install.core.inc

<?php

use Drupal\Component\Utility\SafeMarkup;
use Drupal\Component\Utility\UrlHelper;
use Drupal\Core\DrupalKernel;
use Drupal\Core\Config\BootstrapConfigStorageFactory;
use Drupal\Core\Database\Database;
use Drupal\Core\Database\DatabaseExceptionWrapper;
use Drupal\Core\Database\Install\TaskException;
use Drupal\Core\Form\FormState;
use Drupal\Core\Installer\Exception\AlreadyInstalledException;
use Drupal\Core\Installer\Exception\InstallerException;
use Drupal\Core\Installer\Exception\NoProfilesException;
use Drupal\Core\Installer\InstallerKernel;
use Drupal\Core\Language\Language;
use Drupal\Core\Language\LanguageManager;
use Drupal\Core\Page\DefaultHtmlPageRenderer;
use Drupal\Core\Site\Settings;
use Drupal\Core\StringTranslation\Translator\FileTranslation;
use Drupal\Core\Extension\ExtensionDiscovery;
use Drupal\Core\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Reference;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

use GuzzleHttp\Exception\RequestException;

/**
 * @file
 * API functions for installing Drupal.
 */

/**
 * Do not run the task during the current installation request.
 *
 * This can be used to skip running an installation task when certain
 * conditions are met, even though the task may still show on the list of
 * installation tasks presented to the user. For example, the Drupal installer
 * uses this flag to skip over the database configuration form when valid
 * database connection information is already available from settings.php. It
 * also uses this flag to skip language import tasks when the installation is
 * being performed in English.
 */
const INSTALL_TASK_SKIP = 1;

/**
 * Run the task on each installation request that reaches it.
 *
 * This is primarily used by the Drupal installer for bootstrap-related tasks.
 */
const INSTALL_TASK_RUN_IF_REACHED = 2;

/**
 * Run the task on each installation request until the database is set up.
 *
 * This is the default method for running tasks and should be used for most
 * tasks that occur after the database is set up; these tasks will then run
 * once and be marked complete once they are successfully finished. For
 * example, the Drupal installer uses this flag for the batch installation of
 * modules on the new site, and also for the configuration form that collects
 * basic site information and sets up the site maintenance account.
 */
const INSTALL_TASK_RUN_IF_NOT_COMPLETED = 3;

/**
 * Installs Drupal either interactively or via an array of passed-in settings.
 *
 * The Drupal installation happens in a series of steps, which may be spread
 * out over multiple page requests. Each request begins by trying to determine
 * the last completed installation step (also known as a "task"), if one is
 * available from a previous request. Control is then passed to the task
 * handler, which processes the remaining tasks that need to be run until (a)
 * an error is thrown, (b) a new page needs to be displayed, or (c) the
 * installation finishes (whichever happens first).
 *
 * @param $settings
 *   An optional array of installation settings. Leave this empty for a normal,
 *   interactive, browser-based installation intended to occur over multiple
 *   page requests. Alternatively, if an array of settings is passed in, the
 *   installer will attempt to use it to perform the installation in a single
 *   page request (optimized for the command line) and not send any output
 *   intended for the web browser. See install_state_defaults() for a list of
 *   elements that are allowed to appear in this array.
 *
 * @see install_state_defaults()
 */
function install_drupal($settings = array()) {
  global $install_state;
  // Initialize the installation state with the settings that were passed in,
  // as well as a boolean indicating whether or not this is an interactive
  // installation.
  $interactive = empty($settings);
  $install_state = $settings + array('interactive' => $interactive) + install_state_defaults();

  try {
    // Begin the page request. This adds information about the current state of
    // the Drupal installation to the passed-in array.
    install_begin_request($install_state);
    // Based on the installation state, run the remaining tasks for this page
    // request, and collect any output.
    $output = install_run_tasks($install_state);
  }
  catch (InstallerException $e) {
    // In the non-interactive installer, exceptions are always thrown directly.
    if (!$install_state['interactive']) {
      throw $e;
    }
    $output = array(
      '#title' => $e->getTitle(),
      '#markup' => $e->getMessage(),
    );
  }

  // After execution, all tasks might be complete, in which case
  // $install_state['installation_finished'] is TRUE. In case the last task
  // has been processed, remove the global $install_state, so other code can
  // reliably check whether it is running during the installer.
  // @see drupal_installation_attempted()
  $state = $install_state;
  if (!empty($install_state['installation_finished'])) {
    unset($GLOBALS['install_state']);
  }

