1 files changed, 57 insertions, 0 deletions
diff --git a/core/modules/file/src/FileAccessControlHandler.php b/core/modules/file/src/FileAccessControlHandler.php
new file mode 100644
index 000000000000..ee62c2277e42
--- /dev/null
+++ b/core/modules/file/src/FileAccessControlHandler.php
@@ -0,0 +1,57 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\file\FileAccessControlHandler.
+ */
+
+namespace Drupal\file;
+
+use Drupal\Core\Entity\EntityAccessControlHandler;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Session\AccountInterface;
+
+/**
+ * Provides a File access control handler.
+ */
+class FileAccessControlHandler extends EntityAccessControlHandler {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function checkAccess(EntityInterface $entity, $operation, $langcode, AccountInterface $account) {
+
+    if ($operation == 'download') {
+      foreach ($this->getFileReferences($entity) as $field_name => $entity_map) {
+        foreach ($entity_map as $referencing_entity_type => $referencing_entities) {
+          /** @var \Drupal\Core\Entity\EntityInterface $referencing_entity */
+          foreach ($referencing_entities as $referencing_entity) {
+            if ($referencing_entity->access('view', $account) && $referencing_entity->$field_name->access('view', $account)) {
+              return TRUE;
+            }
+          }
+        }
+      }
+
+      return FALSE;
+    }
+  }
+
+  /**
+   * Wrapper for file_get_file_references().
+   *
+   * @param \Drupal\file\FileInterface $file
+   *   The file object for which to get references.
+   *
+   * @return array
+   *   A multidimensional array. The keys are field_name, entity_type,
+   *   entity_id and the value is an entity referencing this file.
+   *
+   * @see file_get_file_references()
+   */
+  protected function getFileReferences(FileInterface $file) {
+    return file_get_file_references($file, NULL, EntityStorageInterface::FIELD_LOAD_REVISION, NULL);
+  }
+
+}