
	 * and care should be taken to use `$theme::display( 'Name' )` to get a properly
	 * translated header.
	 *
	 * @since  3.4.0
	 *
	 * @param mixed $offset
	 * @return mixed
	 */
	public function offsetGet( $offset ) {
		switch ( $offset ) {
			case 'Name' :
			case 'Title' :
				/*
				 * See note above about using translated data. get() is not ideal.
				 * It is only for backward compatibility. Use display().
				 */
				return $this->get('Name');
			case 'Author' :
				return $this->display( 'Author');
			case 'Author Name' :
				return $this->display( 'Author', false);
			case 'Author URI' :
				return $this->display('AuthorURI');
			case 'Description' :
				return $this->display( 'Description');
			case 'Version' :
			case 'Status' :
				return $this->get( $offset );
			case 'Template' :
				return $this->get_template();
			case 'Stylesheet' :
				return $this->get_stylesheet();
			case 'Template Files' :
				return $this->get_files( 'php', 1, true );
			case 'Stylesheet Files' :
				return $this->get_files( 'css', 0, false );
			case 'Template Dir' :
				return $this->get_template_directory();
			case 'Stylesheet Dir' :
				return $this->get_stylesheet_directory();
			case 'Screenshot' :
				return $this->get_screenshot( 'relative' );
			case 'Tags' :
				return $this->get('Tags');
			case 'Theme Root' :
				return $this->get_theme_root();
			case 'Theme Root URI' :
				return $this->get_theme_root_uri();
			case 'Parent Theme' :
				return $this->parent() ? $this->parent()->get('Name') : '';
			default :
				return null;
		}
	}

	/**
	 * Returns errors property.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return WP_Error|false WP_Error if there are errors, or false.
	 */
	public function errors() {
		return is_wp_error( $this->errors ) ? $this->errors : false;
	}

	/**
	 * Whether the theme exists.
	 *
	 * A theme with errors exists. A theme with the error of 'theme_not_found',
	 * meaning that the theme's directory was not found, does not exist.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return bool Whether the theme exists.
	 */
	public function exists() {
		return ! ( $this->errors() && in_array( 'theme_not_found', $this->errors()->get_error_codes() ) );
	}

	/**
	 * Returns reference to the parent theme.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return WP_Theme|false Parent theme, or false if the current theme is not a child theme.
	 */
	public function parent() {
		return isset( $this->parent ) ? $this->parent : false;
	}

	/**
	 * Adds theme data to cache.
	 *
	 * Cache entries keyed by the theme and the type of data.
	 *
	 * @since 3.4.0
	 * @access private
	 *
	 * @param string $key Type of data to store (theme, screenshot, headers, post_templates)
	 * @param string $data Data to store
	 * @return bool Return value from wp_cache_add()
	 */
	private function cache_add( $key, $data ) {
		return wp_cache_add( $key . '-' . $this->cache_hash, $data, 'themes', self::$cache_expiration );
	}

	/**
	 * Gets theme data from cache.
	 *
	 * Cache entries are keyed by the theme and the type of data.
	 *
	 * @since 3.4.0
	 * @access private
	 *
	 * @param string $key Type of data to retrieve (theme, screenshot, headers, post_templates)
	 * @return mixed Retrieved data
	 */
	private function cache_get( $key ) {
		return wp_cache_get( $key . '-' . $this->cache_hash, 'themes' );
	}

	/**
	 * Clears the cache for the theme.
	 *
	 * @since 3.4.0
	 * @access public
	 */
	public function cache_delete() {
		foreach ( array( 'theme', 'screenshot', 'headers', 'post_templates' ) as $key )
			wp_cache_delete( $key . '-' . $this->cache_hash, 'themes' );
		$this->template = $this->textdomain_loaded = $this->theme_root_uri = $this->parent = $this->errors = $this->headers_sanitized = $this->name_translated = null;
		$this->headers = array();
		$this->__construct( $this->stylesheet, $this->theme_root );
	}

