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nav-menu.php (42181B)


      1 <?php
      2 /**
      3  * Navigation Menu functions
      4  *
      5  * @package WordPress
      6  * @subpackage Nav_Menus
      7  * @since 3.0.0
      8  */
      9 
     10 /**
     11  * Returns a navigation menu object.
     12  *
     13  * @since 3.0.0
     14  *
     15  * @param int|string|WP_Term $menu Menu ID, slug, name, or object.
     16  * @return WP_Term|false Menu object on success, false if $menu param isn't supplied or term does not exist.
     17  */
     18 function wp_get_nav_menu_object( $menu ) {
     19 	$menu_obj = false;
     20 
     21 	if ( is_object( $menu ) ) {
     22 		$menu_obj = $menu;
     23 	}
     24 
     25 	if ( $menu && ! $menu_obj ) {
     26 		$menu_obj = get_term( $menu, 'nav_menu' );
     27 
     28 		if ( ! $menu_obj ) {
     29 			$menu_obj = get_term_by( 'slug', $menu, 'nav_menu' );
     30 		}
     31 
     32 		if ( ! $menu_obj ) {
     33 			$menu_obj = get_term_by( 'name', $menu, 'nav_menu' );
     34 		}
     35 	}
     36 
     37 	if ( ! $menu_obj || is_wp_error( $menu_obj ) ) {
     38 		$menu_obj = false;
     39 	}
     40 
     41 	/**
     42 	 * Filters the nav_menu term retrieved for wp_get_nav_menu_object().
     43 	 *
     44 	 * @since 4.3.0
     45 	 *
     46 	 * @param WP_Term|false      $menu_obj Term from nav_menu taxonomy, or false if nothing had been found.
     47 	 * @param int|string|WP_Term $menu     The menu ID, slug, name, or object passed to wp_get_nav_menu_object().
     48 	 */
     49 	return apply_filters( 'wp_get_nav_menu_object', $menu_obj, $menu );
     50 }
     51 
     52 /**
     53  * Check if the given ID is a navigation menu.
     54  *
     55  * Returns true if it is; false otherwise.
     56  *
     57  * @since 3.0.0
     58  *
     59  * @param int|string|WP_Term $menu Menu ID, slug, name, or object of menu to check.
     60  * @return bool Whether the menu exists.
     61  */
     62 function is_nav_menu( $menu ) {
     63 	if ( ! $menu ) {
     64 		return false;
     65 	}
     66 
     67 	$menu_obj = wp_get_nav_menu_object( $menu );
     68 
     69 	if (
     70 		$menu_obj &&
     71 		! is_wp_error( $menu_obj ) &&
     72 		! empty( $menu_obj->taxonomy ) &&
     73 		'nav_menu' === $menu_obj->taxonomy
     74 	) {
     75 		return true;
     76 	}
     77 
     78 	return false;
     79 }
     80 
     81 /**
     82  * Registers navigation menu locations for a theme.
     83  *
     84  * @since 3.0.0
     85  *
     86  * @global array $_wp_registered_nav_menus
     87  *
     88  * @param string[] $locations Associative array of menu location identifiers (like a slug) and descriptive text.
     89  */
     90 function register_nav_menus( $locations = array() ) {
     91 	global $_wp_registered_nav_menus;
     92 
     93 	add_theme_support( 'menus' );
     94 
     95 	foreach ( $locations as $key => $value ) {
     96 		if ( is_int( $key ) ) {
     97 			_doing_it_wrong( __FUNCTION__, __( 'Nav menu locations must be strings.' ), '5.3.0' );
     98 			break;
     99 		}
    100 	}
    101 
    102 	$_wp_registered_nav_menus = array_merge( (array) $_wp_registered_nav_menus, $locations );
    103 }
    104 
    105 /**
    106  * Unregisters a navigation menu location for a theme.
    107  *
    108  * @since 3.1.0
    109  *
    110  * @global array $_wp_registered_nav_menus
    111  *
    112  * @param string $location The menu location identifier.
    113  * @return bool True on success, false on failure.
    114  */
    115 function unregister_nav_menu( $location ) {
    116 	global $_wp_registered_nav_menus;
    117 
    118 	if ( is_array( $_wp_registered_nav_menus ) && isset( $_wp_registered_nav_menus[ $location ] ) ) {
    119 		unset( $_wp_registered_nav_menus[ $location ] );
    120 		if ( empty( $_wp_registered_nav_menus ) ) {
    121 			_remove_theme_support( 'menus' );
    122 		}
    123 		return true;
    124 	}
    125 	return false;
    126 }
    127 
    128 /**
    129  * Registers a navigation menu location for a theme.
    130  *
    131  * @since 3.0.0
    132  *
    133  * @param string $location    Menu location identifier, like a slug.
    134  * @param string $description Menu location descriptive text.
    135  */
    136 function register_nav_menu( $location, $description ) {
    137 	register_nav_menus( array( $location => $description ) );
    138 }
    139 /**
    140  * Retrieves all registered navigation menu locations in a theme.
    141  *
    142  * @since 3.0.0
    143  *
    144  * @global array $_wp_registered_nav_menus
    145  *
    146  * @return string[] Associative array of egistered navigation menu descriptions keyed
    147  *                  by their location. If none are registered, an empty array.
    148  */
    149 function get_registered_nav_menus() {
    150 	global $_wp_registered_nav_menus;
    151 	if ( isset( $_wp_registered_nav_menus ) ) {
    152 		return $_wp_registered_nav_menus;
    153 	}
    154 	return array();
    155 }
    156 
    157 /**
    158  * Retrieves all registered navigation menu locations and the menus assigned to them.
    159  *
    160  * @since 3.0.0
    161  *
    162  * @return int[] Associative array of egistered navigation menu IDs keyed by their
    163  *               location name. If none are registered, an empty array.
    164  */
    165 function get_nav_menu_locations() {
    166 	$locations = get_theme_mod( 'nav_menu_locations' );
    167 	return ( is_array( $locations ) ) ? $locations : array();
    168 }
    169 
    170 /**
    171  * Determines whether a registered nav menu location has a menu assigned to it.
    172  *
    173  * @since 3.0.0
    174  *
    175  * @param string $location Menu location identifier.
    176  * @return bool Whether location has a menu.
    177  */
    178 function has_nav_menu( $location ) {
    179 	$has_nav_menu = false;
    180 
    181 	$registered_nav_menus = get_registered_nav_menus();
    182 	if ( isset( $registered_nav_menus[ $location ] ) ) {
    183 		$locations    = get_nav_menu_locations();
    184 		$has_nav_menu = ! empty( $locations[ $location ] );
    185 	}
    186 
    187 	/**
    188 	 * Filters whether a nav menu is assigned to the specified location.
    189 	 *
    190 	 * @since 4.3.0
    191 	 *
    192 	 * @param bool   $has_nav_menu Whether there is a menu assigned to a location.
    193 	 * @param string $location     Menu location.
    194 	 */
    195 	return apply_filters( 'has_nav_menu', $has_nav_menu, $location );
    196 }
    197 
    198 /**
    199  * Returns the name of a navigation menu.
