feat: provide a version of FileAccess with built in caching

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/Files/Cache/CacheEntry.php

@@ -110,7 +110,7 @@ class CacheEntry implements ICacheEntry {
 		return $this->data['upload_time'] ?? null;
 	}
 
-	public function getData() {
+	public function getData(): array {
 		return $this->data;
 	}
 

lib/private/Files/Cache/CachedFileAccess.php

@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Robin Appelman <robin@icewind.nl>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OC\Files\Cache;
+
+use OC\FilesMetadata\FilesMetadataManager;
+use OC\SystemConfig;
+use OCP\Files\Cache\ICacheEntry;
+use OCP\Files\IMimeTypeLoader;
+use OCP\ICache;
+use OCP\ICacheFactory;
+use OCP\IDBConnection;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Provides cached access to file metadata.
+ *
+ * Note that this does not include any logic for invalidation and should only be
+ * used in places where up to 5 minute outdated metadata is accepted
+ */
+class CachedFileAccess extends FileAccess {
+	const TTL = 5 * 60;
+
+	private ICache $cache;
+
+	public function __construct(
+		IDBConnection $connection,
+		SystemConfig $systemConfig,
+		LoggerInterface $logger,
+		FilesMetadataManager $metadataManager,
+		IMimeTypeLoader $mimeTypeLoader,
+		ICacheFactory $cacheFactory,
+	) {
+		parent::__construct($connection, $systemConfig, $logger, $metadataManager, $mimeTypeLoader);
+		$this->cache = $cacheFactory->createLocal('file_access::');
+	}
+
+	/**
+	 * @param int[] $fileIds
+	 * @return string
+	 */
+	private function getCacheKey(array $fileIds): string {
+		return md5(implode(',', $fileIds));
+	}
+
+	/**
+	 * @param int[] $fileIds
+	 * @return null|ICacheEntry[]
+	 */
+	private function getCachedByFileIds(array $fileIds): ?array {
+		$cached = $this->cache->get($this->getCacheKey($fileIds));
+		if (is_array($cached)) {
+			return array_map(function ($data) {
+				return new CacheEntry($data);
+			}, $cached);
+		} else {
+			return null;
+		}
+	}
+
+	/**
+	 * @param ICacheEntry[] $results
+	 * @return void
+	 */
+	private function cacheEntries(array $results): void {
+		$resultFileIds = array_map(function(ICacheEntry $result) {
+			return $result->getId();
+		}, $results);
+		$value = array_map(function(ICacheEntry $entry) {
+			return $entry->getData();
+		}, $results);
+		$this->cache->set($this->getCacheKey($resultFileIds), $value, self::TTL);
+	}
+
+	public function getByFileIdInStorage(int $fileId, int $storageId): ?CacheEntry {
+		$items = array_values($this->getByFileIdsInStorage([$fileId], $storageId));
+		return $items[0] ?? null;
+	}
+
+	public function getByFileId(int $fileId): ?CacheEntry {
+		$items = array_values($this->getByFileIds([$fileId]));
+		return $items[0] ?? null;
+	}
+
+	public function getByFileIds(array $fileIds): array {
+		$cached = $this->getCachedByFileIds($fileIds);
+		if ($cached) {
+			return $cached;
+		}
+		$result = parent::getByFileIds($fileIds);
+		$this->cacheEntries($result);
+		return $result;
+	}
+
+	public function getByFileIdsInStorage(array $fileIds, int $storageId): array {
+		$cached = $this->getCachedByFileIds($fileIds);
+		if ($cached) {
+			return $cached;
+		}
+		$result = parent::getByFileIdsInStorage($fileIds, $storageId);
+		$this->cacheEntries($result);
+		return $result;
+	}
+
+
+}