	/**
	 * Get a raw, unformatted theme header.
	 *
	 * The header is sanitized, but is not translated, and is not marked up for display.
	 * To get a theme header for display, use the display() method.
	 *
	 * Use the get_template() method, not the 'Template' header, for finding the template.
	 * The 'Template' header is only good for what was written in the style.css, while
	 * get_template() takes into account where WordPress actually located the theme and
	 * whether it is actually valid.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @param string $header Theme header. Name, Description, Author, Version, ThemeURI, AuthorURI, Status, Tags.
	 * @return string|false String on success, false on failure.
	 */
	public function get( $header ) {
		if ( ! isset( $this->headers[ $header ] ) )
			return false;

		if ( ! isset( $this->headers_sanitized ) ) {
			$this->headers_sanitized = $this->cache_get( 'headers' );
			if ( ! is_array( $this->headers_sanitized ) )
				$this->headers_sanitized = array();
		}

		if ( isset( $this->headers_sanitized[ $header ] ) )
			return $this->headers_sanitized[ $header ];

		// If themes are a persistent group, sanitize everything and cache it. One cache add is better than many cache sets.
		if ( self::$persistently_cache ) {
			foreach ( array_keys( $this->headers ) as $_header )
				$this->headers_sanitized[ $_header ] = $this->sanitize_header( $_header, $this->headers[ $_header ] );
			$this->cache_add( 'headers', $this->headers_sanitized );
		} else {
			$this->headers_sanitized[ $header ] = $this->sanitize_header( $header, $this->headers[ $header ] );
		}

		return $this->headers_sanitized[ $header ];
	}

	/**
	 * Gets a theme header, formatted and translated for display.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @param string $header Theme header. Name, Description, Author, Version, ThemeURI, AuthorURI, Status, Tags.
	 * @param bool $markup Optional. Whether to mark up the header. Defaults to true.
	 * @param bool $translate Optional. Whether to translate the header. Defaults to true.
	 * @return string|false Processed header, false on failure.
	 */
	public function display( $header, $markup = true, $translate = true ) {
		$value = $this->get( $header );
		if ( false === $value ) {
			return false;
		}

		if ( $translate && ( empty( $value ) || ! $this->load_textdomain() ) )
			$translate = false;

		if ( $translate )
			$value = $this->translate_header( $header, $value );

		if ( $markup )
			$value = $this->markup_header( $header, $value, $translate );

		return $value;
	}

	/**
	 * Sanitize a theme header.
	 *
	 * @since 3.4.0
	 * @access private
	 *
	 * @staticvar array $header_tags
	 * @staticvar array $header_tags_with_a
	 *
	 * @param string $header Theme header. Name, Description, Author, Version, ThemeURI, AuthorURI, Status, Tags.
	 * @param string $value Value to sanitize.
	 * @return mixed
	 */
	private function sanitize_header( $header, $value ) {
		switch ( $header ) {
			case 'Status' :
				if ( ! $value ) {
					$value = 'publish';
					break;
				}
				// Fall through otherwise.
			case 'Name' :
				static $header_tags = array(
					'abbr'    => array( 'title' => true ),
					'acronym' => array( 'title' => true ),
					'code'    => true,
					'em'      => true,
					'strong'  => true,
				);
				$value = wp_kses( $value, $header_tags );
				break;
			case 'Author' :
				// There shouldn't be anchor tags in Author, but some themes like to be challenging.
			case 'Description' :
				static $header_tags_with_a = array(
					'a'       => array( 'href' => true, 'title' => true ),
					'abbr'    => array( 'title' => true ),
					'acronym' => array( 'title' => true ),
					'code'    => true,
					'em'      => true,
					'strong'  => true,
				);
				$value = wp_kses( $value, $header_tags_with_a );
				break;
			case 'ThemeURI' :
			case 'AuthorURI' :
				$value = esc_url_raw( $value );
				break;
			case 'Tags' :
				$value = array_filter( array_map( 'trim', explode( ',', strip_tags( $value ) ) ) );
				break;
			case 'Version' :
				$value = strip_tags( $value );
				break;
		}