    200  *
    201  * @since 4.9.0
    202  *
    203  * @param string $location Menu location identifier.
    204  * @return string Menu name.
    205  */
    206 function wp_get_nav_menu_name( $location ) {
    207 	$menu_name = '';
    208 
    209 	$locations = get_nav_menu_locations();
    210 
    211 	if ( isset( $locations[ $location ] ) ) {
    212 		$menu = wp_get_nav_menu_object( $locations[ $location ] );
    213 
    214 		if ( $menu && $menu->name ) {
    215 			$menu_name = $menu->name;
    216 		}
    217 	}
    218 
    219 	/**
    220 	 * Filters the navigation menu name being returned.
    221 	 *
    222 	 * @since 4.9.0
    223 	 *
    224 	 * @param string $menu_name Menu name.
    225 	 * @param string $location  Menu location identifier.
    226 	 */
    227 	return apply_filters( 'wp_get_nav_menu_name', $menu_name, $location );
    228 }
    229 
    230 /**
    231  * Determines whether the given ID is a nav menu item.
    232  *
    233  * @since 3.0.0
    234  *
    235  * @param int $menu_item_id The ID of the potential nav menu item.
    236  * @return bool Whether the given ID is that of a nav menu item.
    237  */
    238 function is_nav_menu_item( $menu_item_id = 0 ) {
    239 	return ( ! is_wp_error( $menu_item_id ) && ( 'nav_menu_item' === get_post_type( $menu_item_id ) ) );
    240 }
    241 
    242 /**
    243  * Creates a navigation menu.
    244  *
    245  * Note that `$menu_name` is expected to be pre-slashed.
    246  *
    247  * @since 3.0.0
    248  *
    249  * @param string $menu_name Menu name.
    250  * @return int|WP_Error Menu ID on success, WP_Error object on failure.
    251  */
    252 function wp_create_nav_menu( $menu_name ) {
    253 	// expected_slashed ($menu_name)
    254 	return wp_update_nav_menu_object( 0, array( 'menu-name' => $menu_name ) );
    255 }
    256 
    257 /**
    258  * Delete a Navigation Menu.
    259  *
    260  * @since 3.0.0
    261  *
    262  * @param int|string|WP_Term $menu Menu ID, slug, name, or object.
    263  * @return bool|WP_Error True on success, false or WP_Error object on failure.
    264  */
    265 function wp_delete_nav_menu( $menu ) {
    266 	$menu = wp_get_nav_menu_object( $menu );
    267 	if ( ! $menu ) {
    268 		return false;
    269 	}
    270 
    271 	$menu_objects = get_objects_in_term( $menu->term_id, 'nav_menu' );
    272 	if ( ! empty( $menu_objects ) ) {
    273 		foreach ( $menu_objects as $item ) {
    274 			wp_delete_post( $item );
    275 		}
    276 	}
    277 
    278 	$result = wp_delete_term( $menu->term_id, 'nav_menu' );
    279 
    280 	// Remove this menu from any locations.
    281 	$locations = get_nav_menu_locations();
    282 	foreach ( $locations as $location => $menu_id ) {
    283 		if ( $menu_id == $menu->term_id ) {
    284 			$locations[ $location ] = 0;
    285 		}
    286 	}
    287 	set_theme_mod( 'nav_menu_locations', $locations );
    288 
    289 	if ( $result && ! is_wp_error( $result ) ) {
    290 
    291 		/**
    292 		 * Fires after a navigation menu has been successfully deleted.
    293 		 *
    294 		 * @since 3.0.0
    295 		 *
    296 		 * @param int $term_id ID of the deleted menu.
    297 		 */
    298 		do_action( 'wp_delete_nav_menu', $menu->term_id );
    299 	}
    300 
    301 	return $result;
    302 }
    303 
    304 /**
    305  * Save the properties of a menu or create a new menu with those properties.
    306  *
    307  * Note that `$menu_data` is expected to be pre-slashed.
    308  *
    309  * @since 3.0.0
    310  *
    311  * @param int   $menu_id   The ID of the menu or "0" to create a new menu.
    312  * @param array $menu_data The array of menu data.
    313  * @return int|WP_Error Menu ID on success, WP_Error object on failure.
    314  */
    315 function wp_update_nav_menu_object( $menu_id = 0, $menu_data = array() ) {
    316 	// expected_slashed ($menu_data)
    317 	$menu_id = (int) $menu_id;
    318 
    319 	$_menu = wp_get_nav_menu_object( $menu_id );
    320 
    321 	$args = array(
    322 		'description' => ( isset( $menu_data['description'] ) ? $menu_data['description'] : '' ),
    323 		'name'        => ( isset( $menu_data['menu-name'] ) ? $menu_data['menu-name'] : '' ),
    324 		'parent'      => ( isset( $menu_data['parent'] ) ? (int) $menu_data['parent'] : 0 ),
    325 		'slug'        => null,
    326 	);
    327 
    328 	// Double-check that we're not going to have one menu take the name of another.
    329 	$_possible_existing = get_term_by( 'name', $menu_data['menu-name'], 'nav_menu' );
    330 	if (
    331 		$_possible_existing &&
    332 		! is_wp_error( $_possible_existing ) &&
    333 		isset( $_possible_existing->term_id ) &&
    334 		$_possible_existing->term_id != $menu_id
    335 	) {
    336 		return new WP_Error(
    337 			'menu_exists',
    338 			sprintf(
    339 				/* translators: %s: Menu name. */
    340 				__( 'The menu name %s conflicts with another menu name. Please try another.' ),
    341 				'<strong>' . esc_html( $menu_data['menu-name'] ) . '</strong>'
    342 			)
    343 		);
    344 	}
    345 
    346 	// Menu doesn't already exist, so create a new menu.
    347 	if ( ! $_menu || is_wp_error( $_menu ) ) {
    348 		$menu_exists = get_term_by( 'name', $menu_data['menu-name'], 'nav_menu' );
    349 
    350 		if ( $menu_exists ) {
    351 			return new WP_Error(
    352 				'menu_exists',
    353 				sprintf(
    354 					/* translators: %s: Menu name. */
    355 					__( 'The menu name %s conflicts with another menu name. Please try another.' ),
    356 					'<strong>' . esc_html( $menu_data['menu-name'] ) . '</strong>'
    357 				)
    358 			);
    359 		}
    360 
    361 		$_menu = wp_insert_term( $menu_data['menu-name'], 'nav_menu', $args );
    362 
    363 		if ( is_wp_error( $_menu ) ) {
    364 			return $_menu;
    365 		}
    366 
    367 		/**
    368 		 * Fires after a navigation menu is successfully created.
    369 		 *
    370 		 * @since 3.0.0
    371 		 *
    372 		 * @param int   $term_id   ID of the new menu.
    373 		 * @param array $menu_data An array of menu data.
