1<?php
  2/**
  3 * Nav Menu API: Walker_Nav_Menu class
  4 *
  5 * @package WordPress
  6 * @subpackage Nav_Menus
  7 * @since 4.6.0
  8 */
  9
 10/**
 11 * Core class used to implement an HTML list of nav menu items.
 12 *
 13 * @since 3.0.0
 14 *
 15 * @see Walker
 16 */
 17class Walker_Nav_Menu extends Walker {
 18	/**
 19	 * What the class handles.
 20	 *
 21	 * @since 3.0.0
 22	 * @var string
 23	 *
 24	 * @see Walker::$tree_type
 25	 */
 26	public $tree_type = array( 'post_type', 'taxonomy', 'custom' );
 27
 28	/**
 29	 * Database fields to use.
 30	 *
 31	 * @since 3.0.0
 32	 * @todo Decouple this.
 33	 * @var string[]
 34	 *
 35	 * @see Walker::$db_fields
 36	 */
 37	public $db_fields = array(
 38		'parent' => 'menu_item_parent',
 39		'id'     => 'db_id',
 40	);
 41
 42	/**
 43	 * The URL to the privacy policy page.
 44	 *
 45	 * @since 6.8.0
 46	 * @var string
 47	 */
 48	private $privacy_policy_url;
 49
 50	/**
 51	 * Constructor.
 52	 *
 53	 * @since 6.8.0
 54	 */
 55	public function __construct() {
 56		$this->privacy_policy_url = get_privacy_policy_url();
 57	}
 58
 59	/**
 60	 * Starts the list before the elements are added.
 61	 *
 62	 * @since 3.0.0
 63	 *
 64	 * @see Walker::start_lvl()
 65	 *
 66	 * @param string   $output Used to append additional content (passed by reference).
 67	 * @param int      $depth  Depth of menu item. Used for padding.
 68	 * @param stdClass $args   An object of wp_nav_menu() arguments.
 69	 */
 70	public function start_lvl( &$output, $depth = 0, $args = null ) {
 71		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
 72			$t = '';
 73			$n = '';
 74		} else {
 75			$t = "\t";
 76			$n = "\n";
 77		}
 78		$indent = str_repeat( $t, $depth );
 79
 80		// Default class.
 81		$classes = array( 'sub-menu' );
 82
 83		/**
 84		 * Filters the CSS class(es) applied to a menu list element.
 85		 *
 86		 * @since 4.8.0
 87		 *
 88		 * @param string[] $classes Array of the CSS classes that are applied to the menu `<ul>` element.
 89		 * @param stdClass $args    An object of `wp_nav_menu()` arguments.
 90		 * @param int      $depth   Depth of menu item. Used for padding.
 91		 */
 92		$class_names = implode( ' ', apply_filters( 'nav_menu_submenu_css_class', $classes, $args, $depth ) );
 93
 94		$atts          = array();
 95		$atts['class'] = ! empty( $class_names ) ? $class_names : '';
 96
 97		/**
 98		 * Filters the HTML attributes applied to a menu list element.
 99		 *
100		 * @since 6.3.0
101		 *
102		 * @param array $atts {
103		 *     The HTML attributes applied to the `<ul>` element, empty strings are ignored.
104		 *
105		 *     @type string $class    HTML CSS class attribute.
106		 * }
107		 * @param stdClass $args      An object of `wp_nav_menu()` arguments.
108		 * @param int      $depth     Depth of menu item. Used for padding.
109		 */
110		$atts       = apply_filters( 'nav_menu_submenu_attributes', $atts, $args, $depth );
111		$attributes = $this->build_atts( $atts );
112
113		$output .= "{$n}{$indent}<ul{$attributes}>{$n}";
114	}
115
116	/**
117	 * Ends the list of after the elements are added.
118	 *
119	 * @since 3.0.0
120	 *
121	 * @see Walker::end_lvl()
122	 *
123	 * @param string   $output Used to append additional content (passed by reference).
124	 * @param int      $depth  Depth of menu item. Used for padding.
125	 * @param stdClass $args   An object of wp_nav_menu() arguments.
126	 */
127	public function end_lvl( &$output, $depth = 0, $args = null ) {
128		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
129			$t = '';
130			$n = '';
131		} else {
132			$t = "\t";
133			$n = "\n";
134		}
135		$indent  = str_repeat( $t, $depth );
136		$output .= "$indent</ul>{$n}";
137	}
138
139	/**
140	 * Starts the element output.
141	 *
142	 * @since 3.0.0
143	 * @since 4.4.0 The {@see 'nav_menu_item_args'} filter was added.
144	 * @since 5.9.0 Renamed `$item` to `$data_object` and `$id` to `$current_object_id`
145	 *              to match parent class for PHP 8 named parameter support.
