fix some crashes

- check some guards as qobject_cast may fail.
- destroyed() is emitted too late, the slot managing it can only access a QObject, Containment members aren't valid anymore

src/shell/shellcorona.cpp

@@ -45,30 +45,28 @@
 #include "widgetexplorer/widgetexplorer.h"
 #include "configview.h"
 
+static const int s_configSyncDelay = 10000; // 10 seconds
+
 class ShellCorona::Private {
 public:
     Private(ShellCorona *corona)
         : q(corona),
-          desktopWidget(QApplication::desktop()),
           activityController(new KActivities::Controller(q)),
           activityConsumer(new KActivities::Consumer(q)),
           addPanelAction(nullptr),
           addPanelsMenu(nullptr)
     {
         appConfigSyncTimer.setSingleShot(true);
-        // constant controlling how long between requesting a configuration sync
+        appConfigSyncTimer.setInterval(s_configSyncDelay);
-        // and one happening should occur. currently 10 seconds
+        connect(&appConfigSyncTimer, &QTimer::timeout, q, &ShellCorona::syncAppConfig);
-        appConfigSyncTimer.setInterval(10000);
 
-        waitingPanelsTimer = new QTimer(q);
+        waitingPanelsTimer.setSingleShot(true);
-        waitingPanelsTimer->setSingleShot(true);
+        waitingPanelsTimer.setInterval(250);
-        waitingPanelsTimer->setInterval(250);
+        connect(&waitingPanelsTimer, &QTimer::timeout, q, &ShellCorona::createWaitingPanels);
-        connect(waitingPanelsTimer, &QTimer::timeout, q, &ShellCorona::createWaitingPanels);
     }
 
     ShellCorona *q;
     QString shell;
-    QDesktopWidget * desktopWidget;
     QList<DesktopView *> views;
     KActivities::Controller *activityController;
     KActivities::Consumer *activityConsumer;
@@ -78,10 +76,10 @@ public:
     QList<Plasma::Containment *> waitingPanels;
     QHash<QString, Activity *> activities;
     QHash<QString, QHash<int, Plasma::Containment *> > desktopContainments;
-    QTimer *waitingPanelsTimer;
     QAction *addPanelAction;
     QMenu *addPanelsMenu;
 
+    QTimer waitingPanelsTimer;
     QTimer appConfigSyncTimer;
 };
 
@@ -97,18 +95,19 @@ ShellCorona::ShellCorona(QObject *parent)
 {
     d->desktopDefaultsConfig = KConfigGroup(KSharedConfig::openConfig(package().filePath("defaults")), "Desktop");
 
-    connect(&d->appConfigSyncTimer, &QTimer::timeout,
-            this, &ShellCorona::syncAppConfig);
-
     connect(this, &ShellCorona::containmentAdded,
             this, &ShellCorona::handleContainmentAdded);
 
     d->scriptEngine = new WorkspaceScripting::DesktopScriptEngine(this, true);
 
     connect(d->scriptEngine, &WorkspaceScripting::ScriptEngine::printError,
-            this, &ShellCorona::printScriptError);
+            [=](const QString &msg) {
+                qWarning() << msg;
+            });
     connect(d->scriptEngine, &WorkspaceScripting::ScriptEngine::print,
-            this, &ShellCorona::printScriptMessage);
+            [=](const QString &msg) {
+                qDebug() << msg;
+            });
 
     QAction *dashboardAction = actions()->add<QAction>("show dashboard");
     QObject::connect(dashboardAction, &QAction::triggered,
@@ -148,7 +147,9 @@ ShellCorona::~ShellCorona()
 
 void ShellCorona::setShell(const QString &shell)
 {
-    if (d->shell == shell) return;
+    if (d->shell == shell) {
+        return;
+    }
 
     unload();
 