  // All available tasks for this page request are now complete. Interactive
  // installations can send output to the browser or redirect the user to the
  // next page.
  if ($state['interactive']) {
    if ($state['parameters_changed']) {
      // Redirect to the correct page if the URL parameters have changed.
      install_goto(install_redirect_url($state));
    }
    elseif (isset($output)) {
      // Display a page only if some output is available. Otherwise it is
      // possible that we are printing a JSON page and theme output should
      // not be shown.
      install_display_output($output, $state);
    }
    elseif ($state['installation_finished']) {
      // Redirect to the newly installed site.
      install_goto('');
    }
  }
}

/**
 * Returns an array of default settings for the global installation state.
 *
 * The installation state is initialized with these settings at the beginning
 * of each page request. They may evolve during the page request, but they are
 * initialized again once the next request begins.
 *
 * Non-interactive Drupal installations can override some of these default
 * settings by passing in an array to the installation script, most notably
 * 'parameters' (which contains one-time parameters such as 'profile' and
 * 'langcode' that are normally passed in via the URL) and 'forms' (which can
 * be used to programmatically submit forms during the installation; the keys
 * of each element indicate the name of the installation task that the form
 * submission is for, and the values are used as the $form_state['values']
 * array that is passed on to the form submission via drupal_form_submit()).
 *
 * @see \Drupal\Core\Form\FormBuilderInterface::submitForm()
 */
function install_state_defaults() {
  $defaults = array(
    // The current task being processed.
    'active_task' => NULL,
    // The last task that was completed during the previous installation
    // request.
    'completed_task' => NULL,
    // TRUE when there are valid config directories.
    'config_verified' => FALSE,
    // TRUE when there is a valid database connection.
    'database_verified' => FALSE,
    // TRUE when a valid settings.php exists (containing both database
    // connection information and config directory names).
    'settings_verified' => FALSE,
    // TRUE when the base system has been installed and is ready to operate.
    'base_system_verified' => FALSE,
    // Whether a translation file for the selected language will be downloaded
    // from the translation server.
    'download_translation' => FALSE,
    // An array of forms to be programmatically submitted during the
    // installation. The keys of each element indicate the name of the
    // installation task that the form submission is for, and the values are
    // used as the $form_state['values'] array that is passed on to the form
    // submission via drupal_form_submit().
    'forms' => array(),
    // This becomes TRUE only at the end of the installation process, after
    // all available tasks have been completed and Drupal is fully installed.
    // It is used by the installer to store correct information in the database
    // about the completed installation, as well as to inform theme functions
    // that all tasks are finished (so that the task list can be displayed
    // correctly).
    'installation_finished' => FALSE,
    // Whether or not this installation is interactive. By default this will
    // be set to FALSE if settings are passed in to install_drupal().
    'interactive' => TRUE,
    // An array of parameters for the installation, pre-populated by the URL
    // or by the settings passed in to install_drupal(). This is primarily
    // used to store 'profile' (the name of the chosen installation profile)
    // and 'langcode' (the code of the chosen installation language), since
    // these settings need to persist from page request to page request before
    // the database is available for storage.
    'parameters' => array(),
    // Whether or not the parameters have changed during the current page
    // request. For interactive installations, this will trigger a page
    // redirect.
    'parameters_changed' => FALSE,
    // An array of information about the chosen installation profile. This will
    // be filled in based on the profile's .info.yml file.
    'profile_info' => array(),
    // An array of available installation profiles.
    'profiles' => array(),
    // The name of the theme to use during installation.
    'theme' => 'seven',
    // The server URL where the interface translation files can be downloaded.
    // Tokens in the pattern will be replaced by appropriate values for the
    // required translation file.
    'server_pattern' => 'http://ftp.drupal.org/files/translations/%core/%project/%project-%version.%language.po',
    // Installation tasks can set this to TRUE to force the page request to
    // end (even if there is no themable output), in the case of an interactive
    // installation. This is needed only rarely; for example, it would be used
    // by an installation task that prints JSON output rather than returning a
    // themed page. The most common example of this is during batch processing,
    // but the Drupal installer automatically takes care of setting this
    // parameter properly in that case, so that individual installation tasks
    // which implement the batch API do not need to set it themselves.
    'stop_page_request' => FALSE,
    // Installation tasks can set this to TRUE to indicate that the task should
    // be run again, even if it normally wouldn't be. This can be used, for
    // example, if a single task needs to be spread out over multiple page
    // requests, or if it needs to perform some validation before allowing
    // itself to be marked complete. The most common examples of this are batch
    // processing and form submissions, but the Drupal installer automatically
    // takes care of setting this parameter properly in those cases, so that
    // individual installation tasks which implement the batch API or form API
    // do not need to set it themselves.
    'task_not_complete' => FALSE,
    // A list of installation tasks which have already been performed during
    // the current page request.
    'tasks_performed' => array(),
    // An array of translation files URIs available for the installation. Keyed
    // by the translation language code.
    'translations' => array(),
  );
  return $defaults;
}

