[Contracts][Cache] allow retrieving metadata of cached items

Author: nicolas-grekas

Cache/CacheInterface.php

@@ -29,19 +29,20 @@ interface CacheInterface
      * requested key, that could be used e.g. for expiration control. It could also
      * be an ItemInterface instance when its additional features are needed.
      *
-     * @param string                     $key      The key of the item to retrieve from the cache
-     * @param callable|CallbackInterface $callback Should return the computed value for the given key/item
-     * @param float|null                 $beta     A float that, as it grows, controls the likeliness of triggering
-     *                                             early expiration. 0 disables it, INF forces immediate expiration.
-     *                                             The default (or providing null) is implementation dependent but should
-     *                                             typically be 1.0, which should provide optimal stampede protection.
-     *                                             See https://en.wikipedia.org/wiki/Cache_stampede#Probabilistic_early_expiration
+     * @param string                     $key       The key of the item to retrieve from the cache
+     * @param callable|CallbackInterface $callback  Should return the computed value for the given key/item
+     * @param float|null                 $beta      A float that, as it grows, controls the likeliness of triggering
+     *                                              early expiration. 0 disables it, INF forces immediate expiration.
+     *                                              The default (or providing null) is implementation dependent but should
+     *                                              typically be 1.0, which should provide optimal stampede protection.
+     *                                              See https://en.wikipedia.org/wiki/Cache_stampede#Probabilistic_early_expiration
+     * @param array                      &$metadata The metadata of the cached item {@see ItemInterface::getMetadata()}
      *
      * @return mixed The value corresponding to the provided key
      *
      * @throws InvalidArgumentException When $key is not valid or when $beta is negative
      */
-    public function get(string $key, callable $callback, float $beta = null);
+    public function get(string $key, callable $callback, float $beta = null, array &$metadata = null);
 
     /**
      * Removes an item from the pool.

Cache/CacheTrait.php

@@ -24,9 +24,9 @@ trait CacheTrait
     /**
      * {@inheritdoc}
      */
-    public function get(string $key, callable $callback, float $beta = null)
+    public function get(string $key, callable $callback, float $beta = null, array &$metadata = null)
     {
-        return $this->doGet($this, $key, $callback, $beta);
+        return $this->doGet($this, $key, $callback, $beta, $metadata);
     }
 
     /**
@@ -37,7 +37,7 @@ public function delete(string $key): bool
         return $this->deleteItem($key);
     }
 
-    private function doGet(CacheItemPoolInterface $pool, string $key, callable $callback, ?float $beta)
+    private function doGet(CacheItemPoolInterface $pool, string $key, callable $callback, ?float $beta, array &$metadata = null)
     {
         if (0 > $beta = $beta ?? 1.0) {
             throw new class(sprintf('Argument "$beta" provided to "%s::get()" must be a positive number, %f given.', \get_class($this), $beta)) extends \InvalidArgumentException implements InvalidArgumentException {
@@ -46,9 +46,9 @@ private function doGet(CacheItemPoolInterface $pool, string $key, callable $call
 
         $item = $pool->getItem($key);
         $recompute = !$item->isHit() || INF === $beta;
+        $metadata = $item instanceof ItemInterface ? $item->getMetadata() : array();
 
-        if (!$recompute && $item instanceof ItemInterface) {
-            $metadata = $item->getMetadata();
+        if (!$recompute && $metadata) {
             $expiry = $metadata[ItemInterface::METADATA_EXPIRY] ?? false;
             $ctime = $metadata[ItemInterface::METADATA_CTIME] ?? false;
 

Cache/TagAwareCacheInterface.php

@@ -20,11 +20,6 @@
  */
 interface TagAwareCacheInterface extends CacheInterface
 {
-    /**
-     * {@inheritdoc}
-     */
-    public function get(string $key, callable $callback, float $beta = null);
-
     /**
      * Invalidates cached items using tags.
      *