/app/system/libraries/Migration.php

<?php defined('BASEPATH') OR exit('No direct script access allowed');

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP 5.1.6 or newer

 *

 * @package		CodeIgniter

 * @author		EllisLab Dev Team

 * @copyright	Copyright (c) 2006 - 2014, EllisLab, Inc.

 * @license		http://codeigniter.com/user_guide/license.html

 * @link		http://codeigniter.com

 * @since		Version 1.0

 * @filesource

 */



// ------------------------------------------------------------------------



/**

 * Migration Class

 *

 * All migrations should implement this, forces up() and down() and gives

 * access to the CI super-global.

 *

 * @package		CodeIgniter

 * @subpackage	Libraries

 * @category	Libraries

 * @author		Reactor Engineers

 * @link

 */

class CI_Migration {



	protected $_migration_enabled = FALSE;

	protected $_migration_path = NULL;

	protected $_migration_version = 0;



	protected $_error_string = '';



	public function __construct($config = array())

	{

		# Only run this constructor on main library load

		if (get_parent_class($this) !== FALSE)

		{

			return;

		}



		foreach ($config as $key => $val)

		{

			$this->{'_' . $key} = $val;

		}



		log_message('debug', 'Migrations class initialized');



		// Are they trying to use migrations while it is disabled?

		if ($this->_migration_enabled !== TRUE)

		{

			show_error('Migrations has been loaded but is disabled or set up incorrectly.');

		}



		// If not set, set it

		$this->_migration_path == '' AND $this->_migration_path = APPPATH . 'migrations/';



		// Add trailing slash if not set

		$this->_migration_path = rtrim($this->_migration_path, '/').'/';



		// Load migration language

		$this->lang->load('migration');



		// They'll probably be using dbforge

		$this->load->dbforge();



		// If the migrations table is missing, make it

		if ( ! $this->db->table_exists('migrations'))

		{

			$this->dbforge->add_field(array(

				'version' => array('type' => 'INT', 'constraint' => 3),

			));



			$this->dbforge->create_table('migrations', TRUE);



			$this->db->insert('migrations', array('version' => 0));

		}

	}



	// --------------------------------------------------------------------



	/**

	 * Migrate to a schema version

	 *

	 * Calls each migration step required to get to the schema version of

	 * choice

	 *

	 * @param	int	Target schema version

	 * @return	mixed	TRUE if already latest, FALSE if failed, int if upgraded

	 */

	public function version($target_version)

	{

		$start = $current_version = $this->_get_version();

		$stop = $target_version;



		if ($target_version > $current_version)

		{

			// Moving Up

			++$start;

			++$stop;

			$step = 1;

		}

		else

		{

			// Moving Down

			$step = -1;

		}



		$method = ($step === 1) ? 'up' : 'down';

		$migrations = array();



		// We now prepare to actually DO the migrations

		// But first let's make sure that everything is the way it should be

		for ($i = $start; $i != $stop; $i += $step)

		{

			$f = glob(sprintf($this->_migration_path . '%03d_*.php', $i));



			// Only one migration per step is permitted

			if (count($f) > 1)

			{

				$this->_error_string = sprintf($this->lang->line('migration_multiple_version'), $i);

				return FALSE;

			}



			// Migration step not found

			if (count($f) == 0)

			{

				// If trying to migrate up to a version greater than the last

				// existing one, migrate to the last one.

				if ($step == 1)

				{

					break;

				}



				// If trying to migrate down but we're missing a step,

				// something must definitely be wrong.