/**
 * Begins an installation request, modifying the installation state as needed.
 *
 * This function performs commands that must run at the beginning of every page
 * request. It throws an exception if the installation should not proceed.
 *
 * @param $install_state
 *   An array of information about the current installation state. This is
 *   modified with information gleaned from the beginning of the page request.
 */
function install_begin_request(&$install_state) {
  $request = Request::createFromGlobals();

  // Add any installation parameters passed in via the URL.
  if ($install_state['interactive']) {
    $install_state['parameters'] += $request->query->all();
  }

  // Validate certain core settings that are used throughout the installation.
  if (!empty($install_state['parameters']['profile'])) {
    $install_state['parameters']['profile'] = preg_replace('/[^a-zA-Z_0-9]/', '', $install_state['parameters']['profile']);
  }
  if (!empty($install_state['parameters']['langcode'])) {
    $install_state['parameters']['langcode'] = preg_replace('/[^a-zA-Z_0-9\-]/', '', $install_state['parameters']['langcode']);
  }

  // Allow command line scripts to override server variables used by Drupal.
  require_once __DIR__ . '/bootstrap.inc';

  // If the hash salt leaks, it becomes possible to forge a valid testing user
  // agent, install a new copy of Drupal, and take over the original site.
  // The user agent header is used to pass a database prefix in the request when
  // running tests. However, for security reasons, it is imperative that no
  // installation be permitted using such a prefix.
  if ($install_state['interactive'] && strpos($request->server->get('HTTP_USER_AGENT'), 'simpletest') !== FALSE && !drupal_valid_test_ua()) {
    header($request->server->get('SERVER_PROTOCOL') . ' 403 Forbidden');
    exit;
  }

  $site_path = DrupalKernel::findSitePath($request, FALSE);
  Settings::initialize($site_path);

  // Ensure that procedural dependencies are loaded as early as possible,
  // since the error/exception handlers depend on them.
  require_once __DIR__ . '/../modules/system/system.install';
  require_once __DIR__ . '/common.inc';
  require_once __DIR__ . '/file.inc';
  require_once __DIR__ . '/install.inc';
  require_once __DIR__ . '/schema.inc';
  require_once __DIR__ . '/../../' . Settings::get('path_inc', 'core/includes/path.inc');
  require_once __DIR__ . '/database.inc';
  require_once __DIR__ . '/form.inc';
  require_once __DIR__ . '/batch.inc';
  require_once __DIR__ . '/ajax.inc';

  // Load module basics (needed for hook invokes).
  include_once __DIR__ . '/module.inc';
  require_once __DIR__ . '/entity.inc';

  // Create a minimal mocked container to support calls to t() in the pre-kernel
  // base system verification code paths below. The strings are not actually
  // used or output for these calls.
  // @todo Separate API level checks from UI-facing error messages.
  $container = new ContainerBuilder();
  $container->setParameter('language.default_values', Language::$defaultValues);
  $container
    ->register('language.default', 'Drupal\Core\Language\LanguageDefault')
    ->addArgument('%language.default_values%');
  $container
    ->register('language_manager', 'Drupal\Core\Language\LanguageManager')
    ->addArgument(new Reference('language.default'));
  $container
    ->register('string_translation', 'Drupal\Core\StringTranslation\TranslationManager')
    ->addArgument(new Reference('language_manager'));
  $container
    ->register('path.matcher', 'Drupal\Core\Path\PathMatcher')
    ->addArgument(new Reference('config.factory'));

  \Drupal::setContainer($container);

  // Determine whether base system services are ready to operate.
  $install_state['config_verified'] = install_verify_config_directory(CONFIG_ACTIVE_DIRECTORY) && install_verify_config_directory(CONFIG_STAGING_DIRECTORY);
  $install_state['database_verified'] = install_verify_database_settings();
  $install_state['settings_verified'] = $install_state['config_verified'] && $install_state['database_verified'];

  if ($install_state['settings_verified']) {
    try {
      $system_schema = system_schema();
      end($system_schema);
      $table = key($system_schema);
      $install_state['base_system_verified'] = Database::getConnection()->schema()->tableExists($table);
    }
    catch (DatabaseExceptionWrapper $e) {
      // The last defined table of the base system_schema() does not exist yet.
      // $install_state['base_system_verified'] defaults to FALSE, so the code
      // following below will use the minimal installer service container.
      // As soon as the base system is verified here, the installer operates in
      // a full and regular Drupal environment, without any kind of exceptions.
    }
  }

