MainWindow: Add FSMs to avoid blocking on the GUI thread.

DSPDevice*Engine: Add signals to indicate when commands have been processed.
DSPDeviceSourceEngine: Fix small memory leak.
DSPEngine::removeDeviceEngineAt: Remove wait to avoid blocking thread. Return QThread to get finished signal.
DSPEngine::addDevice*Engine: Don't call deleteLater for device*Engine, as these objects are deleted manually in MainWindow, which will crash if deleteLater called first.

CMakeLists.txt

@@ -704,6 +704,7 @@ if (BUILD_GUI)
                             QuickWidgets
                             Svg
                             SvgWidgets
+                            StateMachine
                            OPTIONAL_COMPONENTS
                             WebEngineQuick
                             WebEngineCore

sdrbase/dsp/dspdevicemimoengine.cpp

@@ -1030,6 +1030,7 @@ bool DSPDeviceMIMOEngine::handleMessage(const Message& message)
     else if (DSPAcquisitionStop::match(message))
 	{
 		setStateRx(gotoIdle(0));
+        emit acquisitionStopped();
         return true;
 	}
     else if (DSPGenerationInit::match(message))
@@ -1053,11 +1054,13 @@ bool DSPDeviceMIMOEngine::handleMessage(const Message& message)
 	else if (DSPGenerationStop::match(message))
 	{
 		setStateTx(gotoIdle(1));
+        emit generationStopped();
         return true;
 	}
 	else if (SetSampleMIMO::match(message)) {
         const auto& cmd = (const SetSampleMIMO&) message;
         handleSetMIMO(cmd.getSampleMIMO());
+        emit sampleSet();
 		return true;
 	}
 	else if (AddBasebandSampleSink::match(message))
@@ -1194,6 +1197,7 @@ bool DSPDeviceMIMOEngine::handleMessage(const Message& message)
         BasebandSampleSink* spectrumSink = msg.getSampleSink();
         spectrumSink->stop();
         m_spectrumSink = nullptr;
+        emit spectrumSinkRemoved();
         return true;
     }
     else if (SetSpectrumSinkInput::match(message))

sdrbase/dsp/dspdevicemimoengine.h

@@ -356,6 +356,11 @@ private slots:
 
 signals:
 	void stateChanged();
+
+    void acquisitionStopped();
+    void sampleSet();
+    void generationStopped();
+    void spectrumSinkRemoved();
 };
 
 #endif // SDRBASE_DSP_DSPDEVICEMIMOENGINE_H_

sdrbase/dsp/dspdevicesinkengine.cpp

@@ -458,12 +458,14 @@ bool DSPDeviceSinkEngine::handleMessage(const Message& message)
 	else if (DSPGenerationStop::match(message))
 	{
 		setState(gotoIdle());
+		emit generationStopped();
         return true;
 	}
 	else if (DSPSetSink::match(message))
     {
         const auto& cmd = (const DSPSetSink&) message;
 		handleSetSink(cmd.getSampleSink());
+		emit sampleSet();
         return true;
 	}
 	else if (DSPRemoveSpectrumSink::match(message))
@@ -476,6 +478,7 @@ bool DSPDeviceSinkEngine::handleMessage(const Message& message)
 		}
 
 		m_spectrumSink = nullptr;
+		emit spectrumSinkRemoved();
         return true;
 	}
 	else if (DSPAddBasebandSampleSource::match(message))

sdrbase/dsp/dspdevicesinkengine.h

@@ -121,6 +121,10 @@ private slots:
 
 signals:
 	void stateChanged();
+
+	void generationStopped();
+	void sampleSet();
+	void spectrumSinkRemoved();
 };
 