		return $value;
	}

	/**
	 * Mark up a theme header.
	 *
     * @since 3.4.0
	 * @access private
	 *
	 * @staticvar string $comma
	 *
	 * @param string $header Theme header. Name, Description, Author, Version, ThemeURI, AuthorURI, Status, Tags.
	 * @param string $value Value to mark up.
	 * @param string $translate Whether the header has been translated.
	 * @return string Value, marked up.
	 */
	private function markup_header( $header, $value, $translate ) {
		switch ( $header ) {
			case 'Name' :
				if ( empty( $value ) ) {
					$value = esc_html( $this->get_stylesheet() );
				}
				break;
			case 'Description' :
				$value = wptexturize( $value );
				break;
			case 'Author' :
				if ( $this->get('AuthorURI') ) {
					$value = sprintf( '<a href="%1$s">%2$s</a>', $this->display( 'AuthorURI', true, $translate ), $value );
				} elseif ( ! $value ) {
					$value = __( 'Anonymous' );
				}
				break;
			case 'Tags' :
				static $comma = null;
				if ( ! isset( $comma ) ) {
					/* translators: used between list items, there is a space after the comma */
					$comma = __( ', ' );
				}
				$value = implode( $comma, $value );
				break;
			case 'ThemeURI' :
			case 'AuthorURI' :
				$value = esc_url( $value );
				break;
		}

		return $value;
	}

	/**
	 * Translate a theme header.
	 *
	 * @since 3.4.0
	 * @access private
	 *
	 * @staticvar array $tags_list
	 *
	 * @param string $header Theme header. Name, Description, Author, Version, ThemeURI, AuthorURI, Status, Tags.
	 * @param string $value Value to translate.
	 * @return string Translated value.
	 */
	private function translate_header( $header, $value ) {
		switch ( $header ) {
			case 'Name' :
				// Cached for sorting reasons.
				if ( isset( $this->name_translated ) )
					return $this->name_translated;
				$this->name_translated = translate( $value, $this->get('TextDomain' ) );
				return $this->name_translated;
			case 'Tags' :
				if ( empty( $value ) || ! function_exists( 'get_theme_feature_list' ) ) {
					return $value;
				}

				static $tags_list;
				if ( ! isset( $tags_list ) ) {
					$tags_list = array(
						// As of 4.6, deprecated tags which are only used to provide translation for older themes.
						'black' => __( 'Black' ), 'blue' => __( 'Blue' ), 'brown'  => __( 'Brown' ),
						'gray' => __( 'Gray' ), 'green'  => __( 'Green' ), 'orange' => __( 'Orange' ),
						'pink' => __( 'Pink' ), 'purple' => __( 'Purple' ), 'red' => __( 'Red' ),
						'silver' => __( 'Silver' ), 'tan' => __( 'Tan' ), 'white' => __( 'White' ),
						'yellow' => __( 'Yellow' ), 'dark' => __( 'Dark' ), 'light' => __( 'Light' ),
						'fixed-layout' => __( 'Fixed Layout' ), 'fluid-layout' => __( 'Fluid Layout' ),
						'responsive-layout' => __( 'Responsive Layout' ), 'blavatar' => __( 'Blavatar' ),
						'photoblogging' => __( 'Photoblogging' ), 'seasonal' => __( 'Seasonal' ),
					);

					$feature_list = get_theme_feature_list( false ); // No API
					foreach ( $feature_list as $tags ) {
						$tags_list += $tags;
					}
				}

				foreach ( $value as &$tag ) {
					if ( isset( $tags_list[ $tag ] ) ) {
						$tag = $tags_list[ $tag ];
					} elseif ( isset( self::$tag_map[ $tag ] ) ) {
						$tag = $tags_list[ self::$tag_map[ $tag ] ];
					}
				}

				return $value;

			default :
				$value = translate( $value, $this->get('TextDomain') );
		}
		return $value;
	}

	/**
	 * The directory name of the theme's "stylesheet" files, inside the theme root.
	 *
	 * In the case of a child theme, this is directory name of the child theme.
	 * Otherwise, get_stylesheet() is the same as get_template().
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string Stylesheet
	 */
	public function get_stylesheet() {
		return $this->stylesheet;
	}

	/**
	 * The directory name of the theme's "template" files, inside the theme root.
	 *
	 * In the case of a child theme, this is the directory name of the parent theme.
	 * Otherwise, the get_template() is the same as get_stylesheet().
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string Template
	 */
	public function get_template() {
		return $this->template;
	}

