Ref T152, do not start loading if the model dir does not exists/is empty

src/blackmisc/directoryutils.cpp

@@ -360,6 +360,14 @@ namespace BlackMisc
         return failed;
     }
 
+    bool CDirectoryUtils::existsUnemptyDirectory(const QString &testDir)
+    {
+        if (testDir.isEmpty()) { return false; }
+        const QDir dir(testDir);
+        if (!dir.exists()) { return false; }
+        return !dir.isEmpty();
+    }
+
     QSet<QString> CDirectoryUtils::fileNamesToQSet(const QFileInfoList &fileInfoList)
     {
         QSet<QString> sl;

src/blackmisc/directoryutils.h

@@ -112,6 +112,9 @@ namespace BlackMisc
         //! Check if the (most important) runtime directories are available
         static QStringList verifyRuntimeDirectoriesAndFiles();
 
+        //! Exists directory and does it contains files
+        static bool existsUnemptyDirectory(const QString &testDir);
+
         //! Result of directory comparison
         struct DirComparison
         {

src/blackmisc/simulation/aircraftmodelloader.cpp

@@ -11,6 +11,7 @@
 #include "blackmisc/simulation/fscommon/aircraftcfgparser.h"
 #include "blackmisc/simulation/xplane/aircraftmodelloaderxplane.h"
 #include "blackmisc/simulation/xplane/xplaneutil.h"
+#include "blackmisc/directoryutils.h"
 #include "blackmisc/compare.h"
 #include "blackmisc/logmessage.h"
 
@@ -18,6 +19,7 @@
 #include <Qt>
 #include <QtGlobal>
 
+using namespace BlackMisc;
 using namespace BlackMisc::Simulation::Data;
 using namespace BlackMisc::Simulation::FsCommon;
 using namespace BlackMisc::Simulation::XPlane;
@@ -36,6 +38,44 @@ namespace BlackMisc
             connect(&m_caches, &IMultiSimulatorModelCaches::cacheChanged, this, &IAircraftModelLoader::ps_cacheChanged);
         }
 
+        QString IAircraftModelLoader::enumToString(IAircraftModelLoader::LoadFinishedInfo info)
+        {
+            switch (info)
+            {
+            case CacheLoaded: return "cache loaded";
+            case LoadingSkipped: return "loading skipped";
+            case ParsedData: return "parsed data";
+            default: break;
+            }
+            return "??";
+        }
+
+        QString IAircraftModelLoader::enumToString(IAircraftModelLoader::LoadModeFlag modeFlag)
+        {
+            switch (modeFlag)
+            {
+            case NotSet: return "not set";
+            case LoadDirectly: return "load directly";
+            case LoadInBackground: return "load in background";
+            case CacheFirst: return "cache first";
+            case CacheSkipped: return "cache skipped";
+            case CacheOnly: return "cache only";
+            default: break;
+            }
+            return "??";
+        }
+
+        QString IAircraftModelLoader::enumToString(LoadMode mode)
+        {
+            QStringList modes;
+            if (mode.testFlag(NotSet)) modes << enumToString(NotSet);
+            if (mode.testFlag(LoadDirectly)) modes << enumToString(LoadDirectly);
+            if (mode.testFlag(LoadInBackground)) modes << enumToString(LoadInBackground);
+            if (mode.testFlag(CacheFirst)) modes << enumToString(CacheFirst);
+            if (mode.testFlag(CacheSkipped)) modes << enumToString(CacheSkipped);
+            return modes.join(", ");
+        }
+
         IAircraftModelLoader::~IAircraftModelLoader()
         {
             this->gracefulShutdown();
@@ -139,6 +179,8 @@ namespace BlackMisc
         {
             if (m_loadingInProgress) { return; }
             m_loadingInProgress = true;
+            m_loadingMessages.clear();
+
             const bool useCachedData = !mode.testFlag(CacheSkipped) && this->hasCachedData();
             if (useCachedData && (mode.testFlag(CacheFirst) || mode.testFlag(CacheOnly)))
             {
@@ -156,7 +198,16 @@ namespace BlackMisc
                 return;
             }
 
