Issue #2245249 by tim.plunkett: Convert installer forms to FormInterface.

core/lib/Drupal/Core/Installer/Form/SelectLanguageForm.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Installer\Form\SelectLanguageForm.
+ */
+
+namespace Drupal\Core\Installer\Form;
+
+use Drupal\Component\Utility\String;
+use Drupal\Component\Utility\UserAgent;
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Language\LanguageManager;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Provides the language selection form.
+ */
+class SelectLanguageForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'install_select_language_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state, $install_state = NULL) {
+    if (count($install_state['translations']) > 1) {
+      $files = $install_state['translations'];
+    }
+    else {
+      $files = array();
+    }
+    $standard_languages = LanguageManager::getStandardLanguageList();
+    $select_options = array();
+    $browser_options = array();
+
+    $form['#title'] = $this->t('Choose language');
+
+    // Build a select list with language names in native language for the user
+    // to choose from. And build a list of available languages for the browser
+    // to select the language default from.
+    if (count($files)) {
+      // Select lists based on available language files.
+      foreach ($files as $langcode => $uri) {
+        $select_options[$langcode] = isset($standard_languages[$langcode]) ? $standard_languages[$langcode][1] : $langcode;
+        $browser_options[] = $langcode;
+      }
+    }
+    else {
+      // Select lists based on all standard languages.
+      foreach ($standard_languages as $langcode => $language_names) {
+        $select_options[$langcode] = $language_names[1];
+        $browser_options[] = $langcode;
+      }
+    }
+
+    $request = Request::createFromGlobals();
+    $browser_langcode = UserAgent::getBestMatchingLangcode($request->server->get('HTTP_ACCEPT_LANGUAGE'), $browser_options);
+    $form['langcode'] = array(
+      '#type' => 'select',
+      '#title' => $this->t('Choose language'),
+      '#title_display' => 'invisible',
+      '#options' => $select_options,
+      // Use the browser detected language as default or English if nothing found.
+      '#default_value' => !empty($browser_langcode) ? $browser_langcode : 'en',
+    );
+
+    if (empty($files)) {
+      $form['help'] = array(
+        '#type' => 'item',
+        '#markup' => String::format('<p>Translations will be downloaded from the <a href="http://localize.drupal.org">Drupal Translation website</a>.
+        If you do not want this, select <a href="!english">English</a>.</p>', array(
+            '!english' => install_full_redirect_url(array('parameters' => array('langcode' => 'en'))),
+          )),
+        '#states' => array(
+          'invisible' => array(
+            'select[name="langcode"]' => array('value' => 'en'),
+          ),
+        ),
+      );
+    }
+    $form['actions'] = array('#type' => 'actions');
+    $form['actions']['submit'] =  array(
+      '#type' => 'submit',
+      '#value' => $this->t('Save and continue'),
+      '#button_type' => 'primary',
+    );
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, array &$form_state) {
+    $install_state = &$form_state['build_info']['args'][0];
+    $install_state['parameters']['langcode'] = $form_state['values']['langcode'];
+  }
+
+}

core/lib/Drupal/Core/Installer/Form/SelectProfileForm.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Installer\Form\SelectProfileForm.
+ */
+
+namespace Drupal\Core\Installer\Form;
+
+use Drupal\Core\Form\FormBase;
+
+/**
+ * Provides the profile selection form.
+ */
+class SelectProfileForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'install_select_profile_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state, $install_state = NULL) {
+    $form['#title'] = $this->t('Select an installation profile');
+
+    $profiles = array();
+    $names = array();
+    foreach ($install_state['profiles'] as $profile) {
+      /** @var $profile \Drupal\Core\Extension\Extension */
+      $details = install_profile_info($profile->getName());
+      // Skip this extension if its type is not profile.
+      if (!isset($details['type']) || $details['type'] != 'profile') {
+        continue;
+      }
+      // Don't show hidden profiles. This is used by to hide the testing profile,
+      // which only exists to speed up test runs.
+      if ($details['hidden'] === TRUE) {
+        continue;
+      }
+      $profiles[$profile->getName()] = $details;
+
+      // Determine the name of the profile; default to file name if defined name
+      // is unspecified.
+      $name = isset($details['name']) ? $details['name'] : $profile->getName();
+      $names[$profile->getName()] = $name;
+    }
+
+    // Display radio buttons alphabetically by human-readable name, but always
+    // put the core profiles first (if they are present in the filesystem).
+    natcasesort($names);
+    if (isset($names['minimal'])) {
+      // If the expert ("Minimal") core profile is present, put it in front of
+      // any non-core profiles rather than including it with them alphabetically,
+      // since the other profiles might be intended to group together in a
+      // particular way.
+      $names = array('minimal' => $names['minimal']) + $names;
+    }
+    if (isset($names['standard'])) {
+      // If the default ("Standard") core profile is present, put it at the very
+      // top of the list. This profile will have its radio button pre-selected,
+      // so we want it to always appear at the top.
+      $names = array('standard' => $names['standard']) + $names;
+    }
+
+    // The profile name and description are extracted for translation from the
+    // .info file, so we can use $this->t() on them even though they are dynamic
+    // data at this point.
+    $form['profile'] = array(
+      '#type' => 'radios',
+      '#title' => $this->t('Select an installation profile'),
+      '#title_display' => 'invisible',
+      '#options' => array_map(array($this, 't'), $names),
+      '#default_value' => 'standard',
+    );
+    foreach (array_keys($names) as $profile_name) {
+      $form['profile'][$profile_name]['#description'] = isset($profiles[$profile_name]['description']) ? $this->t($profiles[$profile_name]['description']) : '';
+    }
+    $form['actions'] = array('#type' => 'actions');
+    $form['actions']['submit'] =  array(
+      '#type' => 'submit',
+      '#value' => $this->t('Save and continue'),
+      '#button_type' => 'primary',
+    );
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, array &$form_state) {
+    global $install_state;
+    $install_state['parameters']['profile'] = $form_state['values']['profile'];
+  }
+
+}

