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Diffstat (limited to 'srcs/wordpress/wp-includes/class-wp-metadata-lazyloader.php')
| -rw-r--r-- | srcs/wordpress/wp-includes/class-wp-metadata-lazyloader.php | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/srcs/wordpress/wp-includes/class-wp-metadata-lazyloader.php b/srcs/wordpress/wp-includes/class-wp-metadata-lazyloader.php new file mode 100644 index 0000000..80b8bdd --- /dev/null +++ b/srcs/wordpress/wp-includes/class-wp-metadata-lazyloader.php @@ -0,0 +1,170 @@ +<?php +/** + * Meta API: WP_Metadata_Lazyloader class + * + * @package WordPress + * @subpackage Meta + * @since 4.5.0 + */ + +/** + * Core class used for lazy-loading object metadata. + * + * When loading many objects of a given type, such as posts in a WP_Query loop, it often makes + * sense to prime various metadata caches at the beginning of the loop. This means fetching all + * relevant metadata with a single database query, a technique that has the potential to improve + * performance dramatically in some cases. + * + * In cases where the given metadata may not even be used in the loop, we can improve performance + * even more by only priming the metadata cache for affected items the first time a piece of metadata + * is requested - ie, by lazy-loading it. So, for example, comment meta may not be loaded into the + * cache in the comments section of a post until the first time get_comment_meta() is called in the + * context of the comment loop. + * + * WP uses the WP_Metadata_Lazyloader class to queue objects for metadata cache priming. The class + * then detects the relevant get_*_meta() function call, and queries the metadata of all queued objects. + * + * Do not access this class directly. Use the wp_metadata_lazyloader() function. + * + * @since 4.5.0 + */ +class WP_Metadata_Lazyloader { + /** + * Pending objects queue. + * + * @since 4.5.0 + * @var array + */ + protected $pending_objects; + + /** + * Settings for supported object types. + * + * @since 4.5.0 + * @var array + */ + protected $settings = array(); + + /** + * Constructor. + * + * @since 4.5.0 + */ + public function __construct() { + $this->settings = array( + 'term' => array( + 'filter' => 'get_term_metadata', + 'callback' => array( $this, 'lazyload_term_meta' ), + ), + 'comment' => array( + 'filter' => 'get_comment_metadata', + 'callback' => array( $this, 'lazyload_comment_meta' ), + ), + ); + } + + /** + * Adds objects to the metadata lazy-load queue. + * + * @since 4.5.0 + * + * @param string $object_type Type of object whose meta is to be lazy-loaded. Accepts 'term' or 'comment'. + * @param array $object_ids Array of object IDs. + * @return bool|WP_Error True on success, WP_Error on failure. + */ + public function queue_objects( $object_type, $object_ids ) { + if ( ! isset( $this->settings[ $object_type ] ) ) { + return new WP_Error( 'invalid_object_type', __( 'Invalid object type' ) ); + } + + $type_settings = $this->settings[ $object_type ]; + + if ( ! isset( $this->pending_objects[ $object_type ] ) ) { + $this->pending_objects[ $object_type ] = array(); + } + + foreach ( $object_ids as $object_id ) { + // Keyed by ID for faster lookup. + if ( ! isset( $this->pending_objects[ $object_type ][ $object_id ] ) ) { + $this->pending_objects[ $object_type ][ $object_id ] = 1; + } + } + + add_filter( $type_settings['filter'], $type_settings['callback'] ); + + /** + * Fires after objects are added to the metadata lazy-load queue. + * + * @since 4.5.0 + * + * @param array $object_ids Array of object IDs. + * @param string $object_type Type of object being queued. + * @param WP_Metadata_Lazyloader $lazyloader The lazy-loader object. + */ + do_action( 'metadata_lazyloader_queued_objects', $object_ids, $object_type, $this ); + } + + /** + * Resets lazy-load queue for a given object type. + * + * @since 4.5.0 + * + * @param string $object_type Object type. Accepts 'comment' or 'term'. + * @return bool|WP_Error True on success, WP_Error on failure. + */ + public function reset_queue( $object_type ) { + if ( ! isset( $this->settings[ $object_type ] ) ) { + return new WP_Error( 'invalid_object_type', __( 'Invalid object type' ) ); + } + + $type_settings = $this->settings[ $object_type ]; + + $this->pending_objects[ $object_type ] = array(); + remove_filter( $type_settings['filter'], $type_settings['callback'] ); + } + + /** + * Lazy-loads term meta for queued terms. + * + * This method is public so that it can be used as a filter callback. As a rule, there + * is no need to invoke it directly. + * + * @since 4.5.0 + * + * @param mixed $check The `$check` param passed from the 'get_term_metadata' hook. + * @return mixed In order not to short-circuit `get_metadata()`. Generally, this is `null`, but it could be + * another value if filtered by a plugin. + */ + public function lazyload_term_meta( $check ) { + if ( ! empty( $this->pending_objects['term'] ) ) { + update_termmeta_cache( array_keys( $this->pending_objects['term'] ) ); + + // No need to run again for this set of terms. + $this->reset_queue( 'term' ); + } + + return $check; + } + + /** + * Lazy-loads comment meta for queued comments. + * + * This method is public so that it can be used as a filter callback. As a rule, there is no need to invoke it + * directly, from either inside or outside the `WP_Query` object. + * + * @since 4.5.0 + * + * @param mixed $check The `$check` param passed from the {@see 'get_comment_metadata'} hook. + * @return mixed The original value of `$check`, so as not to short-circuit `get_comment_metadata()`. + */ + public function lazyload_comment_meta( $check ) { + if ( ! empty( $this->pending_objects['comment'] ) ) { + update_meta_cache( 'comment', array_keys( $this->pending_objects['comment'] ) ); + + // No need to run again for this set of comments. + $this->reset_queue( 'comment' ); + } + + return $check; + } +} |