--- /dev/null
+<?php
+
+namespace Drupal\video_embed_field\Plugin\Validation\Constraint;
+
+use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Drupal\video_embed_field\ProviderManagerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+
+/**
+ * Validates the video embed providers.
+ */
+class VideoEmbedConstraintValidator extends ConstraintValidator implements ContainerInjectionInterface {
+
+ /**
+ * Video embed provider manager service.
+ *
+ * @var \Drupal\video_embed_field\ProviderManagerInterface
+ */
+ protected $providerManager;
+
+ /**
+ * Create an instance of the validator.
+ *
+ * @param \Drupal\video_embed_field\ProviderManagerInterface $provider_manager
+ * The provider manager service.
+ */
+ public function __construct(ProviderManagerInterface $provider_manager) {
+ $this->providerManager = $provider_manager;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function create(ContainerInterface $container) {
+ return new static(
+ $container->get('video_embed_field.provider_manager')
+ );
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function validate($field, Constraint $constraint) {
+ if (!isset($field->value)) {
+ return NULL;
+ }
+
+ $allowed_providers = $field->getFieldDefinition()->getSetting('allowed_providers');
+ $allowed_provider_definitions = $this->providerManager->loadDefinitionsFromOptionList($allowed_providers);
+
+ if (FALSE === $this->providerManager->filterApplicableDefinitions($allowed_provider_definitions, $field->value)) {
+ $this->context->addViolation($constraint->message);
+ }
+ }
+
+}