system.install

<?php

use Drupal\Core\Database\Database;

/**
 * @file
 * Install, update and uninstall functions for the system module.
 */

/**
 * Test and report Drupal installation requirements.
 *
 * @param $phase
 *   The current system installation phase.
 * @return
 *   An array of system requirements.
 */
function system_requirements($phase) {
  global $base_url;
  $requirements = array();
  // Ensure translations don't break during installation.
  $t = get_t();

  // Report Drupal version
  if ($phase == 'runtime') {
    $requirements['drupal'] = array(
      'title' => $t('Drupal'),
      'value' => VERSION,
      'severity' => REQUIREMENT_INFO,
      'weight' => -10,
    );

    // Display the currently active installation profile, if the site
    // is not running the default installation profile.
    $profile = drupal_get_profile();
    if ($profile != 'standard') {
      $info = system_get_info('module', $profile);
      $requirements['install_profile'] = array(
        'title' => $t('Installation profile'),
        'value' => $t('%profile_name (%profile-%version)', array(
          '%profile_name' => $info['name'],
          '%profile' => $profile,
          '%version' => $info['version']
        )),
        'severity' => REQUIREMENT_INFO,
        'weight' => -9
      );
    }
  }

  // Web server information.
  $software = $_SERVER['SERVER_SOFTWARE'];
  $requirements['webserver'] = array(
    'title' => $t('Web server'),
    'value' => $software,
  );

  // Test PHP version and show link to phpinfo() if it's available
  $phpversion = phpversion();
  if (function_exists('phpinfo')) {
    $requirements['php'] = array(
      'title' => $t('PHP'),
      'value' => ($phase == 'runtime') ? $phpversion .' ('. l($t('more information'), 'admin/reports/status/php') .')' : $phpversion,
    );
  }
  else {
    $requirements['php'] = array(
      'title' => $t('PHP'),
      'value' => $phpversion,
      'description' => $t('The phpinfo() function has been disabled for security reasons. To see your server\'s phpinfo() information, change your PHP settings or contact your server administrator. For more information, <a href="@phpinfo">Enabling and disabling phpinfo()</a> handbook page.', array('@phpinfo' => 'http://drupal.org/node/243993')),
      'severity' => REQUIREMENT_INFO,
    );
  }

  if (version_compare($phpversion, DRUPAL_MINIMUM_PHP) < 0) {
    $requirements['php']['description'] = $t('Your PHP installation is too old. Drupal requires at least PHP %version.', array('%version' => DRUPAL_MINIMUM_PHP));
    $requirements['php']['severity'] = REQUIREMENT_ERROR;
    // If PHP is old, it's not safe to continue with the requirements check.
    return $requirements;
  }

  // Test PHP register_globals setting.
  $requirements['php_register_globals'] = array(
    'title' => $t('PHP register globals'),
  );
  $register_globals = trim(ini_get('register_globals'));
  // Unfortunately, ini_get() may return many different values, and we can't
  // be certain which values mean 'on', so we instead check for 'not off'
  // since we never want to tell the user that their site is secure
  // (register_globals off), when it is in fact on. We can only guarantee
  // register_globals is off if the value returned is 'off', '', or 0.
  if (!empty($register_globals) && strtolower($register_globals) != 'off') {
    $requirements['php_register_globals']['description'] = $t('<em>register_globals</em> is enabled. Drupal requires this configuration directive to be disabled. Your site may not be secure when <em>register_globals</em> is enabled. The PHP manual has instructions for <a href="@url">how to change configuration settings</a>.', array('@url' => 'http://php.net/configuration.changes'));
    $requirements['php_register_globals']['severity'] = REQUIREMENT_ERROR;
    $requirements['php_register_globals']['value'] = $t("Enabled ('@value')", array('@value' => $register_globals));
  }
  else {
    $requirements['php_register_globals']['value'] = $t('Disabled');
  }

  // Test for PHP extensions.
  $requirements['php_extensions'] = array(
    'title' => $t('PHP extensions'),
  );