  // Replace services with in-memory and null implementations. This kernel is
  // replaced with a regular one in drupal_install_system().
  if (!$install_state['base_system_verified']) {
    $environment = 'install';
    $GLOBALS['conf']['container_service_providers']['InstallerServiceProvider'] = 'Drupal\Core\Installer\InstallerServiceProvider';
  }
  else {
    $environment = 'prod';
  }

  // Only allow dumping the container once the hash salt has been created.
  $kernel = InstallerKernel::createFromRequest($request, drupal_classloader(), $environment, (bool) Settings::get('hash_salt', FALSE));
  $kernel->setSitePath($site_path);
  $kernel->boot();
  $container = $kernel->getContainer();
  $container->get('request_stack')->push($request);

  // Register the file translation service.
  if (isset($GLOBALS['config']['locale.settings']['translation.path'])) {
    $directory = $GLOBALS['config']['locale.settings']['translation.path'];
  }
  else {
    $directory = $site_path . '/files/translations';
  }
  $container->set('string_translator.file_translation', new FileTranslation($directory));
  $container->get('string_translation')
    ->addTranslator($container->get('string_translator.file_translation'));

  // Set the default language to the selected language, if any.
  if (isset($install_state['parameters']['langcode'])) {
    $default_language = new Language(array('id' => $install_state['parameters']['langcode']));
    $container->get('language.default')->set($default_language);
    \Drupal::translation()->setDefaultLangcode($install_state['parameters']['langcode']);
  }

  // Add list of all available profiles to the installation state.
  $listing = new ExtensionDiscovery();
  $listing->setProfileDirectories(array());
  $install_state['profiles'] += $listing->scan('profile');

  // Prime drupal_get_filename()'s static cache.
  foreach ($install_state['profiles'] as $name => $profile) {
    drupal_get_filename('profile', $name, $profile->getPathname());
  }

  if ($profile = _install_select_profile($install_state)) {
    $install_state['parameters']['profile'] = $profile;
    install_load_profile($install_state);
    if (isset($install_state['profile_info']['distribution']['install']['theme'])) {
      $install_state['theme'] = $install_state['profile_info']['distribution']['install']['theme'];
    }
  }

  // Override the module list with a minimal set of modules.
  $module_handler = \Drupal::moduleHandler();
  if (!$module_handler->moduleExists('system')) {
    $module_handler->addModule('system', 'core/modules/system');
  }
  if ($profile && !$module_handler->moduleExists($profile)) {
    $module_handler->addProfile($profile, $install_state['profiles'][$profile]->getPath());
  }
  // After setting up a custom and finite module list in a custom low-level
  // bootstrap like here, ensure to use ModuleHandler::loadAll() so that
  // ModuleHandler::isLoaded() returns TRUE, since that is a condition being
  // checked by other subsystems (e.g., the theme system).
  $module_handler->loadAll();

  $kernel->prepareLegacyRequest($request);

  // Prepare for themed output. We need to run this at the beginning of the
  // page request to avoid a different theme accidentally getting set. (We also
  // need to run it even in the case of command-line installations, to prevent
  // any code in the installer that happens to initialize the theme system from
  // accessing the database before it is set up yet.)
  drupal_maintenance_theme();

  if ($install_state['database_verified']) {
    // Verify the last completed task in the database, if there is one.
    $task = install_verify_completed_task();
  }
  else {
    $task = NULL;

    // Do not install over a configured settings.php.
    if (Database::getConnectionInfo()) {
      throw new AlreadyInstalledException($container->get('string_translation'));
    }
  }

  // Ensure that the active configuration is empty before installation starts.
  if ($install_state['config_verified'] && empty($task)) {
    $config = BootstrapConfigStorageFactory::get()->listAll();
    if (!empty($config)) {
      $task = NULL;
      throw new AlreadyInstalledException($container->get('string_translation'));
    }
  }

  // Modify the installation state as appropriate.
  $install_state['completed_task'] = $task;
}

