View file File name : ActionScheduler_Versions.php Content :<?php /** * Class ActionScheduler_Versions */ class ActionScheduler_Versions { /** * @var ActionScheduler_Versions */ private static $instance = NULL; private $versions = array(); public function register( $version_string, $initialization_callback ) { if ( isset($this->versions[$version_string]) ) { return FALSE; } $this->versions[$version_string] = $initialization_callback; return TRUE; } public function get_versions() { return $this->versions; } public function latest_version() { $keys = array_keys($this->versions); if ( empty($keys) ) { return false; } uasort( $keys, 'version_compare' ); return end($keys); } public function latest_version_callback() { $latest = $this->latest_version(); if ( empty($latest) || !isset($this->versions[$latest]) ) { return '__return_null'; } return $this->versions[$latest]; } /** * @return ActionScheduler_Versions * @codeCoverageIgnore */ public static function instance() { if ( empty(self::$instance) ) { self::$instance = new self(); } return self::$instance; } /** * @codeCoverageIgnore */ public static function initialize_latest_version() { $self = self::instance(); call_user_func($self->latest_version_callback()); } }