Add a method to get all users with access to a file in OCP

apps/comments/lib/Activity/Listener.php

@@ -12,7 +12,6 @@
 use OCP\Comments\CommentsEvent;
 use OCP\Files\Config\IMountProviderCollection;
 use OCP\Files\IRootFolder;
-use OCP\Files\Node;
 use OCP\IUser;
 use OCP\IUserSession;
 use OCP\Share\IShareHelper;
@@ -36,24 +35,11 @@ public function commentEvent(CommentsEvent $event): void {
 			return;
 		}
 
-		// Get all mount point owners
 		$cache = $this->mountCollection->getMountCache();
-		$mounts = $cache->getMountsForFileId((int)$event->getComment()->getObjectId());
-		if (empty($mounts)) {
-			return;
-		}
 
-		$users = [];
-		foreach ($mounts as $mount) {
-			$owner = $mount->getUser()->getUID();
-			$ownerFolder = $this->rootFolder->getUserFolder($owner);
-			$nodes = $ownerFolder->getById((int)$event->getComment()->getObjectId());
-			if (!empty($nodes)) {
-				/** @var Node $node */
-				$node = array_shift($nodes);
-				$al = $this->shareHelper->getPathsForAccessList($node);
-				$users += $al['users'];
-			}
+		$users = $cache->getReadablePathByUserForFileId((int)$event->getComment()->getObjectId());
+		if (empty($users)) {
+			return;
 		}
 
 		$actor = $this->session->getUser();

apps/systemtags/lib/Activity/Listener.php

@@ -11,7 +11,6 @@
 use OCP\App\IAppManager;
 use OCP\Files\Config\IMountProviderCollection;
 use OCP\Files\IRootFolder;
-use OCP\Files\Node;
 use OCP\IConfig;
 use OCP\IGroup;
 use OCP\IGroupManager;
@@ -153,22 +152,10 @@ public function mapperEvent(MapperEvent $event) {
 
 		// Get all mount point owners
 		$cache = $this->mountCollection->getMountCache();
-		$mounts = $cache->getMountsForFileId($event->getObjectId());
-		if (empty($mounts)) {
-			return;
-		}
 
-		$users = [];
-		foreach ($mounts as $mount) {
-			$owner = $mount->getUser()->getUID();
-			$ownerFolder = $this->rootFolder->getUserFolder($owner);
-			$nodes = $ownerFolder->getById($event->getObjectId());
-			if (!empty($nodes)) {
-				/** @var Node $node */
-				$node = array_shift($nodes);
-				$al = $this->shareHelper->getPathsForAccessList($node);
-				$users += $al['users'];
-			}
+		$users = $cache->getReadablePathByUserForFileId((int)$event->getObjectId());
+		if (empty($users)) {
+			return;
 		}
 
 		$actor = $this->session->getUser();

core/Command/Info/FileUtils.php

@@ -44,18 +44,7 @@ public function getFilesByUser(FileInfo $file): array {
 			return [];
 		}
 
-		$mounts = $this->userMountCache->getMountsForFileId($id);
-		$result = [];
-		foreach ($mounts as $mount) {
-			if (isset($result[$mount->getUser()->getUID()])) {
-				continue;
-			}
-
-			$userFolder = $this->rootFolder->getUserFolder($mount->getUser()->getUID());
-			$result[$mount->getUser()->getUID()] = $userFolder->getById($id);
-		}
-
-		return $result;
+		return $this->userMountCache->getReadableNodesByUserForFileId($id);
 	}
 
 	/**

lib/private/Files/Config/UserMountCache.php

@@ -14,10 +14,14 @@
 use OCP\Files\Config\ICachedMountFileInfo;
 use OCP\Files\Config\ICachedMountInfo;
 use OCP\Files\Config\IUserMountCache;
+use OCP\Files\IRootFolder;
+use OCP\Files\Mount\IMountPoint;
+use OCP\Files\Node;
 use OCP\Files\NotFoundException;
 use OCP\IDBConnection;
 use OCP\IUser;
 use OCP\IUserManager;
+use OCP\Server;
 use Psr\Log\LoggerInterface;
 
 /**
@@ -380,6 +384,61 @@ public function getMountsForFileId($fileId, $user = null) {
 		}, $filteredMounts);
 	}
 
+	/**
+	 * Get all nodes that give access to a file
+	 *
+	 * @return array<string, Node[]> Nodes giving access to the given fileId, indexed by user ID
+	 * @since 28.0.0
+	 */
+	public function getReadableNodesByUserForFileId(int $fileId): array {
+		$mounts = $this->getMountsForFileId($fileId);
+		$rootFolder = Server::get(IRootFolder::class);
+		$result = [];
+		foreach ($mounts as $mount) {
+			$uid = $mount->getUser()->getUID();
+			if (!isset($result[$uid])) {
+				$result[$uid] = [];
+			}
+
+			$userFolder = $rootFolder->getUserFolder($uid);
+			$result[$uid] = array_merge($result[$uid], $userFolder->getById($fileId));
+		}
+
+		return array_filter($result);
+	}
+
+	/**
+	 * Get all users having read access to a file, with a path they see it as.
+	 * They may see the same file under other paths,
+	 *  to get this information use the exhaustive getReadableNodesByUserForFileId
+	 *
+	 * @return array<string,string> Paths giving access to the given fileId, indexed by user ID
+	 * @since 28.0.0
+	 */
+	public function getReadablePathByUserForFileId(int $fileId): array {
+		$mounts = $this->getMountsForFileId($fileId);
+		$rootFolder = Server::get(IRootFolder::class);
+		$result = [];
+		foreach ($mounts as $mount) {
+			$uid = $mount->getUser()->getUID();
+			if (isset($result[$uid])) {
+				continue;
+			}
+
+			$userFolder = $rootFolder->getUserFolder($uid);
+			$nodes = $userFolder->getById($fileId);
+			$node = reset($nodes);
+			if ($node) {
+				$path = $userFolder->getRelativePath($node->getPath());
+				if ($path !== null) {
+					$result[$uid] = $path;
+				}
+			}
+		}
+
+		return $result;
+	}
+
 	/**
 	 * Remove all cached mounts for a user
 	 *

lib/public/Files/Config/IUserMountCache.php

@@ -8,6 +8,7 @@
 namespace OCP\Files\Config;
 
 use OCP\Files\Mount\IMountPoint;
+use OCP\Files\Node;
 use OCP\Files\NotFoundException;
 use OCP\IUser;
 
@@ -65,6 +66,23 @@ public function getMountsForRootId($rootFileId);
 	 */
 	public function getMountsForFileId($fileId, $user = null);
 
+	/**
+	 * Get all cached nodes that give access to a file
+	 *
+	 * @return array<string, Node[]> Nodes giving access to the given fileId, indexed by user ID
+	 * @since 28.0.0
+	 */
+	public function getReadableNodesByUserForFileId(int $fileId): array;
+
+	/**
+	 * Get all users having read access to a file, with a path they see it as.
+	 * They may see the same file under other paths, to get this information use exhaustive getReadableNodesByUserForFileId
+	 *
+	 * @return array<string, string> Paths giving access to the given fileId, indexed by user ID
+	 * @since 28.0.0
+	 */
+	public function getReadablePathByUserForFileId(int $fileId): array;
+
 	/**
 	 * Remove all cached mounts for a user
 	 *