  $missing_extensions = array();
  $required_extensions = array(
    'date',
    'dom',
    'filter',
    'gd',
    'hash',
    'json',
    'pcre',
    'pdo',
    'session',
    'SimpleXML',
    'SPL',
    'tokenizer',
    'xml',
  );
  foreach ($required_extensions as $extension) {
    if (!extension_loaded($extension)) {
      $missing_extensions[] = $extension;
    }
  }

  if (!empty($missing_extensions)) {
    $description = $t('Drupal requires you to enable the PHP extensions in the following list (see the <a href="@system_requirements">system requirements page</a> for more information):', array(
      '@system_requirements' => 'http://drupal.org/requirements',
    ));

    $description .= theme('item_list', array('items' => $missing_extensions));

    $requirements['php_extensions']['value'] = $t('Disabled');
    $requirements['php_extensions']['severity'] = REQUIREMENT_ERROR;
    $requirements['php_extensions']['description'] = $description;
  }
  else {
    $requirements['php_extensions']['value'] = $t('Enabled');
  }

  if ($phase == 'install' || $phase == 'update') {
    // Test for PDO (database).
    $requirements['database_extensions'] = array(
      'title' => $t('Database support'),
    );

    // Make sure PDO is available.
    $database_ok = extension_loaded('pdo');
    if (!$database_ok) {
      $pdo_message = $t('Your web server does not appear to support PDO (PHP Data Objects). Ask your hosting provider if they support the native PDO extension. See the <a href="@link">system requirements</a> page for more information.', array(
        '@link' => 'http://drupal.org/requirements/pdo',
      ));
    }
    else {
      // Make sure at least one supported database driver exists.
      $drivers = drupal_detect_database_types();
      if (empty($drivers)) {
        $database_ok = FALSE;
        $pdo_message = $t('Your web server does not appear to support any common PDO database extensions. Check with your hosting provider to see if they support PDO (PHP Data Objects) and offer any databases that <a href="@drupal-databases">Drupal supports</a>.', array(
          '@drupal-databases' => 'http://drupal.org/node/270#database',
        ));
      }
      // Make sure the native PDO extension is available, not the older PEAR
      // version. (See install_verify_pdo() for details.)
      if (!defined('PDO::ATTR_DEFAULT_FETCH_MODE')) {
        $database_ok = FALSE;
        $pdo_message = $t('Your web server seems to have the wrong version of PDO installed. Drupal requires the PDO extension from PHP core. This system has the older PECL version. See the <a href="@link">system requirements</a> page for more information.', array(
          '@link' => 'http://drupal.org/requirements/pdo#pecl',
        ));
      }
    }

    if (!$database_ok) {
      $requirements['database_extensions']['value'] = $t('Disabled');
      $requirements['database_extensions']['severity'] = REQUIREMENT_ERROR;
      $requirements['database_extensions']['description'] = $pdo_message;
    }
    else {
      $requirements['database_extensions']['value'] = $t('Enabled');
    }
  }
  else {
    // Database information.
    $class = Database::getConnection()->getDriverClass('Install\\Tasks');
    $tasks = new $class();
    $requirements['database_system'] = array(
      'title' => $t('Database system'),
      'value' => $tasks->name(),
    );
    $requirements['database_system_version'] = array(
      'title' => $t('Database system version'),
      'value' => Database::getConnection()->version(),
    );
  }

  // Test PHP memory_limit
  $memory_limit = ini_get('memory_limit');
  $requirements['php_memory_limit'] = array(
    'title' => $t('PHP memory limit'),
    'value' => $memory_limit == -1 ? t('-1 (Unlimited)') : $memory_limit,
  );

  if (!drupal_check_memory_limit(DRUPAL_MINIMUM_PHP_MEMORY_LIMIT, $memory_limit)) {
    $description = '';
    if ($phase == 'install') {
      $description = $t('Consider increasing your PHP memory limit to %memory_minimum_limit to help prevent errors in the installation process.', array('%memory_minimum_limit' => DRUPAL_MINIMUM_PHP_MEMORY_LIMIT));
    }
    elseif ($phase == 'update') {
      $description = $t('Consider increasing your PHP memory limit to %memory_minimum_limit to help prevent errors in the update process.', array('%memory_minimum_limit' => DRUPAL_MINIMUM_PHP_MEMORY_LIMIT));
    }
    elseif ($phase == 'runtime') {
      $description = $t('Depending on your configuration, Drupal can run with a %memory_limit PHP memory limit. However, a %memory_minimum_limit PHP memory limit or above is recommended, especially if your site uses additional custom or contributed modules.', array('%memory_limit' => $memory_limit, '%memory_minimum_limit' => DRUPAL_MINIMUM_PHP_MEMORY_LIMIT));
    }

