1 files changed, 924 insertions, 0 deletions
diff --git a/phpBB/phpbb/db/migrator.php b/phpBB/phpbb/db/migrator.php
new file mode 100644
index 0000000000..45a333ac94
--- /dev/null
+++ b/phpBB/phpbb/db/migrator.php
@@ -0,0 +1,924 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db;
+
+use Symfony\Component\DependencyInjection\ContainerAwareInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+* The migrator is responsible for applying new migrations in the correct order.
+*/
+class migrator
+{
+	/**
+	 * @var ContainerInterface
+	 */
+	protected $container;
+
+	/** @var \phpbb\config\config */
+	protected $config;
+
+	/** @var \phpbb\db\driver\driver_interface */
+	protected $db;
+
+	/** @var \phpbb\db\tools */
+	protected $db_tools;
+
+	/** @var \phpbb\db\migration\helper */
+	protected $helper;
+
+	/** @var string */
+	protected $table_prefix;
+
+	/** @var string */
+	protected $phpbb_root_path;
+
+	/** @var string */
+	protected $php_ext;
+
+	/** @var string */
+	protected $migrations_table;
+
+	/**
+	* State of all migrations
+	*
+	* (SELECT * FROM migrations table)
+	*
+	* @var array
+	*/
+	protected $migration_state = array();
+
+	/**
+	* Array of all migrations available to be run
+	*
+	* @var array
+	*/
+	protected $migrations = array();
+
+	/**
+	* Array of migrations that have been determined to be fulfillable
+	*
+	* @var array
+	*/
+	protected $fulfillable_migrations = array();
+
+	/**
+	* 'name,' 'class,' and 'state' of the last migration run
+	*
+	* 'effectively_installed' set and set to true if the migration was effectively_installed
+	*
+	* @var array
+	*/
+	protected $last_run_migration = false;
+
+	/**
+	 * The output handler. A null handler is configured by default.
+	 *
+	 * @var migrator_output_handler_interface
+	 */
+	protected $output_handler;
+
+	/**
+	* Constructor of the database migrator
+	*/
+	public function __construct(ContainerInterface $container, \phpbb\config\config $config, \phpbb\db\driver\driver_interface $db, \phpbb\db\tools $db_tools, $migrations_table, $phpbb_root_path, $php_ext, $table_prefix, $tools, \phpbb\db\migration\helper $helper)
+	{
+		$this->container = $container;
+		$this->config = $config;
+		$this->db = $db;
+		$this->db_tools = $db_tools;
+		$this->helper = $helper;
+
+		$this->migrations_table = $migrations_table;
+
+		$this->phpbb_root_path = $phpbb_root_path;
+		$this->php_ext = $php_ext;
+
+		$this->table_prefix = $table_prefix;
+
+		$this->output_handler = new null_migrator_output_handler();
+
+		foreach ($tools as $tool)
+		{
+			$this->tools[$tool->get_name()] = $tool;
+		}
+
+		$this->tools['dbtools'] = $this->db_tools;
+
+		$this->load_migration_state();
+	}
+
+	/**
+	 * Set the output handler.
+	 *
+	 * @param migrator_output_handler $handler The output handler
+	 */
+	public function set_output_handler(migrator_output_handler_interface $handler)
+	{
+		$this->output_handler = $handler;
+	}
+
+	/**
+	* Loads all migrations and their application state from the database.
+	*
+	* @return null
+	*/
+	public function load_migration_state()
+	{
+		$this->migration_state = array();
+
+		// prevent errors in case the table does not exist yet
+		$this->db->sql_return_on_error(true);
+
+		$sql = "SELECT *
+			FROM " . $this->migrations_table;
+		$result = $this->db->sql_query($sql);
+
+		if (!$this->db->get_sql_error_triggered())
+		{
+			while ($migration = $this->db->sql_fetchrow($result))
+			{
+				$this->migration_state[$migration['migration_name']] = $migration;
+
+				$this->migration_state[$migration['migration_name']]['migration_depends_on'] = unserialize($migration['migration_depends_on']);
+				$this->migration_state[$migration['migration_name']]['migration_data_state'] = !empty($migration['migration_data_state']) ? unserialize($migration['migration_data_state']) : '';
+			}
+		}
+
+		$this->db->sql_freeresult($result);
+
+		$this->db->sql_return_on_error(false);
+	}
+
+	/**
+	 * Get an array with information about the last migration run.