				$this->_error_string = sprintf($this->lang->line('migration_not_found'), $i);

				return FALSE;

			}



			$file = basename($f[0]);

			$name = basename($f[0], '.php');



			// Filename validations

			if (preg_match('/^\d{3}_(\w+)$/', $name, $match))

			{

				$match[1] = strtolower($match[1]);



				// Cannot repeat a migration at different steps

				if (in_array($match[1], $migrations))

				{

					$this->_error_string = sprintf($this->lang->line('migration_multiple_version'), $match[1]);

					return FALSE;

				}



				include $f[0];

				$class = 'Migration_' . ucfirst($match[1]);



				if ( ! class_exists($class))

				{

					$this->_error_string = sprintf($this->lang->line('migration_class_doesnt_exist'), $class);

					return FALSE;

				}



				if ( ! is_callable(array($class, $method)))

				{

					$this->_error_string = sprintf($this->lang->line('migration_missing_'.$method.'_method'), $class);

					return FALSE;

				}



				$migrations[] = $match[1];

			}

			else

			{

				$this->_error_string = sprintf($this->lang->line('migration_invalid_filename'), $file);

				return FALSE;

			}

		}



		log_message('debug', 'Current migration: ' . $current_version);



		$version = $i + ($step == 1 ? -1 : 0);



		// If there is nothing to do so quit

		if ($migrations === array())

		{

			return TRUE;

		}



		log_message('debug', 'Migrating from ' . $method . ' to version ' . $version);



		// Loop through the migrations

		foreach ($migrations AS $migration)

		{

			// Run the migration class

			$class = 'Migration_' . ucfirst(strtolower($migration));

			call_user_func(array(new $class, $method));



			$current_version += $step;

			$this->_update_version($current_version);

		}



		log_message('debug', 'Finished migrating to '.$current_version);



		return $current_version;

	}



	// --------------------------------------------------------------------



	/**

	 * Set's the schema to the latest migration

	 *

	 * @return	mixed	true if already latest, false if failed, int if upgraded

	 */

	public function latest()

	{

		if ( ! $migrations = $this->find_migrations())

		{

			$this->_error_string = $this->lang->line('migration_none_found');

			return false;

		}



		$last_migration = basename(end($migrations));



		// Calculate the last migration step from existing migration

		// filenames and procceed to the standard version migration

		return $this->version((int) substr($last_migration, 0, 3));

	}



	// --------------------------------------------------------------------



	/**

	 * Set's the schema to the migration version set in config

	 *

	 * @return	mixed	true if already current, false if failed, int if upgraded

	 */

	public function current()

	{

		return $this->version($this->_migration_version);

	}



	// --------------------------------------------------------------------



	/**

	 * Error string

	 *

	 * @return	string	Error message returned as a string

	 */

	public function error_string()

	{

		return $this->_error_string;

	}



	// --------------------------------------------------------------------



	/**

	 * Set's the schema to the latest migration

	 *

	 * @return	mixed	true if already latest, false if failed, int if upgraded

	 */

	protected function find_migrations()

	{

		// Load all *_*.php files in the migrations path

		$files = glob($this->_migration_path . '*_*.php');

		$file_count = count($files);



		for ($i = 0; $i < $file_count; $i++)

		{

			// Mark wrongly formatted files as false for later filtering

			$name = basename($files[$i], '.php');

			if ( ! preg_match('/^\d{3}_(\w+)$/', $name))

			{

				$files[$i] = FALSE;

			}

		}



		sort($files);

		return $files;

	}



	// --------------------------------------------------------------------



	/**

	 * Retrieves current schema version

	 *

	 * @return	int	Current Migration

	 */

	protected function _get_version()

	{

		$row = $this->db->get('migrations')->row();

		return $row ? $row->version : 0;

	}



	// --------------------------------------------------------------------



	/**

	 * Stores the current schema version

	 *

	 * @param	int	Migration reached

	 * @return	bool

	 */

	protected function _update_version($migrations)

	{

		return $this->db->update('migrations', array(

			'version' => $migrations

		));

	}



	// --------------------------------------------------------------------



	/**

	 * Enable the use of CI super-global

	 *

	 * @param	mixed	$var

	 * @return	mixed

	 */

	public function __get($var)

	{

		return get_instance()->$var;

	}



}



/* End of file Migration.php */

/* Location: ./system/libraries/Migration.php */