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<?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 phpbb\db\output_handler\migrator_output_handler_interface;
use phpbb\db\output_handler\null_migrator_output_handler;
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\tools_interface */
    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\tools_interface $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_interface $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)
    {
        foreach ($class_names as $key => $class)
        {
            if (!self::is_migration($class))
            {
                unset($class_names[$key]);
            }
        }
        $this->migrations = $class_names;
    }
    /**
     * Get the list of available migration class names
     *
     * @return array Array of all migrations available to be run
     */
    public function get_migrations()
    {
        return $this->migrations;
    }
    /**
     * Get the list of available and not installed migration class names
     *
     * @return array
     */
    public function get_installable_migrations()
    {
        $unfinished_migrations = array();
        foreach ($this->migrations as $name)
        {
            if (!isset($this->migration_state[$name]) ||
                !$this->migration_state[$name]['migration_schema_done'] ||
                !$this->migration_state[$name]['migration_data_done'])
            {
                $unfinished_migrations[] = $name;
            }
        }
        return $unfinished_migrations;
    }
    /**
    * 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->migrations as $name)
        {
            $state = $this->migration_state($name);
            if ($state && in_array($migration, $state['migration_depends_on']) && ($state['migration_schema_done'] || $state['migration_data_done']))
            {
                $this->revert_do($name);
                return;
            }
        }
        $this->try_revert($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'])
        {
            $verbosity = empty($state['migration_data_state']) ?
                migrator_output_handler_interface::VERBOSITY_VERBOSE : migrator_output_handler_interface::VERBOSITY_DEBUG;
            $this->output_handler->write(array('MIGRATION_REVERT_DATA_RUNNING', $name), $verbosity);
            $total_time = (is_array($state['migration_data_state']) && isset($state['migration_data_state']['_total_time'])) ?
                $state['migration_data_state']['_total_time'] : 0.0;
            $elapsed_time = microtime(true);
            $steps = array_merge($this->helper->reverse_update_data($migration->update_data()), $migration->revert_data());
            $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;
            $state['migration_data_done'] = ($result === true) ? false : true;
            $this->set_migration_state($name, $state);
            if (!$state['migration_data_done'])
            {
                $this->output_handler->write(array('MIGRATION_REVERT_DATA_DONE', $name, $total_time), migrator_output_handler_interface::VERBOSITY_NORMAL);
            }
            else
            {
                $this->output_handler->write(array('MIGRATION_REVERT_DATA_IN_PROGRESS', $name, $elapsed_time), migrator_output_handler_interface::VERBOSITY_VERY_VERBOSE);
            }
        }
        else if ($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_REVERT_SCHEMA_RUNNING', $name), $verbosity);
            $total_time = (is_array($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->revert_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) ? 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]);
                $this->output_handler->write(array('MIGRATION_REVERT_SCHEMA_DONE', $name, $total_time), migrator_output_handler_interface::VERBOSITY_NORMAL);
            }
            else
            {
                $this->set_migration_state($name, $state);
                $this->output_handler->write(array('MIGRATION_REVERT_SCHEMA_IN_PROGRESS', $name, $elapsed_time), migrator_output_handler_interface::VERBOSITY_VERY_VERBOSE);
            }
        }
        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, $revert = false)
    {
        if (count($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) || $step + 1 < count($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 || (is_array($condition) && !$this->run_step($condition, $last_result, $reverse)))
                {
                    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 $name Name of the migration
    * @return \phpbb\db\migration\migration
    */
    public function get_migration($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',
            ));
        }
    }
    /**
     * Check if a class is a migration.
     *
     * @param string $migration A migration class name
     * @return bool Return true if class is a migration, false otherwise
     */
    static public function is_migration($migration)
    {
        if (class_exists($migration))
        {
            // Migration classes should extend the abstract class
            // phpbb\db\migration\migration (which implements the
            // migration_interface) and be instantiable.
            $reflector = new \ReflectionClass($migration);
            if ($reflector->implementsInterface('\phpbb\db\migration\migration_interface') && $reflector->isInstantiable())
            {
                return true;
            }
        }
        return false;
    }
}