/**
 * Runs all tasks for the current installation request.
 *
 * In the case of an interactive installation, all tasks will be attempted
 * until one is reached that has output which needs to be displayed to the
 * user, or until a page redirect is required. Otherwise, tasks will be
 * attempted until the installation is finished.
 *
 * @param $install_state
 *   An array of information about the current installation state. This is
 *   passed along to each task, so it can be modified if necessary.
 *
 * @return
 *   HTML output from the last completed task.
 */
function install_run_tasks(&$install_state) {
  do {
    // Obtain a list of tasks to perform. The list of tasks itself can be
    // dynamic (e.g., some might be defined by the installation profile,
    // which is not necessarily known until the earlier tasks have run),
    // so we regenerate the remaining tasks based on the installation state,
    // each time through the loop.
    $tasks_to_perform = install_tasks_to_perform($install_state);
    // Run the first task on the list.
    reset($tasks_to_perform);
    $task_name = key($tasks_to_perform);
    $task = array_shift($tasks_to_perform);
    $install_state['active_task'] = $task_name;
    $original_parameters = $install_state['parameters'];
    $output = install_run_task($task, $install_state);
    $install_state['parameters_changed'] = ($install_state['parameters'] != $original_parameters);
    // Store this task as having been performed during the current request,
    // and save it to the database as completed, if we need to and if the
    // database is in a state that allows us to do so. Also mark the
    // installation as 'done' when we have run out of tasks.
    if (!$install_state['task_not_complete']) {
      $install_state['tasks_performed'][] = $task_name;
      $install_state['installation_finished'] = empty($tasks_to_perform);
      if ($task['run'] == INSTALL_TASK_RUN_IF_NOT_COMPLETED || $install_state['installation_finished']) {
        \Drupal::state()->set('install_task', $install_state['installation_finished'] ? 'done' : $task_name);
      }
    }
    // Stop when there are no tasks left. In the case of an interactive
    // installation, also stop if we have some output to send to the browser,
    // the URL parameters have changed, or an end to the page request was
    // specifically called for.
    $finished = empty($tasks_to_perform) || ($install_state['interactive'] && (isset($output) || $install_state['parameters_changed'] || $install_state['stop_page_request']));
  } while (!$finished);
  return $output;
}

/**
 * Runs an individual installation task.
 *
 * @param $task
 *   An array of information about the task to be run.
 * @param $install_state
 *   An array of information about the current installation state. This is
 *   passed in by reference so that it can be modified by the task.
 *
 * @return
 *   The output of the task function, if there is any.
 */
function install_run_task($task, &$install_state) {
  $function = $task['function'];

  if ($task['type'] == 'form') {
    return install_get_form($function, $install_state);
  }
  elseif ($task['type'] == 'batch') {
    // Start a new batch based on the task function, if one is not running
    // already.
    $current_batch = \Drupal::state()->get('install_current_batch');
    if (!$install_state['interactive'] || !$current_batch) {
      $batch = $function($install_state);
      if (empty($batch)) {
        // If the task did some processing and decided no batch was necessary,
        // there is nothing more to do here.
        return;
      }
      batch_set($batch);
      // For interactive batches, we need to store the fact that this batch
      // task is currently running. Otherwise, we need to make sure the batch
      // will complete in one page request.
      if ($install_state['interactive']) {
        \Drupal::state()->set('install_current_batch', $function);
      }
      else {
        $batch =& batch_get();
        $batch['progressive'] = FALSE;
      }
      // Process the batch. For progressive batches, this will redirect.
      // Otherwise, the batch will complete.
      $response = batch_process(install_redirect_url($install_state), install_full_redirect_url($install_state));
      if ($response instanceof Response) {
        // Save $_SESSION data from batch.
        \Drupal::service('session_manager')->save();
        // Send the response.
        $response->send();
        exit;
      }
    }
    // If we are in the middle of processing this batch, keep sending back
    // any output from the batch process, until the task is complete.
    elseif ($current_batch == $function) {
      $output = _batch_page(\Drupal::request());
      // Because Batch API now returns a JSON response for intermediary steps,
      // but the installer doesn't handle Response objects yet, just send the
      // output here and emulate the old model.
      // @todo Replace this when we refactor the installer to use a request-
      //   response workflow.
      if ($output instanceof Response) {
        $output->send();
        $output = NULL;
      }
      // The task is complete when we try to access the batch page and receive
      // FALSE in return, since this means we are at a URL where we are no
      // longer requesting a batch ID.
      if ($output === FALSE) {
        // Return nothing so the next task will run in the same request.
        \Drupal::state()->delete('install_current_batch');
        return;
      }
      else {
        // We need to force the page request to end if the task is not
        // complete, since the batch API sometimes prints JSON output
        // rather than returning a themed page.
        $install_state['task_not_complete'] = $install_state['stop_page_request'] = TRUE;
        return $output;
      }
    }
  }

  else {
    // For normal tasks, just return the function result, whatever it is.
    return $function($install_state);
  }
}