    if (!empty($description)) {
      if ($php_ini_path = get_cfg_var('cfg_file_path')) {
        $description .= ' ' . $t('Increase the memory limit by editing the memory_limit parameter in the file %configuration-file and then restart your web server (or contact your system administrator or hosting provider for assistance).', array('%configuration-file' => $php_ini_path));
      }
      else {
        $description .= ' ' . $t('Contact your system administrator or hosting provider for assistance with increasing your PHP memory limit.');
      }

      $requirements['php_memory_limit']['description'] = $description . ' ' . $t('For more information, see the online handbook entry for <a href="@memory-limit">increasing the PHP memory limit</a>.', array('@memory-limit' => 'http://drupal.org/node/207036'));
      $requirements['php_memory_limit']['severity'] = REQUIREMENT_WARNING;
    }
  }

  // Test configuration files and directory for writability.
  if ($phase == 'runtime') {
    $conf_errors = array();
    $conf_path = conf_path();
    if (!drupal_verify_install_file($conf_path, FILE_NOT_WRITABLE, 'dir')) {
      $conf_errors[] = $t("The directory %file is not protected from modifications and poses a security risk. You must change the directory's permissions to be non-writable.", array('%file' => $conf_path));
    }
    foreach (array('settings.php', 'settings.local.php') as $conf_file) {
      $full_path = $conf_path . '/' . $conf_file;
      if (file_exists($full_path) && !drupal_verify_install_file($full_path, FILE_EXIST|FILE_READABLE|FILE_NOT_WRITABLE)) {
        $conf_errors[] = $t("The file %file is not protected from modifications and poses a security risk. You must change the file's permissions to be non-writable.", array('%file' => $full_path));
      }
    }
    if (!empty($conf_errors)) {
      if (count($conf_errors) == 1) {
        $description = $conf_errors[0];
      }
      else {
        $description = theme('item_list', array('items' => $conf_errors));
      }
      $requirements['settings.php'] = array(
        'value' => $t('Not protected'),
        'severity' => REQUIREMENT_ERROR,
        'description' => $description,
      );
    }
    else {
      $requirements['settings.php'] = array(
        'value' => $t('Protected'),
      );
    }
    $requirements['settings.php']['title'] = $t('Configuration files');
  }

  // Report cron status.
  if ($phase == 'runtime') {
    $cron_config = config('system.cron');
    // Cron warning threshold defaults to two days.
    $threshold_warning = $cron_config->get('threshold.requirements_warning');
    // Cron error threshold defaults to two weeks.
    $threshold_error = $cron_config->get('threshold.requirements_error');
    // Cron configuration help text.
    $help = $t('For more information, see the online handbook entry for <a href="@cron-handbook">configuring cron jobs</a>.', array('@cron-handbook' => 'http://drupal.org/cron'));

    // Determine when cron last ran.
    $cron_last = state()->get('system.cron_last');
    if (!is_numeric($cron_last)) {
      $cron_last = variable_get('install_time', 0);
    }

    // Determine severity based on time since cron last ran.
    $severity = REQUIREMENT_INFO;
    if (REQUEST_TIME - $cron_last > $threshold_error) {
      $severity = REQUIREMENT_ERROR;
    }
    elseif (REQUEST_TIME - $cron_last > $threshold_warning) {
      $severity = REQUIREMENT_WARNING;
    }

    // Set summary and description based on values determined above.
    $summary = $t('Last run !time ago', array('!time' => format_interval(REQUEST_TIME - $cron_last)));
    $description = '';
    if ($severity != REQUIREMENT_INFO) {
      $description = $t('Cron has not run recently.') . ' ' . $help;
    }

