WP_Metadata_Lazyloader

31#[AllowDynamicProperties]32class WP_Metadata_Lazyloader {33	/**34	 * Pending objects queue.35	 *36	 * @since 4.5.037	 * @var array38	 */39	protected $pending_objects;40 41	/**42	 * Settings for supported object types.43	 *44	 * @since 4.5.045	 * @var array46	 */47	protected $settings = array();48 49	/**50	 * Constructor.51	 *52	 * @since 4.5.053	 */54	public function __construct() {55		$this->settings = array(56			'term'    => array(57				'filter'   => 'get_term_metadata',58				'callback' => array( $this, 'lazyload_meta_callback' ),59			),60			'comment' => array(61				'filter'   => 'get_comment_metadata',62				'callback' => array( $this, 'lazyload_meta_callback' ),63			),64			'blog'    => array(65				'filter'   => 'get_blog_metadata',66				'callback' => array( $this, 'lazyload_meta_callback' ),67			),68		);69	}70 71	/**72	 * Adds objects to the metadata lazy-load queue.73	 *74	 * @since 4.5.075	 *76	 * @param string $object_type Type of object whose meta is to be lazy-loaded. Accepts 'term' or 'comment'.77	 * @param array  $object_ids  Array of object IDs.78	 * @return void|WP_Error WP_Error on failure.79	 */80	public function queue_objects( $object_type, $object_ids ) {81		if ( ! isset( $this->settings[ $object_type ] ) ) {82			return new WP_Error( 'invalid_object_type', __( 'Invalid object type.' ) );83		}84 85		$type_settings = $this->settings[ $object_type ];86 87		if ( ! isset( $this->pending_objects[ $object_type ] ) ) {88			$this->pending_objects[ $object_type ] = array();89		}90 91		foreach ( $object_ids as $object_id ) {92			// Keyed by ID for faster lookup.93			if ( ! isset( $this->pending_objects[ $object_type ][ $object_id ] ) ) {94				$this->pending_objects[ $object_type ][ $object_id ] = 1;95			}96		}97 98		add_filter( $type_settings['filter'], $type_settings['callback'], 10, 5 );99 100		/**101		 * Fires after objects are added to the metadata lazy-load queue.102		 *103		 * @since 4.5.0104		 *105		 * @param array                  $object_ids  Array of object IDs.106		 * @param string                 $object_type Type of object being queued.107		 * @param WP_Metadata_Lazyloader $lazyloader  The lazy-loader object.108		 */109		do_action( 'metadata_lazyloader_queued_objects', $object_ids, $object_type, $this );110	}