/**
 * Returns a list of tasks to perform during the current installation request.
 *
 * Note that the list of tasks can change based on the installation state as
 * the page request evolves (for example, if an installation profile hasn't
 * been selected yet, we don't yet know which profile tasks need to be run).
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A list of tasks to be performed, with associated metadata.
 */
function install_tasks_to_perform($install_state) {
  // Start with a list of all currently available tasks.
  $tasks = install_tasks($install_state);
  foreach ($tasks as $name => $task) {
    // Remove any tasks that were already performed or that never should run.
    // Also, if we started this page request with an indication of the last
    // task that was completed, skip that task and all those that come before
    // it, unless they are marked as always needing to run.
    if ($task['run'] == INSTALL_TASK_SKIP || in_array($name, $install_state['tasks_performed']) || (!empty($install_state['completed_task']) && empty($completed_task_found) && $task['run'] != INSTALL_TASK_RUN_IF_REACHED)) {
      unset($tasks[$name]);
    }
    if (!empty($install_state['completed_task']) && $name == $install_state['completed_task']) {
      $completed_task_found = TRUE;
    }
  }
  return $tasks;
}

/**
 * Returns a list of all tasks the installer currently knows about.
 *
 * This function will return tasks regardless of whether or not they are
 * intended to run on the current page request. However, the list can change
 * based on the installation state (for example, if an installation profile
 * hasn't been selected yet, we don't yet know which profile tasks will be
 * available).
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A list of tasks, with associated metadata.
 */
function install_tasks($install_state) {
  // Determine whether a translation file must be imported during the
  // 'install_import_translations' task. Import when a non-English language is
  // available and selected.
  $needs_translations = count($install_state['translations']) > 1 && !empty($install_state['parameters']['langcode']) && $install_state['parameters']['langcode'] != 'en';
  // Determine whether a translation file must be downloaded during the
  // 'install_download_translation' task. Download when a non-English language
  // is selected, but no translation is yet in the translations directory.
  $needs_download = isset($install_state['parameters']['langcode']) && !isset($install_state['translations'][$install_state['parameters']['langcode']]) && $install_state['parameters']['langcode'] != 'en';

  // Start with the core installation tasks that run before handing control
  // to the installation profile.
  $tasks = array(
    'install_select_language' => array(
      'display_name' => t('Choose language'),
      'run' => INSTALL_TASK_RUN_IF_REACHED,
    ),
    'install_download_translation' => array(
      'run' => $needs_download ? INSTALL_TASK_RUN_IF_REACHED : INSTALL_TASK_SKIP,
    ),
    'install_select_profile' => array(
      'display_name' => t('Choose profile'),
      'display' => empty($install_state['profile_info']['distribution']['name']) && count($install_state['profiles']) != 1,
      'run' => INSTALL_TASK_RUN_IF_REACHED,
    ),
    'install_load_profile' => array(
      'run' => INSTALL_TASK_RUN_IF_REACHED,
    ),
    'install_verify_requirements' => array(
      'display_name' => t('Verify requirements'),
    ),
    'install_settings_form' => array(
      'display_name' => t('Set up database'),
      'type' => 'form',
      // Even though the form only allows the user to enter database settings,
      // we still need to display it if settings.php is invalid in any way,
      // since the form submit handler is where settings.php is rewritten.
      'run' => $install_state['settings_verified'] ? INSTALL_TASK_SKIP : INSTALL_TASK_RUN_IF_NOT_COMPLETED,
      'function' => 'Drupal\Core\Installer\Form\SiteSettingsForm',
    ),
    'install_base_system' => array(
      'run' => $install_state['base_system_verified'] ? INSTALL_TASK_SKIP : INSTALL_TASK_RUN_IF_NOT_COMPLETED,
    ),
    // All tasks below are executed in a regular, full Drupal environment.
    'install_bootstrap_full' => array(
      'run' => INSTALL_TASK_RUN_IF_REACHED,
    ),
    'install_profile_modules' => array(
      'display_name' => t('Install site'),
      'type' => 'batch',
    ),
    'install_profile_themes' => array(
    ),
    'install_import_translations' => array(
      'display_name' => t('Set up translations'),
      'display' => $needs_translations,
      'type' => 'batch',
      'run' => $needs_translations ? INSTALL_TASK_RUN_IF_NOT_COMPLETED : INSTALL_TASK_SKIP,
    ),
    'install_configure_form' => array(
      'display_name' => t('Configure site'),
      'type' => 'form',
      'function' => 'Drupal\Core\Installer\Form\SiteConfigureForm',
    ),
  );