+	 *
+	 * The array contains 'name', 'class' and 'state'. 'effectively_installed' is set
+	 * and set to true if the last migration was effectively_installed.
+	 *
+	 * @return array
+	 */
+	public function get_last_run_migration()
+	{
+		return $this->last_run_migration;
+	}
+
+	/**
+	* Sets the list of available migration class names to the given array.
+	*
+	* @param array $class_names An array of migration class names
+	* @return null
+	*/
+	public function set_migrations($class_names)
+	{
+		$this->migrations = $class_names;
+	}
+
+	/**
+	* Runs a single update step from the next migration to be applied.
+	*
+	* The update step can either be a schema or a (partial) data update. To
+	* check if update() needs to be called again use the finished() method.
+	*
+	* @return null
+	*/
+	public function update()
+	{
+		$this->container->get('dispatcher')->disable();
+		$this->update_do();
+		$this->container->get('dispatcher')->enable();
+	}
+
+	/**
+	 * Get a valid migration name from the migration state array in case the
+	 * supplied name is not in the migration state list.
+	 *
+	 * @param string $name Migration name
+	 * @return string Migration name
+	 */
+	protected function get_valid_name($name)
+	{
+		// Try falling back to a valid migration name with or without leading backslash
+		if (!isset($this->migration_state[$name]))
+		{
+			$prepended_name = ($name[0] == '\\' ? '' : '\\') . $name;
+			$prefixless_name = $name[0] == '\\' ? substr($name, 1) : $name;
+
+			if (isset($this->migration_state[$prepended_name]))
+			{
+				$name = $prepended_name;
+			}
+			else if (isset($this->migration_state[$prefixless_name]))
+			{
+				$name = $prefixless_name;
+			}
+		}
+
+		return $name;
+	}
+
+	/**
+	 * Effectively runs a single update step from the next migration to be applied.
+	 *
+	 * @return null
+	 */
+	protected function update_do()
+	{
+		foreach ($this->migrations as $name)
+		{
+			$name = $this->get_valid_name($name);
+
+			if (!isset($this->migration_state[$name]) ||
+				!$this->migration_state[$name]['migration_schema_done'] ||
+				!$this->migration_state[$name]['migration_data_done'])
+			{
+				if (!$this->try_apply($name))
+				{
+					continue;
+				}
+				else
+				{
+					return;
+				}
+			}
+			else
+			{
+				$this->output_handler->write(array('MIGRATION_EFFECTIVELY_INSTALLED', $name), migrator_output_handler_interface::VERBOSITY_DEBUG);
+			}
+		}
+	}
+
+	/**
+	* Attempts to apply a step of the given migration or one of its dependencies
+	*
+	* @param	string	$name The class name of the migration
+	* @return	bool	Whether any update step was successfully run
+	* @throws \phpbb\db\migration\exception
+	*/
+	protected function try_apply($name)
+	{
+		if (!class_exists($name))
+		{
+			$this->output_handler->write(array('MIGRATION_NOT_VALID', $name), migrator_output_handler_interface::VERBOSITY_DEBUG);
+			return false;
+		}
+
+		$migration = $this->get_migration($name);
+
+		$state = (isset($this->migration_state[$name])) ?