 

sdrbase/dsp/dspdevicesourceengine.cpp

@@ -601,12 +601,15 @@ bool DSPDeviceSourceEngine::handleMessage(const Message& message)
 	else if (DSPAcquisitionStop::match(message))
 	{
 		setState(gotoIdle());
+		emit acquistionStopped();
         return true;
 	}
 	else if (DSPSetSource::match(message))
     {
         auto cmd = (const DSPSetSource&) message;
 		handleSetSource(cmd.getSampleSource());
+		emit sampleSet();
+		return true;
 	}
 	else if (DSPAddBasebandSampleSink::match(message))
 	{
@@ -620,6 +623,7 @@ bool DSPDeviceSourceEngine::handleMessage(const Message& message)
         if(m_state == State::StRunning) {
             sink->start();
         }
+		return true;
 	}
 	else if (DSPRemoveBasebandSampleSink::match(message))
 	{
@@ -631,6 +635,8 @@ bool DSPDeviceSourceEngine::handleMessage(const Message& message)
 		}
 
 		m_basebandSampleSinks.remove(sink);
+		emit sinkRemoved();
+		return true;
 	}
 
     return false;

sdrbase/dsp/dspdevicesourceengine.h

@@ -142,6 +142,10 @@ private slots:
 
 signals:
 	void stateChanged();
+
+	void acquistionStopped();
+	void sampleSet();
+	void sinkRemoved();
 };
 
 #endif // INCLUDE_DSPDEVICEENGINE_H

sdrbase/dsp/dspengine.cpp

@@ -70,12 +70,6 @@ DSPDeviceSourceEngine *DSPEngine::addDeviceSourceEngine()
     m_deviceEngineReferences.push_back(DeviceEngineReference{0, m_deviceSourceEngines.back(), nullptr, nullptr, deviceThread});
     deviceSourceEngine->moveToThread(deviceThread);
 
-    QObject::connect(
-        deviceThread,
-        &QThread::finished,
-        deviceSourceEngine,
-        &QObject::deleteLater
-    );
     QObject::connect(
         deviceThread,
         &QThread::finished,
@@ -118,12 +112,6 @@ DSPDeviceSinkEngine *DSPEngine::addDeviceSinkEngine()
     m_deviceEngineReferences.push_back(DeviceEngineReference{1, nullptr, m_deviceSinkEngines.back(), nullptr, deviceThread});
     deviceSinkEngine->moveToThread(deviceThread);
 
-    QObject::connect(
-        deviceThread,
-        &QThread::finished,
-        deviceSinkEngine,
-        &QObject::deleteLater
-    );
     QObject::connect(
         deviceThread,
         &QThread::finished,
@@ -166,12 +154,6 @@ DSPDeviceMIMOEngine *DSPEngine::addDeviceMIMOEngine()
     m_deviceEngineReferences.push_back(DeviceEngineReference{2, nullptr, nullptr, m_deviceMIMOEngines.back(), deviceThread});
     deviceMIMOEngine->moveToThread(deviceThread);
 
-    QObject::connect(
-        deviceThread,
-        &QThread::finished,
-        deviceMIMOEngine,
-        &QObject::deleteLater
-    );
     QObject::connect(
         deviceThread,
         &QThread::finished,
@@ -205,38 +187,39 @@ void DSPEngine::removeLastDeviceMIMOEngine()
     }
 }
 
-void DSPEngine::removeDeviceEngineAt(int deviceIndex)
+QThread * DSPEngine::removeDeviceEngineAt(int deviceIndex)
 {
     if (deviceIndex >= m_deviceEngineReferences.size()) {
-        return;
+        return nullptr;
     }
 
+    QThread *deviceThread = nullptr;
+
     if (m_deviceEngineReferences[deviceIndex].m_deviceEngineType == 0) // source
     {
         DSPDeviceSourceEngine *deviceEngine = m_deviceEngineReferences[deviceIndex].m_deviceSourceEngine;
-        QThread *deviceThread = m_deviceEngineReferences[deviceIndex].m_thread;
+        deviceThread = m_deviceEngineReferences[deviceIndex].m_thread;
         deviceThread->exit();
-        deviceThread->wait();
         m_deviceSourceEngines.removeAll(deviceEngine);
     }
     else if (m_deviceEngineReferences[deviceIndex].m_deviceEngineType == 1) // sink
     {
         DSPDeviceSinkEngine *deviceEngine = m_deviceEngineReferences[deviceIndex].m_deviceSinkEngine;
-        QThread *deviceThread = m_deviceEngineReferences[deviceIndex].m_thread;
+        deviceThread = m_deviceEngineReferences[deviceIndex].m_thread;
         deviceThread->exit();
-        deviceThread->wait();
         m_deviceSinkEngines.removeAll(deviceEngine);
     }
     else if (m_deviceEngineReferences[deviceIndex].m_deviceEngineType == 2) // MIMO
     {
         DSPDeviceMIMOEngine *deviceEngine = m_deviceEngineReferences[deviceIndex].m_deviceMIMOEngine;
-        QThread *deviceThread = m_deviceEngineReferences[deviceIndex].m_thread;
+        deviceThread = m_deviceEngineReferences[deviceIndex].m_thread;
         deviceThread->exit();
-        deviceThread->wait();
         m_deviceMIMOEngines.removeAll(deviceEngine);
     }
 