    $description .= ' ' . $t('You can <a href="@cron">run cron manually</a>.', array('@cron' => url('admin/reports/status/run-cron')));
    $description .= '<br />' . $t('To run cron from outside the site, go to <a href="!cron">!cron</a>', array('!cron' => url('cron/' . state()->get('system.cron_key'), array('absolute' => TRUE))));

    $requirements['cron'] = array(
      'title' => $t('Cron maintenance tasks'),
      'severity' => $severity,
      'value' => $summary,
      'description' => $description
    );
  }

  // Test files directories.
  // If we are installing Drupal, the settings.php file might not exist yet in
  // the intended conf_path() directory, so don't require it. The conf_path()
  // cache must also be reset in this case.
  $require_settings = ($phase != 'install');
  $reset_cache = !$require_settings;
  $directories = array(
    variable_get('file_public_path', conf_path($require_settings, $reset_cache) . '/files'),
    // By default no private files directory is configured. For private files
    // to be secure the admin needs to provide a path outside the webroot.
    variable_get('file_private_path', FALSE),
  );

  // Do not check for the temporary files directory during installation
  // unless it has been set in settings.php. In this case the user has
  // no alternative but to fix the directory if it is not writable.
  if ($phase == 'install') {
    $directories[] = variable_get('file_temporary_path', FALSE);
  }
  else {
    $directories[] = variable_get('file_temporary_path', file_directory_temp());
  }

  // Check the config directory if it is defined in settings.php. If it isn't
  // defined, the installer will create a valid config directory later, but
  // during runtime we must always display an error.
  if (!empty($GLOBALS['config_directories'])) {
    $directories[] = config_get_config_directory(CONFIG_ACTIVE_DIRECTORY);
    $directories[] = config_get_config_directory(CONFIG_STAGING_DIRECTORY);
  }
  elseif ($phase != 'install') {
    $requirements['config directories'] = array(
      'title' => $t('Configuration directories'),
      'value' => $t('Not present'),
      'description' => $t('Your %file file must define the $config_directories variable as an array containing the name of a directories in which configuration files can be written.', array('%file' => conf_path() . '/settings.php')),
      'severity' => REQUIREMENT_ERROR,
    );
  }

  $requirements['file system'] = array(
    'title' => $t('File system'),
  );

  $error = '';
  // For installer, create the directories if possible.
  foreach ($directories as $directory) {
    if (!$directory) {
      continue;
    }
    if ($phase == 'install') {
      file_prepare_directory($directory, FILE_CREATE_DIRECTORY | FILE_MODIFY_PERMISSIONS);
    }
    $is_writable = is_writable($directory);
    $is_directory = is_dir($directory);
    if (!$is_writable || !$is_directory) {
      $description = '';
      $requirements['file system']['value'] = $t('Not writable');
      if (!$is_directory) {
        $error .= $t('The directory %directory does not exist.', array('%directory' => $directory)) . ' ';
      }
      else {
        $error .= $t('The directory %directory is not writable.', array('%directory' => $directory)) . ' ';
      }
      // The files directory requirement check is done only during install and runtime.
      if ($phase == 'runtime') {
        $description = $error . $t('You may need to set the correct directory at the <a href="@admin-file-system">file system settings page</a> or change the current directory\'s permissions so that it is writable.', array('@admin-file-system' => url('admin/config/media/file-system')));
      }
      elseif ($phase == 'install') {
        // For the installer UI, we need different wording. 'value' will
        // be treated as version, so provide none there.
        $description = $error . $t('An automated attempt to create this directory failed, possibly due to a permissions problem. To proceed with the installation, either create the directory and modify its permissions manually or ensure that the installer has the permissions to create it automatically. For more information, see INSTALL.txt or the <a href="@handbook_url">online handbook</a>.', array('@handbook_url' => 'http://drupal.org/server-permissions'));
        $requirements['file system']['value'] = '';
      }
      if (!empty($description)) {
        $requirements['file system']['description'] = $description;
        $requirements['file system']['severity'] = REQUIREMENT_ERROR;
      }
    }
    else {
      if (file_default_scheme() == 'public') {
        $requirements['file system']['value'] = $t('Writable (<em>public</em> download method)');
      }
      else {
        $requirements['file system']['value'] = $t('Writable (<em>private</em> download method)');
      }
    }
  }