  // Now add any tasks defined by the installation profile.
  if (!empty($install_state['parameters']['profile'])) {
    // Load the profile install file, because it is not always loaded when
    // hook_install_tasks() is invoked (e.g. batch processing).
    $profile = $install_state['parameters']['profile'];
    $profile_install_file = $install_state['profiles'][$profile]->getPath() . '/' . $profile . '.install';
    if (file_exists($profile_install_file)) {
      include_once DRUPAL_ROOT . '/' . $profile_install_file;
    }
    $function = $install_state['parameters']['profile'] . '_install_tasks';
    if (function_exists($function)) {
      $result = $function($install_state);
      if (is_array($result)) {
        $tasks += $result;
      }
    }
  }

  // Finish by adding the remaining core tasks.
  $tasks += array(
    'install_import_translations_remaining' => array(
      'display_name' => t('Finish translations'),
      'display' => $needs_translations,
      'type' => 'batch',
      'run' => $needs_translations ? INSTALL_TASK_RUN_IF_NOT_COMPLETED : INSTALL_TASK_SKIP,
    ),
    'install_update_configuration_translations' => array(
      'display_name' => t('Translate configuration'),
      'display' => $needs_translations,
      'type' => 'batch',
      'run' => $needs_translations ? INSTALL_TASK_RUN_IF_NOT_COMPLETED : INSTALL_TASK_SKIP,
    ),
    'install_finished' => array(
    ),
  );

  // Allow the installation profile to modify the full list of tasks.
  if (!empty($install_state['parameters']['profile'])) {
    $profile = $install_state['parameters']['profile'];
    if ($install_state['profiles'][$profile]->load()) {
      $function = $install_state['parameters']['profile'] . '_install_tasks_alter';
      if (function_exists($function)) {
        $function($tasks, $install_state);
      }
    }
  }

  // Fill in default parameters for each task before returning the list.
  foreach ($tasks as $task_name => &$task) {
    $task += array(
      'display_name' => NULL,
      'display' => !empty($task['display_name']),
      'type' => 'normal',
      'run' => INSTALL_TASK_RUN_IF_NOT_COMPLETED,
      'function' => $task_name,
    );
  }
  return $tasks;
}

/**
 * Returns a list of tasks that should be displayed to the end user.
 *
 * The output of this function is a list suitable for sending to
 * theme_task_list().
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A list of tasks, with keys equal to the machine-readable task name and
 *   values equal to the name that should be displayed.
 *
 * @see theme_task_list()
 */
function install_tasks_to_display($install_state) {
  $displayed_tasks = array();
  foreach (install_tasks($install_state) as $name => $task) {
    if ($task['display']) {
      $displayed_tasks[$name] = $task['display_name'];
    }
  }
  return $displayed_tasks;
}

/**
 * Builds and processes a form for the installer environment.
 *
 * Ensures that FormBuilder does not redirect after submitting a form, since the
 * installer uses a custom step/flow logic via install_run_tasks().
 *
 * @param string|array $form_id
 *   The form ID to build and process.
 * @param array $install_state
 *   The current state of the installation.
 *
 * @return array|null
 *   A render array containing the form to render, or NULL in case the form was
 *   successfully submitted.
 *
 * @throws \Drupal\Core\Installer\Exception\InstallerException
 */
function install_get_form($form_id, array &$install_state) {
  // Ensure the form will not redirect, since install_run_tasks() uses a custom
  // redirection logic.
  $form_state = new FormState(array(
    'build_info' => array(
      'args' => array(&$install_state),
    ),
    'no_redirect' => TRUE,
  ));
  $form_builder = \Drupal::formBuilder();
  if ($install_state['interactive']) {
    $form = $form_builder->buildForm($form_id, $form_state);
    // If the form submission was not successful, the form needs to be rendered,
    // which means the task is not complete yet.
    if (empty($form_state['executed'])) {
      $install_state['task_not_complete'] = TRUE;
      return $form;
    }
  }
  else {
    // For non-interactive installs, submit the form programmatically with the
    // values taken from the installation state.
    $form_state['values'] = array();
    $install_form_id = $form_builder->getFormId($form_id, $form_state);
    if (!empty($install_state['forms'][$install_form_id])) {
      $form_state['values'] = $install_state['forms'][$install_form_id];
    }
    $form_builder->submitForm($form_id, $form_state);

    // Throw an exception in case of any form validation error.
    if ($errors = $form_state->getErrors()) {
      throw new InstallerException(implode("\n", $errors));
    }
  }
}

