Wait for the reloading cells thread on DataFilesPage destruction

Run a single thread and notify it when it has to reload cells.

CHANGELOG.md

@@ -231,6 +231,7 @@
     Bug #8378: Korean bitmap fonts are unusable
     Bug #8439: Creatures without models can crash the game
     Bug #8441: Freeze when using video main menu replacers
+    Bug #8445: Launcher crashes on exit when cell name loading thread is still running
     Bug #8462: Crashes when resizing the window on macOS
     Feature #1415: Infinite fall failsafe
     Feature #2566: Handle NAM9 records for manual cell references

apps/launcher/datafilespage.cpp

@@ -159,6 +159,7 @@ Launcher::DataFilesPage::DataFilesPage(const Files::ConfigurationManager& cfg, C
     , mGameSettings(gameSettings)
     , mLauncherSettings(launcherSettings)
     , mNavMeshToolInvoker(new Process::ProcessInvoker(this))
+    , mReloadCellsThread(&DataFilesPage::reloadCells, this)
 {
     ui.setupUi(this);
     setObjectName("DataFilesPage");
@@ -205,6 +206,16 @@ Launcher::DataFilesPage::DataFilesPage(const Files::ConfigurationManager& cfg, C
     slotAddonDataChanged();
 }
 
+Launcher::DataFilesPage::~DataFilesPage()
+{
+    {
+        const std::lock_guard lock(mReloadCellsMutex);
+        mAbortReloadCells = true;
+        mStartReloadCells.notify_one();
+    }
+    mReloadCellsThread.join();
+}
+
 void Launcher::DataFilesPage::buildView()
 {
     QToolButton* refreshButton = mSelector->refreshButton();
@@ -991,31 +1002,45 @@ bool Launcher::DataFilesPage::showDeleteMessageBox(const QString& text)
 void Launcher::DataFilesPage::slotAddonDataChanged()
 {
     QStringList selectedFiles = selectedFilePaths();
-    if (previousSelectedFiles != selectedFiles)
+    if (mSelectedFiles != selectedFiles)
     {
-        previousSelectedFiles = selectedFiles;
-        // Loading cells for core Morrowind + Expansions takes about 0.2 seconds, which is enough to cause a
-        // barely perceptible UI lag. Splitting into its own thread to alleviate that.
-        std::thread loadCellsThread(&DataFilesPage::reloadCells, this, selectedFiles);
-        loadCellsThread.detach();
+        const std::lock_guard lock(mReloadCellsMutex);
+        mSelectedFiles = std::move(selectedFiles);
+        mReloadCells = true;
+        mStartReloadCells.notify_one();
     }
 }
 
-// Mutex lock to run reloadCells synchronously.
-static std::mutex reloadCellsMutex;
-
-void Launcher::DataFilesPage::reloadCells(QStringList selectedFiles)
+void Launcher::DataFilesPage::reloadCells()
 {
-    // Use a mutex lock so that we can prevent two threads from executing the rest of this code at the same time
-    // Based on https://stackoverflow.com/a/5429695/531762
-    std::unique_lock<std::mutex> lock(reloadCellsMutex);
+    std::unique_lock lock(mReloadCellsMutex);
+
+    while (true)
+    {
+        mStartReloadCells.wait(lock);
+
+        if (mAbortReloadCells)
+            return;
+
+        if (!std::exchange(mReloadCells, false))
+            continue;
+
+        QStringList selectedFiles = mSelectedFiles;
+
+        lock.unlock();
 
-    // The following code will run only if there is not another thread currently running it
         CellNameLoader cellNameLoader;
         QSet<QString> set = cellNameLoader.getCellNames(selectedFiles);
         QStringList cellNamesList(set.begin(), set.end());
         std::sort(cellNamesList.begin(), cellNamesList.end());
-    emit signalLoadedCellsChanged(cellNamesList);
+
+        emit signalLoadedCellsChanged(std::move(cellNamesList));
+
+        lock.lock();
+
+        if (mAbortReloadCells)
+            return;
+    }
 }
 
 void Launcher::DataFilesPage::startNavMeshTool()

apps/launcher/datafilespage.hpp

@@ -10,6 +10,10 @@
 #include <QStringList>
 #include <QWidget>
 
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+
 class QSortFilterProxyModel;
 class QAbstractItemModel;
 class QMenu;
@@ -47,6 +51,7 @@ namespace Launcher
     public:
         explicit DataFilesPage(const Files::ConfigurationManager& cfg, Config::GameSettings& gameSettings,
             Config::LauncherSettings& launcherSettings, MainDialog* parent = nullptr);
+        ~DataFilesPage();
 
         QAbstractItemModel* profilesModel() const;
 
@@ -119,7 +124,7 @@ namespace Launcher
         Config::LauncherSettings& mLauncherSettings;
 
         QString mPreviousProfile;
-        QStringList previousSelectedFiles;
+        QStringList mSelectedFiles;
         QString mDataLocal;
         QStringList mKnownArchives;
         QStringList mNewDataDirs;
@@ -127,6 +132,12 @@ namespace Launcher
         Process::ProcessInvoker* mNavMeshToolInvoker;
         NavMeshToolProgress mNavMeshToolProgress;
 
+        bool mReloadCells = false;
+        bool mAbortReloadCells = false;
+        std::mutex mReloadCellsMutex;
+        std::condition_variable mStartReloadCells;
+        std::thread mReloadCellsThread;
+
         void addArchive(const QString& name, Qt::CheckState selected, int row = -1);
         void addArchivesFromDir(const QString& dir);
         void buildView();
@@ -140,7 +151,7 @@ namespace Launcher
         void addProfile(const QString& profile, bool setAsCurrent);
         void checkForDefaultProfile();
         void populateFileViews(const QString& contentModelName);
-        void reloadCells(QStringList selectedFiles);
+        void reloadCells();
         void refreshDataFilesView();
         void updateNavMeshProgress(int minDataSize);
         void slotCopySelectedItemsPaths();