    374 		 */
    375 		do_action( 'wp_create_nav_menu', $_menu['term_id'], $menu_data );
    376 
    377 		return (int) $_menu['term_id'];
    378 	}
    379 
    380 	if ( ! $_menu || ! isset( $_menu->term_id ) ) {
    381 		return 0;
    382 	}
    383 
    384 	$menu_id = (int) $_menu->term_id;
    385 
    386 	$update_response = wp_update_term( $menu_id, 'nav_menu', $args );
    387 
    388 	if ( is_wp_error( $update_response ) ) {
    389 		return $update_response;
    390 	}
    391 
    392 	$menu_id = (int) $update_response['term_id'];
    393 
    394 	/**
    395 	 * Fires after a navigation menu has been successfully updated.
    396 	 *
    397 	 * @since 3.0.0
    398 	 *
    399 	 * @param int   $menu_id   ID of the updated menu.
    400 	 * @param array $menu_data An array of menu data.
    401 	 */
    402 	do_action( 'wp_update_nav_menu', $menu_id, $menu_data );
    403 	return $menu_id;
    404 }
    405 
    406 /**
    407  * Save the properties of a menu item or create a new one.
    408  *
    409  * The menu-item-title, menu-item-description, and menu-item-attr-title are expected
    410  * to be pre-slashed since they are passed directly into `wp_insert_post()`.
    411  *
    412  * @since 3.0.0
    413  *
    414  * @param int   $menu_id         The ID of the menu. Required. If "0", makes the menu item a draft orphan.
    415  * @param int   $menu_item_db_id The ID of the menu item. If "0", creates a new menu item.
    416  * @param array $menu_item_data  The menu item's data.
    417  * @return int|WP_Error The menu item's database ID or WP_Error object on failure.
    418  */
    419 function wp_update_nav_menu_item( $menu_id = 0, $menu_item_db_id = 0, $menu_item_data = array() ) {
    420 	$menu_id         = (int) $menu_id;
    421 	$menu_item_db_id = (int) $menu_item_db_id;
    422 
    423 	// Make sure that we don't convert non-nav_menu_item objects into nav_menu_item objects.
    424 	if ( ! empty( $menu_item_db_id ) && ! is_nav_menu_item( $menu_item_db_id ) ) {
    425 		return new WP_Error( 'update_nav_menu_item_failed', __( 'The given object ID is not that of a menu item.' ) );
    426 	}
    427 
    428 	$menu = wp_get_nav_menu_object( $menu_id );
    429 
    430 	if ( ! $menu && 0 !== $menu_id ) {
    431 		return new WP_Error( 'invalid_menu_id', __( 'Invalid menu ID.' ) );
    432 	}
    433 
    434 	if ( is_wp_error( $menu ) ) {
    435 		return $menu;
    436 	}
    437 
    438 	$defaults = array(
    439 		'menu-item-db-id'         => $menu_item_db_id,
    440 		'menu-item-object-id'     => 0,
    441 		'menu-item-object'        => '',
    442 		'menu-item-parent-id'     => 0,
    443 		'menu-item-position'      => 0,
    444 		'menu-item-type'          => 'custom',
    445 		'menu-item-title'         => '',
    446 		'menu-item-url'           => '',
    447 		'menu-item-description'   => '',
    448 		'menu-item-attr-title'    => '',
    449 		'menu-item-target'        => '',
    450 		'menu-item-classes'       => '',
    451 		'menu-item-xfn'           => '',
    452 		'menu-item-status'        => '',
    453 		'menu-item-post-date'     => '',
    454 		'menu-item-post-date-gmt' => '',
    455 	);
    456 
    457 	$args = wp_parse_args( $menu_item_data, $defaults );
    458 
    459 	if ( 0 == $menu_id ) {
    460 		$args['menu-item-position'] = 1;
    461 	} elseif ( 0 == (int) $args['menu-item-position'] ) {
    462 		$menu_items                 = 0 == $menu_id ? array() : (array) wp_get_nav_menu_items( $menu_id, array( 'post_status' => 'publish,draft' ) );
    463 		$last_item                  = array_pop( $menu_items );
    464 		$args['menu-item-position'] = ( $last_item && isset( $last_item->menu_order ) ) ? 1 + $last_item->menu_order : count( $menu_items );
    465 	}
    466 
    467 	$original_parent = 0 < $menu_item_db_id ? get_post_field( 'post_parent', $menu_item_db_id ) : 0;
    468 
    469 	if ( 'custom' === $args['menu-item-type'] ) {
    470 		// If custom menu item, trim the URL.
    471 		$args['menu-item-url'] = trim( $args['menu-item-url'] );
    472 	} else {
    473 		/*
    474 		 * If non-custom menu item, then:
    475 		 * - use the original object's URL.
    476 		 * - blank default title to sync with the original object's title.
    477 		 */
    478 
    479 		$args['menu-item-url'] = '';
    480 
    481 		$original_title = '';
    482 		if ( 'taxonomy' === $args['menu-item-type'] ) {
    483 			$original_parent = get_term_field( 'parent', $args['menu-item-object-id'], $args['menu-item-object'], 'raw' );
    484 			$original_title  = get_term_field( 'name', $args['menu-item-object-id'], $args['menu-item-object'], 'raw' );
    485 		} elseif ( 'post_type' === $args['menu-item-type'] ) {
    486 
    487 			$original_object = get_post( $args['menu-item-object-id'] );
    488 			$original_parent = (int) $original_object->post_parent;
    489 			$original_title  = $original_object->post_title;
    490 		} elseif ( 'post_type_archive' === $args['menu-item-type'] ) {
    491 			$original_object = get_post_type_object( $args['menu-item-object'] );
    492 			if ( $original_object ) {
    493 				$original_title = $original_object->labels->archives;
    494 			}
    495 		}
    496 
    497 		if ( wp_unslash( $args['menu-item-title'] ) === wp_specialchars_decode( $original_title ) ) {
    498 			$args['menu-item-title'] = '';
    499 		}
    500 
    501 		// Hack to get wp to create a post object when too many properties are empty.
    502 		if ( '' === $args['menu-item-title'] && '' === $args['menu-item-description'] ) {
    503 			$args['menu-item-description'] = ' ';
    504 		}
    505 	}
    506 
    507 	// Populate the menu item object.
    508 	$post = array(
    509 		'menu_order'   => $args['menu-item-position'],
    510 		'ping_status'  => 0,
    511 		'post_content' => $args['menu-item-description'],
    512 		'post_excerpt' => $args['menu-item-attr-title'],
    513 		'post_parent'  => $original_parent,
    514 		'post_title'   => $args['menu-item-title'],
    515 		'post_type'    => 'nav_menu_item',
    516 	);
    517 
    518 	$post_date = wp_resolve_post_date( $args['menu-item-post-date'], $args['menu-item-post-date-gmt'] );
    519 	if ( $post_date ) {
    520 		$post['post_date'] = $post_date;
    521 	}
    522 
    523 	$update = 0 != $menu_item_db_id;
    524 
    525 	// New menu item. Default is draft status.
