fs: fix recursion in folder previews

Signed-off-by: Varun Patil <radialapps@gmail.com>

lib/Controller/FoldersController.php

@@ -2,7 +2,7 @@
 
 namespace OCA\Memories\Controller;
 
-use OCA\Memories\Db\TimelineQuery;
+use OCA\Memories\Db\TimelineRoot;
 use OCA\Memories\Exceptions;
 use OCA\Memories\Util;
 use OCP\AppFramework\Http;
@@ -11,8 +11,6 @@ use OCP\Files\Folder;
 
 class FoldersController extends GenericApiController
 {
-    protected TimelineQuery $timelineQuery;
-
     /**
      * @NoAdminRequired
      */
@@ -42,13 +40,23 @@ class FoldersController extends GenericApiController
             // Sort by name
             usort($folders, static fn ($a, $b) => strnatcmp($a->getName(), $b->getName()));
 
+            // Construct root for the base folder. This way we can reuse the
+            // root by filtering out the subfolders we don't want.
+            $root = new TimelineRoot();
+            $this->fs->populateRoot($root);
+
             // Process to response type
-            $list = array_map(fn ($node) => [
+            $list = array_map(function ($node) use ($root) {
+                $root->addFolder($node);
+                $root->baseChange($node->getPath());
+
+                return [
                     'fileid' => $node->getId(),
                     'name' => $node->getName(),
                     'path' => $node->getPath(),
-                'previews' => $this->timelineQuery->getFolderPreviews($node),
-            ], $folders);
+                    'previews' => $this->timelineQuery->getRootPreviews($root),
+                ];
+            }, $folders);
 
             return new Http\JSONResponse($list, Http::STATUS_OK);
         });

lib/Db/FsManager.php

@@ -68,8 +68,13 @@ class FsManager
         $this->nomediaCache = $cacheFactory->createLocal('memories:nomedia');
     }
 
-    /** Get the TimelineRoot object relevant to the request */
-    public function populateRoot(TimelineRoot &$root, bool $recursive)
+    /**
+     * Populate TimelineRoot object relevant to the request.
+     *
+     * @param TimelineRoot $root      Root object to populate (by reference)
+     * @param bool         $recursive Whether to get the folders recursively
+     */
+    public function populateRoot(TimelineRoot &$root, bool $recursive = true)
     {
         $user = $this->userSession->getUser();
 

lib/Db/TimelineQueryFolders.php

@@ -4,14 +4,20 @@ declare(strict_types=1);
 
 namespace OCA\Memories\Db;
 
-use OCP\Files\FileInfo;
 use OCP\IDBConnection;
 
 trait TimelineQueryFolders
 {
     protected IDBConnection $connection;
 
-    public function getFolderPreviews(FileInfo $folder)
+    /**
+     * Get the previews inside a given TimelineRoot.
+     * The root folder passed to this function must already be populated
+     * with the mount points recursively, if this is desired.
+     *
+     * @param TimelineRoot $root The root to use for the query
+     */
+    public function getRootPreviews(TimelineRoot $root)
     {
         $query = $this->connection->getQueryBuilder();
 
@@ -19,8 +25,6 @@ trait TimelineQueryFolders
         $query->select('f.fileid', 'f.etag')->from('memories', 'm');
 
         // WHERE these photos are in the user's requested folder recursively
-        $root = new TimelineRoot();
-        $root->addFolder($folder);
         $query = $this->joinFilecache($query, $root, true, false);
 
         // ORDER descending by fileid

lib/Db/TimelineRoot.php

@@ -39,7 +39,9 @@ class TimelineRoot
         $this->setFolder($info->getId(), $info, $path);
     }
 
-    // Add mountpoints recursively
+    /**
+     * Add mountpoints recursively.
+     */
     public function addMountPoints()
     {
         $manager = \OC\Files\Filesystem::getMountManager();
@@ -51,6 +53,11 @@ class TimelineRoot
         }
     }
 
+    /**
+     * Exclude all folders that are in the given paths.
+     *
+     * @param string[] $paths The paths to exclude
+     */
     public function excludePaths(array $paths)
     {
         foreach ($paths as $path) {
@@ -65,6 +72,21 @@ class TimelineRoot
         }
     }
 
+    /**
+     * Change the base folder to a different one.
+     * This excludes all folders not prefixed with the new base path.
+     *
+     * @param string $path The new base path
+     */
+    public function baseChange(string $path)
+    {
+        foreach ($this->folderPaths as $id => $folderPath) {
+            if (!str_starts_with($folderPath.'/', $path.'/')) {
+                unset($this->folderPaths[$id], $this->folders[$id]);
+            }
+        }
+    }
+
     public function getFolderPath(int $id)
     {
         return $this->folderPaths[$id];