Making cache tags more efficient by rewriting the API.

Related to php-cache/issues#21

Author: Nyholm

FilesystemCachePool.php

@@ -13,16 +13,22 @@
 
 use Cache\Adapter\Common\AbstractCachePool;
 use Cache\Adapter\Common\Exception\InvalidArgumentException;
+use Cache\Taggable\TaggableItemInterface;
+use Cache\Taggable\TaggablePoolInterface;
+use Cache\Taggable\TaggablePoolTrait;
 use League\Flysystem\FileNotFoundException;
 use League\Flysystem\Filesystem;
 use Psr\Cache\CacheItemInterface;
 
 /**
  * @author Tobias Nyholm <[email protected]>
  */
-class FilesystemCachePool extends AbstractCachePool
+class FilesystemCachePool extends AbstractCachePool implements TaggablePoolInterface
 {
     const CACHE_PATH = 'cache';
+
+    use TaggablePoolTrait;
+
     /**
      * @type Filesystem
      */
@@ -41,17 +47,20 @@ protected function fetchObjectFromCache($key)
     {
         $file = $this->getFilePath($key);
         if (!$this->filesystem->has($file)) {
-            return [false, null];
+            return [false, null, []];
         }
 
         $data = unserialize($this->filesystem->read($file));
         if ($data[0] !== null && time() > $data[0]) {
-            $this->clearOneObjectFromCache($key);
+            foreach ($data[2] as $tag) {
+                $this->removeListItem($this->getTagKey($tag), $key);
+            }
+            $this->forceClear($key);
 
-            return [false, null];
+            return [false, null, []];
         }
 
-        return [true, $data[1]];
+        return [true, $data[1], $data[2]];
     }
 
     protected function clearAllObjectsFromCache()
@@ -64,23 +73,27 @@ protected function clearAllObjectsFromCache()
 
     protected function clearOneObjectFromCache($key)
     {
-        try {
-            return $this->filesystem->delete($this->getFilePath($key));
-        } catch (FileNotFoundException $e) {
-            return true;
-        }
+        $this->preRemoveItem($key);
+
+        return $this->forceClear($key);
     }
 
-    protected function storeItemInCache($key, CacheItemInterface $item, $ttl)
+    protected function storeItemInCache(CacheItemInterface $item, $ttl)
     {
-        $file = $this->getFilePath($key);
+        $file = $this->getFilePath($item->getKey());
         if ($this->filesystem->has($file)) {
             $this->filesystem->delete($file);
         }
 
+        $tags = [];
+        if ($item instanceof TaggableItemInterface) {
+            $tags = $item->getTags();
+        }
+
         return $this->filesystem->write($file, serialize([
             ($ttl === null ? null : time() + $ttl),
             $item->get(),
+            $tags,
         ]));
     }
 
@@ -99,4 +112,64 @@ private function getFilePath($key)
 
         return sprintf('%s/%s', self::CACHE_PATH, $key);
     }
+
+    public function save(CacheItemInterface $item)
+    {
+        if ($item instanceof TaggableItemInterface) {
+            $this->saveTags($item);
+        }
+
+        return parent::save($item);
+    }
+
+    protected function getList($name)
+    {
+        $file = $this->getFilePath($name);
+
+        if (!$this->filesystem->has($file)) {
+            $this->filesystem->write($file, serialize([]));
+        }
+
+        return unserialize($this->filesystem->read($file));
+    }
+
+    protected function removeList($name)
+    {
+        $file = $this->getFilePath($name);
+        $this->filesystem->delete($file);
+    }
+
+    protected function appendListItem($name, $key)
+    {
+        $list   = $this->getList($name);
+        $list[] = $key;
+
+        return $this->filesystem->update($this->getFilePath($name), serialize($list));
+    }
+
+    protected function removeListItem($name, $key)
+    {
+        $list = $this->getList($name);
+        foreach ($list as $i => $item) {
+            if ($item === $key) {
+                unset($list[$i]);
+            }
+        }
+
+        return $this->filesystem->update($this->getFilePath($name), serialize($list));
+    }
+
+    /**
+     * @param $key
+     *
+     * @return bool
+     */
+    private function forceClear($key)
+    {
+        try {
+            return $this->filesystem->delete($this->getFilePath($key));
+        } catch (FileNotFoundException $e) {
+            return true;
+        }
+    }
 }

composer.json

@@ -32,7 +32,7 @@
     },
     "require-dev":       {
         "phpunit/phpunit":         "^4.0|^5.1",
-        "cache/integration-tests": "0.7.0"
+        "cache/integration-tests": "0.9.0"
     },
     "provide":           {
         "psr/cache-implementation": "^1.0"