[libtaskmanager] Fix shared VirtualDesktopInfo::Private tied to the 1st creator

Summary:
VirtualDesktopInfo::Private is ref counted and shared between N
VirtualDesktopInfo's.

We were passing the first VirtualDesktopInfo as a parent to
VirtualDesktopInfo::Private which didn't manage the lifespan or do
anything useful.

The wayland backend incorrectly used this 'q' object and spanned
mulitple internal objects and connections to the first object that
created the shared private instance, leaving us with dangly objects
inside.

BUG: 415200
(and possibly several other bugs of wayland task manager not updating
correctly)

Test Plan:
Compiles
Plasma still loads

Reviewers: #plasma, zzag

Reviewed By: #plasma, zzag

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D27266

libtaskmanager/virtualdesktopinfo.cpp

@@ -42,7 +42,7 @@ class Q_DECL_HIDDEN VirtualDesktopInfo::Private : public QObject
     Q_OBJECT
 
 public:
-    Private(VirtualDesktopInfo *q);
+    Private();
     virtual ~Private() {}
 
     uint refCount = 1;
@@ -64,21 +64,18 @@ Q_SIGNALS:
     void desktopIdsChanged() const;
     void desktopNamesChanged() const;
     void desktopLayoutRowsChanged() const;
-
-protected:
-    VirtualDesktopInfo *q;
 };
 
-VirtualDesktopInfo::Private::Private(VirtualDesktopInfo *q)
-    : q(q)
+VirtualDesktopInfo::Private::Private()
 {
 }
 
 #if HAVE_X11
 class Q_DECL_HIDDEN VirtualDesktopInfo::XWindowPrivate : public VirtualDesktopInfo::Private
 {
+    Q_OBJECT
 public:
-    XWindowPrivate(VirtualDesktopInfo *q);
+    XWindowPrivate();
 
     void init() override;
     QVariant currentDesktop() const override;
@@ -92,8 +89,8 @@ public:
     void requestRemoveDesktop(quint32 position) override;
 };
 
-VirtualDesktopInfo::XWindowPrivate::XWindowPrivate(VirtualDesktopInfo *q)
-    : VirtualDesktopInfo::Private(q)
+VirtualDesktopInfo::XWindowPrivate::XWindowPrivate()
+    : VirtualDesktopInfo::Private()
 {
     init();
 }
@@ -199,8 +196,9 @@ void VirtualDesktopInfo::XWindowPrivate::requestRemoveDesktop(quint32 position)
 
 class Q_DECL_HIDDEN VirtualDesktopInfo::WaylandPrivate : public VirtualDesktopInfo::Private
 {
+    Q_OBJECT
 public:
-    WaylandPrivate(VirtualDesktopInfo *q);
+    WaylandPrivate();
 
     QVariant currentVirtualDesktop;
     QStringList virtualDesktops;
@@ -219,8 +217,8 @@ public:
     void requestRemoveDesktop(quint32 position) override;
 };
 
-VirtualDesktopInfo::WaylandPrivate::WaylandPrivate(VirtualDesktopInfo *q)
-    : VirtualDesktopInfo::Private(q)
+VirtualDesktopInfo::WaylandPrivate::WaylandPrivate()
+    : VirtualDesktopInfo::Private()
 {
     init();
 }
@@ -231,28 +229,28 @@ void VirtualDesktopInfo::WaylandPrivate::init()
         return;
     }
 
-    KWayland::Client::ConnectionThread *connection = KWayland::Client::ConnectionThread::fromApplication(q);
+    KWayland::Client::ConnectionThread *connection = KWayland::Client::ConnectionThread::fromApplication(this);
 
     if (!connection) {
         return;
     }
 
-    KWayland::Client::Registry *registry = new KWayland::Client::Registry(q);
+    KWayland::Client::Registry *registry = new KWayland::Client::Registry(this);
     registry->create(connection);
 
     QObject::connect(registry, &KWayland::Client::Registry::plasmaVirtualDesktopManagementAnnounced,
         [this, registry] (quint32 name, quint32 version) {
-            virtualDesktopManagement = registry->createPlasmaVirtualDesktopManagement(name, version, q);
+            virtualDesktopManagement = registry->createPlasmaVirtualDesktopManagement(name, version, this);
 
             const QList<KWayland::Client::PlasmaVirtualDesktop *> &desktops = virtualDesktopManagement->desktops();
 
-            QObject::connect(virtualDesktopManagement, &KWayland::Client::PlasmaVirtualDesktopManagement::desktopCreated, q,
+            QObject::connect(virtualDesktopManagement, &KWayland::Client::PlasmaVirtualDesktopManagement::desktopCreated, this,
                 [this](const QString &id, quint32 position) {
                     addDesktop(id, position);
                 }
             );
 
-            QObject::connect(virtualDesktopManagement, &KWayland::Client::PlasmaVirtualDesktopManagement::desktopRemoved, q,
+            QObject::connect(virtualDesktopManagement, &KWayland::Client::PlasmaVirtualDesktopManagement::desktopRemoved, this,
                 [this](const QString &id) {
                     virtualDesktops.removeOne(id);
 
@@ -289,14 +287,14 @@ void VirtualDesktopInfo::WaylandPrivate::addDesktop(const QString &id, quint32 p
 
     const KWayland::Client::PlasmaVirtualDesktop *desktop = virtualDesktopManagement->getVirtualDesktop(id);
 
-    QObject::connect(desktop, &KWayland::Client::PlasmaVirtualDesktop::activated, q,
+    QObject::connect(desktop, &KWayland::Client::PlasmaVirtualDesktop::activated, this,
         [desktop, this]() {
             currentVirtualDesktop = desktop->id();
             emit currentDesktopChanged();
         }
     );
 
-    QObject::connect(desktop, &KWayland::Client::PlasmaVirtualDesktop::done, q,
+    QObject::connect(desktop, &KWayland::Client::PlasmaVirtualDesktop::done, this,
         [this]() {
             emit desktopNamesChanged();
         }
@@ -404,11 +402,11 @@ VirtualDesktopInfo::VirtualDesktopInfo(QObject *parent) : QObject(parent)
     if (!d) {
     #if HAVE_X11
         if (KWindowSystem::isPlatformX11()) {
-            d = new VirtualDesktopInfo::XWindowPrivate(this);
+            d = new VirtualDesktopInfo::XWindowPrivate;
         } else
     #endif
         {
-            d = new VirtualDesktopInfo::WaylandPrivate(this);
+            d = new VirtualDesktopInfo::WaylandPrivate;
         }
     } else {
         ++d->refCount;