165 lines
5.1 KiB
PHP
165 lines
5.1 KiB
PHP
<?php
|
|
|
|
/**
|
|
* Lazyloader for 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 lazyloading 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' ),
|
|
),
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Add objects to the metadata lazyload queue.
|
|
*
|
|
* @since 4.5.0
|
|
*
|
|
* @param string $object_type Type of object whose meta is to be lazyloaded. 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 lazyload queue.
|
|
*
|
|
* @since 4.5.0
|
|
*
|
|
* @param array $object_ids Object IDs.
|
|
* @param string $object_type Type of object being queued.
|
|
* @param WP_Metadata_Lazyloader $lazyloader The lazyloader object.
|
|
*/
|
|
do_action( 'metadata_lazyloader_queued_objects', $object_ids, $object_type, $this );
|
|
}
|
|
|
|
/**
|
|
* Reset lazyload 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'] );
|
|
}
|
|
|
|
/**
|
|
* Lazyloads 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
|
|
* @access public
|
|
*
|
|
* @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;
|
|
}
|
|
|
|
/**
|
|
* Lazyload 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 '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;
|
|
}
|
|
}
|