201 lines
		
	
	
		
			6.7 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
			
		
		
	
	
			201 lines
		
	
	
		
			6.7 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
| <?php
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| /**
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|  * Meta API: WP_Metadata_Lazyloader class
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|  *
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|  * @package WordPress
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|  * @subpackage Meta
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|  * @since 4.5.0
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|  */
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| 
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| /**
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|  * Core class used for lazy-loading object metadata.
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|  *
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|  * When loading many objects of a given type, such as posts in a WP_Query loop, it often makes
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|  * sense to prime various metadata caches at the beginning of the loop. This means fetching all
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|  * relevant metadata with a single database query, a technique that has the potential to improve
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|  * performance dramatically in some cases.
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|  *
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|  * In cases where the given metadata may not even be used in the loop, we can improve performance
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|  * even more by only priming the metadata cache for affected items the first time a piece of metadata
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|  * is requested - ie, by lazy-loading it. So, for example, comment meta may not be loaded into the
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|  * cache in the comments section of a post until the first time get_comment_meta() is called in the
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|  * context of the comment loop.
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|  *
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|  * WP uses the WP_Metadata_Lazyloader class to queue objects for metadata cache priming. The class
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|  * then detects the relevant get_*_meta() function call, and queries the metadata of all queued objects.
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|  *
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|  * Do not access this class directly. Use the wp_metadata_lazyloader() function.
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|  *
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|  * @since 4.5.0
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|  */
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| #[AllowDynamicProperties]
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| class WP_Metadata_Lazyloader {
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| 	/**
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| 	 * Pending objects queue.
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| 	 *
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| 	 * @since 4.5.0
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| 	 * @var array
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| 	 */
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| 	protected $pending_objects;
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| 
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| 	/**
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| 	 * Settings for supported object types.
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| 	 *
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| 	 * @since 4.5.0
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| 	 * @var array
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| 	 */
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| 	protected $settings = array();
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| 
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| 	/**
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| 	 * Constructor.
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| 	 *
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| 	 * @since 4.5.0
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| 	 */
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| 	public function __construct() {
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| 		$this->settings = array(
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| 			'term'    => array(
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| 				'filter'   => 'get_term_metadata',
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| 				'callback' => array( $this, 'lazyload_meta_callback' ),
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| 			),
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| 			'comment' => array(
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| 				'filter'   => 'get_comment_metadata',
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| 				'callback' => array( $this, 'lazyload_meta_callback' ),
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| 			),
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| 			'blog'    => array(
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| 				'filter'   => 'get_blog_metadata',
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| 				'callback' => array( $this, 'lazyload_meta_callback' ),
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| 			),
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| 		);
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| 	}
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| 
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| 	/**
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| 	 * Adds objects to the metadata lazy-load queue.
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| 	 *
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| 	 * @since 4.5.0
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| 	 *
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| 	 * @param string $object_type Type of object whose meta is to be lazy-loaded. Accepts 'term' or 'comment'.
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| 	 * @param array  $object_ids  Array of object IDs.
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| 	 * @return void|WP_Error WP_Error on failure.
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| 	 */
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| 	public function queue_objects( $object_type, $object_ids ) {
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| 		if ( ! isset( $this->settings[ $object_type ] ) ) {
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| 			return new WP_Error( 'invalid_object_type', __( 'Invalid object type.' ) );
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| 		}
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| 
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| 		$type_settings = $this->settings[ $object_type ];
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| 
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| 		if ( ! isset( $this->pending_objects[ $object_type ] ) ) {
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| 			$this->pending_objects[ $object_type ] = array();
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| 		}
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| 
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| 		foreach ( $object_ids as $object_id ) {
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| 			// Keyed by ID for faster lookup.
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| 			if ( ! isset( $this->pending_objects[ $object_type ][ $object_id ] ) ) {
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| 				$this->pending_objects[ $object_type ][ $object_id ] = 1;
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| 			}
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| 		}
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| 
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| 		add_filter( $type_settings['filter'], $type_settings['callback'], 10, 5 );
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| 
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| 		/**
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| 		 * Fires after objects are added to the metadata lazy-load queue.
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| 		 *
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| 		 * @since 4.5.0
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| 		 *
