Add getCacheData() method instead of option

src/Slot.php

@@ -102,16 +102,22 @@ class Slot implements SlotInterface {
     return TRUE;
   }
 
+  /**
+   * {@inheritDoc}
+   */
+  public function getCache() {
+    return $this->cache->get($this->id);
+  }
 
   /**
    * {@inheritDoc}
    */
-  public function getCache($data_only = FALSE) {
+  public function getCacheData() {
     if (!$cache_item = $this->cache->get($this->id)) {
       return FALSE;
     }
 
-    return $data_only ? $cache_item->data : $cache_item;
+    return $cache_item->data;
   }
 
   /**

src/SlotInterface.php

@@ -52,16 +52,25 @@ interface SlotInterface {
   public function addCacheTags($tags);
 
   /**
-   * Gets the slots cache entry.
-   *
-   * @param bool $data_only
-   *  If true, returns the data cache entry's data
-   *  instead of the entry itself.
+   * Gets the slot's cache entry.
    *
    * @return object|false
    *   The cache item or FALSE on failure.
    */
-  public function getCache($data_only = FALSE);
+  public function getCache();
+
+  /**
+   * Gets the data from the slot's cache entry.
+   *
+   * Do not use this method if the data itself is
+   * a boolean, as there is no way to tell whether
+   * FALSE was returned because the cache is not set
+   * or because the value of the data is FALSE.
+   *
+   * @return mixed
+   *   The cache item's data  or FALSE on failure.
+   */
+  public function getCacheData();
 
   /**
    * Delete the slot's cache entry.