    526 	if ( ! $update ) {
    527 		$post['ID']          = 0;
    528 		$post['post_status'] = 'publish' === $args['menu-item-status'] ? 'publish' : 'draft';
    529 		$menu_item_db_id     = wp_insert_post( $post );
    530 		if ( ! $menu_item_db_id || is_wp_error( $menu_item_db_id ) ) {
    531 			return $menu_item_db_id;
    532 		}
    533 
    534 		/**
    535 		 * Fires immediately after a new navigation menu item has been added.
    536 		 *
    537 		 * @since 4.4.0
    538 		 *
    539 		 * @see wp_update_nav_menu_item()
    540 		 *
    541 		 * @param int   $menu_id         ID of the updated menu.
    542 		 * @param int   $menu_item_db_id ID of the new menu item.
    543 		 * @param array $args            An array of arguments used to update/add the menu item.
    544 		 */
    545 		do_action( 'wp_add_nav_menu_item', $menu_id, $menu_item_db_id, $args );
    546 	}
    547 
    548 	// Associate the menu item with the menu term.
    549 	// Only set the menu term if it isn't set to avoid unnecessary wp_get_object_terms().
    550 	if ( $menu_id && ( ! $update || ! is_object_in_term( $menu_item_db_id, 'nav_menu', (int) $menu->term_id ) ) ) {
    551 		wp_set_object_terms( $menu_item_db_id, array( $menu->term_id ), 'nav_menu' );
    552 	}
    553 
    554 	if ( 'custom' === $args['menu-item-type'] ) {
    555 		$args['menu-item-object-id'] = $menu_item_db_id;
    556 		$args['menu-item-object']    = 'custom';
    557 	}
    558 
    559 	$menu_item_db_id = (int) $menu_item_db_id;
    560 
    561 	update_post_meta( $menu_item_db_id, '_menu_item_type', sanitize_key( $args['menu-item-type'] ) );
    562 	update_post_meta( $menu_item_db_id, '_menu_item_menu_item_parent', (string) ( (int) $args['menu-item-parent-id'] ) );
    563 	update_post_meta( $menu_item_db_id, '_menu_item_object_id', (string) ( (int) $args['menu-item-object-id'] ) );
    564 	update_post_meta( $menu_item_db_id, '_menu_item_object', sanitize_key( $args['menu-item-object'] ) );
    565 	update_post_meta( $menu_item_db_id, '_menu_item_target', sanitize_key( $args['menu-item-target'] ) );
    566 
    567 	$args['menu-item-classes'] = array_map( 'sanitize_html_class', explode( ' ', $args['menu-item-classes'] ) );
    568 	$args['menu-item-xfn']     = implode( ' ', array_map( 'sanitize_html_class', explode( ' ', $args['menu-item-xfn'] ) ) );
    569 	update_post_meta( $menu_item_db_id, '_menu_item_classes', $args['menu-item-classes'] );
    570 	update_post_meta( $menu_item_db_id, '_menu_item_xfn', $args['menu-item-xfn'] );
    571 	update_post_meta( $menu_item_db_id, '_menu_item_url', esc_url_raw( $args['menu-item-url'] ) );
    572 
    573 	if ( 0 == $menu_id ) {
    574 		update_post_meta( $menu_item_db_id, '_menu_item_orphaned', (string) time() );
    575 	} elseif ( get_post_meta( $menu_item_db_id, '_menu_item_orphaned' ) ) {
    576 		delete_post_meta( $menu_item_db_id, '_menu_item_orphaned' );
    577 	}
    578 
    579 	// Update existing menu item. Default is publish status.
    580 	if ( $update ) {
    581 		$post['ID']          = $menu_item_db_id;
    582 		$post['post_status'] = ( 'draft' === $args['menu-item-status'] ) ? 'draft' : 'publish';
    583 		wp_update_post( $post );
    584 	}
    585 
    586 	/**
    587 	 * Fires after a navigation menu item has been updated.
    588 	 *
    589 	 * @since 3.0.0
    590 	 *
    591 	 * @see wp_update_nav_menu_item()
    592 	 *
    593 	 * @param int   $menu_id         ID of the updated menu.
    594 	 * @param int   $menu_item_db_id ID of the updated menu item.
    595 	 * @param array $args            An array of arguments used to update a menu item.
    596 	 */
    597 	do_action( 'wp_update_nav_menu_item', $menu_id, $menu_item_db_id, $args );
    598 
    599 	return $menu_item_db_id;
    600 }
    601 
    602 /**
    603  * Returns all navigation menu objects.
    604  *
    605  * @since 3.0.0
    606  * @since 4.1.0 Default value of the 'orderby' argument was changed from 'none'
    607  *              to 'name'.
    608  *
    609  * @param array $args Optional. Array of arguments passed on to get_terms().
    610  *                    Default empty array.
    611  * @return WP_Term[] An array of menu objects.
    612  */
    613 function wp_get_nav_menus( $args = array() ) {
    614 	$defaults = array(
    615 		'taxonomy'   => 'nav_menu',
    616 		'hide_empty' => false,
    617 		'orderby'    => 'name',
    618 	);
    619 	$args     = wp_parse_args( $args, $defaults );
    620 
    621 	/**
    622 	 * Filters the navigation menu objects being returned.
    623 	 *
    624 	 * @since 3.0.0
    625 	 *
    626 	 * @see get_terms()
    627 	 *
    628 	 * @param WP_Term[] $menus An array of menu objects.
    629 	 * @param array     $args  An array of arguments used to retrieve menu objects.
    630 	 */
    631 	return apply_filters( 'wp_get_nav_menus', get_terms( $args ), $args );
    632 }
    633 
    634 /**
    635  * Return if a menu item is valid.
    636  *
    637  * @link https://core.trac.wordpress.org/ticket/13958
    638  *
    639  * @since 3.2.0
    640  * @access private
    641  *
    642  * @param object $item The menu item to check.
    643  * @return bool False if invalid, otherwise true.
    644  */
    645 function _is_valid_nav_menu_item( $item ) {
    646 	return empty( $item->_invalid );
    647 }
    648 
    649 /**
    650  * Retrieves all menu items of a navigation menu.
    651  *
    652  * Note: Most arguments passed to the `$args` parameter – save for 'output_key' – are
    653  * specifically for retrieving nav_menu_item posts from get_posts() and may only
    654  * indirectly affect the ultimate ordering and content of the resulting nav menu
    655  * items that get returned from this function.
    656  *
    657  * @since 3.0.0
    658  *
    659  * @param int|string|WP_Term $menu Menu ID, slug, name, or object.
    660  * @param array              $args {
    661  *     Optional. Arguments to pass to get_posts().
    662  *
    663  *     @type string $order       How to order nav menu items as queried with get_posts(). Will be ignored
    664  *                               if 'output' is ARRAY_A. Default 'ASC'.
    665  *     @type string $orderby     Field to order menu items by as retrieved from get_posts(). Supply an orderby
    666  *                               field via 'output_key' to affect the output order of nav menu items.
    667  *                               Default 'menu_order'.
    668  *     @type string $post_type   Menu items post type. Default 'nav_menu_item'.