-            // really load from disk
+            // really load from disk?
+            if (m_skipLoadingEmptyModelDir && !CDirectoryUtils::existsUnemptyDirectory(directory))
+            {
+                const CStatusMessage status = CStatusMessage(this, CStatusMessage::SeverityWarning, "Empty or not existing %1 directory '%2', skipping read")
+                                              << this->getSimulator().toQString() << directory;
+                m_loadingMessages.push_back(status);
+                emit loadingFinished(status, this->getSimulator(), LoadingSkipped);
+                return;
+            }
+
             this->startLoadingFromDisk(mode, modelConsolidation, directory);
         }
 
@@ -177,13 +228,14 @@ namespace BlackMisc
 
         void IAircraftModelLoader::cancelLoading()
         {
+            if (!m_loadingInProgress) { return; }
             m_cancelLoading = true;
-            m_loadingInProgress = true;
         }
 
         void IAircraftModelLoader::gracefulShutdown()
         {
             this->cancelLoading();
+            m_loadingInProgress = true; // avoids further startups
         }
 
         QString IAircraftModelLoader::getInfoString() const

src/blackmisc/simulation/aircraftmodelloader.h

@@ -68,10 +68,20 @@ namespace BlackMisc
             //! Load mode
             enum LoadFinishedInfo
             {
-                CacheLoaded, //!< cache was loaded
+                CacheLoaded,   //!< cache was loaded
-                ParsedData   //!< parsed data
+                ParsedData,    //!< parsed data
+                LoadingSkipped //!< Loading skipped (empty directory)
             };
 
+            //! Enum as string
+            static QString enumToString(LoadFinishedInfo info);
+
+            //! Enum as string
+            static QString enumToString(LoadModeFlag modeFlag);
+
+            //! Enum as string
+            static QString enumToString(LoadMode mode);
+
             //! Destructor
             virtual ~IAircraftModelLoader();
 
@@ -102,8 +112,14 @@ namespace BlackMisc
             BlackMisc::Simulation::CAircraftModelList getCachedAircraftModels(const CSimulatorInfo &simulator) const;
 
             //! Count of loaded models
+            //! \threadsafe
             int getAircraftModelsCount() const { return getAircraftModels().size(); }
 
+            //! Skip the loading of empty (model) directories
+            //! \remark loading of empty directories might erase the cache and is normally disable
+            //! \threadsafe
+            void setSkipLoadingOfEmptyDirectories(bool skip);
+
             //! Which simulator is supported by that very loader
             const CSimulatorInfo getSimulator() const;
 
@@ -122,7 +138,7 @@ namespace BlackMisc
             //! Exclude directories
             QStringList getModelExcludeDirectoryPatterns() const;
 
-            //! Cancel read
+            //! Cancel loading
             void cancelLoading();
 
             //! Shutdown
@@ -176,11 +192,12 @@ namespace BlackMisc
             //! Start the loading process from disk
             virtual void startLoadingFromDisk(LoadMode mode, const ModelConsolidation &modelConsolidation, const QString &directory) = 0;
 
-            std::atomic<bool> m_cancelLoading { false };                        //!< flag, requesting to cancel loading
+            std::atomic<bool> m_cancelLoading { false };            //!< flag, requesting to cancel loading
-            std::atomic<bool> m_loadingInProgress { false };                    //!< Loading in progress
+            std::atomic<bool> m_loadingInProgress { false };        //!< Loading in progress
-            BlackMisc::Simulation::Data::CModelCaches m_caches { false, this }; //!< caches
+            std::atomic<bool> m_skipLoadingEmptyModelDir { true };  //!< Loading empty model dirs might erase the cache, so normally we skip it
-            BlackMisc::Simulation::Settings::CMultiSimulatorSettings m_settings { this }; //!< settings
+            Data::CModelCaches m_caches { false, this };            //!< caches used with this loader
-            BlackMisc::CStatusMessageList m_loadingMessages;                    //!< loading messages
+            Settings::CMultiSimulatorSettings m_settings { this };  //!< settings
+            CStatusMessageList m_loadingMessages;                   //!< loading messages
 
         protected slots:
             //! Loading finished, also logs messages