From 9f62a23895e115b2a59d5efb77f09bf7f50e0a45 Mon Sep 17 00:00:00 2001
From: Varun Patil <varunpatil@ucla.edu>
Date: Sat, 15 Apr 2023 12:02:07 -0700
Subject: [PATCH] tw: acquire lock before processing

Signed-off-by: Varun Patil <varunpatil@ucla.edu>
---
 lib/Db/TimelineWrite.php            | 33 ++++++++++++++++++++++++++---
 lib/Listeners/PostWriteListener.php | 17 ++++++++++++---
 lib/Service/Index.php               |  8 +++++--
 3 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/lib/Db/TimelineWrite.php b/lib/Db/TimelineWrite.php
index 4248aeaa..845f9f78 100644
--- a/lib/Db/TimelineWrite.php
+++ b/lib/Db/TimelineWrite.php
@@ -9,6 +9,7 @@ use OCA\Memories\Service\Index;
 use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\Files\File;
 use OCP\IDBConnection;
+use OCP\Lock\ILockingProvider;
 
 require_once __DIR__.'/../ExifFields.php';
 
@@ -22,28 +23,54 @@ class TimelineWrite
     use TimelineWritePlaces;
     protected IDBConnection $connection;
     protected LivePhoto $livePhoto;
+    protected ILockingProvider $lockingProvider;
 
     public function __construct(
         IDBConnection $connection,
-        LivePhoto $livePhoto
+        LivePhoto $livePhoto,
+        ILockingProvider $lockingProvider
     ) {
         $this->connection = $connection;
         $this->livePhoto = $livePhoto;
+        $this->lockingProvider = $lockingProvider;
     }
 
     /**
      * Process a file to insert Exif data into the database.
      *
      * @param File $file  File node to process
+     * @param bool $lock  Lock the file before processing
      * @param bool $force Update the record even if the file has not changed
+     *
+     * @return bool True if the file was processed
+     *
+     * @throws \OCP\Lock\LockedException If the file is locked
+     * @throws \OCP\DB\Exception         If the database query fails
      */
-    public function processFile(File $file, bool $force = false): bool
-    {
+    public function processFile(
+        File $file,
+        bool $lock = true,
+        bool $force = false
+    ): bool {
         // Check if we want to process this file
         if (!Index::isSupported($file)) {
             return false;
         }
 
+        // Check if we need to lock the file
+        if ($lock) {
+            $lockKey = 'memories/'.$file->getId();
+            $lockType = ILockingProvider::LOCK_EXCLUSIVE;
+
+            try {
+                $this->lockingProvider->acquireLock($lockKey, $lockType);
+
+                return $this->processFile($file, false, $force);
+            } finally {
+                $this->lockingProvider->releaseLock($lockKey, $lockType);
+            }
+        }
+
         // Get parameters
         $mtime = $file->getMtime();
         $fileId = $file->getId();
diff --git a/lib/Listeners/PostWriteListener.php b/lib/Listeners/PostWriteListener.php
index 65f06560..cfabffdb 100644
--- a/lib/Listeners/PostWriteListener.php
+++ b/lib/Listeners/PostWriteListener.php
@@ -27,14 +27,19 @@ use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventListener;
 use OCP\Files\Events\Node\NodeTouchedEvent;
 use OCP\Files\Events\Node\NodeWrittenEvent;
+use Psr\Log\LoggerInterface;
 
 class PostWriteListener implements IEventListener
 {
     private TimelineWrite $timelineWrite;
+    private LoggerInterface $logger;
 
-    public function __construct(TimelineWrite $timelineWrite)
-    {
+    public function __construct(
+        TimelineWrite $timelineWrite,
+        LoggerInterface $logger
+    ) {
         $this->timelineWrite = $timelineWrite;
+        $this->logger = $logger;
     }
 
     public function handle(Event $event): void
@@ -64,6 +69,12 @@ class PostWriteListener implements IEventListener
             // and getParent() is called on it.
         }
 
-        $this->timelineWrite->processFile($node);
+        try {
+            $this->timelineWrite->processFile($node);
+        } catch (\Exception $e) {
+            $this->logger->error('Memories failed to process file: {message}', [
+                'message' => $e->getMessage(),
+            ]);
+        }
     }
 }
diff --git a/lib/Service/Index.php b/lib/Service/Index.php
index dec12cf3..f779f29c 100644
--- a/lib/Service/Index.php
+++ b/lib/Service/Index.php
@@ -185,11 +185,15 @@ class Index
      */
     public function indexFile(File $file): void
     {
+        $path = $file->getPath();
+
         try {
-            $this->log("Indexing file {$file->getPath()}", true);
+            $this->log("Indexing file {$path}", true);
             $this->timelineWrite->processFile($file);
+        } catch (\OCP\Lock\LockedException $e) {
+            $this->log("Skipping file {$path} due to lock\n", true);
         } catch (\Exception $e) {
-            $this->error("Failed to index file {$file->getPath()}: {$e->getMessage()}");
+            $this->error("Failed to index file {$path}: {$e->getMessage()}");
         } finally {
             $this->tempManager->clean();
         }