    669  *     @type string $post_status Menu items post status. Default 'publish'.
    670  *     @type string $output      How to order outputted menu items. Default ARRAY_A.
    671  *     @type string $output_key  Key to use for ordering the actual menu items that get returned. Note that
    672  *                               that is not a get_posts() argument and will only affect output of menu items
    673  *                               processed in this function. Default 'menu_order'.
    674  *     @type bool   $nopaging    Whether to retrieve all menu items (true) or paginate (false). Default true.
    675  * }
    676  * @return array|false Array of menu items, otherwise false.
    677  */
    678 function wp_get_nav_menu_items( $menu, $args = array() ) {
    679 	$menu = wp_get_nav_menu_object( $menu );
    680 
    681 	if ( ! $menu ) {
    682 		return false;
    683 	}
    684 
    685 	static $fetched = array();
    686 
    687 	$items = get_objects_in_term( $menu->term_id, 'nav_menu' );
    688 	if ( is_wp_error( $items ) ) {
    689 		return false;
    690 	}
    691 
    692 	$defaults        = array(
    693 		'order'       => 'ASC',
    694 		'orderby'     => 'menu_order',
    695 		'post_type'   => 'nav_menu_item',
    696 		'post_status' => 'publish',
    697 		'output'      => ARRAY_A,
    698 		'output_key'  => 'menu_order',
    699 		'nopaging'    => true,
    700 	);
    701 	$args            = wp_parse_args( $args, $defaults );
    702 	$args['include'] = $items;
    703 
    704 	if ( ! empty( $items ) ) {
    705 		$items = get_posts( $args );
    706 	} else {
    707 		$items = array();
    708 	}
    709 
    710 	// Get all posts and terms at once to prime the caches.
    711 	if ( empty( $fetched[ $menu->term_id ] ) && ! wp_using_ext_object_cache() ) {
    712 		$fetched[ $menu->term_id ] = true;
    713 		$posts                     = array();
    714 		$terms                     = array();
    715 		foreach ( $items as $item ) {
    716 			$object_id = get_post_meta( $item->ID, '_menu_item_object_id', true );
    717 			$object    = get_post_meta( $item->ID, '_menu_item_object', true );
    718 			$type      = get_post_meta( $item->ID, '_menu_item_type', true );
    719 
    720 			if ( 'post_type' === $type ) {
    721 				$posts[ $object ][] = $object_id;
    722 			} elseif ( 'taxonomy' === $type ) {
    723 				$terms[ $object ][] = $object_id;
    724 			}
    725 		}
    726 
    727 		if ( ! empty( $posts ) ) {
    728 			foreach ( array_keys( $posts ) as $post_type ) {
    729 				get_posts(
    730 					array(
    731 						'post__in'               => $posts[ $post_type ],
    732 						'post_type'              => $post_type,
    733 						'nopaging'               => true,
    734 						'update_post_term_cache' => false,
    735 					)
    736 				);
    737 			}
    738 		}
    739 		unset( $posts );
    740 
    741 		if ( ! empty( $terms ) ) {
    742 			foreach ( array_keys( $terms ) as $taxonomy ) {
    743 				get_terms(
    744 					array(
    745 						'taxonomy'     => $taxonomy,
    746 						'include'      => $terms[ $taxonomy ],
    747 						'hierarchical' => false,
    748 					)
    749 				);
    750 			}
    751 		}
    752 		unset( $terms );
    753 	}
    754 
    755 	$items = array_map( 'wp_setup_nav_menu_item', $items );
    756 
    757 	if ( ! is_admin() ) { // Remove invalid items only on front end.
    758 		$items = array_filter( $items, '_is_valid_nav_menu_item' );
    759 	}
    760 
    761 	if ( ARRAY_A === $args['output'] ) {
    762 		$items = wp_list_sort(
    763 			$items,
    764 			array(
    765 				$args['output_key'] => 'ASC',
    766 			)
    767 		);
    768 
    769 		$i = 1;
    770 
    771 		foreach ( $items as $k => $item ) {
    772 			$items[ $k ]->{$args['output_key']} = $i++;
    773 		}
    774 	}
    775 
    776 	/**
    777 	 * Filters the navigation menu items being returned.
    778 	 *
    779 	 * @since 3.0.0
    780 	 *
    781 	 * @param array  $items An array of menu item post objects.
    782 	 * @param object $menu  The menu object.
    783 	 * @param array  $args  An array of arguments used to retrieve menu item objects.
    784 	 */
    785 	return apply_filters( 'wp_get_nav_menu_items', $items, $menu, $args );
    786 }
    787 
    788 /**
    789  * Decorates a menu item object with the shared navigation menu item properties.
    790  *
    791  * Properties:
    792  * - ID:               The term_id if the menu item represents a taxonomy term.
    793  * - attr_title:       The title attribute of the link element for this menu item.
    794  * - classes:          The array of class attribute values for the link element of this menu item.
    795  * - db_id:            The DB ID of this item as a nav_menu_item object, if it exists (0 if it doesn't exist).
    796  * - description:      The description of this menu item.
    797  * - menu_item_parent: The DB ID of the nav_menu_item that is this item's menu parent, if any. 0 otherwise.
    798  * - object:           The type of object originally represented, such as 'category', 'post', or 'attachment'.
    799  * - object_id:        The DB ID of the original object this menu item represents, e.g. ID for posts and term_id for categories.
    800  * - post_parent:      The DB ID of the original object's parent object, if any (0 otherwise).
    801  * - post_title:       A "no title" label if menu item represents a post that lacks a title.
    802  * - target:           The target attribute of the link element for this menu item.
    803  * - title:            The title of this menu item.
    804  * - type:             The family of objects originally represented, such as 'post_type' or 'taxonomy'.
    805  * - type_label:       The singular label used to describe this type of menu item.
    806  * - url:              The URL to which this menu item points.
    807  * - xfn:              The XFN relationship expressed in the link of this menu item.
    808  * - _invalid:         Whether the menu item represents an object that no longer exists.
    809  *
    810  * @since 3.0.0
    811  *
    812  * @param object $menu_item The menu item to modify.
    813  * @return object The menu item with standard menu item properties.
    814  */
    815 function wp_setup_nav_menu_item( $menu_item ) {
    816 	if ( isset( $menu_item->post_type ) ) {
    817 		if ( 'nav_menu_item' === $menu_item->post_type ) {
    818 			$menu_item->db_id            = (int) $menu_item->ID;
    819 			$menu_item->menu_item_parent = ! isset( $menu_item->menu_item_parent ) ? get_post_meta( $menu_item->ID, '_menu_item_menu_item_parent', true ) : $menu_item->menu_item_parent;
    820 			$menu_item->object_id        = ! isset( $menu_item->object_id ) ? get_post_meta( $menu_item->ID, '_menu_item_object_id', true ) : $menu_item->object_id;
    821 			$menu_item->object           = ! isset( $menu_item->object ) ? get_post_meta( $menu_item->ID, '_menu_item_object', true ) : $menu_item->object;
    822 			$menu_item->type             = ! isset( $menu_item->type ) ? get_post_meta( $menu_item->ID, '_menu_item_type', true ) : $menu_item->type;
    823 
    824 			if ( 'post_type' === $menu_item->type ) {
    825 				$object = get_post_type_object( $menu_item->object );
    826 				if ( $object ) {
    827 					$menu_item->type_label = $object->labels->singular_name;
    828 					// Denote post states for special pages (only in the admin).
