Add cacheItemCount property to PathView

cacheItemCount specifies the number of items to cache off the path when
pathItemCount is specified.  This allows up to cacheItemCount items to be
kept alive when they move off the path, and also to asynchronously
create items off path in preparation for display when the path offset
changes.  This is the equivalent of cacheBuffer for other views.

Task-number: QTBUG-23931
Change-Id: I03497537d3f929e5e3579536850dd43eb2724c38
Reviewed-by: Bea Lam <bea.lam@nokia.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/quick/items/qquickpathview_p_p.h b/src/quick/items/qquickpathview_p_p.h
index 2a547d9b47..46ad22f3f8 100644
--- a/src/quick/items/qquickpathview_p_p.h
+++ b/src/quick/items/qquickpathview_p_p.h
@@ -95,13 +95,14 @@ public:
         }
     }
 
-    QQuickItem *getItem(int modelIndex, qreal z = 0, bool onPath=true);
+    QQuickItem *getItem(int modelIndex, qreal z = 0, bool async=false);
     void releaseItem(QQuickItem *item);
     QQuickPathViewAttached *attached(QQuickItem *item);
     QQmlOpenMetaObjectType *attachedType();
     void clear();
     void updateMappedRange();
     qreal positionOfIndex(qreal index) const;
+    bool isInBound(qreal position, qreal lower, qreal upper) const;
     void createHighlight();
     void updateHighlight();
     void setHighlightPosition(qreal pos);
@@ -138,6 +139,7 @@ public:
     qreal offset;
     qreal offsetAdj;
     qreal mappedRange;
+    qreal mappedCache;
     bool stealMouse : 1;
     bool ownModel : 1;
     bool interactive : 1;
@@ -162,6 +164,7 @@ public:
     int firstIndex;
     int pathItems;
     int requestedIndex;
+    int cacheSize;
     qreal requestedZ;
     QList<QQuickItem *> items;
     QList<QQuickItem *> itemCache;