Issue #3488426: Support Custom Field module

Closes #3488426

src/Plugin/LingotekFieldProcessor/LingotekCustomFieldProcessor.php

+<?php
+
+namespace Drupal\lingotek\Plugin\LingotekFieldProcessor;
+
+use Drupal\Core\Entity\ContentEntityInterface;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\Core\Plugin\PluginBase;
+use Drupal\lingotek\FieldProcessor\LingotekFieldProcessorInterface;
+use Drupal\lingotek\LingotekContentTranslationEntityRevisionResolver;
+
+/**
+ * @LingotekFieldProcessor(
+ *   id = "custom_field",
+ *   weight = 5,
+ * )
+ */
+class LingotekCustomFieldProcessor extends PluginBase implements LingotekFieldProcessorInterface {
+
+  /**
+   * Translatable field type.
+   *
+   * @see \Drupal\custom_field\Plugin\CustomField\FieldType.
+   */
+  protected array $translatableFieldTypes = ['string', 'string_long'];
+
+  /**
+   * Translatable field width.
+   *
+   * @see \Drupal\custom_field\Plugin\CustomField\FieldWidget
+   */
+  protected array $translatableFieldWidgets = ['text', 'textarea'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function appliesToField(FieldDefinitionInterface $field_definition, ContentEntityInterface &$entity) {
+    return ('custom' === $field_definition->getType());
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function extract(ContentEntityInterface &$entity, string $field_name, FieldDefinitionInterface $field_definition, array &$data, array &$visited = [], string $revision_mode = LingotekContentTranslationEntityRevisionResolver::RESOLVE_LATEST_TRANSLATION_AFFECTED) {
+    // Get columns and field settings.
+    $settings = $field_definition->getSettings();
+    $columns = $settings['columns'];
+    $field_settings = $settings['field_settings'];
+
+    // Get translatable columns.
+    $translatable_columns = [];
+    foreach ($columns as $column_name => $column) {
+      $field_type = $column['type'];
+      $widget_type = $field_settings[$column_name]['type'] ?? NULL;
+      if (in_array($field_type, $this->translatableFieldTypes)
+        && in_array($widget_type, $this->translatableFieldWidgets)
+      ) {
+        $translatable_columns[$column_name] = $column_name;
+      }
+    }
+
+    // Extract translatable data.
+    $data[$field_name] = [];
+    foreach ($entity->get($field_name) as $delta => $field_item) {
+      $data[$field_name][$delta] = array_intersect_key(
+        $field_item->toArray(),
+        $translatable_columns
+      );
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function store(ContentEntityInterface &$translation, string $langcode, ContentEntityInterface &$revision, string $field_name, FieldDefinitionInterface $field_definition, array &$field_data) {
+    foreach ($field_data as $delta => $field_value) {
+      $existing_value = $translation->get($field_name)->get($delta)->getValue();
+      $value = $field_value + $existing_value;
+      $translation->get($field_name)->set($delta, $value);
+    }
+  }
+
+}