  // See if updates are available in update.php.
  if ($phase == 'runtime') {
    $requirements['update'] = array(
      'title' => $t('Database updates'),
      'value' => $t('Up to date'),
    );

    // Check installed modules.
    foreach (module_list() as $module) {
      $updates = drupal_get_schema_versions($module);
      if ($updates !== FALSE) {
        $default = drupal_get_installed_schema_version($module);
        if (max($updates) > $default) {
          $requirements['update']['severity'] = REQUIREMENT_ERROR;
          $requirements['update']['value'] = $t('Out of date');
          $requirements['update']['description'] = $t('Some modules have database schema updates to install. You should run the <a href="@update">database update script</a> immediately.', array('@update' => base_path() . 'core/update.php'));
          break;
        }
      }
    }
  }

  // Verify the update.php access setting
  if ($phase == 'runtime') {
    if (settings()->get('update_free_access')) {
      $requirements['update access'] = array(
        'value' => $t('Not protected'),
        'severity' => REQUIREMENT_ERROR,
        'description' => $t('The update.php script is accessible to everyone without authentication check, which is a security risk. You must change the @settings_name value in your settings.php back to FALSE.', array('@settings_name' => '$settings[\'update_free_access\']')),
      );
    }
    else {
      $requirements['update access'] = array(
        'value' => $t('Protected'),
      );
    }
    $requirements['update access']['title'] = $t('Access to update.php');
  }

  // Display an error if a newly introduced dependency in a module is not resolved.
  if ($phase == 'update') {
    $profile = drupal_get_profile();
    $files = system_rebuild_module_data();
    foreach ($files as $module => $file) {
      // Ignore disabled modules and installation profiles.
      if (!$file->status || $module == $profile) {
        continue;
      }
      // Check the module's PHP version.
      $name = $file->info['name'];
      $php = $file->info['php'];
      if (version_compare($php, PHP_VERSION, '>')) {
        $requirements['php']['description'] .= $t('@name requires at least PHP @version.', array('@name' => $name, '@version' => $php));
        $requirements['php']['severity'] = REQUIREMENT_ERROR;
      }
      // Check the module's required modules.
      foreach ($file->requires as $requirement) {
        $required_module = $requirement['name'];
        // Check if the module exists.
        if (!isset($files[$required_module])) {
          $requirements["$module-$required_module"] = array(
            'title' => $t('Unresolved dependency'),
            'description' => $t('@name requires this module.', array('@name' => $name)),
            'value' => t('@required_name (Missing)', array('@required_name' => $required_module)),
            'severity' => REQUIREMENT_ERROR,
          );
          continue;
        }
        // Check for an incompatible version.
        $required_file = $files[$required_module];
        $required_name = $required_file->info['name'];
        $version = str_replace(DRUPAL_CORE_COMPATIBILITY . '-', '', $required_file->info['version']);
        $compatibility = drupal_check_incompatibility($requirement, $version);
        if ($compatibility) {
          $compatibility = rtrim(substr($compatibility, 2), ')');
          $requirements["$module-$required_module"] = array(
            'title' => $t('Unresolved dependency'),
            'description' => $t('@name requires this module and version. Currently using @required_name version @version', array('@name' => $name, '@required_name' => $required_name, '@version' => $version)),
            'value' => t('@required_name (Version @compatibility required)', array('@required_name' => $required_name, '@compatibility' => $compatibility)),
            'severity' => REQUIREMENT_ERROR,
          );
          continue;
        }
      }
    }
  }

