Avoid using QQuickViewItem as base class

This patch renames it to QQuickItemViewTransitionableItem, and
FxViewItem and PositionedItem now create instances of this instead of
subclassing it, to reduce the memory used when transitions are not
required.

Change-Id: Ie050cda5a121bff9542c7ba7356f6eacf37d241a
Reviewed-by: Alan Alpert <alan.alpert@nokia.com>

1 files changed, 86 insertions, 19 deletions

diff --git a/src/quick/items/qquickitemview.cpp b/src/quick/items/qquickitemview.cpp
index e368d1aaec..aafddb40c8 100644
--- a/src/quick/items/qquickitemview.cpp
+++ b/src/quick/items/qquickitemview.cpp
@@ -46,12 +46,16 @@ QT_BEGIN_NAMESPACE
 
 
 FxViewItem::FxViewItem(QQuickItem *i, bool own)
-    : QQuickViewItem(i), ownItem(own), releaseAfterTransition(false)
+    : item(i)
+    , transitionableItem(0)
+    , ownItem(own)
+    , releaseAfterTransition(false)
 {
 }
 
 FxViewItem::~FxViewItem()
 {
+    delete transitionableItem;
     if (ownItem && item) {
         item->setParentItem(0);
         item->deleteLater();
@@ -59,6 +63,71 @@ FxViewItem::~FxViewItem()
     }
 }
 
+qreal FxViewItem::itemX() const
+{
+    return transitionableItem ? transitionableItem->itemX() : item->x();
+}
+
+qreal FxViewItem::itemY() const
+{
+    return transitionableItem ? transitionableItem->itemY() : item->y();
+}
+
+void FxViewItem::moveTo(const QPointF &pos)
+{
+    if (transitionableItem)
+        transitionableItem->moveTo(pos);
+    else
+        item->setPos(pos);
+}
+
+void FxViewItem::setVisible(bool visible)
+{
+    if (!visible && transitionableItem && transitionableItem->transitionScheduledOrRunning())
+        return;
+    item->setVisible(visible);
+}
+
+QQuickItemViewTransitioner::TransitionType FxViewItem::scheduledTransitionType() const
+{
+    return transitionableItem ? transitionableItem->nextTransitionType : QQuickItemViewTransitioner::NoTransition;
+}
+
+bool FxViewItem::transitionScheduledOrRunning() const
+{
+    return transitionableItem ? transitionableItem->transitionScheduledOrRunning() : false;
+}
+
+bool FxViewItem::transitionRunning() const
+{
+    return transitionableItem ? transitionableItem->transitionRunning() : false;
+}
+
+bool FxViewItem::isPendingRemoval() const
+{
+    return transitionableItem ? transitionableItem->isPendingRemoval() : false;
+}
+
+void FxViewItem::transitionNextReposition(QQuickItemViewTransitioner *transitioner, QQuickItemViewTransitioner::TransitionType type, bool asTarget)
+{
+    if (!transitioner)
+        return;
+    if (!transitionableItem)
+        transitionableItem = new QQuickItemViewTransitionableItem(item);
+    transitioner->transitionNextReposition(transitionableItem, type, asTarget);
+}
+
+bool FxViewItem::prepareTransition(QQuickItemViewTransitioner *transitioner, const QRectF &viewBounds)
+{
+    return transitionableItem ? transitionableItem->prepareTransition(transitioner, index, viewBounds) : false;
+}
+
+void FxViewItem::startTransition(QQuickItemViewTransitioner *transitioner)
+{
+    if (transitionableItem)
+        transitionableItem->startTransition(transitioner, index);
+}
+
 
 QQuickItemViewChangeSet::QQuickItemViewChangeSet()
     : active(false)
@@ -1615,7 +1684,7 @@ void QQuickItemViewPrivate::layout()
         // assume that any items moving now are moving due to the remove - if they schedule
         // a different transition, that will override this one anyway
         for (int i=0; i<visibleItems.count(); i++)
-            transitioner->transitionNextReposition(visibleItems[i], QQuickItemViewTransitioner::RemoveTransition, false);
+            visibleItems[i]->transitionNextReposition(transitioner, QQuickItemViewTransitioner::RemoveTransition, false);
     }
 
