*/ private $versions = array(); /** * Register version's callback. * * @param string $version_string Action Scheduler version. * @param callable $initialization_callback Callback to initialize the version. */ public function register( $version_string, $initialization_callback ) { if ( isset( $this->versions[ $version_string ] ) ) { return false; } $this->versions[ $version_string ] = $initialization_callback; return true; } /** * Get all versions. */ public function get_versions() { return $this->versions; } /** * Get latest version registered. */ public function latest_version() { $keys = array_keys( $this->versions ); if ( empty( $keys ) ) { return false; } uasort( $keys, 'version_compare' ); return end( $keys ); } /** * Get callback for latest registered version. */ public function latest_version_callback() { $latest = $this->latest_version(); if ( empty( $latest ) || ! isset( $this->versions[ $latest ] ) ) { return '__return_null'; } return $this->versions[ $latest ]; } /** * Get instance. * * @return ActionScheduler_Versions * @codeCoverageIgnore */ public static function instance() { if ( empty( self::$instance ) ) { self::$instance = new self(); } return self::$instance; } /** * Initialize. * * @codeCoverageIgnore */ public static function initialize_latest_version() { $self = self::instance(); call_user_func( $self->latest_version_callback() ); } }