  // Test Unicode library
  include_once DRUPAL_ROOT . '/core/includes/unicode.inc';
  $requirements = array_merge($requirements, unicode_requirements());

  if ($phase == 'runtime') {
    // Check for update status module.
    if (!module_exists('update')) {
      $requirements['update status'] = array(
        'value' => $t('Not enabled'),
        'severity' => REQUIREMENT_WARNING,
        'description' => $t('Update notifications are not enabled. It is <strong>highly recommended</strong> that you enable the Update Manager module from the <a href="@module">module administration page</a> in order to stay up-to-date on new releases. For more information, <a href="@update">Update status handbook page</a>.', array('@update' => 'http://drupal.org/documentation/modules/update', '@module' => url('admin/modules'))),
      );
    }
    else {
      $requirements['update status'] = array(
        'value' => $t('Enabled'),
      );
    }
    $requirements['update status']['title'] = $t('Update notifications');
  }

  return $requirements;
}

/**
 * Implements hook_install().
 */
function system_install() {
  // Enable the default theme. Can't use theme_enable() this early in
  // installation.
  variable_set('theme_default', 'stark');
  config_install_default_config('theme', 'stark');

  // Populate the cron key state variable.
  $cron_key = drupal_hash_base64(drupal_random_bytes(55));
  state()->set('system.cron_key', $cron_key);
}

/**
 * Implements hook_schema().
 */
function system_schema() {
  // NOTE: {variable} needs to be created before all other tables, as
  // some database drivers, e.g. Oracle and DB2, will require variable_get()
  // and variable_set() for overcoming some database specific limitations.
  $schema['variable'] = array(
    'description' => 'Named variable/value pairs created by Drupal core or any other module or theme. All variables are cached in memory at the start of every Drupal request so developers should not be careless about what is stored here.',
    'fields' => array(
      'name' => array(
        'description' => 'The name of the variable.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'value' => array(
        'description' => 'The value of the variable.',
        'type' => 'blob',
        'not null' => TRUE,
        'size' => 'big',
        'translatable' => TRUE,
      ),
    ),
    'primary key' => array('name'),
  );

  $schema['batch'] = array(
    'description' => 'Stores details about batches (processes that run in multiple HTTP requests).',
    'fields' => array(
      'bid' => array(
        'description' => 'Primary Key: Unique batch ID.',
        // This is not a serial column, to allow both progressive and
        // non-progressive batches. See batch_process().
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
      ),
      'token' => array(
        'description' => "A string token generated against the current user's session id and the batch id, used to ensure that only the user who submitted the batch can effectively access it.",
        'type' => 'varchar',
        'length' => 64,
        'not null' => TRUE,
      ),
      'timestamp' => array(
        'description' => 'A Unix timestamp indicating when this batch was submitted for processing. Stale batches are purged at cron time.',
        'type' => 'int',
        'not null' => TRUE,
      ),
      'batch' => array(
        'description' => 'A serialized array containing the processing data for the batch.',
        'type' => 'blob',
        'not null' => FALSE,
        'size' => 'big',
      ),
    ),
    'primary key' => array('bid'),
    'indexes' => array(
      'token' => array('token'),
    ),
  );

  $schema['cache_tags'] = array(
    'description' => 'Cache table for tracking cache tags related to the cache bin.',
    'fields' => array(
      'tag' => array(
        'description' => 'Namespace-prefixed tag string.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'invalidations' => array(
        'description' => 'Number incremented when the tag is invalidated.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'deletions' => array(
        'description' => 'Number incremented when the tag is deleted.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
    ),
    'primary key' => array('tag'),
  );