     m_deviceEngineReferences.removeAt(deviceIndex);
+
+    return deviceThread;
 }
 
 void DSPEngine::createFFTFactory(const QString& fftWisdomFileName)

sdrbase/dsp/dspengine.h

@@ -53,7 +53,7 @@ public:
 	DSPDeviceMIMOEngine *addDeviceMIMOEngine();
 	void removeLastDeviceMIMOEngine();
 
-    void removeDeviceEngineAt(int deviceIndex);
+    QThread *removeDeviceEngineAt(int deviceIndex);
 
 	AudioDeviceManager *getAudioDeviceManager() { return &m_audioDeviceManager; }
 

sdrgui/CMakeLists.txt

@@ -343,6 +343,9 @@ target_link_libraries(sdrgui
   logging
   )
 if (Qt6_FOUND)
+  target_link_libraries(sdrgui
+    Qt6::StateMachine
+  )
   target_link_libraries(sdrbase
     Qt::OpenGLWidgets
   )

sdrgui/mainwindow.h

@@ -27,6 +27,11 @@
 #include <QTimer>
 #include <QList>
 #include <QProcess>
+#include <QStateMachine>
+#include <QState>
+#include <QFinalState>
+#include <QSignalTransition>
+#include <QProgressDialog>
 
 #include "settings/mainsettings.h"
 #include "util/message.h"
@@ -43,6 +48,7 @@ class QToolButton;
 class DSPEngine;
 class DSPDeviceSourceEngine;
 class DSPDeviceSinkEngine;
+class DSPDeviceMIMOEngine;
 class Indicator;
 class GLSpectrumGUI;
 class MainSpectrumGUI;
@@ -65,13 +71,217 @@ class CommandKeyReceiver;
 class ConfigurationsDialog;
 class ProfileDialog;
 class SerializableInterface;
+class SDRangelSplash;
 