    829 					if ( function_exists( 'get_post_states' ) ) {
    830 						$menu_post   = get_post( $menu_item->object_id );
    831 						$post_states = get_post_states( $menu_post );
    832 						if ( $post_states ) {
    833 							$menu_item->type_label = wp_strip_all_tags( implode( ', ', $post_states ) );
    834 						}
    835 					}
    836 				} else {
    837 					$menu_item->type_label = $menu_item->object;
    838 					$menu_item->_invalid   = true;
    839 				}
    840 
    841 				if ( 'trash' === get_post_status( $menu_item->object_id ) ) {
    842 					$menu_item->_invalid = true;
    843 				}
    844 
    845 				$original_object = get_post( $menu_item->object_id );
    846 
    847 				if ( $original_object ) {
    848 					$menu_item->url = get_permalink( $original_object->ID );
    849 					/** This filter is documented in wp-includes/post-template.php */
    850 					$original_title = apply_filters( 'the_title', $original_object->post_title, $original_object->ID );
    851 				} else {
    852 					$menu_item->url      = '';
    853 					$original_title      = '';
    854 					$menu_item->_invalid = true;
    855 				}
    856 
    857 				if ( '' === $original_title ) {
    858 					/* translators: %d: ID of a post. */
    859 					$original_title = sprintf( __( '#%d (no title)' ), $menu_item->object_id );
    860 				}
    861 
    862 				$menu_item->title = ( '' === $menu_item->post_title ) ? $original_title : $menu_item->post_title;
    863 
    864 			} elseif ( 'post_type_archive' === $menu_item->type ) {
    865 				$object = get_post_type_object( $menu_item->object );
    866 				if ( $object ) {
    867 					$menu_item->title      = ( '' === $menu_item->post_title ) ? $object->labels->archives : $menu_item->post_title;
    868 					$post_type_description = $object->description;
    869 				} else {
    870 					$post_type_description = '';
    871 					$menu_item->_invalid   = true;
    872 				}
    873 
    874 				$menu_item->type_label = __( 'Post Type Archive' );
    875 				$post_content          = wp_trim_words( $menu_item->post_content, 200 );
    876 				$post_type_description = ( '' === $post_content ) ? $post_type_description : $post_content;
    877 				$menu_item->url        = get_post_type_archive_link( $menu_item->object );
    878 
    879 			} elseif ( 'taxonomy' === $menu_item->type ) {
    880 				$object = get_taxonomy( $menu_item->object );
    881 				if ( $object ) {
    882 					$menu_item->type_label = $object->labels->singular_name;
    883 				} else {
    884 					$menu_item->type_label = $menu_item->object;
    885 					$menu_item->_invalid   = true;
    886 				}
    887 
    888 				$original_object = get_term( (int) $menu_item->object_id, $menu_item->object );
    889 
    890 				if ( $original_object && ! is_wp_error( $original_object ) ) {
    891 					$menu_item->url = get_term_link( (int) $menu_item->object_id, $menu_item->object );
    892 					$original_title = $original_object->name;
    893 				} else {
    894 					$menu_item->url      = '';
    895 					$original_title      = '';
    896 					$menu_item->_invalid = true;
    897 				}
    898 
    899 				if ( '' === $original_title ) {
    900 					/* translators: %d: ID of a term. */
    901 					$original_title = sprintf( __( '#%d (no title)' ), $menu_item->object_id );
    902 				}
    903 
    904 				$menu_item->title = ( '' === $menu_item->post_title ) ? $original_title : $menu_item->post_title;
    905 
    906 			} else {
    907 				$menu_item->type_label = __( 'Custom Link' );
    908 				$menu_item->title      = $menu_item->post_title;
    909 				$menu_item->url        = ! isset( $menu_item->url ) ? get_post_meta( $menu_item->ID, '_menu_item_url', true ) : $menu_item->url;
    910 			}
    911 
    912 			$menu_item->target = ! isset( $menu_item->target ) ? get_post_meta( $menu_item->ID, '_menu_item_target', true ) : $menu_item->target;
    913 
    914 			/**
    915 			 * Filters a navigation menu item's title attribute.
    916 			 *
    917 			 * @since 3.0.0
    918 			 *
    919 			 * @param string $item_title The menu item title attribute.
    920 			 */
    921 			$menu_item->attr_title = ! isset( $menu_item->attr_title ) ? apply_filters( 'nav_menu_attr_title', $menu_item->post_excerpt ) : $menu_item->attr_title;
    922 
    923 			if ( ! isset( $menu_item->description ) ) {
    924 				/**
    925 				 * Filters a navigation menu item's description.
    926 				 *
    927 				 * @since 3.0.0
    928 				 *
    929 				 * @param string $description The menu item description.
    930 				 */
    931 				$menu_item->description = apply_filters( 'nav_menu_description', wp_trim_words( $menu_item->post_content, 200 ) );
    932 			}
    933 
    934 			$menu_item->classes = ! isset( $menu_item->classes ) ? (array) get_post_meta( $menu_item->ID, '_menu_item_classes', true ) : $menu_item->classes;
    935 			$menu_item->xfn     = ! isset( $menu_item->xfn ) ? get_post_meta( $menu_item->ID, '_menu_item_xfn', true ) : $menu_item->xfn;
    936 		} else {
    937 			$menu_item->db_id            = 0;
    938 			$menu_item->menu_item_parent = 0;
    939 			$menu_item->object_id        = (int) $menu_item->ID;
    940 			$menu_item->type             = 'post_type';
    941 
    942 			$object                = get_post_type_object( $menu_item->post_type );
    943 			$menu_item->object     = $object->name;
    944 			$menu_item->type_label = $object->labels->singular_name;
    945 
    946 			if ( '' === $menu_item->post_title ) {
    947 				/* translators: %d: ID of a post. */
    948 				$menu_item->post_title = sprintf( __( '#%d (no title)' ), $menu_item->ID );
    949 			}
    950 
    951 			$menu_item->title  = $menu_item->post_title;
    952 			$menu_item->url    = get_permalink( $menu_item->ID );
    953 			$menu_item->target = '';
    954 
    955 			/** This filter is documented in wp-includes/nav-menu.php */
    956 			$menu_item->attr_title = apply_filters( 'nav_menu_attr_title', '' );
    957 
    958 			/** This filter is documented in wp-includes/nav-menu.php */
    959 			$menu_item->description = apply_filters( 'nav_menu_description', '' );
    960 			$menu_item->classes     = array();
    961 			$menu_item->xfn         = '';
    962 		}
    963 	} elseif ( isset( $menu_item->taxonomy ) ) {
    964 		$menu_item->ID               = $menu_item->term_id;
    965 		$menu_item->db_id            = 0;
    966 		$menu_item->menu_item_parent = 0;
    967 		$menu_item->object_id        = (int) $menu_item->term_id;
    968 		$menu_item->post_parent      = (int) $menu_item->parent;
    969 		$menu_item->type             = 'taxonomy';
    970 
    971 		$object                = get_taxonomy( $menu_item->taxonomy );
    972 		$menu_item->object     = $object->name;
    973 		$menu_item->type_label = $object->labels->singular_name;
    974 
    975 		$menu_item->title       = $menu_item->name;
    976 		$menu_item->url         = get_term_link( $menu_item, $menu_item->taxonomy );
    977 		$menu_item->target      = '';
    978 		$menu_item->attr_title  = '';
    979 		$menu_item->description = get_term_field( 'description', $menu_item->term_id, $menu_item->taxonomy );
    980 		$menu_item->classes     = array();
    981 		$menu_item->xfn         = '';
    982 
    983 	}
    984 
    985 	/**
    986 	 * Filters a navigation menu item object.
