convert to UTF8 Plugin

Closes #3471059

src/Plugin/Tamper/ConvertToUtf8.php

+<?php
+
+namespace Drupal\tamper\Plugin\Tamper;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\tamper\Exception\TamperException;
+use Drupal\tamper\TamperableItemInterface;
+use Drupal\tamper\TamperBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Plugin implementation for transliteration.
+ *
+ * @Tamper(
+ *   id = "convertToUtf8",
+ *   label = @Translation("Converts to UTF-8"),
+ *   description = @Translation("Runs the value through mb_convert_encoding to convert it to UTF-8."),
+ *   category = "Text"
+ * )
+ */
+class ConvertToUtf8 extends TamperBase implements ContainerFactoryPluginInterface {
+
+  const SETTING_MODE = 'mode';
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $configuration['source_definition']
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function defaultConfiguration() {
+    $config = parent::defaultConfiguration();
+    $config[self::SETTING_MODE] = 'ISO-8859-1';
+    return $config;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
+    $form[self::SETTING_MODE] = [
+      '#type' => 'select',
+      '#title' => $this->t('Source Encoding:'),
+      '#options' => $this->getOptions(),
+      '#default_value' => $this->getSetting(self::SETTING_MODE),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * Provides Options for the configuration Form.
+   */
+  protected function getOptions() {
+    $encodings = mb_list_encodings();
+    $options = [];
+    foreach ($encodings as $encoding) {
+      if ($encoding != "UTF-8") {
+        $options[$encoding] = $encoding;
+      }
+    }
+    return $options;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function tamper($data, TamperableItemInterface $item = NULL) {
+    if (!is_string($data)) {
+      throw new TamperException('Input should be a string.');
+    }
+
+    $sourceencoding = $this->getSetting(self::SETTING_MODE);
+
+    return mb_convert_encoding($data, "UTF-8", $sourceencoding);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
+    parent::submitConfigurationForm($form, $form_state);
+
+    $this->setConfiguration([
+      self::SETTING_MODE => $form_state->getValue(self::SETTING_MODE),
+    ]);
+  }
+
+}