146	 * @since 6.7.0 Removed redundant title attributes.
147	 *
148	 * @see Walker::start_el()
149	 *
150	 * @param string   $output            Used to append additional content (passed by reference).
151	 * @param WP_Post  $data_object       Menu item data object.
152	 * @param int      $depth             Depth of menu item. Used for padding.
153	 * @param stdClass $args              An object of wp_nav_menu() arguments.
154	 * @param int      $current_object_id Optional. ID of the current menu item. Default 0.
155	 */
156	public function start_el( &$output, $data_object, $depth = 0, $args = null, $current_object_id = 0 ) {
157		// Restores the more descriptive, specific name for use within this method.
158		$menu_item = $data_object;
159
160		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
161			$t = '';
162			$n = '';
163		} else {
164			$t = "\t";
165			$n = "\n";
166		}
167		$indent = ( $depth ) ? str_repeat( $t, $depth ) : '';
168
169		$classes   = empty( $menu_item->classes ) ? array() : (array) $menu_item->classes;
170		$classes[] = 'menu-item-' . $menu_item->ID;
171
172		/**
173		 * Filters the arguments for a single nav menu item.
174		 *
175		 * @since 4.4.0
176		 *
177		 * @param stdClass $args      An object of wp_nav_menu() arguments.
178		 * @param WP_Post  $menu_item Menu item data object.
179		 * @param int      $depth     Depth of menu item. Used for padding.
180		 */
181		$args = apply_filters( 'nav_menu_item_args', $args, $menu_item, $depth );
182
183		/**
184		 * Filters the CSS classes applied to a menu item's list item element.
185		 *
186		 * @since 3.0.0
187		 * @since 4.1.0 The `$depth` parameter was added.
188		 *
189		 * @param string[] $classes   Array of the CSS classes that are applied to the menu item's `<li>` element.
190		 * @param WP_Post  $menu_item The current menu item object.
191		 * @param stdClass $args      An object of wp_nav_menu() arguments.
192		 * @param int      $depth     Depth of menu item. Used for padding.
193		 */
194		$class_names = implode( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $menu_item, $args, $depth ) );
195
196		/**
197		 * Filters the ID attribute applied to a menu item's list item element.
198		 *
199		 * @since 3.0.1
200		 * @since 4.1.0 The `$depth` parameter was added.
201		 *
202		 * @param string   $menu_item_id The ID attribute applied to the menu item's `<li>` element.
203		 * @param WP_Post  $menu_item    The current menu item.
204		 * @param stdClass $args         An object of wp_nav_menu() arguments.
205		 * @param int      $depth        Depth of menu item. Used for padding.
206		 */
207		$id = apply_filters( 'nav_menu_item_id', 'menu-item-' . $menu_item->ID, $menu_item, $args, $depth );
208
209		$li_atts          = array();
210		$li_atts['id']    = ! empty( $id ) ? $id : '';
211		$li_atts['class'] = ! empty( $class_names ) ? $class_names : '';
212
213		/**
214		 * Filters the HTML attributes applied to a menu's list item element.
215		 *
216		 * @since 6.3.0
217		 *
218		 * @param array $li_atts {
219		 *     The HTML attributes applied to the menu item's `<li>` element, empty strings are ignored.
220		 *
221		 *     @type string $class        HTML CSS class attribute.
222		 *     @type string $id           HTML id attribute.
223		 * }
224		 * @param WP_Post  $menu_item The current menu item object.
225		 * @param stdClass $args      An object of wp_nav_menu() arguments.
226		 * @param int      $depth     Depth of menu item. Used for padding.
227		 */
228		$li_atts       = apply_filters( 'nav_menu_item_attributes', $li_atts, $menu_item, $args, $depth );
229		$li_attributes = $this->build_atts( $li_atts );
230
231		$output .= $indent . '<li' . $li_attributes . '>';
232
233		/** This filter is documented in wp-includes/post-template.php */
234		$title = apply_filters( 'the_title', $menu_item->title, $menu_item->ID );
235
236		// Save filtered value before filtering again.
237		$the_title_filtered = $title;
238
239		/**
240		 * Filters a menu item's title.
241		 *
242		 * @since 4.4.0
243		 *
244		 * @param string   $title     The menu item's title.
245		 * @param WP_Post  $menu_item The current menu item object.
246		 * @param stdClass $args      An object of wp_nav_menu() arguments.
247		 * @param int      $depth     Depth of menu item. Used for padding.