@@ -171,8 +172,11 @@ QString ShellCorona::shell() const
 
 void ShellCorona::load()
 {
-    if (d->shell.isEmpty() || d->activityConsumer->serviceStatus() == KActivities::Consumer::Unknown)
+    if (d->shell.isEmpty() ||
+        d->activityConsumer->serviceStatus() == KActivities::Consumer::Unknown) {
         return;
+    }
+
     disconnect(d->activityConsumer, SIGNAL(serviceStatusChanged(Consumer::ServiceStatus)), this, SLOT(load()));
 
     loadLayout("plasma-" + d->shell + "-appletsrc");
@@ -209,13 +213,16 @@ void ShellCorona::load()
             this, &ShellCorona::screenAdded);
 
     if (!d->waitingPanels.isEmpty()) {
-        d->waitingPanelsTimer->start();
+        d->waitingPanelsTimer.start();
     }
 }
 
 void ShellCorona::unload()
 {
-    if (d->shell.isEmpty()) return;
+    if (d->shell.isEmpty()) {
+        return;
+    }
+
     qDeleteAll(containments());
 }
 
@@ -231,9 +238,7 @@ void ShellCorona::requestApplicationConfigSync()
 
 void ShellCorona::loadDefaultLayout()
 {
-    QString script = package().filePath("defaultlayout");
+    const QString script = package().filePath("defaultlayout");
-    qDebug() << "This is the default layout we are using:";
-
     QFile file(script);
     if (file.open(QIODevice::ReadOnly | QIODevice::Text) ) {
         QString code = file.readAll();
@@ -256,22 +261,22 @@ KActivities::Controller *ShellCorona::activityController()
 
 int ShellCorona::numScreens() const
 {
-    return d->desktopWidget->screenCount();
+    return QApplication::desktop()->screenCount();
 }
 
 QRect ShellCorona::screenGeometry(int id) const
 {
-    return d->desktopWidget->screenGeometry(id);
+    return QApplication::desktop()->screenGeometry(id);
 }
 
 QRegion ShellCorona::availableScreenRegion(int id) const
 {
-    return d->desktopWidget->availableGeometry(id);
+    return QApplication::desktop()->availableGeometry(id);
 }
 
 QRect ShellCorona::availableScreenRect(int id) const
 {
-    return d->desktopWidget->availableGeometry(id);
+    return QApplication::desktop()->availableGeometry(id);
 }
 
 PanelView *ShellCorona::panelView(Plasma::Containment *containment) const
@@ -332,9 +337,9 @@ void ShellCorona::screenRemoved(QObject *screen)
     //desktop containments
     for (auto i = d->views.begin(); i != d->views.end(); i++) {
         if ((*i)->screen() == screen) {
-            (*i)->deleteLater();
             d->views.erase(i);
             (*i)->containment()->reactToScreenChange();
+            (*i)->deleteLater();
             break;
         }
     }
@@ -367,7 +372,7 @@ void ShellCorona::handleContainmentAdded(Plasma::Containment* c)
 
 void ShellCorona::toggleWidgetExplorer()
 {
-    QPoint cursorPos = QCursor::pos();
+    const QPoint cursorPos = QCursor::pos();
     foreach (DesktopView *view, d->views) {
         if (view->screen()->geometry().contains(cursorPos)) {
             //The view QML has to provide something to display the activity explorer
@@ -379,7 +384,7 @@ void ShellCorona::toggleWidgetExplorer()
 
 void ShellCorona::toggleActivityManager()
 {
-    QPoint cursorPos = QCursor::pos();
+    const QPoint cursorPos = QCursor::pos();
     foreach (DesktopView *view, d->views) {
         if (view->screen()->geometry().contains(cursorPos)) {
             //The view QML has to provide something to display the activity explorer
@@ -404,6 +409,7 @@ void ShellCorona::setDashboardShown(bool show)
     if (dashboardAction) {
         dashboardAction->setText(show ? i18n("Hide Dashboard") : i18n("Show Dashboard"));
     }
+
     foreach (DesktopView *view, d->views) {
         view->setDashboardShown(show);
     }
@@ -539,12 +545,14 @@ void ShellCorona::addPanel(const QString &plugin)
     foreach (const Plasma::Containment *cont, d->panelViews.keys()) {
         availableLocations.removeAll(cont->location());
     }
+
     Plasma::Types::Location loc;
     if (availableLocations.isEmpty()) {
         loc = Plasma::Types::TopEdge;
     } else {
         loc = availableLocations.first();
     }
+
     panel->setLocation(loc);
     switch (loc) {
     case Plasma::Types::LeftEdge:
@@ -557,62 +565,59 @@ void ShellCorona::addPanel(const QString &plugin)
     }
 