+			$this->migration_state[$name] :
+			array(
+				'migration_depends_on'	=> $migration->depends_on(),
+				'migration_schema_done' => false,
+				'migration_data_done'	=> false,
+				'migration_data_state'	=> '',
+				'migration_start_time'	=> 0,
+				'migration_end_time'	=> 0,
+			);
+
+		if (!empty($state['migration_depends_on']))
+		{
+			$this->output_handler->write(array('MIGRATION_APPLY_DEPENDENCIES', $name), migrator_output_handler_interface::VERBOSITY_DEBUG);
+		}
+
+		foreach ($state['migration_depends_on'] as $depend)
+		{
+			$depend = $this->get_valid_name($depend);
+
+			// Test all possible namings before throwing exception
+			if ($this->unfulfillable($depend) !== false)
+			{
+				throw new \phpbb\db\migration\exception('MIGRATION_NOT_FULFILLABLE', $name, $depend);
+			}
+
+			if (!isset($this->migration_state[$depend]) ||
+				!$this->migration_state[$depend]['migration_schema_done'] ||
+				!$this->migration_state[$depend]['migration_data_done'])
+			{
+				return $this->try_apply($depend);
+			}
+		}
+
+		$this->last_run_migration = array(
+			'name'	=> $name,
+			'class'	=> $migration,
+			'state'	=> $state,
+			'task'	=> '',
+		);
+
+		if (!isset($this->migration_state[$name]))
+		{
+			if ($state['migration_start_time'] == 0 && $migration->effectively_installed())
+			{
+				$state = array(
+					'migration_depends_on'	=> $migration->depends_on(),
+					'migration_schema_done' => true,
+					'migration_data_done'	=> true,
+					'migration_data_state'	=> '',
+					'migration_start_time'	=> 0,
+					'migration_end_time'	=> 0,
+				);
+
+				$this->last_run_migration['effectively_installed'] = true;
+
+				$this->output_handler->write(array('MIGRATION_EFFECTIVELY_INSTALLED', $name), migrator_output_handler_interface::VERBOSITY_VERBOSE);
+			}
+			else
+			{
+				$state['migration_start_time'] = time();
+			}
+		}
+
+		$this->set_migration_state($name, $state);
+
+		if (!$state['migration_schema_done'])
+		{
+			$verbosity = empty($state['migration_data_state']) ?
+				migrator_output_handler_interface::VERBOSITY_VERBOSE : migrator_output_handler_interface::VERBOSITY_DEBUG;
+			$this->output_handler->write(array('MIGRATION_SCHEMA_RUNNING', $name), $verbosity);
+
+			$this->last_run_migration['task'] = 'process_schema_step';
+
+			$total_time = (is_array($state['migration_data_state']) && isset($state['migration_data_state']['_total_time'])) ?
+				$state['migration_data_state']['_total_time'] : 0.0;
+			$elapsed_time = microtime(true);
+
+			$steps = $this->helper->get_schema_steps($migration->update_schema());
+			$result = $this->process_data_step($steps, $state['migration_data_state']);
+
+			$elapsed_time = microtime(true) - $elapsed_time;
+			$total_time += $elapsed_time;
+
+			if (is_array($result))
+			{
+				$result['_total_time'] = $total_time;
+			}
+
+			$state['migration_data_state'] = ($result === true) ? '' : $result;
+			$state['migration_schema_done'] = ($result === true);
+
+			if ($state['migration_schema_done'])
+			{
+				$this->output_handler->write(array('MIGRATION_SCHEMA_DONE', $name, $total_time), migrator_output_handler_interface::VERBOSITY_NORMAL);
+			}
+			else
+			{
+				$this->output_handler->write(array('MIGRATION_SCHEMA_IN_PROGRESS', $name, $elapsed_time), migrator_output_handler_interface::VERBOSITY_VERY_VERBOSE);
+			}
+		}
+		else if (!$state['migration_data_done'])
+		{
+			try
+			{
+				$verbosity = empty($state['migration_data_state']) ?
+					migrator_output_handler_interface::VERBOSITY_VERBOSE : migrator_output_handler_interface::VERBOSITY_DEBUG;
+				$this->output_handler->write(array('MIGRATION_DATA_RUNNING', $name), $verbosity);
+
+				$this->last_run_migration['task'] = 'process_data_step';
+
+				$total_time = (is_array($state['migration_data_state']) && isset($state['migration_data_state']['_total_time'])) ?