248		 */
249		$title = apply_filters( 'nav_menu_item_title', $title, $menu_item, $args, $depth );
250
251		$atts           = array();
252		$atts['target'] = ! empty( $menu_item->target ) ? $menu_item->target : '';
253		$atts['rel']    = ! empty( $menu_item->xfn ) ? $menu_item->xfn : '';
254
255		if ( ! empty( $menu_item->url ) ) {
256			if ( $this->privacy_policy_url === $menu_item->url ) {
257				$atts['rel'] = empty( $atts['rel'] ) ? 'privacy-policy' : $atts['rel'] . ' privacy-policy';
258			}
259
260			$atts['href'] = $menu_item->url;
261		} else {
262			$atts['href'] = '';
263		}
264
265		$atts['aria-current'] = $menu_item->current ? 'page' : '';
266
267		// Add title attribute only if it does not match the link text (before or after filtering).
268		if ( ! empty( $menu_item->attr_title )
269			&& trim( strtolower( $menu_item->attr_title ) ) !== trim( strtolower( $menu_item->title ) )
270			&& trim( strtolower( $menu_item->attr_title ) ) !== trim( strtolower( $the_title_filtered ) )
271			&& trim( strtolower( $menu_item->attr_title ) ) !== trim( strtolower( $title ) )
272		) {
273			$atts['title'] = $menu_item->attr_title;
274		} else {
275			$atts['title'] = '';
276		}
277
278		/**
279		 * Filters the HTML attributes applied to a menu item's anchor element.
280		 *
281		 * @since 3.6.0
282		 * @since 4.1.0 The `$depth` parameter was added.
283		 *
284		 * @param array $atts {
285		 *     The HTML attributes applied to the menu item's `<a>` element, empty strings are ignored.
286		 *
287		 *     @type string $title        Title attribute.
288		 *     @type string $target       Target attribute.
289		 *     @type string $rel          The rel attribute.
290		 *     @type string $href         The href attribute.
291		 *     @type string $aria-current The aria-current attribute.
292		 * }
293		 * @param WP_Post  $menu_item The current menu item object.
294		 * @param stdClass $args      An object of wp_nav_menu() arguments.
295		 * @param int      $depth     Depth of menu item. Used for padding.
296		 */
297		$atts       = apply_filters( 'nav_menu_link_attributes', $atts, $menu_item, $args, $depth );
298		$attributes = $this->build_atts( $atts );
299
300		$item_output  = $args->before;
301		$item_output .= '<a' . $attributes . '>';
302		$item_output .= $args->link_before . $title . $args->link_after;
303		$item_output .= '</a>';
304		$item_output .= $args->after;
305
306		/**
307		 * Filters a menu item's starting output.
308		 *
309		 * The menu item's starting output only includes `$args->before`, the opening `<a>`,
310		 * the menu item's title, the closing `</a>`, and `$args->after`. Currently, there is
311		 * no filter for modifying the opening and closing `<li>` for a menu item.
312		 *
313		 * @since 3.0.0
314		 *
315		 * @param string   $item_output The menu item's starting HTML output.
316		 * @param WP_Post  $menu_item   Menu item data object.
317		 * @param int      $depth       Depth of menu item. Used for padding.
318		 * @param stdClass $args        An object of wp_nav_menu() arguments.
319		 */
320		$output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $menu_item, $depth, $args );
321	}
322
323	/**
324	 * Ends the element output, if needed.
325	 *
326	 * @since 3.0.0
327	 * @since 5.9.0 Renamed `$item` to `$data_object` to match parent class for PHP 8 named parameter support.
328	 *
329	 * @see Walker::end_el()
330	 *
331	 * @param string   $output      Used to append additional content (passed by reference).
332	 * @param WP_Post  $data_object Menu item data object. Not used.
333	 * @param int      $depth       Depth of page. Not Used.
334	 * @param stdClass $args        An object of wp_nav_menu() arguments.
335	 */
336	public function end_el( &$output, $data_object, $depth = 0, $args = null ) {
337		if ( isset( $args->item_spacing ) && 'discard' === $args->item_spacing ) {
338			$t = '';
339			$n = '';
340		} else {
341			$t = "\t";
342			$n = "\n";
343		}
344		$output .= "</li>{$n}";
345	}
346
347	/**
348	 * Builds a string of HTML attributes from an array of key/value pairs.
349	 * Empty values are ignored.
350	 *
351	 * @since 6.3.0
352	 *
353	 * @param  array $atts Optional. An array of HTML attribute key/value pairs. Default empty array.
354	 * @return string A string of HTML attributes.
355	 */
356	protected function build_atts( $atts = array() ) {
357		$attribute_string = '';
358		foreach ( $atts as $attr => $value ) {
359			if ( false !== $value && '' !== $value && is_scalar( $value ) ) {
360				$value             = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
361				$attribute_string .= ' ' . $attr . '="' . $value . '"';
362			}
363		}
364		return $attribute_string;
365	}
366}
367