     d->waitingPanels << panel;
-    d->waitingPanelsTimer->start();
+    d->waitingPanelsTimer.start();
-}
-
-void ShellCorona::printScriptError(const QString &error)
-{
-    qWarning() << error;
-}
-
-void ShellCorona::printScriptMessage(const QString &message)
-{
-    qDebug() << message;
 }
 
 int ShellCorona::screenForContainment(const Plasma::Containment *containment) const
 {
-    QScreen* s = nullptr;
+    QScreen *screen = nullptr;
     for (int i = 0; i < d->views.size(); i++) {
         if (d->views[i]->containment() == containment) {
-            s = d->views[i]->screen();
+            screen = d->views[i]->screen();
         }
     }
-    if(!s) {
+
+    if (!screen) {
         PanelView *view = d->panelViews[containment];
         if (view) {
-            s = view->screen();
+            screen = view->screen();
         }
     }
-    return s? qApp->screens().indexOf(s) : -1;
+
+    return screen ? qApp->screens().indexOf(screen) : -1;
 }
 
 void ShellCorona::activityOpened()
 {
     Activity *activity = qobject_cast<Activity *>(sender());
+    if (activity) {
         QList<Plasma::Containment*> cs = importLayout(activity->config());
         for (Plasma::Containment *containment : cs) {
             insertContainment(activity->name(), containment->lastScreen(), containment);
         }
     }
+}
 
 void ShellCorona::activityClosed()
 {
     Activity *activity = qobject_cast<Activity *>(sender());
+    if (activity) {
         KConfigGroup cg = activity->config();
         exportLayout(cg, d->desktopContainments.value(activity->name()).values());
     }
+}
 
 void ShellCorona::activityRemoved()
 {
     //when an activity is removed delete all associated desktop containments
     Activity *activity = qobject_cast<Activity *>(sender());
-
+    if (activity) {
         QHash< int, Plasma::Containment* > containmentHash = d->desktopContainments.take(activity->name());
         for (auto a : containmentHash) {
             a->destroy();
         }
     }
+}
 
 void ShellCorona::insertContainment(const QString &activity, int screenNum, Plasma::Containment* containment)
 {
@@ -620,8 +625,20 @@ void ShellCorona::insertContainment(const QString &activity, int screenNum, Plas
 
     //when a containment gets deleted update our map of containments
     connect(containment, &QObject::destroyed, [=](QObject *obj) {
-        auto containment = qobject_cast<Plasma::Containment*>(obj);
+        // when QObject::destroyed arrives, ~Plasma::Containment has run,
-        d->desktopContainments[containment->activity()].remove(containment->lastScreen());
+        // members of Containment are not accessible anymore,
+        // so keep ugly bookeeping by hand
+        auto containment = static_cast<Plasma::Containment*>(obj);
+        for (auto a : d->desktopContainments) {
+            QMutableHashIterator<int, Plasma::Containment *> it(a);
+            while (it.hasNext()) {
+                it.next();
+                if (it.value() == containment) {
+                    it.remove();
+                    return;
+                }
+            }
+        }
     });
 }
 

src/shell/shellcorona.h

@@ -84,9 +84,6 @@ protected Q_SLOTS:
     void screenAdded(QScreen *screen);
     void screenRemoved(QObject *screen);
 
-    void printScriptError(const QString &error);
-    void printScriptMessage(const QString &message);
-
     /**
      * Loads the layout and performs the needed checks
      */