drupal/core/modules/settings_tray/settings_tray.module

<?php

/**
 * @file
 * Allows configuring blocks and other configuration from the site front-end.
 */

use Drupal\Core\Asset\AttachedAssetsInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\block\entity\Block;
use Drupal\block\BlockInterface;
use Drupal\settings_tray\Block\BlockEntitySettingTrayForm;

/**
 * Implements hook_help().
 */
function settings_tray_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.settings_tray':
      $output = '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Settings Tray module allows users with the <a href=":administer_block_permission">Administer blocks</a> and <a href=":contextual_permission">Use contextual links</a> permissions to edit blocks without visiting a separate page. For more information, see the <a href=":handbook_url">online documentation for the Settings Tray module</a>.', [':handbook_url' => 'https://www.drupal.org/documentation/modules/settings_tray', ':administer_block_permission' => \Drupal::url('user.admin_permissions', [], ['fragment' => 'module-block']), ':contextual_permission' => \Drupal::url('user.admin_permissions', [], ['fragment' => 'module-contextual'])]) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Editing blocks in place') . '</dt>';
      $output .= '<dd>';
      $output .= '<p>' . t('To edit blocks in place, either click the <strong>Edit</strong> button in the toolbar and then click on the block, or choose "Quick edit" from the block\'s contextual link. (See the <a href=":contextual">Contextual Links module help</a> for more information about how to use contextual links.)', [':contextual' => \Drupal::url('help.page', ['name' => 'contextual'])]) . '</p>';
      $output .= '<p>' . t('The Settings Tray for the block will open in a sidebar, with a compact form for configuring what the block shows.') . '</p>';
      $output .= '<p>' . t('Save the form and the changes will be immediately visible on the page.') . '</p>';
      $output .= '</dd>';
      $output .= '</dl>';
      return ['#markup' => $output];
  }
}

/**
 * Implements hook_contextual_links_view_alter().
 *
 * Change Configure Blocks into off_canvas links.
 */
function settings_tray_contextual_links_view_alter(&$element, $items) {
  if (isset($element['#links']['settings-trayblock-configure'])) {
    // Place settings_tray link first.
    $settings_tray_link = $element['#links']['settings-trayblock-configure'];
    unset($element['#links']['settings-trayblock-configure']);
    $element['#links'] = ['settings-trayblock-configure' => $settings_tray_link] + $element['#links'];

    // If this is content block change title to avoid duplicate "Quick Edit".
    if (isset($element['#links']['block-contentblock-edit'])) {
      $element['#links']['settings-trayblock-configure']['title'] = t('Quick edit settings');
    }

    $element['#attached']['library'][] = 'core/drupal.dialog.off_canvas';
  }
}

/**
 * Checks if a block has overrides.
 *
 * @param \Drupal\block\BlockInterface $block
 *   The block to check for overrides.
 *
 * @return bool
 *   TRUE if the block has overrides otherwise FALSE.
 *
 * @internal
 */
function _settings_tray_has_block_overrides(BlockInterface $block) {
  // @todo Replace the following with $block->hasOverrides() in https://www.drupal.org/project/drupal/issues/2910353
  //   and remove this function.
  return \Drupal::config($block->getEntityType()->getConfigPrefix() . '.' . $block->id())->hasOverrides();
}

/**
 * Implements hook_block_view_alter().
 */
function settings_tray_block_view_alter(array &$build) {
  if (isset($build['#contextual_links']['block'])) {
    // Ensure that contextual links vary by whether the block has config overrides
    // or not.
    // @see _contextual_links_to_id()
    $build['#contextual_links']['block']['metadata']['has_overrides'] = _settings_tray_has_block_overrides($build['#block']) ? 1 : 0;
  }

  // Force a new 'data-contextual-id' attribute on blocks when this module is
  // enabled so as not to reuse stale data cached client-side.
  // @todo Remove when https://www.drupal.org/node/2773591 is fixed.
  $build['#contextual_links']['settings_tray'] = [
    'route_parameters' => [],
  ];
}

/**
 * Implements hook_entity_type_build().
 */
function settings_tray_entity_type_build(array &$entity_types) {
  /* @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
  $entity_types['block']
    ->setFormClass('settings_tray', BlockEntitySettingTrayForm::class)
    ->setLinkTemplate('settings_tray-form', '/admin/structure/block/manage/{block}/settings-tray');
}