     ChangeResult insertionPosChanges;
@@ -1631,7 +1700,7 @@ void QQuickItemViewPrivate::layout()
 
     if (transitioner && transitioner->canTransition(QQuickItemViewTransitioner::PopulateTransition, true)) {
         for (int i=0; i<visibleItems.count(); i++)
-            transitioner->transitionNextReposition(visibleItems.at(i), QQuickItemViewTransitioner::PopulateTransition, true);
+            visibleItems.at(i)->transitionNextReposition(transitioner, QQuickItemViewTransitioner::PopulateTransition, true);
     }
     layoutVisibleItems();
 
@@ -1791,7 +1860,7 @@ bool QQuickItemViewPrivate::applyModelChanges(ChangeResult *totalInsertionResult
                     repositionItemAt(movingIntoView[i].item, fromIndex, -totalInsertionResult->sizeChangesAfterVisiblePos);
                 else
                     repositionItemAt(movingIntoView[i].item, fromIndex, totalInsertionResult->sizeChangesAfterVisiblePos);
-                transitioner->transitionNextReposition(movingIntoView[i].item, QQuickItemViewTransitioner::MoveTransition, true);
+                movingIntoView[i].item->transitionNextReposition(transitioner, QQuickItemViewTransitioner::MoveTransition, true);
             }
         }
     }
@@ -1855,12 +1924,10 @@ bool QQuickItemViewPrivate::applyRemovalChange(const QQuickChangeSet::Remove &re
         } else if (item->index >= removal.index + removal.count) {
             // after removed items
             item->index -= removal.count;
-            if (transitioner) {
-                if (removal.isMove())
-                    transitioner->transitionNextReposition(item, QQuickItemViewTransitioner::MoveTransition, false);
-                else
-                    transitioner->transitionNextReposition(item, QQuickItemViewTransitioner::RemoveTransition, false);
-            }
+            if (removal.isMove())
+                item->transitionNextReposition(transitioner, QQuickItemViewTransitioner::MoveTransition, false);
+            else
+                item->transitionNextReposition(transitioner, QQuickItemViewTransitioner::RemoveTransition, false);
             ++it;
         } else {
             // removed item
@@ -1894,8 +1961,7 @@ void QQuickItemViewPrivate::removeItem(FxViewItem *item, const QQuickChangeSet::
     }
     if (removal.isMove()) {
         currentChanges.removedItems.insert(removal.moveKey(item->index), item);
-        if (transitioner)
-            transitioner->transitionNextReposition(item, QQuickItemViewTransitioner::MoveTransition, true);
+        item->transitionNextReposition(transitioner, QQuickItemViewTransitioner::MoveTransition, true);
     } else {
         // track item so it is released later
         currentChanges.removedItems.insertMulti(QQuickChangeSet::MoveKey(), item);
@@ -1977,7 +2043,7 @@ void QQuickItemViewPrivate::prepareRemoveTransitions(QHash<QQuickChangeSet::Move
                 FxViewItem *item = *it;
                 item->releaseAfterTransition = true;
                 releasePendingTransition.append(item);
-                transitioner->transitionNextReposition(item, QQuickItemViewTransitioner::RemoveTransition, true);
+                item->transitionNextReposition(transitioner, QQuickItemViewTransitioner::RemoveTransition, true);
                 it = removedItems->erase(it);
             } else {
                 ++it;
@@ -1996,7 +2062,7 @@ bool QQuickItemViewPrivate::prepareNonVisibleItemTransition(FxViewItem *item, co
     if (!transitioner)
         return false;
 
-    if (item->nextTransitionType == QQuickItemViewTransitioner::MoveTransition)
+    if (item->scheduledTransitionType() == QQuickItemViewTransitioner::MoveTransition)
         repositionItemAt(item, item->index, 0);
 
     if (item->prepareTransition(transitioner, viewBounds)) {
@@ -2006,12 +2072,13 @@ bool QQuickItemViewPrivate::prepareNonVisibleItemTransition(FxViewItem *item, co
     return false;
 }
 
-void QQuickItemViewPrivate::viewItemTransitionFinished(QQuickViewItem *i)
+void QQuickItemViewPrivate::viewItemTransitionFinished(QQuickItemViewTransitionableItem *item)
 {
-    FxViewItem *item = static_cast<FxViewItem *>(i);
-    if (item->releaseAfterTransition) {
-        releasePendingTransition.removeOne(item);
-        releaseItem(item);
+    for (int i=0; i<releasePendingTransition.count(); i++) {
+        if (releasePendingTransition[i]->transitionableItem == item) {
+            releaseItem(releasePendingTransition.takeAt(i));
+            return;
+        }
     }
 }