/**
 * Returns the URL that should be redirected to during an installation request.
 *
 * The output of this function is suitable for sending to install_goto().
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   The URL to redirect to.
 *
 * @see install_full_redirect_url()
 */
function install_redirect_url($install_state) {
  return 'core/install.php?' . UrlHelper::buildQuery($install_state['parameters']);
}

/**
 * Returns the complete URL redirected to during an installation request.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   The complete URL to redirect to.
 *
 * @see install_redirect_url()
 */
function install_full_redirect_url($install_state) {
  global $base_url;
  return $base_url . '/' . install_redirect_url($install_state);
}

/**
 * Displays themed installer output and ends the page request.
 *
 * Installation tasks should use #title to set the desired page
 * title, but otherwise this function takes care of theming the overall page
 * output during every step of the installation.
 *
 * @param $output
 *   The content to display on the main part of the page.
 * @param $install_state
 *   An array of information about the current installation state.
 */
function install_display_output($output, $install_state) {
  // Ensure the maintenance theme is initialized.
  // The regular initialization call in install_begin_request() may not be
  // reached in case of an early installer error.
  drupal_maintenance_theme();

  drupal_page_header();

  // Prevent install.php from being indexed when installed in a sub folder.
  // robots.txt rules are not read if the site is within domain.com/subfolder
  // resulting in /subfolder/install.php being found through search engines.
  // When settings.php is writeable this can be used via an external database
  // leading a malicious user to gain php access to the server.
  $noindex_meta_tag = array(
    '#tag' => 'meta',
    '#attributes' => array(
      'name' => 'robots',
      'content' => 'noindex, nofollow',
    ),
  );
  drupal_add_html_head($noindex_meta_tag, 'install_meta_robots');

  // Only show the task list if there is an active task; otherwise, the page
  // request has ended before tasks have even been started, so there is nothing
  // meaningful to show.
  $regions = array();
  if (isset($install_state['active_task'])) {
    // Let the theming function know when every step of the installation has
    // been completed.
    $active_task = $install_state['installation_finished'] ? NULL : $install_state['active_task'];
    $task_list = array(
      '#theme' => 'task_list',
      '#items' => install_tasks_to_display($install_state),
      '#active' => $active_task,
    );
    $regions['sidebar_first'] = $task_list;
  }

  print DefaultHtmlPageRenderer::renderPage($output, $output['#title'], 'install', $regions);
  exit;
}

/**
 * Verifies the requirements for installing Drupal.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A themed status report, or an exception if there are requirement errors.
 */
function install_verify_requirements(&$install_state) {
  // Check the installation requirements for Drupal and this profile.
  $requirements = install_check_requirements($install_state);

  // Verify existence of all required modules.
  $requirements += drupal_verify_profile($install_state);

  return install_display_requirements($install_state, $requirements);
}

/**
 * Installation task; install the base functionality Drupal needs to bootstrap.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 */
function install_base_system(&$install_state) {
  // Install system.module.
  drupal_install_system($install_state);

  // Call file_ensure_htaccess() to ensure that all of Drupal's standard
  // directories (e.g., the public files directory and config directory) have
  // appropriate .htaccess files. These directories will have already been
  // created by this point in the installer, since Drupal creates them during
  // the install_verify_requirements() task. Note that we cannot call
  // file_ensure_access() any earlier than this, since it relies on
  // system.module in order to work.
  file_ensure_htaccess();

  // Enable the user module so that sessions can be recorded during the
  // upcoming bootstrap step.
  \Drupal::moduleHandler()->install(array('user'), FALSE);

  // Save the list of other modules to install for the upcoming tasks.
  // State can be set to the database now that system.module is installed.
  $modules = $install_state['profile_info']['dependencies'];

  // The installation profile is also a module, which needs to be installed
  // after all the dependencies have been installed.
  $modules[] = drupal_get_profile();

  \Drupal::state()->set('install_profile_modules', array_diff($modules, array('system')));
  $install_state['base_system_verified'] = TRUE;
}

/**
 * Verifies and returns the last installation task that was completed.
 *
 * @return
 *   The last completed task, if there is one. An exception is thrown if Drupal
 *   is already installed.
 */
function install_verify_completed_task() {
  try {
    $task = \Drupal::state()->get('install_task');
  }
  // Do not trigger an error if the database query fails, since the database
  // might not be set up yet.
  catch (\Exception $e) {
  }
  if (isset($task)) {
    if ($task == 'done') {
      throw new AlreadyInstalledException(\Drupal::service('string_translation'));
    }