+					$state['migration_data_state']['_total_time'] : 0.0;
+				$elapsed_time = microtime(true);
+
+				$result = $this->process_data_step($migration->update_data(), $state['migration_data_state']);
+
+				$elapsed_time = microtime(true) - $elapsed_time;
+				$total_time += $elapsed_time;
+
+				if (is_array($result))
+				{
+					$result['_total_time'] = $total_time;
+				}
+
+				$state['migration_data_state'] = ($result === true) ? '' : $result;
+				$state['migration_data_done'] = ($result === true);
+				$state['migration_end_time'] = ($result === true) ? time() : 0;
+
+				if ($state['migration_data_done'])
+				{
+					$this->output_handler->write(array('MIGRATION_DATA_DONE', $name, $total_time), migrator_output_handler_interface::VERBOSITY_NORMAL);
+				}
+				else
+				{
+					$this->output_handler->write(array('MIGRATION_DATA_IN_PROGRESS', $name, $elapsed_time), migrator_output_handler_interface::VERBOSITY_VERY_VERBOSE);
+				}
+			}
+			catch (\phpbb\db\migration\exception $e)
+			{
+				// Reset data state and revert the schema changes
+				$state['migration_data_state'] = '';
+				$this->set_migration_state($name, $state);
+
+				$this->revert_do($name);
+
+				throw $e;
+			}
+		}
+
+		$this->set_migration_state($name, $state);
+
+		return true;
+	}
+
+	/**
+	* Runs a single revert step from the last migration installed
+	*
+	* YOU MUST ADD/SET ALL MIGRATIONS THAT COULD BE DEPENDENT ON THE MIGRATION TO REVERT TO BEFORE CALLING THIS METHOD!
+	* The revert step can either be a schema or a (partial) data revert. To
+	* check if revert() needs to be called again use the migration_state() method.
+	*
+	* @param string $migration String migration name to revert (including any that depend on this migration)
+	*/
+	public function revert($migration)
+	{
+		$this->container->get('dispatcher')->disable();
+		$this->revert_do($migration);
+		$this->container->get('dispatcher')->enable();
+	}
+
+	/**
+	 * Effectively runs a single revert step from the last migration installed
+	 *
+	 * @param string $migration String migration name to revert (including any that depend on this migration)
+	 * @return null
+	 */
+	protected function revert_do($migration)
+	{
+		if (!isset($this->migration_state[$migration]))
+		{
+			// Not installed
+			return;
+		}
+
+		foreach ($this->migration_state as $name => $state)
+		{
+			if (!empty($state['migration_depends_on']) && in_array($migration, $state['migration_depends_on']))
+			{
+				$this->revert_do($name);
+			}
+		}
+
+		$this->try_revert($migration);
+	}
+
+	/**
+	* Attempts to revert a step of the given migration or one of its dependencies
+	*
+	* @param	string	$name The class name of the migration
+	* @return	bool	Whether any update step was successfully run
+	*/
+	protected function try_revert($name)
+	{
+		if (!class_exists($name))
+		{
+			return false;
+		}
+
+		$migration = $this->get_migration($name);
+
+		$state = $this->migration_state[$name];
+
+		$this->last_run_migration = array(
+			'name'	=> $name,
+			'class'	=> $migration,
+			'task'	=> '',
+		);
+
+		if ($state['migration_data_done'])
+		{
+			$steps = array_merge($this->helper->reverse_update_data($migration->update_data()), $migration->revert_data());
+			$result = $this->process_data_step($steps, $state['migration_data_state']);
+
+			$state['migration_data_state'] = ($result === true) ? '' : $result;
+			$state['migration_data_done'] = ($result === true) ? false : true;
+
+			$this->set_migration_state($name, $state);