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| 		 * @param array                  $object_ids  Array of object IDs.
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| 		 * @param string                 $object_type Type of object being queued.
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| 		 * @param WP_Metadata_Lazyloader $lazyloader  The lazy-loader object.
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| 		 */
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| 		do_action( 'metadata_lazyloader_queued_objects', $object_ids, $object_type, $this );
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| 	}
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| 
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| 	/**
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| 	 * Resets lazy-load queue for a given object type.
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| 	 *
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| 	 * @since 4.5.0
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| 	 *
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| 	 * @param string $object_type Object type. Accepts 'comment' or 'term'.
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| 	 * @return void|WP_Error WP_Error on failure.
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| 	 */
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| 	public function reset_queue( $object_type ) {
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| 		if ( ! isset( $this->settings[ $object_type ] ) ) {
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| 			return new WP_Error( 'invalid_object_type', __( 'Invalid object type.' ) );
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| 		}
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| 
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| 		$type_settings = $this->settings[ $object_type ];
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| 
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| 		$this->pending_objects[ $object_type ] = array();
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| 		remove_filter( $type_settings['filter'], $type_settings['callback'] );
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| 	}
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| 
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| 	/**
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| 	 * Lazy-loads term meta for queued terms.
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| 	 *
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| 	 * This method is public so that it can be used as a filter callback. As a rule, there
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| 	 * is no need to invoke it directly.
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| 	 *
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| 	 * @since 4.5.0
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| 	 * @deprecated 6.3.0 Use WP_Metadata_Lazyloader::lazyload_meta_callback() instead.
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| 	 *
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| 	 * @param mixed $check The `$check` param passed from the 'get_term_metadata' hook.
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| 	 * @return mixed In order not to short-circuit `get_metadata()`. Generally, this is `null`, but it could be
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| 	 *               another value if filtered by a plugin.
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| 	 */
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| 	public function lazyload_term_meta( $check ) {
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| 		_deprecated_function( __METHOD__, '6.3.0', 'WP_Metadata_Lazyloader::lazyload_meta_callback' );
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| 		return $this->lazyload_meta_callback( $check, 0, '', false, 'term' );
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| 	}
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| 
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| 	/**
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| 	 * Lazy-loads comment meta for queued comments.
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| 	 *
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| 	 * This method is public so that it can be used as a filter callback. As a rule, there is no need to invoke it
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| 	 * directly, from either inside or outside the `WP_Query` object.
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| 	 *
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| 	 * @since 4.5.0
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| 	 * @deprecated 6.3.0 Use WP_Metadata_Lazyloader::lazyload_meta_callback() instead.
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| 	 *
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| 	 * @param mixed $check The `$check` param passed from the {@see 'get_comment_metadata'} hook.
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| 	 * @return mixed The original value of `$check`, so as not to short-circuit `get_comment_metadata()`.
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| 	 */
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| 	public function lazyload_comment_meta( $check ) {
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| 		_deprecated_function( __METHOD__, '6.3.0', 'WP_Metadata_Lazyloader::lazyload_meta_callback' );
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| 		return $this->lazyload_meta_callback( $check, 0, '', false, 'comment' );
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| 	}
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| 
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| 	/**
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| 	 * Lazy-loads meta for queued objects.
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| 	 *
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| 	 * This method is public so that it can be used as a filter callback. As a rule, there
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| 	 * is no need to invoke it directly.
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| 	 *
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| 	 * @since 6.3.0
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| 	 *
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| 	 * @param mixed  $check     The `$check` param passed from the 'get_*_metadata' hook.
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| 	 * @param int    $object_id ID of the object metadata is for.
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| 	 * @param string $meta_key  Unused.
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| 	 * @param bool   $single    Unused.
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| 	 * @param string $meta_type Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user',
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| 	 *                          or any other object type with an associated meta table.
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| 	 * @return mixed In order not to short-circuit `get_metadata()`. Generally, this is `null`, but it could be
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| 	 *               another value if filtered by a plugin.
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| 	 */
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| 	public function lazyload_meta_callback( $check, $object_id, $meta_key, $single, $meta_type ) {
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| 		if ( empty( $this->pending_objects[ $meta_type ] ) ) {
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| 			return $check;
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| 		}
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| 
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| 		$object_ids = array_keys( $this->pending_objects[ $meta_type ] );
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| 		if ( $object_id && ! in_array( $object_id, $object_ids, true ) ) {
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| 			$object_ids[] = $object_id;
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| 		}
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| 
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| 		update_meta_cache( $meta_type, $object_ids );
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| 
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| 		// No need to run again for this set of objects.
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| 		$this->reset_queue( $meta_type );
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| 
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| 		return $check;
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| 	}
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| }
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