core/lib/Drupal/Core/Installer/Form/SiteSettingsForm.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Installer\Form\SiteSettingsForm.
+ */
+
+namespace Drupal\Core\Installer\Form;
+
+use Drupal\Component\Utility\Crypt;
+use Drupal\Core\Form\FormBase;
+
+/**
+ * Provides a form to configure and rewrite settings.php.
+ */
+class SiteSettingsForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'install_settings_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state) {
+    global $databases;
+
+    $conf_path = './' . conf_path(FALSE);
+    $settings_file = $conf_path . '/settings.php';
+
+    $form['#title'] = $this->t('Database configuration');
+
+    $drivers = drupal_get_database_types();
+    $drivers_keys = array_keys($drivers);
+
+    // If database connection settings have been prepared in settings.php already,
+    // then the existing values need to be taken over.
+    // Note: The installer even executes this form if there is a valid database
+    // connection already, since the submit handler of this form is responsible
+    // for writing all $settings to settings.php (not limited to $databases).
+    if (isset($databases['default']['default'])) {
+      $default_driver = $databases['default']['default']['driver'];
+      $default_options = $databases['default']['default'];
+    }
+    // Otherwise, use the database connection settings from the form input.
+    // For a non-interactive installation, this is derived from the original
+    // $settings array passed into install_drupal().
+    elseif (isset($form_state['input']['driver'])) {
+      $default_driver = $form_state['input']['driver'];
+      $default_options = $form_state['input'][$default_driver];
+    }
+    // If there is no database information at all yet, just suggest the first
+    // available driver as default value, so that its settings form is made
+    // visible via #states when JavaScript is enabled (see below).
+    else {
+      $default_driver = current($drivers_keys);
+      $default_options = array();
+    }
+
+    $form['driver'] = array(
+      '#type' => 'radios',
+      '#title' => $this->t('Database type'),
+      '#required' => TRUE,
+      '#default_value' => $default_driver,
+    );
+    if (count($drivers) == 1) {
+      $form['driver']['#disabled'] = TRUE;
+    }
+
+    // Add driver specific configuration options.
+    foreach ($drivers as $key => $driver) {
+      $form['driver']['#options'][$key] = $driver->name();
+
+      $form['settings'][$key] = $driver->getFormOptions($default_options);
+      $form['settings'][$key]['#prefix'] = '<h2 class="js-hide">' . $this->t('@driver_name settings', array('@driver_name' => $driver->name())) . '</h2>';
+      $form['settings'][$key]['#type'] = 'container';
+      $form['settings'][$key]['#tree'] = TRUE;
+      $form['settings'][$key]['advanced_options']['#parents'] = array($key);
+      $form['settings'][$key]['#states'] = array(
+        'visible' => array(
+          ':input[name=driver]' => array('value' => $key),
+        )
+      );
+    }
+
+    $form['actions'] = array('#type' => 'actions');
+    $form['actions']['save'] = array(
+      '#type' => 'submit',
+      '#value' => $this->t('Save and continue'),
+      '#button_type' => 'primary',
+      '#limit_validation_errors' => array(
+        array('driver'),
+        array($default_driver),
+      ),
+      '#submit' => array(array($this, 'submitForm')),
+    );
+
+    $form['errors'] = array();
+    $form['settings_file'] = array('#type' => 'value', '#value' => $settings_file);
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, array &$form_state) {
+    $driver = $form_state['values']['driver'];
+    $database = $form_state['values'][$driver];
+    $drivers = drupal_get_database_types();
+    $reflection = new \ReflectionClass($drivers[$driver]);
+    $install_namespace = $reflection->getNamespaceName();
+    // Cut the trailing \Install from namespace.
+    $database['namespace'] = substr($install_namespace, 0, strrpos($install_namespace, '\\'));
+    $database['driver'] = $driver;
+
+    $form_state['storage']['database'] = $database;
+    $errors = install_database_errors($database, $form_state['values']['settings_file']);
+    foreach ($errors as $name => $message) {
+      $this->setFormError($name, $form_state, $message);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, array &$form_state) {
+    global $install_state;
+
+    // Update global settings array and save.
+    $settings = array();
+    $database = $form_state['storage']['database'];
+    $settings['databases']['default']['default'] = (object) array(
+      'value'    => $database,
+      'required' => TRUE,
+    );
+    $settings['settings']['hash_salt'] = (object) array(
+      'value'    => Crypt::randomBytesBase64(55),
+      'required' => TRUE,
+    );
+    // Remember the profile which was used.
+    $settings['settings']['install_profile'] = (object) array(
+      'value' => $install_state['parameters']['profile'],
+      'required' => TRUE,
+    );
+
+    drupal_rewrite_settings($settings);
+
+    // Add the config directories to settings.php.
+    drupal_install_config_directories();
+
+    // Indicate that the settings file has been verified, and check the database
+    // for the last completed task, now that we have a valid connection. This
+    // last step is important since we want to trigger an error if the new
+    // database already has Drupal installed.
+    $install_state['settings_verified'] = TRUE;
+    $install_state['config_verified'] = TRUE;
+    $install_state['database_verified'] = TRUE;
+    $install_state['completed_task'] = install_verify_completed_task();
+  }
+
+}