	/**
	 * Returns the absolute path to the directory of a theme's "stylesheet" files.
	 *
	 * In the case of a child theme, this is the absolute path to the directory
	 * of the child theme's files.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string Absolute path of the stylesheet directory.
	 */
	public function get_stylesheet_directory() {
		if ( $this->errors() && in_array( 'theme_root_missing', $this->errors()->get_error_codes() ) )
			return '';

		return $this->theme_root . '/' . $this->stylesheet;
	}

	/**
	 * Returns the absolute path to the directory of a theme's "template" files.
	 *
	 * In the case of a child theme, this is the absolute path to the directory
	 * of the parent theme's files.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string Absolute path of the template directory.
	 */
	public function get_template_directory() {
		if ( $this->parent() )
			$theme_root = $this->parent()->theme_root;
		else
			$theme_root = $this->theme_root;

		return $theme_root . '/' . $this->template;
	}

	/**
	 * Returns the URL to the directory of a theme's "stylesheet" files.
	 *
	 * In the case of a child theme, this is the URL to the directory of the
	 * child theme's files.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string URL to the stylesheet directory.
	 */
	public function get_stylesheet_directory_uri() {
		return $this->get_theme_root_uri() . '/' . str_replace( '%2F', '/', rawurlencode( $this->stylesheet ) );
	}

	/**
	 * Returns the URL to the directory of a theme's "template" files.
	 *
	 * In the case of a child theme, this is the URL to the directory of the
	 * parent theme's files.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string URL to the template directory.
	 */
	public function get_template_directory_uri() {
		if ( $this->parent() )
			$theme_root_uri = $this->parent()->get_theme_root_uri();
		else
			$theme_root_uri = $this->get_theme_root_uri();

		return $theme_root_uri . '/' . str_replace( '%2F', '/', rawurlencode( $this->template ) );
	}

	/**
	 * The absolute path to the directory of the theme root.
	 *
	 * This is typically the absolute path to wp-content/themes.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string Theme root.
	 */
	public function get_theme_root() {
		return $this->theme_root;
	}

	/**
	 * Returns the URL to the directory of the theme root.
	 *
	 * This is typically the absolute URL to wp-content/themes. This forms the basis
	 * for all other URLs returned by WP_Theme, so we pass it to the public function
	 * get_theme_root_uri() and allow it to run the {@see 'theme_root_uri'} filter.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return string Theme root URI.
	 */
	public function get_theme_root_uri() {
		if ( ! isset( $this->theme_root_uri ) )
			$this->theme_root_uri = get_theme_root_uri( $this->stylesheet, $this->theme_root );
		return $this->theme_root_uri;
	}

	/**
	 * Returns the main screenshot file for the theme.
	 *
	 * The main screenshot is called screenshot.png. gif and jpg extensions are also allowed.
	 *
	 * Screenshots for a theme must be in the stylesheet directory. (In the case of child
	 * themes, parent theme screenshots are not inherited.)
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @param string $uri Type of URL to return, either 'relative' or an absolute URI. Defaults to absolute URI.
	 * @return string|false Screenshot file. False if the theme does not have a screenshot.
	 */
	public function get_screenshot( $uri = 'uri' ) {
		$screenshot = $this->cache_get( 'screenshot' );
		if ( $screenshot ) {
			if ( 'relative' == $uri )
				return $screenshot;
			return $this->get_stylesheet_directory_uri() . '/' . $screenshot;
		} elseif ( 0 === $screenshot ) {
			return false;
		}

		foreach ( array( 'png', 'gif', 'jpg', 'jpeg' ) as $ext ) {
			if ( file_exists( $this->get_stylesheet_directory() . "/screenshot.$ext" ) ) {
				$this->cache_add( 'screenshot', 'screenshot.' . $ext );
				if ( 'relative' == $uri )
					return 'screenshot.' . $ext;
				return $this->get_stylesheet_directory_uri() . '/' . 'screenshot.' . $ext;
			}
		}