 class QMenuBar;
 class Workspace;
+class MainWindow;
+
+// Would preferablly have these FSM classes as nested classes of MainWindow
+// However, as they inherit from QObject, they should have Q_OBJECT macro which isn't supported for nested classes
+// Instead we have to declare them as friend classes to MainWindow
+
+class MainWindowFSM : public QStateMachine {
+    Q_OBJECT
+
+public:
+
+    MainWindowFSM(MainWindow *mainWindow, QObject *parent=nullptr);
+
+protected:
+
+    void createStates(int states); // number of states to create, including final state
+
+    MainWindow *m_mainWindow;
+    QList<QState *> m_states;
+    QFinalState *m_finalState;
+
+};
+
+class AddSampleSourceFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+
+    AddSampleSourceFSM(MainWindow *mainWindow, Workspace *deviceWorkspace, Workspace *spectrumWorkspace, int deviceIndex, bool loadDefaults, QObject *parent=nullptr);
+
+private:
+
+    Workspace *m_deviceWorkspace;
+    Workspace *m_spectrumWorkspace;
+    int m_deviceIndex;
+    bool m_loadDefaults;
+
+    int m_deviceSetIndex;
+    DeviceAPI *m_deviceAPI;
+    DeviceUISet *m_deviceUISet;
+
+    DSPDeviceSourceEngine *m_dspDeviceSourceEngine;
+
+    void addEngine();
+    void addDevice();
+    void addDeviceUI();
+};
+
+class AddSampleSinkFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+
+    AddSampleSinkFSM(MainWindow *mainWindow, Workspace *deviceWorkspace, Workspace *spectrumWorkspace, int deviceIndex, bool loadDefaults, QObject *parent=nullptr);
+
+private:
+
+    Workspace *m_deviceWorkspace;
+    Workspace *m_spectrumWorkspace;
+    int m_deviceIndex;
+    bool m_loadDefaults;
+
+    int m_deviceSetIndex;
+    DeviceAPI *m_deviceAPI;
+    DeviceUISet *m_deviceUISet;
+
+    DSPDeviceSinkEngine *m_dspDeviceSinkEngine;
+
+    void addEngine();
+    void addDevice();
+    void addDeviceUI();
+};
+
+class AddSampleMIMOFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+
+    AddSampleMIMOFSM(MainWindow *mainWindow, Workspace *deviceWorkspace, Workspace *spectrumWorkspace, int deviceIndex, bool loadDefaults, QObject *parent=nullptr);
+
+private:
+
+    Workspace *m_deviceWorkspace;
+    Workspace *m_spectrumWorkspace;
+    int m_deviceIndex;
+    bool m_loadDefaults;
+
+    int m_deviceSetIndex;
+    DeviceAPI *m_deviceAPI;
+    DeviceUISet *m_deviceUISet;
+
+    DSPDeviceMIMOEngine *m_dspDeviceMIMOEngine;
+
+    void addEngine();
+    void addDevice();
+    void addDeviceUI();
+};
+
+class RemoveDeviceSetFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+    RemoveDeviceSetFSM(MainWindow *mainWindow, int deviceSetIndex, QObject *parent=nullptr);
+
+private:
+    int m_deviceSetIndex;
+    DeviceUISet *m_deviceUISet;
+    DSPDeviceSourceEngine *m_deviceSourceEngine;
+    DSPDeviceSinkEngine *m_deviceSinkEngine;
+    DSPDeviceMIMOEngine *m_deviceMIMOEngine;
+    QSignalTransition *m_t1;
+    QSignalTransition *m_t2;
+
+    void stopAcquisition();
+    void removeSink();
+    void removeUI();
+    void stopEngine();
+    void removeDeviceSet();
+};
+
+class RemoveAllDeviceSetsFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+    RemoveAllDeviceSetsFSM(MainWindow *mainWindow, QObject *parent=nullptr);
+
+private:
+
+    void removeNext();
+
+};
+
+class RemoveAllWorkspacesFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+    RemoveAllWorkspacesFSM(MainWindow *mainWindow, QObject *parent=nullptr);
+
+private:
+
+    RemoveAllDeviceSetsFSM *m_removeAllDeviceSetsFSM;
+
+    void removeDeviceSets();
+    void removeWorkspaces();
+
+};
+
+class LoadConfigurationFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+    LoadConfigurationFSM(MainWindow *mainWindow, const Configuration *configuration, QProgressDialog *waitBox, QObject *parent=nullptr);
+
+private:
+
+    const Configuration *m_configuration;
+    QProgressDialog *m_waitBox;
+
+    RemoveAllWorkspacesFSM *m_removeAllWorkspacesFSM;
+
+    void clearWorkspace();
+    void createWorkspaces();
+    void loadDeviceSets();
+    void loadDeviceSetSettings();
+    void loadFeatureSets();
+    void restoreGeometry();
+};
+
+class CloseFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+    CloseFSM(MainWindow *mainWindow, QObject *parent=nullptr);
+
+private:
+    void on_started();
+    void on_finished();
+};
+
+class InitFSM : public MainWindowFSM {
+    Q_OBJECT
+
+public:
+    InitFSM(MainWindow *mainWindow, SDRangelSplash *splash, bool loadDefault, QObject *parent=nullptr);
+
+private:
+    SDRangelSplash *m_splash;
+    LoadConfigurationFSM *m_loadConfigurationFSM;
+
+    void loadDefaultConfiguration();
+    void showDefaultConfigurations();
+};
+
 