+		}
+		else if ($state['migration_schema_done'])
+		{
+			$steps = $this->helper->get_schema_steps($migration->revert_schema());
+			$result = $this->process_data_step($steps, $state['migration_data_state']);
+
+			$state['migration_data_state'] = ($result === true) ? '' : $result;
+			$state['migration_schema_done'] = ($result === true) ? false : true;
+
+			if (!$state['migration_schema_done'])
+			{
+				$sql = 'DELETE FROM ' . $this->migrations_table . "
+					WHERE migration_name = '" . $this->db->sql_escape($name) . "'";
+				$this->db->sql_query($sql);
+
+				$this->last_run_migration = false;
+				unset($this->migration_state[$name]);
+			}
+			else
+			{
+				$this->set_migration_state($name, $state);
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	* Process the data step of the migration
+	*
+	* @param array $steps The steps to run
+	* @param bool|string $state Current state of the migration
+	* @param bool $revert true to revert a data step
+	* @return bool|string migration state. True if completed, serialized array if not finished
+	* @throws \phpbb\db\migration\exception
+	*/
+	protected function process_data_step($steps, $state, $revert = false)
+	{
+		if (sizeof($steps) === 0)
+		{
+			return true;
+		}
+
+		$state = is_array($state) ? $state : false;
+
+		// reverse order of steps if reverting
+		if ($revert === true)
+		{
+			$steps = array_reverse($steps);
+		}
+
+		$step = $last_result = 0;
+		if ($state)
+		{
+			$step = $state['step'];
+
+			// We send the result from last time to the callable function
+			$last_result = $state['result'];
+		}
+
+		try
+		{
+			// Result will be null or true if everything completed correctly
+			// Stop after each update step, to let the updater control the script runtime
+			$result = $this->run_step($steps[$step], $last_result, $revert);
+			if (($result !== null && $result !== true) || $step + 1 < sizeof($steps))
+			{
+				return array(
+					'result'	=> $result,
+					// Move on if the last call finished
+					'step'		=> ($result !== null && $result !== true) ? $step : $step + 1,
+				);
+			}
+		}
+		catch (\phpbb\db\migration\exception $e)
+		{
+			// We should try rolling back here
+			foreach ($steps as $reverse_step_identifier => $reverse_step)
+			{
+				// If we've reached the current step we can break because we reversed everything that was run
+				if ($reverse_step_identifier == $step)
+				{
+					break;
+				}
+
+				// Reverse the step that was run
+				$result = $this->run_step($reverse_step, false, !$revert);
+			}
+
+			throw $e;
+		}
+
+		return true;
+	}
+
+	/**
+	* Run a single step
+	*
+	* An exception should be thrown if an error occurs
+	*
+	* @param mixed $step Data step from migration
+	* @param mixed $last_result Result to pass to the callable (only for 'custom' method)
+	* @param bool $reverse False to install, True to attempt uninstallation by reversing the call
+	* @return null
+	*/
+	protected function run_step($step, $last_result = 0, $reverse = false)
+	{
+		$callable_and_parameters = $this->get_callable_from_step($step, $last_result, $reverse);
+
+		if ($callable_and_parameters === false)
+		{
+			return;
+		}
+
+		$callable = $callable_and_parameters[0];
+		$parameters = $callable_and_parameters[1];
+
+		return call_user_func_array($callable, $parameters);
+	}
+
+	/**
+	* Get a callable statement from a data step
+	*
+	* @param array $step Data step from migration
+	* @param mixed $last_result Result to pass to the callable (only for 'custom' method)