/**
 * Implements hook_preprocess_HOOK() for block templates.
 */
function settings_tray_preprocess_block(&$variables) {
  // Only blocks that have a settings_tray form and have no configuration
  // overrides will have a "Quick Edit" link. We could wait for the contextual
  // links to be initialized on the client side,  and then add the class and
  // data- attribute below there (via JavaScript). But that would mean that it
  // would be impossible to show Settings Tray's clickable regions immediately
  // when the page loads. When latency is high, this will cause flicker.
  // @see \Drupal\settings_tray\Access\BlockPluginHasSettingsTrayFormAccessCheck
  /** @var \Drupal\settings_tray\Access\BlockPluginHasSettingsTrayFormAccessCheck $access_checker */
  $access_checker = \Drupal::service('access_check.settings_tray.block.settings_tray_form');
  /** @var \Drupal\Core\Block\BlockManagerInterface $block_plugin_manager */
  $block_plugin_manager = \Drupal::service('plugin.manager.block');
  /** @var \Drupal\Core\Block\BlockPluginInterface $block_plugin */
  $block_plugin = $block_plugin_manager->createInstance($variables['plugin_id']);
  if (isset($variables['elements']['#contextual_links']['block']['route_parameters']['block'])) {
    $block = Block::load($variables['elements']['#contextual_links']['block']['route_parameters']['block']);
    if ($access_checker->accessBlockPlugin($block_plugin)->isAllowed() && !_settings_tray_has_block_overrides($block)) {
      // Add class and attributes to all blocks to allow Javascript to target.
      $variables['attributes']['class'][] = 'settings-tray-editable';
      $variables['attributes']['data-drupal-settingstray'] = 'editable';
    }
  }
}

/**
 * Implements hook_toolbar_alter().
 *
 * Alters the 'contextual' toolbar tab if it exists (meaning the user is allowed
 * to use contextual links) and if they can administer blocks.
 *
 * @todo Remove the "administer blocks" requirement in
 *   https://www.drupal.org/node/2822965.
 *
 * @see contextual_toolbar()
 */
function settings_tray_toolbar_alter(&$items) {
  $items['contextual']['#cache']['contexts'][] = 'user.permissions';
  if (isset($items['contextual']['tab']) && \Drupal::currentUser()->hasPermission('administer blocks')) {
    $items['contextual']['#weight'] = -1000;
    $items['contextual']['#attached']['library'][] = 'settings_tray/drupal.settings_tray';
    $items['contextual']['tab']['#attributes']['data-drupal-settingstray'] = 'toggle';

    // Set a class on items to mark whether they should be active in edit mode.
    // @todo Create a dynamic method for modules to set their own items.
    //   https://www.drupal.org/node/2784589.
    $edit_mode_items = ['contextual', 'block_place'];
    foreach ($items as $key => $item) {
      if (!in_array($key, $edit_mode_items) && (!isset($items[$key]['#wrapper_attributes']['class']) || !in_array('hidden', $items[$key]['#wrapper_attributes']['class']))) {
        $items[$key]['#wrapper_attributes']['class'][] = 'edit-mode-inactive';
      }
    }
  }
}

/**
 * Implements hook_block_alter().
 *
 * Ensures every block plugin definition has an 'settings_tray' form specified.
 *
 * @see \Drupal\settings_tray\Access\BlockPluginHasSettingsTrayFormAccessCheck
 */
function settings_tray_block_alter(&$definitions) {
  foreach ($definitions as &$definition) {
    // If a block plugin does not define its own 'settings_tray' form, use the
    // plugin class itself.
    if (!isset($definition['forms']['settings_tray'])) {
      $definition['forms']['settings_tray'] = $definition['class'];
    }
  }
}

/**
 * Implements hook_css_alter().
 */
function settings_tray_css_alter(&$css, AttachedAssetsInterface $assets) {
  // @todo Remove once conditional ordering is introduced in
  //   https://www.drupal.org/node/1945262.
  $path = drupal_get_path('module', 'settings_tray') . '/css/settings_tray.theme.css';
  if (isset($css[$path])) {
    // Use 200 to come after CSS_AGGREGATE_THEME.
    $css[$path]['group'] = 200;
  }
}