Improve memory usage of the connectionlists inside QObject

... by not allocating space for slots in the vector.

Before, the vector uses the signal index as index. The problem is that
the slots and signal are mixed in the same index space.

We solve the problem by having a different index space for the signal in
the connectionlists vector.  All we need to do is to add the information
about the number of signals in the moc.

Also, we are not connecting to cloned signal but only to the orginial
ones.  For example,  destroyed(QObject * = 0) would generate two signal,
we now only connect to the first one.

This also improve a little bit the performence while activating signals
since it removed one call to indexOfMethod.

Reviewed-by: Brad

3 files changed, 12 insertions, 9 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 675fc0d..708ba09 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -6589,7 +6589,7 @@ void QGraphicsItem::prepareGeometryChange()
         // if someone is connected to the changed signal or the scene has no views.
         // Note that this has to be done *after* markDirty to ensure that
         // _q_processDirtyItems is called before _q_emitUpdated.
-	if ((scenePrivate->connectedSignals[0] & scenePrivate->changedSignalMask)
+	if (scenePrivate->isSignalConnected(scenePrivate->changedSignalIndex)
             || scenePrivate->views.isEmpty()) {
             if (d_ptr->hasTranslateOnlySceneTransform()) {
                 d_ptr->scene->update(boundingRect().translated(d_ptr->sceneTransform.dx(),
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 3f13a86..7fa565d 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -265,12 +265,13 @@ static void _q_hoverFromMouseEvent(QGraphicsSceneHoverEvent *hover, const QGraph
     hover->setAccepted(mouseEvent->isAccepted());
 }
 
+int QGraphicsScenePrivate::changedSignalIndex;
+
 /*!
     \internal
 */
 QGraphicsScenePrivate::QGraphicsScenePrivate()
-    : changedSignalMask(0),
-      indexMethod(QGraphicsScene::BspTreeIndex),
+    : indexMethod(QGraphicsScene::BspTreeIndex),
       index(0),
       lastItemCount(0),
       hasSceneRect(false),
@@ -311,7 +312,9 @@ void QGraphicsScenePrivate::init()
     index = new QGraphicsSceneBspTreeIndex(q);
 
     // Keep this index so we can check for connected slots later on.
-    changedSignalMask = (1 << q->metaObject()->indexOfSignal("changed(QList<QRectF>)"));
+    if (!changedSignalIndex) {
+        changedSignalIndex = signalIndex("changed(QList<QRectF>)");
+    }
     qApp->d_func()->scene_list.append(q);
     q->update();
 }
@@ -343,7 +346,7 @@ void QGraphicsScenePrivate::_q_emitUpdated()
     // the optimization that items send updates directly to the views, but it
     // needs to happen in order to keep compatibility with the behavior from
     // Qt 4.4 and backward.
-    if (connectedSignals[0] & changedSignalMask) {
+    if (isSignalConnected(changedSignalIndex)) {
         for (int i = 0; i < views.size(); ++i) {
             QGraphicsView *view = views.at(i);
             if (!view->d_func()->connectedToScene) {
@@ -2894,7 +2897,7 @@ void QGraphicsScene::update(const QRectF &rect)
 
     // Check if anyone's connected; if not, we can send updates directly to
     // the views. Otherwise or if there are no views, use old behavior.
-    bool directUpdates = !(d->connectedSignals[0] & d->changedSignalMask) && !d->views.isEmpty();
+    bool directUpdates = !(d->isSignalConnected(d->changedSignalIndex)) && !d->views.isEmpty();
     if (rect.isNull()) {
         d->updateAll = true;
         d->updatedRects.clear();
@@ -4473,7 +4476,7 @@ void QGraphicsScenePrivate::markDirty(QGraphicsItem *item, const QRectF &rect, b
     if (removingItemFromScene) {
         // Note that this function can be called from the item's destructor, so
         // do NOT call any virtual functions on it within this block.
-        if ((connectedSignals[0] & changedSignalMask) || views.isEmpty()) {
+        if (isSignalConnected(changedSignalIndex) || views.isEmpty()) {
             // This block of code is kept for compatibility. Since 4.5, by default
             // QGraphicsView does not connect the signal and we use the below
             // method of delivering updates.
@@ -4619,7 +4622,7 @@ void QGraphicsScenePrivate::processDirtyItemsRecursive(QGraphicsItem *item, bool
 
     // Process item.
     if (item->d_ptr->dirty || item->d_ptr->paintedViewBoundingRectsNeedRepaint) {
-        const bool useCompatUpdate = views.isEmpty() || (connectedSignals[0] & changedSignalMask);
+        const bool useCompatUpdate = views.isEmpty() || isSignalConnected(changedSignalIndex);
         const QRectF itemBoundingRect = adjustedItemBoundingRect(item);
 
         if (useCompatUpdate && !itemIsUntransformable && qFuzzyIsNull(item->boundingRegionGranularity())) {
diff --git a/src/gui/graphicsview/qgraphicsscene_p.h b/src/gui/graphicsview/qgraphicsscene_p.h
index 685f534..f1ddb5a 100644
--- a/src/gui/graphicsview/qgraphicsscene_p.h
+++ b/src/gui/graphicsview/qgraphicsscene_p.h
@@ -87,7 +87,7 @@ public:
 
     static QGraphicsScenePrivate *get(QGraphicsScene *q);
 
-    quint32 changedSignalMask;
+    static int changedSignalIndex;
 
     QGraphicsScene::ItemIndexMethod indexMethod;
     QGraphicsSceneIndex *index;