 class SDRGUI_API MainWindow : public QMainWindow {
 	Q_OBJECT
 
+    friend InitFSM;
+    friend AddSampleSourceFSM;
+    friend AddSampleSinkFSM;
+    friend AddSampleMIMOFSM;
+    friend LoadConfigurationFSM;
+    friend RemoveDeviceSetFSM;
+    friend RemoveAllDeviceSetsFSM;
+    friend RemoveAllWorkspacesFSM;
+    friend CloseFSM;
+
 public:
 	explicit MainWindow(qtwebapp::LoggerWithFile *logger, const MainParser& parser, QWidget* parent = nullptr);
 	~MainWindow() final;
@@ -130,7 +340,11 @@ private:
 	CommandKeyReceiver *m_commandKeyReceiver;
     ProfileDialog *m_profileDialog;
 
+#if QT_CONFIG(process)
 	QProcess *m_fftWisdomProcess;
+#endif
+
+    bool m_settingsSaved;               // Records if settings have already been saved in response to a QCloseEvent
 
 	void loadSettings();
 	void loadDeviceSetPresetSettings(const Preset* preset, int deviceSetIndex);
@@ -146,6 +360,7 @@ private:
 
     void removeDeviceSet(int deviceSetIndex);
     void removeLastDeviceSet();
+    void removeAllDeviceSets();
     void addFeatureSet();
     void removeFeatureSet(unsigned int featureSetIndex);
     void removeAllFeatureSets();
@@ -160,15 +375,30 @@ private:
         int deviceIndex,
         DeviceUISet *deviceUISet
     );
+    void sampleSourceCreateUI(
+        int deviceSetIndex,
+        int deviceIndex,
+        DeviceUISet *deviceUISet
+    );
     void sampleSinkCreate(
         int deviceSetIndex,
         int deviceIndex,
         DeviceUISet *deviceUISet
     );
+    void sampleSinkCreateUI(
+        int deviceSetIndex,
+        int deviceIndex,
+        DeviceUISet *deviceUISet
+    );
     void sampleMIMOCreate(
         int deviceSetIndex,
         int deviceIndex,
         DeviceUISet *deviceUISet
+    );
+     void sampleMIMOCreateUI(
+        int deviceSetIndex,
+        int deviceIndex,
+        DeviceUISet *deviceUISet
     );
     void deleteFeature(int featureSetIndex, int featureIndex);
     void loadDefaultPreset(const QString& pluginId, SerializableInterface *serializableInterface);
@@ -178,6 +408,12 @@ private:
 protected:
     void keyPressEvent(QKeyEvent* event) override;
 
+signals:
+    // For internal FSM usage
+    void allDeviceSetsRemoved();
+    void allDeviceSetsAdded();
+    void engineStopped();
+
 private slots:
 	void handleMessages();
     void handleWorkspaceVisibility(Workspace *workspace, bool visibility);
@@ -193,10 +429,13 @@ private slots:
 	void on_action_Graphics_triggered();
     void on_action_Logging_triggered();
 	void on_action_FFT_triggered();
+#if QT_CONFIG(process)
 	void on_action_FFTWisdom_triggered();
+    void on_action_commands_triggered();
+#endif
 	void on_action_My_Position_triggered();
     void on_action_DeviceUserArguments_triggered();
-    void on_action_commands_triggered();
+    void on_action_Welcome_triggered();
     void on_action_Quick_Start_triggered() const;
     void on_action_Main_Window_triggered() const;
 	void on_action_Loaded_Plugins_triggered();
@@ -228,7 +467,9 @@ private slots:
     void showAllChannels(int deviceSetIndex);
     void openDeviceSetPresetsDialog(QPoint p, const DeviceGUI *deviceGUI);
 	void commandKeyPressed(Qt::Key key, Qt::KeyboardModifiers keyModifiers, bool release) const;
+#if QT_CONFIG(process)
 	void fftWisdomProcessFinished(int exitCode, QProcess::ExitStatus exitStatus);
+#endif
     void orientationChanged(Qt::ScreenOrientation orientation);
 };