+	* @param bool $reverse False to install, True to attempt uninstallation by reversing the call
+	* @return array Array with parameters for call_user_func_array(), 0 is the callable, 1 is parameters
+	* @throws \phpbb\db\migration\exception
+	*/
+	protected function get_callable_from_step(array $step, $last_result = 0, $reverse = false)
+	{
+		$type = $step[0];
+		$parameters = $step[1];
+
+		$parts = explode('.', $type);
+
+		$class = $parts[0];
+		$method = false;
+
+		if (isset($parts[1]))
+		{
+			$method = $parts[1];
+		}
+
+		switch ($class)
+		{
+			case 'if':
+				if (!isset($parameters[0]))
+				{
+					throw new \phpbb\db\migration\exception('MIGRATION_INVALID_DATA_MISSING_CONDITION', $step);
+				}
+
+				if (!isset($parameters[1]))
+				{
+					throw new \phpbb\db\migration\exception('MIGRATION_INVALID_DATA_MISSING_STEP', $step);
+				}
+
+				if ($reverse)
+				{
+					// We might get unexpected results when trying
+					// to revert this, so just avoid it
+					return false;
+				}
+
+				$condition = $parameters[0];
+
+				if (!$condition)
+				{
+					return false;
+				}
+
+				$step = $parameters[1];
+
+				return $this->get_callable_from_step($step);
+			break;
+
+			case 'custom':
+				if (!is_callable($parameters[0]))
+				{
+					throw new \phpbb\db\migration\exception('MIGRATION_INVALID_DATA_CUSTOM_NOT_CALLABLE', $step);
+				}
+
+				if ($reverse)
+				{
+					return false;
+				}
+				else
+				{
+					return array(
+						$parameters[0],
+						array($last_result),
+					);
+				}
+			break;
+
+			default:
+				if (!$method)
+				{
+					throw new \phpbb\db\migration\exception('MIGRATION_INVALID_DATA_UNKNOWN_TYPE', $step);
+				}
+
+				if (!isset($this->tools[$class]))
+				{
+					throw new \phpbb\db\migration\exception('MIGRATION_INVALID_DATA_UNDEFINED_TOOL', $step);
+				}
+
+				if (!method_exists(get_class($this->tools[$class]), $method))
+				{
+					throw new \phpbb\db\migration\exception('MIGRATION_INVALID_DATA_UNDEFINED_METHOD', $step);
+				}
+
+				// Attempt to reverse operations
+				if ($reverse)
+				{
+					array_unshift($parameters, $method);
+
+					return array(
+						array($this->tools[$class], 'reverse'),
+						$parameters,
+					);
+				}
+
+				return array(
+					array($this->tools[$class], $method),
+					$parameters,
+				);
+			break;
+		}
+	}
+
+	/**
+	* Insert/Update migration row into the database
+	*
+	* @param string $name Name of the migration
+	* @param array $state
+	* @return null
+	*/
+	protected function set_migration_state($name, $state)
+	{
+		$migration_row = $state;
+		$migration_row['migration_depends_on'] = serialize($state['migration_depends_on']);
+		$migration_row['migration_data_state'] = !empty($state['migration_data_state']) ? serialize($state['migration_data_state']) : '';
+
+		if (isset($this->migration_state[$name]))
+		{
+			$sql = 'UPDATE ' . $this->migrations_table . '
+				SET ' . $this->db->sql_build_array('UPDATE', $migration_row) . "
+				WHERE migration_name = '" . $this->db->sql_escape($name) . "'";
+			$this->db->sql_query($sql);
+		}
+		else
+		{
+			$migration_row['migration_name'] = $name;
+			$sql = 'INSERT INTO ' . $this->migrations_table . '
+				' . $this->db->sql_build_array('INSERT', $migration_row);
+			$this->db->sql_query($sql);
+		}
+
+		$this->migration_state[$name] = $state;
+
+		$this->last_run_migration['state'] = $state;
+	}
+
+	/**
+	* Checks if a migration's dependencies can even theoretically be satisfied.
