Added docs and made tags lazy load.

Author: magnusnordlander

TaggablePSR6ItemAdapter.php

@@ -1,5 +1,14 @@
 <?php
 
+/*
+ * This file is part of php-cache organization.
+ *
+ * (c) 2015-2015 Aaron Scherer <aequasi@gmail.com>, Tobias Nyholm <tobias.nyholm@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
 namespace Cache\Taggable;
 
 use Cache\Taggable\TaggableItemInterface;
@@ -9,30 +18,53 @@
 use Psr\Cache\CacheItemPoolInterface;
 
 /**
-* 
-*/
+ * @internal
+ *
+ * An adapter for non-taggable cache items, to be used with the cache pool
+ * adapter.
+ *
+ * This adapter stores tags along with the cached value, by storing wrapping
+ * the item in an array structure containing both.
+ *
+ * @author Magnus Nordlander <magnus@fervo.se>
+ */
 class TaggablePSR6ItemAdapter implements TaggableItemInterface
 {
+    /**
+     * @type boolean
+     */
+    private $initialized = false;
+
+    /**
+     * @type CacheItemInterface
+     */
     private $cacheItem;
+
+    /**
+     * @type array<string>
+     */
     private $tags = [];
 
+    /**
+     * @param CacheItemInterface $cacheItem
+     */
     private function __construct(CacheItemInterface $cacheItem)
     {
         $this->cacheItem = $cacheItem;
-        if ($this->cacheItem->isHit()) {
-            $rawItem = $this->cacheItem->get();
-
-            if (is_array($rawItem) && isset($rawItem['tags'])) {
-                $this->tags = $rawItem['tags'];
-            }
-        }
     }
 
-    public static function makeTaggable(CacheItemInterface $cacheItem) // @TODO naming?
+    /**
+     * @param CacheItemInterface $cacheItem
+     * @return TaggableItemInterface
+     */
+    public static function makeTaggable(CacheItemInterface $cacheItem)
     {
         return new self($cacheItem);
     }
 
+    /**
+     * @return CacheItemInterface
+     */
     public function unwrap()
     {
         return $this->cacheItem;
@@ -73,6 +105,8 @@ public function isHit()
      */
     public function set($value)
     {
+        $this->initializeTags();
+
         $this->cacheItem->set([
             'value' => $value,
             'tags' => $this->tags,
@@ -86,6 +120,7 @@ public function set($value)
      */
     public function getTags()
     {
+        $this->initializeTags();
         return $this->tags;
     }
 
@@ -94,6 +129,7 @@ public function getTags()
      */
     public function setTags(array $tags)
     {
+        $this->initialized = true;
         $this->tags = $tags;
         $this->updateTags();
 
@@ -105,6 +141,7 @@ public function setTags(array $tags)
      */
     public function addTag($tag)
     {
+        $this->initializeTags();
         $this->tags[] = $tag;
         $this->updateTags();
 
@@ -136,4 +173,19 @@ private function updateTags()
             'tags' => $this->tags,
         ]);
     }
+
+    private function initializeTags()
+    {
+        if (!$this->initialized) {
+            if ($this->cacheItem->isHit()) {
+                $rawItem = $this->cacheItem->get();
+
+                if (is_array($rawItem) && isset($rawItem['tags'])) {
+                    $this->tags = $rawItem['tags'];
+                }
+            }
+
+            $this->initialized = true;
+        }
+    }
 }

TaggablePSR6PoolAdapter.php

@@ -1,5 +1,14 @@
 <?php
 
+/*
+ * This file is part of php-cache organization.
+ *
+ * (c) 2015-2015 Aaron Scherer <aequasi@gmail.com>, Tobias Nyholm <tobias.nyholm@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
 namespace Cache\Taggable;
 
 use Cache\Taggable\TaggableItemInterface;
@@ -9,15 +18,44 @@
 use Psr\Cache\CacheItemPoolInterface;
 
 /**
-* 
-*/
+ * This adapter lets you make any PSR-6 cache pool taggable. If a pool is
+ * already taggable, it is simply returned by makeTaggable. Tags are stored
+ * either in the same cache pool, or a a separate pool, and both of these
+ * appoaches come with different caveats.
+ *
+ * A general caveat is that using this adapter reserves any cache key starting
+ * with '__tag.'.
+ *
+ * Using the same pool is precarious if your cache does LRU evictions of items
+ * even if they do not expire (as in e.g. memcached). If so, the tag item may
+ * be evicted without all of the tagged items having been evicted first,
+ * causing items to lose their tags.
+ *
+ * In order to mitigate this issue, you may use a separate, more persistent
+ * pool for your tag items. Do however note that if you are doing so, the
+ * entire pool is reserved for tags, as this pool is cleared whenever the
+ * main pool is cleared.
+ *
+ * @author Magnus Nordlander <magnus@fervo.se>
+ */
 class TaggablePSR6PoolAdapter implements TaggablePoolInterface
 {
     use TaggablePoolTrait;
 
+    /**
+     * @type CacheItemPoolInterface
+     */
     private $cachePool;
+
+    /**
+     * @type CacheItemPoolInterface
+     */
     private $tagStorePool;
 
+    /**
+     * @param CacheItemPoolInterface $cachePool
+     * @param CacheItemPoolInterface $tagStorePool
+     */
     private function __construct(CacheItemPoolInterface $cachePool, CacheItemPoolInterface $tagStorePool = null)
     {
         $this->cachePool = $cachePool;
@@ -28,7 +66,13 @@ private function __construct(CacheItemPoolInterface $cachePool, CacheItemPoolInt
         }
     }
 
-    public static function makeTaggable(CacheItemPoolInterface $cachePool, CacheItemPoolInterface $tagStorePool = null) // @TODO naming?
+    /**
+     * @param CacheItemPoolInterface $cachePool The pool to which to add tagging capabilities.
+     * @param CacheItemPoolInterface|null $tagStorePool The pool to store tags in. If null is passed, the main pool is used.
+     *
+     * @return TaggablePoolInterface
+     */
+    public static function makeTaggable(CacheItemPoolInterface $cachePool, CacheItemPoolInterface $tagStorePool = null)
     {
         if ($cachePool instanceOf TaggablePoolInterface && $tagStorePool === null) {
             return $cachePool;