    987 	 *
    988 	 * @since 3.0.0
    989 	 *
    990 	 * @param object $menu_item The menu item object.
    991 	 */
    992 	return apply_filters( 'wp_setup_nav_menu_item', $menu_item );
    993 }
    994 
    995 /**
    996  * Get the menu items associated with a particular object.
    997  *
    998  * @since 3.0.0
    999  *
   1000  * @param int    $object_id   Optional. The ID of the original object. Default 0.
   1001  * @param string $object_type Optional. The type of object, such as 'post_type' or 'taxonomy'.
   1002  *                            Default 'post_type'.
   1003  * @param string $taxonomy    Optional. If $object_type is 'taxonomy', $taxonomy is the name
   1004  *                            of the tax that $object_id belongs to. Default empty.
   1005  * @return int[] The array of menu item IDs; empty array if none.
   1006  */
   1007 function wp_get_associated_nav_menu_items( $object_id = 0, $object_type = 'post_type', $taxonomy = '' ) {
   1008 	$object_id     = (int) $object_id;
   1009 	$menu_item_ids = array();
   1010 
   1011 	$query      = new WP_Query;
   1012 	$menu_items = $query->query(
   1013 		array(
   1014 			'meta_key'       => '_menu_item_object_id',
   1015 			'meta_value'     => $object_id,
   1016 			'post_status'    => 'any',
   1017 			'post_type'      => 'nav_menu_item',
   1018 			'posts_per_page' => -1,
   1019 		)
   1020 	);
   1021 	foreach ( (array) $menu_items as $menu_item ) {
   1022 		if ( isset( $menu_item->ID ) && is_nav_menu_item( $menu_item->ID ) ) {
   1023 			$menu_item_type = get_post_meta( $menu_item->ID, '_menu_item_type', true );
   1024 			if (
   1025 				'post_type' === $object_type &&
   1026 				'post_type' === $menu_item_type
   1027 			) {
   1028 				$menu_item_ids[] = (int) $menu_item->ID;
   1029 			} elseif (
   1030 				'taxonomy' === $object_type &&
   1031 				'taxonomy' === $menu_item_type &&
   1032 				get_post_meta( $menu_item->ID, '_menu_item_object', true ) == $taxonomy
   1033 			) {
   1034 				$menu_item_ids[] = (int) $menu_item->ID;
   1035 			}
   1036 		}
   1037 	}
   1038 
   1039 	return array_unique( $menu_item_ids );
   1040 }
   1041 
   1042 /**
   1043  * Callback for handling a menu item when its original object is deleted.
   1044  *
   1045  * @since 3.0.0
   1046  * @access private
   1047  *
   1048  * @param int $object_id The ID of the original object being trashed.
   1049  */
   1050 function _wp_delete_post_menu_item( $object_id ) {
   1051 	$object_id = (int) $object_id;
   1052 
   1053 	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id, 'post_type' );
   1054 
   1055 	foreach ( (array) $menu_item_ids as $menu_item_id ) {
   1056 		wp_delete_post( $menu_item_id, true );
   1057 	}
   1058 }
   1059 
   1060 /**
   1061  * Serves as a callback for handling a menu item when its original object is deleted.
   1062  *
   1063  * @since 3.0.0
   1064  * @access private
   1065  *
   1066  * @param int    $object_id The ID of the original object being trashed.
   1067  * @param int    $tt_id     Term taxonomy ID. Unused.
   1068  * @param string $taxonomy  Taxonomy slug.
   1069  */
   1070 function _wp_delete_tax_menu_item( $object_id, $tt_id, $taxonomy ) {
   1071 	$object_id = (int) $object_id;
   1072 
   1073 	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id, 'taxonomy', $taxonomy );
   1074 
   1075 	foreach ( (array) $menu_item_ids as $menu_item_id ) {
   1076 		wp_delete_post( $menu_item_id, true );
   1077 	}
   1078 }
   1079 
   1080 /**
   1081  * Automatically add newly published page objects to menus with that as an option.
   1082  *
   1083  * @since 3.0.0
   1084  * @access private
   1085  *
   1086  * @param string  $new_status The new status of the post object.
   1087  * @param string  $old_status The old status of the post object.
   1088  * @param WP_Post $post       The post object being transitioned from one status to another.
   1089  */
   1090 function _wp_auto_add_pages_to_menu( $new_status, $old_status, $post ) {
   1091 	if ( 'publish' !== $new_status || 'publish' === $old_status || 'page' !== $post->post_type ) {
   1092 		return;
   1093 	}
   1094 	if ( ! empty( $post->post_parent ) ) {
   1095 		return;
   1096 	}
   1097 	$auto_add = get_option( 'nav_menu_options' );
   1098 	if ( empty( $auto_add ) || ! is_array( $auto_add ) || ! isset( $auto_add['auto_add'] ) ) {
   1099 		return;
   1100 	}
   1101 	$auto_add = $auto_add['auto_add'];
   1102 	if ( empty( $auto_add ) || ! is_array( $auto_add ) ) {
   1103 		return;
   1104 	}
   1105 
   1106 	$args = array(
   1107 		'menu-item-object-id' => $post->ID,
   1108 		'menu-item-object'    => $post->post_type,
   1109 		'menu-item-type'      => 'post_type',
   1110 		'menu-item-status'    => 'publish',
   1111 	);
   1112 
   1113 	foreach ( $auto_add as $menu_id ) {
   1114 		$items = wp_get_nav_menu_items( $menu_id, array( 'post_status' => 'publish,draft' ) );
   1115 		if ( ! is_array( $items ) ) {
   1116 			continue;
   1117 		}
   1118 		foreach ( $items as $item ) {
   1119 			if ( $post->ID == $item->object_id ) {
   1120 				continue 2;
   1121 			}
   1122 		}
   1123 		wp_update_nav_menu_item( $menu_id, 0, $args );
   1124 	}
   1125 }
   1126 
   1127 /**
   1128  * Delete auto-draft posts associated with the supplied changeset.
