shimmie2/ext/upgrade/main.php

<?php

class Upgrade implements Extension {
	public function receive_event(Event $event) {
		if($event instanceof InitExtEvent) {
			$this->do_things();
		}
	}

	private function do_things() {
		global $config, $database;

		if(!is_numeric($config->get_string("db_version"))) {
			$config->set_int("db_version", 2);
		}

		if($config->get_int("db_version") < 6) {
			// cry :S
		}

		if($config->get_int("db_version") < 7) {
			if($database->engine->name == "mysql") {
				$tables = $database->db->MetaTables();
				foreach($tables as $table) {
					log_info("upgrade", "converting $table to innodb");
					$database->execute("ALTER TABLE $table TYPE=INNODB");
				}
			}
			$config->set_int("db_version", 7);
			log_info("Database at version 7");
		}

		// TODO:
		// add column image->locked
	}
}
add_event_listener(new Upgrade(), 5);
?>