Turn ScreenEdges into a Singleton

In fact it already used to be a Singleton as there is just one object
hold by the Singleton Workspace. So let's make it a proper Singleton
following our kind of standard approach of having a ::create factory
method called from Workspace ctor and a ::self to get to the singleton
instance.

effects.cpp

@@ -1072,7 +1072,7 @@ xcb_window_t EffectsHandlerImpl::createInputWindow(Effect* e, int x, int y, int
     // Raise electric border windows above the input windows
     // so they can still be triggered.
 #ifdef KWIN_BUILD_SCREENEDGES
-    Workspace::self()->screenEdge()->ensureOnTop();
+    ScreenEdges::self()->ensureOnTop();
 #endif
     if (input_windows.count() > 10) // that sounds like some leak - could still be correct, thoug - so NO ABORT HERE!
         kDebug() << "** warning ** there are now " << input_windows.count() <<
@@ -1086,7 +1086,7 @@ void EffectsHandlerImpl::destroyInputWindow(xcb_window_t w)
         if (pos.second == w) {
             xcb_unmap_window(connection(), w);
 #ifdef KWIN_BUILD_SCREENEDGES
-            Workspace::self()->screenEdge()->raisePanelProxies();
+            ScreenEdges::self()->raisePanelProxies();
 #endif
             return;
         }
@@ -1169,7 +1169,7 @@ void EffectsHandlerImpl::checkInputWindowStacking()
     // so they can still be triggered. TODO: Do both at once.
 #ifdef KWIN_BUILD_SCREENEDGES
     if (pos)
-        Workspace::self()->screenEdge()->ensureOnTop();
+        ScreenEdges::self()->ensureOnTop();
 #endif
 }
 
@@ -1181,7 +1181,7 @@ QPoint EffectsHandlerImpl::cursorPos() const
 void EffectsHandlerImpl::reserveElectricBorder(ElectricBorder border, Effect *effect)
 {
 #ifdef KWIN_BUILD_SCREENEDGES
-    Workspace::self()->screenEdge()->reserve(border, effect, "borderActivated");
+    ScreenEdges::self()->reserve(border, effect, "borderActivated");
 #else
     Q_UNUSED(border)
     Q_UNUSED(effect)
@@ -1191,7 +1191,7 @@ void EffectsHandlerImpl::reserveElectricBorder(ElectricBorder border, Effect *ef
 void EffectsHandlerImpl::unreserveElectricBorder(ElectricBorder border, Effect *effect)
 {
 #ifdef KWIN_BUILD_SCREENEDGES
-    Workspace::self()->screenEdge()->unreserve(border, effect);
+    ScreenEdges::self()->unreserve(border, effect);
 #else
     Q_UNUSED(border)
     Q_UNUSED(effect)

events.cpp

@@ -386,7 +386,7 @@ bool Workspace::workspaceEvent(XEvent * e)
                 QWhatsThis::leaveWhatsThisMode();
         }
 #ifdef KWIN_BUILD_SCREENEDGES
-        if (m_screenEdge->isEntered(e))
+        if (ScreenEdges::self()->isEntered(e))
             return true;
 #endif
         break;
@@ -440,7 +440,7 @@ bool Workspace::workspaceEvent(XEvent * e)
         return true; // always eat these, they would tell Qt that KWin is the active app
     case ClientMessage:
 #ifdef KWIN_BUILD_SCREENEDGES
-        if (m_screenEdge->isEntered(e))
+        if (ScreenEdges::self()->isEntered(e))
             return true;
 #endif
         break;

geometry.cpp

@@ -82,7 +82,7 @@ void Workspace::desktopResized()
 
     // TODO: emit a signal instead and remove the deep function calls into edges and effects
 #ifdef KWIN_BUILD_SCREENEDGES
-    m_screenEdge->recreateEdges();
+    ScreenEdges::self()->recreateEdges();
 #endif
 
