Fix crash related to async content loading (#7508)

apps/openmw/engine.cpp

@@ -2,8 +2,8 @@
 
 #include <cerrno>
 #include <chrono>
+#include <future>
 #include <system_error>
-#include <thread>
 
 #include <osgDB/WriteFile>
 #include <osgViewer/ViewerEventHandlers>
@@ -38,6 +38,7 @@
 
 #include <components/l10n/manager.hpp>
 
+#include <components/loadinglistener/asynclistener.hpp>
 #include <components/loadinglistener/loadinglistener.hpp>
 
 #include <components/misc/frameratelimiter.hpp>
@@ -742,8 +743,10 @@ void OMW::Engine::prepareEngine()
     mWorld = std::make_unique<MWWorld::World>(
         mResourceSystem.get(), mActivationDistanceOverride, mCellName, mCfgMgr.getUserDataPath());
 
-    std::thread loadDataThread(
-        [&] { mWorld->loadData(mFileCollections, mContentFiles, mGroundcoverFiles, mEncoder.get()); });
+    Loading::Listener* listener = MWBase::Environment::get().getWindowManager()->getLoadingScreen();
+    Loading::AsyncListener asyncListener(*listener);
+    auto dataLoading = std::async(std::launch::async,
+        [&] { mWorld->loadData(mFileCollections, mContentFiles, mGroundcoverFiles, mEncoder.get(), &asyncListener); });
 
     if (!mSkipMenu)
     {
@@ -752,9 +755,12 @@ void OMW::Engine::prepareEngine()
             mWindowManager->playVideo(logo, true);
     }
 
-    Loading::Listener* listener = MWBase::Environment::get().getWindowManager()->getLoadingScreen();
     listener->loadingOn();
-    loadDataThread.join();
+    {
+        using namespace std::chrono_literals;
+        while (dataLoading.wait_for(50ms) != std::future_status::ready)
+            asyncListener.update();
+    }
     listener->loadingOff();
 
     mWorld->init(mViewer, rootNode, mWorkQueue.get(), *mUnrefQueue);

apps/openmw/mwgui/loadingscreen.cpp

@@ -76,10 +76,6 @@ namespace MWGui
 
     void LoadingScreen::setLabel(const std::string& label, bool important)
     {
-        std::lock_guard<std::mutex> guard(mMutex);
-        if (!isVisible())
-            return;
-
         mImportantLabel = important;
 
         mLoadingText->setCaptionWithReplacing(label);
@@ -145,8 +141,6 @@ namespace MWGui
 
     void LoadingScreen::loadingOn(bool visible)
     {
-        std::lock_guard<std::mutex> guard(mMutex);
-
         // Early-out if already on
         if (mNestedLoadingCount++ > 0 && mMainWidget->getVisible())
             return;
@@ -187,8 +181,6 @@ namespace MWGui
 
     void LoadingScreen::loadingOff()
     {
-        std::lock_guard<std::mutex> guard(mMutex);
-
         if (--mNestedLoadingCount > 0)
             return;
         mLoadingBox->setVisible(true); // restore
@@ -247,10 +239,6 @@ namespace MWGui
 
     void LoadingScreen::setProgress(size_t value)
     {
-        std::lock_guard<std::mutex> guard(mMutex);
-        if (!isVisible())
-            return;
-
         // skip expensive update if there isn't enough visible progress
         if (mProgressBar->getWidth() <= 0
             || value - mProgress < mProgressBar->getScrollRange() / mProgressBar->getWidth())
@@ -265,10 +253,6 @@ namespace MWGui
 
     void LoadingScreen::increaseProgress(size_t increase)
     {
-        std::lock_guard<std::mutex> guard(mMutex);
-        if (!isVisible())
-            return;
-
         mProgressBar->setScrollPosition(0);
         size_t value = mProgress + increase;
         value = std::min(value, mProgressBar->getScrollRange() - 1);

apps/openmw/mwgui/loadingscreen.hpp

@@ -2,7 +2,6 @@
 #define MWGUI_LOADINGSCREEN_H
 
 #include <memory>
-#include <mutex>
 
 #include <osg/Timer>
 #include <osg/ref_ptr>
@@ -70,8 +69,6 @@ namespace MWGui
         bool mVisible;
         int mNestedLoadingCount;
 