		$this->cache_add( 'screenshot', 0 );
		return false;
	}

	/**
	 * Return files in the theme's directory.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @param mixed $type Optional. Array of extensions to return. Defaults to all files (null).
	 * @param int $depth Optional. How deep to search for files. Defaults to a flat scan (0 depth). -1 depth is infinite.
	 * @param bool $search_parent Optional. Whether to return parent files. Defaults to false.
	 * @return array Array of files, keyed by the path to the file relative to the theme's directory, with the values
	 * 	             being absolute paths.
	 */
	public function get_files( $type = null, $depth = 0, $search_parent = false ) {
		$files = (array) self::scandir( $this->get_stylesheet_directory(), $type, $depth );

		if ( $search_parent && $this->parent() )
			$files += (array) self::scandir( $this->get_template_directory(), $type, $depth );

		return $files;
	}

	/**
	 * Returns the theme's post templates.
	 *
	 * @since 4.7.0
	 * @access public
	 *
	 * @return array Array of page templates, keyed by filename and post type,
	 *               with the value of the translated header name.
	 */
	public function get_post_templates() {
		// If you screw up your current theme and we invalidate your parent, most things still work. Let it slide.
		if ( $this->errors() && $this->errors()->get_error_codes() !== array( 'theme_parent_invalid' ) ) {
			return array();
		}

		$post_templates = $this->cache_get( 'post_templates' );

		if ( ! is_array( $post_templates ) ) {
			$post_templates = array();

			$files = (array) $this->get_files( 'php', 1 );

			foreach ( $files as $file => $full_path ) {
				if ( ! preg_match( '|Template Name:(.*)$|mi', file_get_contents( $full_path ), $header ) ) {
					continue;
				}

				$types = array( 'page' );
				if ( preg_match( '|Template Post Type:(.*)$|mi', file_get_contents( $full_path ), $type ) ) {
					$types = explode( ',', _cleanup_header_comment( $type[1] ) );
				}

				foreach ( $types as $type ) {
					$type = sanitize_key( $type );
					if ( ! isset( $post_templates[ $type ] ) ) {
						$post_templates[ $type ] = array();
					}

					$post_templates[ $type ][ $file ] = _cleanup_header_comment( $header[1] );
				}
			}

			$this->cache_add( 'post_templates', $post_templates );
		}

		if ( $this->load_textdomain() ) {
			foreach ( $post_templates as &$post_type ) {
				foreach ( $post_type as &$post_template ) {
					$post_template = $this->translate_header( 'Template Name', $post_template );
				}
			}
		}

		return $post_templates;
	}

	/**
	 * Returns the theme's post templates for a given post type.
	 *
	 * @since 3.4.0
	 * @since 4.7.0 Added the `$post_type` parameter.
	 * @access public
	 *
	 * @param WP_Post|null $post      Optional. The post being edited, provided for context.
	 * @param string       $post_type Optional. Post type to get the templates for. Default 'page'.
	 *                                If a post is provided, its post type is used.
	 * @return array Array of page templates, keyed by filename, with the value of the translated header name.
	 */
	public function get_page_templates( $post = null, $post_type = 'page' ) {
		if ( $post ) {
			$post_type = get_post_type( $post );
		}

		$post_templates = $this->get_post_templates();
		$post_templates = isset( $post_templates[ $post_type ] ) ? $post_templates[ $post_type ] : array();

		if ( $this->parent() ) {
			$post_templates += $this->parent()->get_page_templates( $post, $post_type );
		}

		/**
		 * Filters list of page templates for a theme.
		 *
		 * The dynamic portion of the hook name, `$post_type`, refers to the post type.
		 *
		 * @since 3.9.0
		 * @since 4.4.0 Converted to allow complete control over the `$page_templates` array.
		 * @since 4.7.0 Added the `$post_type` parameter.
		 *
		 * @param array        $post_templates Array of page templates. Keys are filenames,
		 *                                     values are translated names.
		 * @param WP_Theme     $this           The theme object.
		 * @param WP_Post|null $post           The post being edited, provided for context, or null.
		 * @param string       $post_type      Post type to get the templates for.
		 */
		return (array) apply_filters( "theme_{$post_type}_templates", $post_templates, $this, $post, $post_type );
	}