  $schema['cache'] = array(
    'description' => 'Generic cache table for caching things not separated out into their own tables. Contributed modules may also use this to store cached items.',
    'fields' => array(
      'cid' => array(
        'description' => 'Primary Key: Unique cache ID.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'data' => array(
        'description' => 'A collection of data to cache.',
        'type' => 'blob',
        'not null' => FALSE,
        'size' => 'big',
      ),
      'expire' => array(
        'description' => 'A Unix timestamp indicating when the cache entry should expire, or 0 for never.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'created' => array(
        'description' => 'A Unix timestamp indicating when the cache entry was created.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'serialized' => array(
        'description' => 'A flag to indicate whether content is serialized (1) or not (0).',
        'type' => 'int',
        'size' => 'small',
        'not null' => TRUE,
        'default' => 0,
      ),
      'tags' => array(
        'description' => 'Space-separated list of cache tags for this entry.',
        'type' => 'text',
        'size' => 'big',
        'not null' => FALSE,
      ),
      'checksum_invalidations' => array(
        'description' => 'The tag invalidation sum when this entry was saved.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'checksum_deletions' => array(
        'description' => 'The tag deletion sum when this entry was saved.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
    ),
    'indexes' => array(
      'expire' => array('expire'),
    ),
    'primary key' => array('cid'),
  );
  $schema['cache_bootstrap'] = $schema['cache'];
  $schema['cache_bootstrap']['description'] = 'Cache table for data required to bootstrap Drupal, may be routed to a shared memory cache.';
  $schema['cache_config'] = $schema['cache'];
  $schema['cache_config']['description'] = 'Cache table for configuration data.';
  $schema['cache_form'] = $schema['cache'];
  $schema['cache_form']['description'] = 'Cache table for the form system to store recently built forms and their storage data, to be used in subsequent page requests.';
  $schema['cache_page'] = $schema['cache'];
  $schema['cache_page']['description'] = 'Cache table used to store compressed pages for anonymous users, if page caching is enabled.';
  $schema['cache_menu'] = $schema['cache'];
  $schema['cache_menu']['description'] = 'Cache table for the menu system to store router information as well as generated link trees for various menu/page/user combinations.';
  $schema['cache_path'] = $schema['cache'];
  $schema['cache_path']['description'] = 'Cache table for path alias lookup.';

  $schema['flood'] = array(
    'description' => 'Flood controls the threshold of events, such as the number of contact attempts.',
    'fields' => array(
      'fid' => array(
        'description' => 'Unique flood event ID.',
        'type' => 'serial',
        'not null' => TRUE,
      ),
      'event' => array(
        'description' => 'Name of event (e.g. contact).',
        'type' => 'varchar',
        'length' => 64,
        'not null' => TRUE,
        'default' => '',
      ),
      'identifier' => array(
        'description' => 'Identifier of the visitor, such as an IP address or hostname.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'timestamp' => array(
        'description' => 'Timestamp of the event.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'expiration' => array(
        'description' => 'Expiration timestamp. Expired events are purged on cron run.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
    ),
    'primary key' => array('fid'),
    'indexes' => array(
      'allow' => array('event', 'identifier', 'timestamp'),
      'purge' => array('expiration'),
    ),
  );

  $schema['key_value'] = array(
    'description' => 'Generic key-value storage table. See state() for an example.',
    'fields' => array(
      'collection' => array(
        'description' => 'A named collection of key and value pairs.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'name' => array(
        'description' => 'The key of the key-value pair. As KEY is a SQL reserved keyword, name was chosen instead.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'value' => array(
        'description' => 'The value.',
        'type' => 'blob',
        'not null' => TRUE,
        'size' => 'big',
        'translatable' => TRUE,
      ),
    ),
    'primary key' => array('collection', 'name'),
  );

  $schema['key_value_expire'] = array(
    'description' => 'Generic key/value storage table with an expiration.',
    'fields' => array(
      'collection' => array(
        'description' => 'A named collection of key and value pairs.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'name' => array(
        // KEY is an SQL reserved word, so use 'name' as the key's field name.
        'description' => 'The key of the key/value pair.',
        'type' => 'varchar',
        'length' => 128,
        'not null' => TRUE,
        'default' => '',
      ),
      'value' => array(
        'description' => 'The value of the key/value pair.',
        'type' => 'blob',
        'not null' => TRUE,
        'size' => 'big',
        'translatable' => TRUE,
      ),
      'expire' => array(
        'description' => 'The time since Unix epoch in seconds when this item expires. Defaults to the maximum possible time.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 2147483647,
      ),
    ),
    'primary key' => array('collection', 'name'),
    'indexes' => array(
      'all' => array('name', 'collection', 'expire'),
    ),
  );

