Add CellPreloader::clear to avoid potential dangling CellStore pointer and to more aggressively clear preload state from a previous game

apps/openmw/mwworld/cellpreloader.cpp

@@ -272,13 +272,31 @@ namespace MWWorld
         }
     }
 
+    void CellPreloader::clear()
+    {
+        for (PreloadMap::iterator it = mPreloadCells.begin(); it != mPreloadCells.end();)
+        {
+            if (it->second.mWorkItem)
+            {
+                it->second.mWorkItem->abort();
+                mUnrefQueue->push(it->second.mWorkItem);
+            }
+
+            mPreloadCells.erase(it++);
+        }
+    }
+
     void CellPreloader::updateCache(double timestamp)
     {
         for (PreloadMap::iterator it = mPreloadCells.begin(); it != mPreloadCells.end();)
         {
             if (mPreloadCells.size() >= mMinCacheSize && it->second.mTimeStamp < timestamp - mExpiryDelay)
             {
-                it->second.mWorkItem->abort();
+                if (it->second.mWorkItem)
+                {
+                    it->second.mWorkItem->abort();
+                    mUnrefQueue->push(it->second.mWorkItem);
+                }
                 mPreloadCells.erase(it++);
             }
             else

apps/openmw/mwworld/cellpreloader.hpp

@@ -37,6 +37,8 @@ namespace MWWorld
 
         void notifyLoaded(MWWorld::CellStore* cell);
 
+        void clear();
+
         /// Removes preloaded cells that have not had a preload request for a while.
         void updateCache(double timestamp);
 

apps/openmw/mwworld/scene.cpp

@@ -315,13 +315,15 @@ namespace MWWorld
         mPreloader->notifyLoaded(cell);
     }
 
-    void Scene::changeToVoid()
+    void Scene::clear()
     {
         CellStoreCollection::iterator active = mActiveCells.begin();
         while (active!=mActiveCells.end())
             unloadCell (active++);
         assert(mActiveCells.empty());
         mCurrentCell = NULL;
+
+        mPreloader->clear();
     }
 
     void Scene::playerMoved(const osg::Vec3f &pos)

apps/openmw/mwworld/scene.hpp

@@ -113,7 +113,7 @@ namespace MWWorld
             ///< Move to exterior cell.
             /// @param changeEvent Set cellChanged flag?
 
-            void changeToVoid();
+            void clear();
             ///< Change into a void
 
             void markCellAsUnchanged();

apps/openmw/mwworld/worldimp.cpp

@@ -290,7 +290,7 @@ namespace MWWorld
         mProjectileManager->clear();
         mLocalScripts.clear();
 
-        mWorldScene->changeToVoid();
+        mWorldScene->clear();
 
         mStore.clearDynamic();
         mStore.setUp();