     if (effects) {
@@ -2580,8 +2580,8 @@ bool Client::startMoveResize()
     Notify::raise(isResize() ? Notify::ResizeStart : Notify::MoveStart);
     emit clientStartUserMovedResized(this);
 #ifdef KWIN_BUILD_SCREENEDGES
-    if (workspace()->screenEdge()->isDesktopSwitchingMovingClients())
-        workspace()->screenEdge()->reserveDesktopSwitching(true, Qt::Vertical|Qt::Horizontal);
+    if (ScreenEdges::self()->isDesktopSwitchingMovingClients())
+        ScreenEdges::self()->reserveDesktopSwitching(true, Qt::Vertical|Qt::Horizontal);
 #endif
     if (fakeMove) // fix geom_restore position - it HAS to happen at the end, ie. when all moving is set up. inline call will lock focus!!
         handleMoveResize(QCursor::pos().x(), QCursor::pos().y(), QCursor::pos().x(), QCursor::pos().y());
@@ -2662,8 +2662,8 @@ void Client::leaveMoveResize()
     syncRequest.timeout = NULL;
 #endif
 #ifdef KWIN_BUILD_SCREENEDGES
-    if (workspace()->screenEdge()->isDesktopSwitchingMovingClients())
-        workspace()->screenEdge()->reserveDesktopSwitching(false, Qt::Vertical|Qt::Horizontal);
+    if (ScreenEdges::self()->isDesktopSwitchingMovingClients())
+        ScreenEdges::self()->reserveDesktopSwitching(false, Qt::Vertical|Qt::Horizontal);
 #endif
 }
 
@@ -3027,11 +3027,11 @@ void Client::handleMoveResize(int x, int y, int x_root, int y_root)
 #endif
         performMoveResize();
 
-    if (isMove()) {
 #ifdef KWIN_BUILD_SCREENEDGES
-        workspace()->screenEdge()->check(globalPos, QDateTime::fromMSecsSinceEpoch(xTime()));
-#endif
+    if (isMove()) {
+        ScreenEdges::self()->check(globalPos, QDateTime::fromMSecsSinceEpoch(xTime()));
     }
+#endif
 }
 
 void Client::performMoveResize()

layers.cpp

@@ -163,7 +163,7 @@ void Workspace::propagateClients(bool propagate_new_clients)
     // windows (e.g. popups).
     newWindowStack << (Window*)supportWindow->winId();
 #ifdef KWIN_BUILD_SCREENEDGES
-    QVectorIterator<xcb_window_t> it(m_screenEdge->windows());
+    QVectorIterator<xcb_window_t> it(ScreenEdges::self()->windows());
     while (it.hasNext()) {
         if ((Window)it.next() != None) {
             newWindowStack << (Window*)&it;

screenedge.cpp

@@ -338,6 +338,15 @@ void WindowBasedEdge::doGeometryUpdate()
 /**********************************************************
  * ScreenEdges
  *********************************************************/
+ScreenEdges *ScreenEdges::s_self = NULL;
+
+ScreenEdges *ScreenEdges::create(QObject *parent)
+{
+    Q_ASSERT(!s_self);
+    s_self = new ScreenEdges(parent);
+    return s_self;
+}
+
 ScreenEdges::ScreenEdges(QObject *parent)
     : QObject(parent)
     , m_desktopSwitching(false)
@@ -358,6 +367,7 @@ ScreenEdges::ScreenEdges(QObject *parent)
 
 ScreenEdges::~ScreenEdges()
 {
+    s_self = NULL;
 }
 
 void ScreenEdges::init()

screenedge.h

@@ -261,6 +261,20 @@ public:
     ElectricBorderAction actionBottom() const;
     ElectricBorderAction actionBottomLeft() const;
     ElectricBorderAction actionLeft() const;
+
+    /**
+     * Singleton getter for this manager.
+     *
+     * Does not create a new instance. If the manager has not been created yet a @c null pointer
+     * is returned.
+     * @see create
+     **/
+    static ScreenEdges *self();
+    /**
+     * Factory method to create the ScreenEdges.
+     * @see self
+     **/
+    static ScreenEdges *create(QObject *parent = NULL);
 public Q_SLOTS:
     void reconfigure();
     /**
@@ -300,6 +314,8 @@ private:
     ElectricBorderAction m_actionBottom;
     ElectricBorderAction m_actionBottomLeft;
     ElectricBorderAction m_actionLeft;
+
+    static ScreenEdges *s_self;
 };
 
 /**********************************************************
@@ -479,5 +495,11 @@ ACTION(actionLeft)
 