	/**
	 * Scans a directory for files of a certain extension.
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access private
	 *
	 * @param string            $path          Absolute path to search.
	 * @param array|string|null $extensions    Optional. Array of extensions to find, string of a single extension,
	 *                                         or null for all extensions. Default null.
	 * @param int               $depth         Optional. How many levels deep to search for files. Accepts 0, 1+, or
	 *                                         -1 (infinite depth). Default 0.
	 * @param string            $relative_path Optional. The basename of the absolute path. Used to control the
	 *                                         returned path for the found files, particularly when this function
	 *                                         recurses to lower depths. Default empty.
	 * @return array|false Array of files, keyed by the path to the file relative to the `$path` directory prepended
	 *                     with `$relative_path`, with the values being absolute paths. False otherwise.
	 */
	private static function scandir( $path, $extensions = null, $depth = 0, $relative_path = '' ) {
		if ( ! is_dir( $path ) )
			return false;

		if ( $extensions ) {
			$extensions = (array) $extensions;
			$_extensions = implode( '|', $extensions );
		}

		$relative_path = trailingslashit( $relative_path );
		if ( '/' == $relative_path )
			$relative_path = '';

		$results = scandir( $path );
		$files = array();

		/**
		 * Filters the array of excluded directories and files while scanning theme folder.
		 *
 		 * @since 4.7.4
		 *
		 * @param array $exclusions Array of excluded directories and files.
		 */
		$exclusions = (array) apply_filters( 'theme_scandir_exclusions', array( 'CVS', 'node_modules' ) );

		foreach ( $results as $result ) {
			if ( '.' == $result[0] || in_array( $result, $exclusions, true ) ) {
				continue;
			}
			if ( is_dir( $path . '/' . $result ) ) {
				if ( ! $depth )
					continue;
				$found = self::scandir( $path . '/' . $result, $extensions, $depth - 1 , $relative_path . $result );
				$files = array_merge_recursive( $files, $found );
			} elseif ( ! $extensions || preg_match( '~\.(' . $_extensions . ')$~', $result ) ) {
				$files[ $relative_path . $result ] = $path . '/' . $result;
			}
		}

		return $files;
	}

	/**
	 * Loads the theme's textdomain.
	 *
	 * Translation files are not inherited from the parent theme. Todo: if this fails for the
	 * child theme, it should probably try to load the parent theme's translations.
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @return bool True if the textdomain was successfully loaded or has already been loaded.
	 * 	False if no textdomain was specified in the file headers, or if the domain could not be loaded.
	 */
	public function load_textdomain() {
		if ( isset( $this->textdomain_loaded ) )
			return $this->textdomain_loaded;

		$textdomain = $this->get('TextDomain');
		if ( ! $textdomain ) {
			$this->textdomain_loaded = false;
			return false;
		}

		if ( is_textdomain_loaded( $textdomain ) ) {
			$this->textdomain_loaded = true;
			return true;
		}

		$path = $this->get_stylesheet_directory();
		if ( $domainpath = $this->get('DomainPath') )
			$path .= $domainpath;
		else
			$path .= '/languages';

		$this->textdomain_loaded = load_theme_textdomain( $textdomain, $path );
		return $this->textdomain_loaded;
	}

	/**
	 * Whether the theme is allowed (multisite only).
	 *
	 * @since 3.4.0
	 * @access public
	 *
	 * @param string $check Optional. Whether to check only the 'network'-wide settings, the 'site'
	 * 	settings, or 'both'. Defaults to 'both'.
	 * @param int $blog_id Optional. Ignored if only network-wide settings are checked. Defaults to current site.
	 * @return bool Whether the theme is allowed for the network. Returns true in single-site.
	 */
	public function is_allowed( $check = 'both', $blog_id = null ) {
		if ( ! is_multisite() )
			return true;

		if ( 'both' == $check || 'network' == $check ) {
			$allowed = self::get_allowed_on_network();
			if ( ! empty( $allowed[ $this->get_stylesheet() ] ) )
				return true;
		}

