From 66e44f3448c8ef0b9fbf63f06211f8cdee55e0be Mon Sep 17 00:00:00 2001
From: RickyRister <42636155+RickyRister@users.noreply.github.com>
Date: Sun, 22 Jun 2025 15:29:20 -0700
Subject: [PATCH] [PictureLoader] Fix worker leak (#6001)

---
 .../ui/picture_loader/picture_loader_worker_work.cpp | 12 ++++++------
 .../ui/picture_loader/picture_loader_worker_work.h   |  9 +++++++--
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.cpp b/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.cpp
index 3f508aee0..bcc5772f4 100644
--- a/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.cpp
+++ b/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.cpp
@@ -16,7 +16,7 @@
 QStringList PictureLoaderWorkerWork::md5Blacklist = QStringList() << "db0c48db407a907c16ade38de048a441";
 
 PictureLoaderWorkerWork::PictureLoaderWorkerWork(const PictureLoaderWorker *worker, const CardInfoPtr &toLoad)
-    : QThread(nullptr), cardToDownload(toLoad), picDownload(SettingsCache::instance().getPicDownload())
+    : QObject(nullptr), cardToDownload(toLoad), picDownload(SettingsCache::instance().getPicDownload())
 {
     // Hook up signals to the orchestrator
     connect(this, &PictureLoaderWorkerWork::requestImageDownload, worker, &PictureLoaderWorker::queueRequest,
@@ -32,12 +32,12 @@ PictureLoaderWorkerWork::PictureLoaderWorkerWork(const PictureLoaderWorker *work
 
     connect(pictureLoaderThread, &QThread::started, this, &PictureLoaderWorkerWork::startNextPicDownload);
 
-    pictureLoaderThread->start(QThread::LowPriority);
-}
+    // clean up worker once loading finishes
+    connect(this, &PictureLoaderWorkerWork::imageLoaded, this, &QObject::deleteLater);
+    connect(this, &QObject::destroyed, pictureLoaderThread, &QThread::quit);
+    connect(pictureLoaderThread, &QThread::finished, pictureLoaderThread, &QObject::deleteLater);
 
-PictureLoaderWorkerWork::~PictureLoaderWorkerWork()
-{
-    pictureLoaderThread->deleteLater();
+    pictureLoaderThread->start(QThread::LowPriority);
 }
 
 void PictureLoaderWorkerWork::startNextPicDownload()
diff --git a/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.h b/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.h
index 887479591..5db97938e 100644
--- a/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.h
+++ b/cockatrice/src/client/ui/picture_loader/picture_loader_worker_work.h
@@ -20,12 +20,12 @@
 inline Q_LOGGING_CATEGORY(PictureLoaderWorkerWorkLog, "picture_loader.worker");
 
 class PictureLoaderWorker;
-class PictureLoaderWorkerWork : public QThread
+
+class PictureLoaderWorkerWork : public QObject
 {
     Q_OBJECT
 public:
     explicit PictureLoaderWorkerWork(const PictureLoaderWorker *worker, const CardInfoPtr &toLoad);
-    ~PictureLoaderWorkerWork() override;
 
     PictureToLoad cardToDownload;
 
@@ -46,6 +46,11 @@ private slots:
     void picDownloadChanged();
 
 signals:
+    /**
+     * Emitted when this worker has successfully loaded the image or has exhausted all attempts at loading the image.
+     * Failures are represented by an empty QImage.
+     * Note that this object will delete itself as this signal is emitted.
+     */
     void imageLoaded(CardInfoPtr card, const QImage &image);
     void requestImageDownload(const QUrl &url, PictureLoaderWorkerWork *instance);
 };