function public static function Bootstrap::alter

Manages theme alter hooks as classes and allows sub-themes to sub-class.

Parameters

string $function: The procedural function name of the alter (e.g. FUNCTION).

mixed $data: The variable that was passed to the hook_TYPE_alter() implementation to be altered. The type of this variable depends on the value of the $type argument. For example, when altering a 'form', $data will be a structured array. When altering a 'profile', $data will be an object.

mixed $context1: (optional) An additional variable that is passed by reference.

mixed $context2: (optional) An additional variable that is passed by reference. If more context needs to be provided to implementations, then this should be an associative array as described above.

Class

Bootstrap

The primary class for the Drupal Bootstrap base theme.

Namespace

Source src/Bootstrap.php (line 220)

public static function alter($function, &$data, &$context1 = NULL, &$context2 = NULL) {
  // Do not statically cache this as the active theme may change.
  $theme = static::getTheme();
  $theme_name = $theme->getName();

  // Immediately return if the active theme is not Bootstrap based.
  if (!$theme->isBootstrap()) {
    return;
  }

  // Handle alter and form managers.
  static $drupal_static_fast;
  if (!isset($drupal_static_fast)) {
    $drupal_static_fast['alter_managers'] = &drupal_static(__METHOD__ . '__alterManagers', []);
    $drupal_static_fast['form_managers'] = &drupal_static(__METHOD__ . '__formManagers', []);
  }

  /* @var \Drupal\bootstrap\Plugin\AlterManager[] $alter_managers */
  $alter_managers = &$drupal_static_fast['alter_managers'];
  if (!isset($alter_managers[$theme_name])) {
    $alter_managers[$theme_name] = new AlterManager($theme);
  }

  /* @var \Drupal\bootstrap\Plugin\FormManager[] $form_managers */
  $form_managers = &$drupal_static_fast['form_managers'];
  if (!isset($form_managers[$theme_name])) {
    $form_managers[$theme_name] = new FormManager($theme);
  }

  // Retrieve the alter and form managers for this theme.
  $alter_manager = $alter_managers[$theme_name];
  $form_manager = $form_managers[$theme_name];

  // Extract the alter hook name.
  $hook = Unicode::extractHook($function, 'alter');

  // Handle form alters as a separate plugin.
  if (strpos($hook, 'form') === 0 && $context1 instanceof FormStateInterface) {
    $form_state = $context1;
    $form_id = $context2;

    // Due to a core bug that affects admin themes, we should not double
    // process the "system_theme_settings" form twice in the global
    // hook_form_alter() invocation.
    // @see https://www.drupal.org/node/943212
    if ($form_id === 'system_theme_settings') {
      return;
    }

    // Keep track of the form identifiers.
    $ids = [];

    // Get the build data.
    $build_info = $form_state->getBuildInfo();

    // Extract the base_form_id.
    $base_form_id = !empty($build_info['base_form_id']) ? $build_info['base_form_id'] : FALSE;
    if ($base_form_id) {
      $ids[] = $base_form_id;
    }

    // If there was no provided form identifier, extract it.
    if (!$form_id) {
      $form_id = !empty($build_info['form_id']) ? $build_info['form_id'] : Unicode::extractHook($function, 'alter', 'form');
    }
    if ($form_id) {
      $ids[] = $form_id;
    }

    // Iterate over each form identifier and look for a possible plugin.
    foreach ($ids as $id) {
      /** @var \Drupal\bootstrap\Plugin\Form\FormInterface $form */
      if ($form_manager->hasDefinition($id) && ($form = $form_manager->createInstance($id, ['theme' => $theme]))) {
        $data['#submit'][] = [get_class($form), 'submitForm'];
        $data['#validate'][] = [get_class($form), 'validateForm'];
        $form->alterForm($data, $form_state, $form_id);
      }
    }
  }
  // Process hook alter normally.
  else {
    /** @var \Drupal\bootstrap\Plugin\Alter\AlterInterface $class */
    if ($alter_manager->hasDefinition($hook) && ($class = $alter_manager->createInstance($hook, ['theme' => $theme]))) {
      $class->alter($data, $context1, $context2);
    }
  }
}