		if ( 'both' == $check || 'site' == $check ) {
			$allowed = self::get_allowed_on_site( $blog_id );
			if ( ! empty( $allowed[ $this->get_stylesheet() ] ) )
				return true;
		}

		return false;
	}

	/**
	 * Determines the latest WordPress default theme that is installed.
	 *
	 * This hits the filesystem.
	 *
	 * @since  4.4.0
	 *
	 * @return WP_Theme|false Object, or false if no theme is installed, which would be bad.
	 */
	public static function get_core_default_theme() {
		foreach ( array_reverse( self::$default_themes ) as $slug => $name ) {
			$theme = wp_get_theme( $slug );
			if ( $theme->exists() ) {
				return $theme;
			}
		}
		return false;
	}

	/**
	 * Returns array of stylesheet names of themes allowed on the site or network.
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access public
	 *
	 * @param int $blog_id Optional. ID of the site. Defaults to the current site.
	 * @return array Array of stylesheet names.
	 */
	public static function get_allowed( $blog_id = null ) {
		/**
		 * Filters the array of themes allowed on the network.
		 *
		 * Site is provided as context so that a list of network allowed themes can
		 * be filtered further.
		 *
		 * @since 4.5.0
		 *
		 * @param array $allowed_themes An array of theme stylesheet names.
		 * @param int   $blog_id        ID of the site.
		 */
		$network = (array) apply_filters( 'network_allowed_themes', self::get_allowed_on_network(), $blog_id );
		return $network + self::get_allowed_on_site( $blog_id );
	}

	/**
	 * Returns array of stylesheet names of themes allowed on the network.
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access public
	 *
	 * @staticvar array $allowed_themes
	 *
	 * @return array Array of stylesheet names.
	 */
	public static function get_allowed_on_network() {
		static $allowed_themes;
		if ( ! isset( $allowed_themes ) ) {
			$allowed_themes = (array) get_site_option( 'allowedthemes' );
		}

		/**
		 * Filters the array of themes allowed on the network.
		 *
		 * @since MU
		 *
		 * @param array $allowed_themes An array of theme stylesheet names.
		 */
		$allowed_themes = apply_filters( 'allowed_themes', $allowed_themes );

		return $allowed_themes;
	}

	/**
	 * Returns array of stylesheet names of themes allowed on the site.
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access public
	 *
	 * @staticvar array $allowed_themes
	 *
	 * @param int $blog_id Optional. ID of the site. Defaults to the current site.
	 * @return array Array of stylesheet names.
	 */
	public static function get_allowed_on_site( $blog_id = null ) {
		static $allowed_themes = array();

		if ( ! $blog_id || ! is_multisite() )
			$blog_id = get_current_blog_id();

		if ( isset( $allowed_themes[ $blog_id ] ) ) {
			/**
			 * Filters the array of themes allowed on the site.
			 *
			 * @since 4.5.0
			 *
			 * @param array $allowed_themes An array of theme stylesheet names.
			 * @param int   $blog_id        ID of the site. Defaults to current site.
			 */
			return (array) apply_filters( 'site_allowed_themes', $allowed_themes[ $blog_id ], $blog_id );
		}

		$current = $blog_id == get_current_blog_id();

		if ( $current ) {
			$allowed_themes[ $blog_id ] = get_option( 'allowedthemes' );
		} else {
			switch_to_blog( $blog_id );
			$allowed_themes[ $blog_id ] = get_option( 'allowedthemes' );
			restore_current_blog();
		}

		// This is all super old MU back compat joy.
		// 'allowedthemes' keys things by stylesheet. 'allowed_themes' keyed things by name.
		if ( false === $allowed_themes[ $blog_id ] ) {
			if ( $current ) {
				$allowed_themes[ $blog_id ] = get_option( 'allowed_themes' );
			} else {
				switch_to_blog( $blog_id );
				$allowed_themes[ $blog_id ] = get_option( 'allowed_themes' );
				restore_current_blog();
			}