 #undef ACTION
 
+inline ScreenEdges *ScreenEdges::self()
+{
+    Q_ASSERT(s_self);
+    return s_self;
+}
+
 }
 #endif // KWIN_SCREENEDGE_H

scripting/scriptingutils.h

@@ -162,7 +162,7 @@ QScriptValue registerScreenEdge(QScriptContext *context, QScriptEngine *engine)
     if (it == script->screenEdgeCallbacks().end()) {
         // not yet registered
 #ifdef KWIN_BUILD_SCREENEDGES
-        KWin::Workspace::self()->screenEdge()->reserve(static_cast<KWin::ElectricBorder>(edge), script, "borderActivated");
+        ScreenEdges::self()->reserve(static_cast<KWin::ElectricBorder>(edge), script, "borderActivated");
 #endif
         script->screenEdgeCallbacks().insert(edge, QList<QScriptValue>() << context->argument(1));
     } else {

workspace.cpp

@@ -99,9 +99,6 @@ Workspace* Workspace::_self = 0;
 
 Workspace::Workspace(bool restore)
     : QObject(0)
-#ifdef KWIN_BUILD_SCREENEDGES
-    , m_screenEdge(new ScreenEdges(this))
-#endif
     , m_compositor(NULL)
     // Unsorted
     , active_popup(NULL)
@@ -197,6 +194,10 @@ Workspace::Workspace(bool restore)
                  ExposureMask
                 );
 
+#ifdef KWIN_BUILD_SCREENEDGES
+    ScreenEdges::create(this);
+#endif
+
     // VirtualDesktopManager needs to be created prior to init shortcuts
     // and prior to TabBox, due to TabBox connecting to signals
     // actual initialization happens in init()
@@ -261,10 +262,11 @@ void Workspace::screenChangeTimeout()
 void Workspace::init()
 {
 #ifdef KWIN_BUILD_SCREENEDGES
-    m_screenEdge->setConfig(KGlobal::config());
-    m_screenEdge->init();
-    connect(options, SIGNAL(configChanged()), m_screenEdge, SLOT(reconfigure()));
-    connect(VirtualDesktopManager::self(), SIGNAL(layoutChanged(int,int)), m_screenEdge, SLOT(updateLayout()));
+    ScreenEdges *screenEdges = ScreenEdges::self();
+    screenEdges->setConfig(KGlobal::config());
+    screenEdges->init();
+    connect(options, SIGNAL(configChanged()), screenEdges, SLOT(reconfigure()));
+    connect(VirtualDesktopManager::self(), SIGNAL(layoutChanged(int,int)), screenEdges, SLOT(updateLayout()));
 #endif
 
     supportWindow = new QWidget(NULL, Qt::X11BypassWindowManagerHint);
@@ -1934,13 +1936,6 @@ Outline* Workspace::outline()
     return m_outline;
 }
 
-#ifdef KWIN_BUILD_SCREENEDGES
-ScreenEdges* Workspace::screenEdge()
-{
-    return m_screenEdge;
-}
-#endif
-
 bool Workspace::hasTabBox() const
 {
 #ifdef KWIN_BUILD_TABBOX
@@ -1999,13 +1994,13 @@ QString Workspace::supportInformation() const
 #ifdef KWIN_BUILD_SCREENEDGES
     support.append("\nScreen Edges\n");
     support.append(  "============\n");
-    const QMetaObject *metaScreenEdges = m_screenEdge->metaObject();
+    const QMetaObject *metaScreenEdges = ScreenEdges::self()->metaObject();
     for (int i=0; i<metaScreenEdges->propertyCount(); ++i) {
         const QMetaProperty property = metaScreenEdges->property(i);
         if (QLatin1String(property.name()) == "objectName") {
             continue;
         }
-        support.append(QLatin1String(property.name()) % ": " % m_screenEdge->property(property.name()).toString() % '\n');
+        support.append(QLatin1String(property.name()) % ": " % ScreenEdges::self()->property(property.name()).toString() % '\n');
     }
 #endif
     support.append("\nScreens\n");

workspace.h

@@ -75,7 +75,6 @@ class Scripting;
 class UserActionsMenu;
 class WindowRules;
 class Compositor;
-class ScreenEdges;
 
 class Workspace : public QObject, public KDecorationDefines
 {
@@ -199,9 +198,6 @@ public:
     }
 
     Outline* outline();
-#ifdef KWIN_BUILD_SCREENEDGES
-    ScreenEdges* screenEdge();
-#endif
 
 public:
     QPoint cascadeOffset(const Client *c) const;
@@ -214,9 +210,6 @@ private:
 #endif
 
     Outline* m_outline;
-#ifdef KWIN_BUILD_SCREENEDGES
-    ScreenEdges *m_screenEdge;
-#endif
     Compositor *m_compositor;
 
     //-------------------------------------------------