ConfigImporter::createExtensionChangelist

protected ConfigImporter::createExtensionChangelist()

protected function createExtensionChangelist() {
  // Create an empty changelist.
  $this->extensionChangelist = $this->getEmptyExtensionsProcessedList();

  // Read the extensions information to determine changes.
  $current_extensions = $this->storageComparer->getTargetStorage()->read('core.extension');
  $new_extensions = $this->storageComparer->getSourceStorage()->read('core.extension');

  // If there is no extension information in sync then exit. This is probably
  // due to an empty sync directory.
  if (!$new_extensions) {
    return;
  }

  // Get a list of modules with dependency weights as values.
  $module_data = system_rebuild_module_data();
  // Set the actual module weights.
  $module_list = array_combine(array_keys($module_data), array_keys($module_data));
  $module_list = array_map(function($module) use ($module_data) {
    return $module_data[$module]->sort;
  }, $module_list);

  // Determine which modules to uninstall.
  $uninstall = array_keys(array_diff_key($current_extensions['module'], $new_extensions['module']));
  // Sort the list of newly uninstalled extensions by their weights, so that
  // dependencies are uninstalled last. Extensions of the same weight are
  // sorted in reverse alphabetical order, to ensure the order is exactly
  // opposite from installation. For example, this module list:
  // array(
  //   'actions' => 0,
  //   'ban' => 0,
  //   'options' => -2,
  //   'text' => -1,
  // );
  // will result in the following sort order:
  // -2   options
  // -1   text
  //  0 0 ban
  //  0 1 actions
  // @todo Move this sorting functionality to the extension system.
  array_multisort(array_values($module_list), SORT_ASC, array_keys($module_list), SORT_DESC, $module_list);
  $this->extensionChangelist['module']['uninstall'] = array_intersect(array_keys($module_list), $uninstall);

  // Determine which modules to install.
  $install = array_keys(array_diff_key($new_extensions['module'], $current_extensions['module']));
  // Ensure that installed modules are sorted in exactly the reverse order
  // (with dependencies installed first, and modules of the same weight sorted
  // in alphabetical order).
  $module_list = array_reverse($module_list);
  $this->extensionChangelist['module']['install'] = array_intersect(array_keys($module_list), $install);

  // Work out what themes to install and to uninstall.
  $this->extensionChangelist['theme']['install'] = array_keys(array_diff_key($new_extensions['theme'], $current_extensions['theme']));
  $this->extensionChangelist['theme']['uninstall'] = array_keys(array_diff_key($current_extensions['theme'], $new_extensions['theme']));
}