-        std::mutex mMutex;
-
         size_t mProgress;
 
         bool mShowWallpaper;

apps/openmw/mwworld/worldimp.cpp

@@ -270,13 +270,12 @@ namespace MWWorld
     }
 
     void World::loadData(const Files::Collections& fileCollections, const std::vector<std::string>& contentFiles,
-        const std::vector<std::string>& groundcoverFiles, ToUTF8::Utf8Encoder* encoder)
+        const std::vector<std::string>& groundcoverFiles, ToUTF8::Utf8Encoder* encoder, Loading::Listener* listener)
     {
         mContentFiles = contentFiles;
         if (encoder)
             mReaders.setStatelessEncoder(encoder->getStatelessEncoder());
         mESMVersions.resize(mContentFiles.size(), -1);
-        Loading::Listener* listener = MWBase::Environment::get().getWindowManager()->getLoadingScreen();
 
         loadContentFiles(fileCollections, contentFiles, encoder, listener);
         loadGroundcoverFiles(fileCollections, groundcoverFiles, encoder, listener);

apps/openmw/mwworld/worldimp.hpp

@@ -199,7 +199,8 @@ namespace MWWorld
             const std::filesystem::path& userDataPath);
 
         void loadData(const Files::Collections& fileCollections, const std::vector<std::string>& contentFiles,
-            const std::vector<std::string>& groundcoverFiles, ToUTF8::Utf8Encoder* encoder);
+            const std::vector<std::string>& groundcoverFiles, ToUTF8::Utf8Encoder* encoder,
+            Loading::Listener* listener);
 
         // Must be called after `loadData`.
         void init(osgViewer::Viewer* viewer, osg::ref_ptr<osg::Group> rootNode, SceneUtil::WorkQueue* workQueue,

components/CMakeLists.txt

@@ -292,7 +292,7 @@ add_component_dir (terrain
     )
 
 add_component_dir (loadinglistener
-    loadinglistener
+    loadinglistener asynclistener
     )
 
 add_component_dir (myguiplatform

components/loadinglistener/asynclistener.hpp

@@ -0,0 +1,67 @@
+#ifndef COMPONENTS_LOADINGLISTENER_ASYNCLISTENER_H
+#define COMPONENTS_LOADINGLISTENER_ASYNCLISTENER_H
+
+#include <mutex>
+#include <optional>
+#include <string>
+
+#include "loadinglistener.hpp"
+
+namespace Loading
+{
+    class AsyncListener : public Listener
+    {
+    public:
+        AsyncListener(Listener& baseListener)
+            : mBaseListener(baseListener)
+        {
+        }
+
+        void setLabel(const std::string& label, bool important) override
+        {
+            std::lock_guard<std::mutex> guard(mMutex);
+            mLabelUpdate = label;
+            mImportantLabel = important;
+        }
+
+        void setProgressRange(size_t range) override
+        {
+            std::lock_guard<std::mutex> guard(mMutex);
+            mRangeUpdate = range;
+        }
+
+        void setProgress(size_t value) override
+        {
+            std::lock_guard<std::mutex> guard(mMutex);
+            mProgressUpdate = value;
+        }
+
+        void increaseProgress(size_t increase) override
+        { /* not implemented */
+        }
+
+        void update()
+        {
+            std::lock_guard<std::mutex> guard(mMutex);
+            if (mLabelUpdate)
+                mBaseListener.setLabel(*mLabelUpdate, mImportantLabel);
+            if (mRangeUpdate)
+                mBaseListener.setProgressRange(*mRangeUpdate);
+            if (mProgressUpdate)
+                mBaseListener.setProgress(*mProgressUpdate);
+            mLabelUpdate = std::nullopt;
+            mRangeUpdate = std::nullopt;
+            mProgressUpdate = std::nullopt;
+        }
+
+    private:
+        Listener& mBaseListener;
+        std::mutex mMutex;
+        std::optional<std::string> mLabelUpdate;
+        bool mImportantLabel = false;
+        std::optional<size_t> mRangeUpdate;
+        std::optional<size_t> mProgressUpdate;
+    };
+}
+
+#endif // COMPONENTS_LOADINGLISTENER_ASYNCLISTENER_H