+	*
+	* @param string	$name The class name of the migration
+	* @return bool|string False if fulfillable, string of missing migration name if unfulfillable
+	*/
+	public function unfulfillable($name)
+	{
+		$name = $this->get_valid_name($name);
+
+		if (isset($this->migration_state[$name]) || isset($this->fulfillable_migrations[$name]))
+		{
+			return false;
+		}
+
+		if (!class_exists($name))
+		{
+			return $name;
+		}
+
+		$migration = $this->get_migration($name);
+		$depends = $migration->depends_on();
+
+		foreach ($depends as $depend)
+		{
+			$depend = $this->get_valid_name($depend);
+			$unfulfillable = $this->unfulfillable($depend);
+			if ($unfulfillable !== false)
+			{
+				return $unfulfillable;
+			}
+		}
+		$this->fulfillable_migrations[$name] = true;
+
+		return false;
+	}
+
+	/**
+	* Checks whether all available, fulfillable migrations have been applied.
+	*
+	* @return bool Whether the migrations have been applied
+	*/
+	public function finished()
+	{
+		foreach ($this->migrations as $name)
+		{
+			if (!isset($this->migration_state[$name]))
+			{
+				// skip unfulfillable migrations, but fulfillables mean we
+				// are not finished yet
+				if ($this->unfulfillable($name) !== false)
+				{
+					continue;
+				}
+
+				return false;
+			}
+
+			$migration = $this->migration_state[$name];
+
+			if (!$migration['migration_schema_done'] || !$migration['migration_data_done'])
+			{
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	* Gets a migration state (whether it is installed and to what extent)
+	*
+	* @param string $migration String migration name to check if it is installed
+	* @return bool|array False if the migration has not at all been installed, array
+	*/
+	public function migration_state($migration)
+	{
+		if (!isset($this->migration_state[$migration]))
+		{
+			return false;
+		}
+
+		return $this->migration_state[$migration];
+	}
+
+	/**
+	* Helper to get a migration
+	*
+	* @param string $name Name of the migration
+	* @return \phpbb\db\migration\migration
+	*/
+	protected function get_migration($name)
+	{
+		$migration = new $name($this->config, $this->db, $this->db_tools, $this->phpbb_root_path, $this->php_ext, $this->table_prefix);
+
+		if ($migration instanceof ContainerAwareInterface)
+		{
+			$migration->setContainer($this->container);
+		}
+
+		return $migration;
+	}
+
+	/**
+	* This function adds all migrations sent to it to the migrations table
+	*
+	* THIS SHOULD NOT GENERALLY BE USED! THIS IS FOR THE PHPBB INSTALLER.
+	* THIS WILL THROW ERRORS IF MIGRATIONS ALREADY EXIST IN THE TABLE, DO NOT CALL MORE THAN ONCE!
+	*
+	* @param array $migrations Array of migrations (names) to add to the migrations table
+	* @return null
+	*/
+	public function populate_migrations($migrations)
+	{
+		foreach ($migrations as $name)
+		{
+			if ($this->migration_state($name) === false)
+			{
+				$state = array(
+					'migration_depends_on'	=> $name::depends_on(),
+					'migration_schema_done' => true,
+					'migration_data_done'	=> true,
+					'migration_data_state'	=> '',
+					'migration_start_time'	=> time(),
+					'migration_end_time'	=> time(),
+				);
+				$this->set_migration_state($name, $state);
+			}
+		}
+	}
+
+	/**
+	* Creates the migrations table if it does not exist.
+	* @return null
+	*/
+	public function create_migrations_table()
+	{
+		// Make sure migrations have been installed.
+		if (!$this->db_tools->sql_table_exists($this->table_prefix . 'migrations'))
+		{
+			$this->db_tools->sql_create_table($this->table_prefix . 'migrations', array(
+				'COLUMNS'		=> array(
+					'migration_name'			=> array('VCHAR', ''),
+					'migration_depends_on'		=> array('TEXT', ''),
+					'migration_schema_done'		=> array('BOOL', 0),
+					'migration_data_done'		=> array('BOOL', 0),
+					'migration_data_state'		=> array('TEXT', ''),
+					'migration_start_time'		=> array('TIMESTAMP', 0),
+					'migration_end_time'		=> array('TIMESTAMP', 0),
+				),
+				'PRIMARY_KEY'	=> 'migration_name',
+			));
+		}
+	}
+}