   1129  *
   1130  * @since 4.8.0
   1131  * @access private
   1132  *
   1133  * @param int $post_id Post ID for the customize_changeset.
   1134  */
   1135 function _wp_delete_customize_changeset_dependent_auto_drafts( $post_id ) {
   1136 	$post = get_post( $post_id );
   1137 
   1138 	if ( ! $post || 'customize_changeset' !== $post->post_type ) {
   1139 		return;
   1140 	}
   1141 
   1142 	$data = json_decode( $post->post_content, true );
   1143 	if ( empty( $data['nav_menus_created_posts']['value'] ) ) {
   1144 		return;
   1145 	}
   1146 	remove_action( 'delete_post', '_wp_delete_customize_changeset_dependent_auto_drafts' );
   1147 	foreach ( $data['nav_menus_created_posts']['value'] as $stub_post_id ) {
   1148 		if ( empty( $stub_post_id ) ) {
   1149 			continue;
   1150 		}
   1151 		if ( 'auto-draft' === get_post_status( $stub_post_id ) ) {
   1152 			wp_delete_post( $stub_post_id, true );
   1153 		} elseif ( 'draft' === get_post_status( $stub_post_id ) ) {
   1154 			wp_trash_post( $stub_post_id );
   1155 			delete_post_meta( $stub_post_id, '_customize_changeset_uuid' );
   1156 		}
   1157 	}
   1158 	add_action( 'delete_post', '_wp_delete_customize_changeset_dependent_auto_drafts' );
   1159 }
   1160 
   1161 /**
   1162  * Handle menu config after theme change.
   1163  *
   1164  * @access private
   1165  * @since 4.9.0
   1166  */
   1167 function _wp_menus_changed() {
   1168 	$old_nav_menu_locations    = get_option( 'theme_switch_menu_locations', array() );
   1169 	$new_nav_menu_locations    = get_nav_menu_locations();
   1170 	$mapped_nav_menu_locations = wp_map_nav_menu_locations( $new_nav_menu_locations, $old_nav_menu_locations );
   1171 
   1172 	set_theme_mod( 'nav_menu_locations', $mapped_nav_menu_locations );
   1173 	delete_option( 'theme_switch_menu_locations' );
   1174 }
   1175 
   1176 /**
   1177  * Maps nav menu locations according to assignments in previously active theme.
   1178  *
   1179  * @since 4.9.0
   1180  *
   1181  * @param array $new_nav_menu_locations New nav menu locations assignments.
   1182  * @param array $old_nav_menu_locations Old nav menu locations assignments.
   1183  * @return array Nav menus mapped to new nav menu locations.
   1184  */
   1185 function wp_map_nav_menu_locations( $new_nav_menu_locations, $old_nav_menu_locations ) {
   1186 	$registered_nav_menus   = get_registered_nav_menus();
   1187 	$new_nav_menu_locations = array_intersect_key( $new_nav_menu_locations, $registered_nav_menus );
   1188 
   1189 	// Short-circuit if there are no old nav menu location assignments to map.
   1190 	if ( empty( $old_nav_menu_locations ) ) {
   1191 		return $new_nav_menu_locations;
   1192 	}
   1193 
   1194 	// If old and new theme have just one location, map it and we're done.
   1195 	if ( 1 === count( $old_nav_menu_locations ) && 1 === count( $registered_nav_menus ) ) {
   1196 		$new_nav_menu_locations[ key( $registered_nav_menus ) ] = array_pop( $old_nav_menu_locations );
   1197 		return $new_nav_menu_locations;
   1198 	}
   1199 
   1200 	$old_locations = array_keys( $old_nav_menu_locations );
   1201 
   1202 	// Map locations with the same slug.
   1203 	foreach ( $registered_nav_menus as $location => $name ) {
   1204 		if ( in_array( $location, $old_locations, true ) ) {
   1205 			$new_nav_menu_locations[ $location ] = $old_nav_menu_locations[ $location ];
   1206 			unset( $old_nav_menu_locations[ $location ] );
   1207 		}
   1208 	}
   1209 
   1210 	// If there are no old nav menu locations left, then we're done.
   1211 	if ( empty( $old_nav_menu_locations ) ) {
   1212 		return $new_nav_menu_locations;
   1213 	}
   1214 
   1215 	/*
   1216 	 * If old and new theme both have locations that contain phrases
   1217 	 * from within the same group, make an educated guess and map it.
   1218 	 */
   1219 	$common_slug_groups = array(
   1220 		array( 'primary', 'menu-1', 'main', 'header', 'navigation', 'top' ),
   1221 		array( 'secondary', 'menu-2', 'footer', 'subsidiary', 'bottom' ),
   1222 		array( 'social' ),
   1223 	);
   1224 
   1225 	// Go through each group...
   1226 	foreach ( $common_slug_groups as $slug_group ) {
   1227 
   1228 		// ...and see if any of these slugs...
   1229 		foreach ( $slug_group as $slug ) {
   1230 
   1231 			// ...and any of the new menu locations...
   1232 			foreach ( $registered_nav_menus as $new_location => $name ) {
   1233 
   1234 				// ...actually match!
   1235 				if ( is_string( $new_location ) && false === stripos( $new_location, $slug ) && false === stripos( $slug, $new_location ) ) {
   1236 					continue;
   1237 				} elseif ( is_numeric( $new_location ) && $new_location !== $slug ) {
   1238 					continue;
   1239 				}
   1240 
   1241 				// Then see if any of the old locations...
   1242 				foreach ( $old_nav_menu_locations as $location => $menu_id ) {
   1243 
   1244 					// ...and any slug in the same group...
   1245 					foreach ( $slug_group as $slug ) {
   1246 
   1247 						// ... have a match as well.
   1248 						if ( is_string( $location ) && false === stripos( $location, $slug ) && false === stripos( $slug, $location ) ) {
   1249 							continue;
   1250 						} elseif ( is_numeric( $location ) && $location !== $slug ) {
   1251 							continue;
   1252 						}
   1253 
   1254 						// Make sure this location wasn't mapped and removed previously.
   1255 						if ( ! empty( $old_nav_menu_locations[ $location ] ) ) {
   1256 
   1257 							// We have a match that can be mapped!
   1258 							$new_nav_menu_locations[ $new_location ] = $old_nav_menu_locations[ $location ];
   1259 
   1260 							// Remove the mapped location so it can't be mapped again.
   1261 							unset( $old_nav_menu_locations[ $location ] );
   1262 
   1263 							// Go back and check the next new menu location.
   1264 							continue 3;
   1265 						}
   1266 					} // End foreach ( $slug_group as $slug ).
   1267 				} // End foreach ( $old_nav_menu_locations as $location => $menu_id ).
   1268 			} // End foreach foreach ( $registered_nav_menus as $new_location => $name ).
   1269 		} // End foreach ( $slug_group as $slug ).
   1270 	} // End foreach ( $common_slug_groups as $slug_group ).
   1271 
   1272 	return $new_nav_menu_locations;
   1273 }