add metadata cache

composer.json

@@ -25,6 +25,8 @@
     "cspray/phinal": "^2.0",
     "infection/infection": "^0.27.0",
     "patchlevel/coding-standard": "^1.2.0",
+    "psr/cache": "^2.0.0|^3.0.0",
+    "psr/simple-cache": "^2.0.0|^3.0.0",
     "phpbench/phpbench": "^1.2.6",
     "phpspec/prophecy-phpunit": "^2.0.1",
     "phpstan/phpstan": "^1.8.2",

src/Metadata/Psr16MetadataFactory.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\Hydrator\Metadata;
+
+use Psr\SimpleCache\CacheInterface;
+
+final class Psr16MetadataFactory implements MetadataFactory
+{
+    public function __construct(
+        private readonly MetadataFactory $metadataFactory,
+        private readonly CacheInterface $cache,
+    ) {
+    }
+
+    /**
+     * @param class-string<T> $class
+     *
+     * @return ClassMetadata<T>
+     *
+     * @template T of object
+     */
+    public function metadata(string $class): ClassMetadata
+    {
+        /** @var ?ClassMetadata<T> $metadata */
+        $metadata = $this->cache->get($class);
+
+        if ($metadata !== null) {
+            return $metadata;
+        }
+
+        $metadata = $this->metadataFactory->metadata($class);
+
+        $this->cache->set($class, $metadata);
+
+        return $metadata;
+    }
+}