  $schema['menu_router'] = array(
    'description' => 'Maps paths to various callbacks (access, page and title)',
    'fields' => array(
      'path' => array(
        'description' => 'Primary Key: the Drupal path this entry describes',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'load_functions' => array(
        'description' => 'A serialized array of function names (like node_load) to be called to load an object corresponding to a part of the current path.',
        'type' => 'blob',
        'not null' => TRUE,
      ),
      'to_arg_functions' => array(
        'description' => 'A serialized array of function names (like user_uid_optional_to_arg) to be called to replace a part of the router path with another string.',
        'type' => 'blob',
        'not null' => TRUE,
      ),
      'access_callback' => array(
        'description' => 'The callback which determines the access to this router path. Defaults to user_access.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'access_arguments' => array(
        'description' => 'A serialized array of arguments for the access callback.',
        'type' => 'blob',
        'not null' => FALSE,
      ),
      'page_callback' => array(
        'description' => 'The name of the function that renders the page.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'page_arguments' => array(
        'description' => 'A serialized array of arguments for the page callback.',
        'type' => 'blob',
        'not null' => FALSE,
      ),
      'fit' => array(
        'description' => 'A numeric representation of how specific the path is.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'number_parts' => array(
        'description' => 'Number of parts in this router path.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'size' => 'small',
      ),
      'context' => array(
        'description' => 'Only for local tasks (tabs) - the context of a local task to control its placement.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'tab_parent' => array(
        'description' => 'Only for local tasks (tabs) - the router path of the parent page (which may also be a local task).',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'tab_root' => array(
        'description' => 'Router path of the closest non-tab parent page. For pages that are not local tasks, this will be the same as the path.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'title' => array(
        'description' => 'The title for the current page, or the title for the tab if this is a local task.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'title_callback' => array(
        'description' => 'A function which will alter the title. Defaults to t()',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'title_arguments' => array(
        'description' => 'A serialized array of arguments for the title callback. If empty, the title will be used as the sole argument for the title callback.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'theme_callback' => array(
        'description' => 'A function which returns the name of the theme that will be used to render this page. If left empty, the default theme will be used.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'theme_arguments' => array(
        'description' => 'A serialized array of arguments for the theme callback.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'type' => array(
        'description' => 'Numeric representation of the type of the menu item, like MENU_LOCAL_TASK.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'description' => array(
        'description' => 'A description of this item.',
        'type' => 'text',
        'not null' => TRUE,
      ),
      'description_callback' => array(
        'description' => 'A function which will alter the description. Defaults to t().',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'description_arguments' => array(
        'description' => 'A serialized array of arguments for the description callback. If empty, the description will be used as the sole argument for the description callback.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'position' => array(
        'description' => 'The position of the block (left or right) on the system administration page for this item.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'weight' => array(
        'description' => 'Weight of the element. Lighter weights are higher up, heavier weights go down.',
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
      ),
      'include_file' => array(
        'description' => 'The file to include for this element, usually the page callback function lives in this file.',
        'type' => 'text',
        'size' => 'medium',
      ),
    ),
    'indexes' => array(
      'fit' => array('fit'),
      'tab_parent' => array(array('tab_parent', 64), 'weight', 'title'),
      'tab_root_weight_title' => array(array('tab_root', 64), 'weight', 'title'),
    ),
    'primary key' => array('path'),
  );

  $schema['menu_links'] = array(
    'description' => 'Contains the individual links within a menu.',
    'fields' => array(
     'menu_name' => array(
        'description' => "The menu name. All links with the same menu name (such as 'tools') are part of the same menu.",
        'type' => 'varchar',
        'length' => 32,
        'not null' => TRUE,
        'default' => '',
      ),
      'mlid' => array(
        'description' => 'The menu link ID (mlid) is the integer primary key.',
        'type' => 'serial',
        'unsigned' => TRUE,
        'not null' => TRUE,
      ),
      'plid' => array(
        'description' => 'The parent link ID (plid) is the mlid of the link above in the hierarchy, or zero if the link is at the top level in its menu.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
      ),
      'link_path' => array(
        'description' => 'The Drupal path or external path this link points to.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'router_path' => array(
        'description' => 'For links corresponding to a Drupal path (external = 0), this connects the link to a {menu_router}.path for joins.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'link_title' => array(
      'description' => 'The text displayed for the link, which may be modified by a title callback stored in {menu_router}.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
        'translatable' => TRUE,
      ),
      'options' => array(
        'description' => 'A serialized array of options to be passed to the url() or l() function, such as a query string or HTML attributes.',
        'type' => 'blob',