Force app exit if session manager signals a shutdown. (#3666)

Resolves #3410.

Additionally, "fix" main window toggling behaviour when
clicking the tray icon while the window is visible, but
not in focus (e.g. hidden by other windows). On platforms
other than Windows, the window is now brought to the front
if it does not already have focus or is toggled otherwise.

Remove obsolete Windows session end handling code.

src/core/OSEventFilter.cpp

@@ -37,16 +37,8 @@ bool OSEventFilter::nativeEventFilter(const QByteArray& eventType, void* message
 #if defined(Q_OS_UNIX)
     if (eventType == QByteArrayLiteral("xcb_generic_event_t")) {
 #elif defined(Q_OS_WIN)
-    auto winmsg = static_cast<MSG*>(message);
-    if (winmsg->message == WM_QUERYENDSESSION) {
-        *result = 1;
-        return true;
-    } else if (winmsg->message == WM_ENDSESSION) {
-        getMainWindow()->appExit();
-        *result = 0;
-        return true;
-    } else if (eventType == QByteArrayLiteral("windows_generic_MSG")
-               || eventType == QByteArrayLiteral("windows_dispatcher_MSG")) {
+    if (eventType == QByteArrayLiteral("windows_generic_MSG")
+        || eventType == QByteArrayLiteral("windows_dispatcher_MSG")) {
 #endif
         return autoType()->callEventFilter(message) == 1;
     }

src/gui/MainWindow.cpp

@@ -142,10 +142,6 @@ MainWindow* getMainWindow()
 
 MainWindow::MainWindow()
     : m_ui(new Ui::MainWindow())
-    , m_trayIcon(nullptr)
-    , m_appExitCalled(false)
-    , m_appExiting(false)
-    , m_lastFocusOutTime(0)
 {
     g_MainWindow = this;
 
@@ -990,31 +986,29 @@ void MainWindow::toggleUsernamesHidden()
 
 void MainWindow::closeEvent(QCloseEvent* event)
 {
-    // ignore double close events (happens on macOS when closing from the dock)
     if (m_appExiting) {
         event->accept();
         return;
     }
 
-    // Don't ignore close event when the app is hidden to tray.
-    // This can occur when the OS issues close events on shutdown.
-    if (config()->get("GUI/MinimizeOnClose").toBool() && !isHidden() && !m_appExitCalled) {
+    // Ignore event and hide to tray if this is not an actual close
+    // request by the system's session manager.
+    if (config()->get("GUI/MinimizeOnClose").toBool() && !m_appExitCalled && !isHidden() && !qApp->isSavingSession()) {
         event->ignore();
         hideWindow();
         return;
     }
 
-    bool accept = saveLastDatabases();
-
-    if (accept) {
-        m_appExiting = true;
+    m_appExiting = saveLastDatabases();
+    if (m_appExiting) {
         saveWindowInformation();
-
         event->accept();
         QApplication::quit();
-    } else {
-        event->ignore();
+        return;
     }
+
+    m_appExitCalled = false;
+    event->ignore();
 }
 
 void MainWindow::changeEvent(QEvent* event)
@@ -1208,15 +1202,14 @@ void MainWindow::processTrayIconTrigger()
         toggleWindow();
     } else if (m_trayIconTriggerReason == QSystemTrayIcon::Trigger
                || m_trayIconTriggerReason == QSystemTrayIcon::MiddleClick) {
-        // Toggle window if hidden
-        // If on windows, check if focus switched within the last second because
-        // clicking the tray icon removes focus from main window
-        // If on Linux or macOS, check if the window is active
-        if (isHidden()
+        // Toggle window if is not in front.
 #ifdef Q_OS_WIN
-            || (Clock::currentSecondsSinceEpoch() - m_lastFocusOutTime) <= 1) {
+        // If on Windows, check if focus switched within the last second because
+        // clicking the tray icon removes focus from main window.
+        if (isHidden() || (Clock::currentSecondsSinceEpoch() - m_lastFocusOutTime) <= 1) {
 #else
-            || windowHandle()->isActive()) {
+        // If on Linux or macOS, check if the window has focus.
+        if (hasFocus() || isHidden() || windowHandle()->isActive()) {
 #endif
             toggleWindow();
         } else {

src/gui/MainWindow.h

@@ -144,24 +144,24 @@ private:
 
     const QScopedPointer<Ui::MainWindow> m_ui;
     SignalMultiplexer m_actionMultiplexer;
-    QAction* m_clearHistoryAction;
-    QAction* m_searchWidgetAction;
-    QMenu* m_entryContextMenu;
-    QActionGroup* m_lastDatabasesActions;
-    QActionGroup* m_copyAdditionalAttributeActions;
-    InactivityTimer* m_inactivityTimer;
-    InactivityTimer* m_touchIDinactivityTimer;
+    QPointer<QAction> m_clearHistoryAction;
+    QPointer<QAction> m_searchWidgetAction;
+    QPointer<QMenu> m_entryContextMenu;
+    QPointer<QActionGroup> m_lastDatabasesActions;
+    QPointer<QActionGroup> m_copyAdditionalAttributeActions;
+    QPointer<InactivityTimer> m_inactivityTimer;
+    QPointer<InactivityTimer> m_touchIDinactivityTimer;
     int m_countDefaultAttributes;
-    QSystemTrayIcon* m_trayIcon;
-    ScreenLockListener* m_screenLockListener;
+    QPointer<QSystemTrayIcon> m_trayIcon;
+    QPointer<ScreenLockListener> m_screenLockListener;
     QPointer<SearchWidget> m_searchWidget;
 
     Q_DISABLE_COPY(MainWindow)
 
-    bool m_appExitCalled;
-    bool m_appExiting;
-    bool m_contextMenuFocusLock;
-    uint m_lastFocusOutTime;
+    bool m_appExitCalled = false;
+    bool m_appExiting = false;
+    bool m_contextMenuFocusLock = false;
+    uint m_lastFocusOutTime = 0;
     QTimer m_trayIconTriggerTimer;
     QSystemTrayIcon::ActivationReason m_trayIconTriggerReason;
 };