WordPress add_metadata() function kodu

WordPress add_metadata() function kodu

function add_metadata( $meta_type, $object_id, $meta_key, $meta_value, $unique = false ) {
    global $wpdb;
 
    if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) ) {
        return false;
    }
 
    $object_id = absint( $object_id );
    if ( ! $object_id ) {
        return false;
    }
 
    $table = _get_meta_table( $meta_type );
    if ( ! $table ) {
        return false;
    }
 
    $meta_subtype = get_object_subtype( $meta_type, $object_id );
 
    $column = sanitize_key( $meta_type . '_id' );
 
    // expected_slashed ($meta_key)
    $meta_key   = wp_unslash( $meta_key );
    $meta_value = wp_unslash( $meta_value );
    $meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type, $meta_subtype );
 
    /**
     * Filters whether to add metadata of a specific type.
     *
     * The dynamic portion of the hook, `$meta_type`, refers to the meta
     * object type (comment, post, term, or user). Returning a non-null value
     * will effectively short-circuit the function.
     *
     * @since 3.1.0
     *
     * @param null|bool $check      Whether to allow adding metadata for the given type.
     * @param int       $object_id  Object ID.
     * @param string    $meta_key   Meta key.
     * @param mixed     $meta_value Meta value. Must be serializable if non-scalar.
     * @param bool      $unique     Whether the specified meta key should be unique
     *                              for the object. Optional. Default false.
     */
    $check = apply_filters( "add_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $unique );
    if ( null !== $check ) {
        return $check;
    }
 
    if ( $unique && $wpdb->get_var(
        $wpdb->prepare(
            "SELECT COUNT(*) FROM $table WHERE meta_key = %s AND $column = %d",
            $meta_key,
            $object_id
        )
    ) ) {
        return false;
    }
 
    $_meta_value = $meta_value;
    $meta_value  = maybe_serialize( $meta_value );
 
    /**
     * Fires immediately before meta of a specific type is added.
     *
     * The dynamic portion of the hook, `$meta_type`, refers to the meta
     * object type (comment, post, term, or user).
     *
     * @since 3.1.0
     *
     * @param int    $object_id   Object ID.
     * @param string $meta_key    Meta key.
     * @param mixed  $_meta_value Meta value.
     */
    do_action( "add_{$meta_type}_meta", $object_id, $meta_key, $_meta_value );
 
    $result = $wpdb->insert(
        $table,
        array(
            $column      => $object_id,
            'meta_key'   => $meta_key,
            'meta_value' => $meta_value,
        )
    );
 
    if ( ! $result ) {
        return false;
    }
 
    $mid = (int) $wpdb->insert_id;
 
    wp_cache_delete( $object_id, $meta_type . '_meta' );
 
    /**
     * Fires immediately after meta of a specific type is added.
     *
     * The dynamic portion of the hook, `$meta_type`, refers to the meta
     * object type (comment, post, term, or user).
     *
     * @since 2.9.0
     *
     * @param int    $mid         The meta ID after successful update.
     * @param int    $object_id   Object ID.
     * @param string $meta_key    Meta key.
     * @param mixed  $_meta_value Meta value.
     */
    do_action( "added_{$meta_type}_meta", $mid, $object_id, $meta_key, $_meta_value );
 
    return $mid;
}