entity_embed-8.x-1.x-dev/src/Plugin/entity_embed/EntityEmbedDisplay/FileFieldFormatter.php

<?php

namespace Drupal\entity_embed\Plugin\entity_embed\EntityEmbedDisplay;

use Drupal\Core\Form\FormStateInterface;

/**
 * Entity Embed Display reusing file field formatters.
 *
 * @see \Drupal\entity_embed\EntityEmbedDisplay\EntityEmbedDisplayInterface
 *
 * @EntityEmbedDisplay(
 *   id = "file",
 *   label = @Translation("File"),
 *   entity_types = {"file"},
 *   deriver = "Drupal\entity_embed\Plugin\Derivative\FieldFormatterDeriver",
 *   field_type = "file",
 *   provider = "file"
 * )
 */
class FileFieldFormatter extends EntityReferenceFieldFormatter {

  /**
   * {@inheritdoc}
   */
  public function getFieldValue() {
    $value = parent::getFieldValue();
    $value += array_intersect_key($this->getConfiguration(), ['description' => '']);
    return $value;
  }

  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration() {
    $defaults = parent::defaultConfiguration();
    // Add support to store file description.
    $defaults['description'] = '';
    return $defaults;
  }

  /**
   * {@inheritdoc}
   */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    $form = parent::buildConfigurationForm($form, $form_state);

    // Description is stored in the configuration since it doesn't map to an
    // actual HTML attribute.
    $form['description'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Description'),
      '#default_value' => $this->getConfigurationValue('description'),
      '#description' => $this->t('The description may be used as the label of the link to the file.'),
    ];

    return $form;
  }

}