			if ( ! is_array( $allowed_themes[ $blog_id ] ) || empty( $allowed_themes[ $blog_id ] ) ) {
				$allowed_themes[ $blog_id ] = array();
			} else {
				$converted = array();
				$themes = wp_get_themes();
				foreach ( $themes as $stylesheet => $theme_data ) {
					if ( isset( $allowed_themes[ $blog_id ][ $theme_data->get('Name') ] ) )
						$converted[ $stylesheet ] = true;
				}
				$allowed_themes[ $blog_id ] = $converted;
			}
			// Set the option so we never have to go through this pain again.
			if ( is_admin() && $allowed_themes[ $blog_id ] ) {
				if ( $current ) {
					update_option( 'allowedthemes', $allowed_themes[ $blog_id ] );
					delete_option( 'allowed_themes' );
				} else {
					switch_to_blog( $blog_id );
					update_option( 'allowedthemes', $allowed_themes[ $blog_id ] );
					delete_option( 'allowed_themes' );
					restore_current_blog();
				}
			}
		}

		/** This filter is documented in wp-includes/class-wp-theme.php */
		return (array) apply_filters( 'site_allowed_themes', $allowed_themes[ $blog_id ], $blog_id );
	}

	/**
	 * Enables a theme for all sites on the current network.
	 *
	 * @since 4.6.0
	 * @access public
	 * @static
	 *
	 * @param string|array $stylesheets Stylesheet name or array of stylesheet names.
	 */
	public static function network_enable_theme( $stylesheets ) {
		if ( ! is_multisite() ) {
			return;
		}

		if ( ! is_array( $stylesheets ) ) {
			$stylesheets = array( $stylesheets );
		}

		$allowed_themes = get_site_option( 'allowedthemes' );
		foreach ( $stylesheets as $stylesheet ) {
			$allowed_themes[ $stylesheet ] = true;
		}

		update_site_option( 'allowedthemes', $allowed_themes );
	}

	/**
	 * Disables a theme for all sites on the current network.
	 *
	 * @since 4.6.0
	 * @access public
	 * @static
	 *
	 * @param string|array $stylesheets Stylesheet name or array of stylesheet names.
	 */
	public static function network_disable_theme( $stylesheets ) {
		if ( ! is_multisite() ) {
			return;
		}

		if ( ! is_array( $stylesheets ) ) {
			$stylesheets = array( $stylesheets );
		}

		$allowed_themes = get_site_option( 'allowedthemes' );
		foreach ( $stylesheets as $stylesheet ) {
			if ( isset( $allowed_themes[ $stylesheet ] ) ) {
				unset( $allowed_themes[ $stylesheet ] );
			}
		}

		update_site_option( 'allowedthemes', $allowed_themes );
	}

	/**
	 * Sorts themes by name.
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access public
	 *
	 * @param array $themes Array of themes to sort, passed by reference.
	 */
	public static function sort_by_name( &$themes ) {
		if ( 0 === strpos( get_user_locale(), 'en_' ) ) {
			uasort( $themes, array( 'WP_Theme', '_name_sort' ) );
		} else {
			uasort( $themes, array( 'WP_Theme', '_name_sort_i18n' ) );
		}
	}

	/**
	 * Callback function for usort() to naturally sort themes by name.
	 *
	 * Accesses the Name header directly from the class for maximum speed.
	 * Would choke on HTML but we don't care enough to slow it down with strip_tags().
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access private
	 *
	 * @param string $a First name.
	 * @param string $b Second name.
	 * @return int Negative if `$a` falls lower in the natural order than `$b`. Zero if they fall equally.
	 *             Greater than 0 if `$a` falls higher in the natural order than `$b`. Used with usort().
	 */
	private static function _name_sort( $a, $b ) {
		return strnatcasecmp( $a->headers['Name'], $b->headers['Name'] );
	}

	/**
	 * Name sort (with translation).
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access private
	 *
	 * @param string $a First name.
	 * @param string $b Second name.
	 * @return int Negative if `$a` falls lower in the natural order than `$b`. Zero if they fall equally.
	 *             Greater than 0 if `$a` falls higher in the natural order than `$b`. Used with usort().
	 */
	private static function _name_sort_i18n( $a, $b ) {
		// Don't mark up; Do translate.
		return strnatcasecmp( $a->display( 'Name', false, true ), $b->display( 'Name', false, true ) );
	}
}