PathView: fix item creation

First call of QQuickPathView::refill() did not use currentIndex
for item prepending and there was situation when items were
not created, e.g.:

PathView with current item in center and currentIndex was set
so that item with index 0 was after current item and before path
end. The result of this situation: items from path begin to current
item were not created.

The reason was that idx always equaled (modelCount-1) for item
prepending.

Now first filling uses currentIndex to calculate valid idx.

Task-number: QTBUG-53464
Change-Id: I7e343b0712c9c5c5cd56b1d8e020cf8c0f6e6301
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

src/quick/items/qquickpathview.cpp

@@ -1854,6 +1854,14 @@ void QQuickPathView::updatePolish()
     refill();
 }
 
+static inline int currentIndexRemainder(int currentIndex, int modelCount) Q_DECL_NOTHROW
+{
+    if (currentIndex < 0)
+        return modelCount + currentIndex % modelCount;
+    else
+        return currentIndex % modelCount;
+}
+
 void QQuickPathView::componentComplete()
 {
     Q_D(QQuickPathView);
@@ -1865,7 +1873,7 @@ void QQuickPathView::componentComplete()
     if (d->model) {
         d->modelCount = d->model->count();
         if (d->modelCount && d->currentIndex != 0) // an initial value has been provided for currentIndex
-            d->offset = qmlMod(d->modelCount - d->currentIndex, d->modelCount);
+            d->offset = qmlMod(d->modelCount - currentIndexRemainder(d->currentIndex, d->modelCount), d->modelCount);
     }
 
     d->createHighlight();
@@ -1939,7 +1947,8 @@ void QQuickPathView::refill()
             qreal endPos;
             int startIdx = 0;
             qreal startPos = 0.0;
-            if (d->items.count()) {
+            const bool wasEmpty = d->items.isEmpty();
+            if (!wasEmpty) {
                 //Find the beginning and end, items may not be in sorted order
                 endPos = -1.0;
                 startPos = 2.0;
@@ -1998,7 +2007,8 @@ void QQuickPathView::refill()
             }
 
             //Prepend
-            idx = startIdx - 1;
+            idx = (wasEmpty ? d->calcCurrentIndex() : startIdx) - 1;
+
             if (idx < 0)
                 idx = d->modelCount - 1;
             nextPos = d->positionOfIndex(idx);

tests/auto/quick/qquickpathview/data/qtbug53464.qml

@@ -0,0 +1,77 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 Netris
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+
+Rectangle {
+    width: 600
+    height: 400
+    PathView {
+        objectName: "pathView"
+        model: 10
+        anchors.fill: parent
+        pathItemCount: 5
+        highlightRangeMode: PathView.StrictlyEnforceRange
+        preferredHighlightBegin: 0.5
+        preferredHighlightEnd: 0.5
+        currentIndex: 8
+
+        path: Path {
+            startX: 0
+            startY: 50
+            PathLine {
+                x: 600
+                y: 50
+            }
+        }
+
+        delegate: Component {
+            Text {
+                width: 50
+                height: 50
+                text: index
+                objectName: "delegate" + index
+                font.pixelSize: 24
+                color: PathView.isCurrentItem ? "green" : "black"
+            }
+        }
+    }
+}
+

tests/auto/quick/qquickpathview/tst_qquickpathview.cpp

@@ -141,6 +141,7 @@ private slots:
     void flickableDelegate();
     void jsArrayChange();
     void qtbug42716();
+    void qtbug53464();
     void addCustomAttribute();
 };
 
@@ -2381,6 +2382,29 @@ void tst_QQuickPathView::qtbug42716()
     QVERIFY(!itemMiss);
 }
 
+void tst_QQuickPathView::qtbug53464()
+{
+    QScopedPointer<QQuickView> window(createView());
+
+    window->setSource(testFileUrl("qtbug53464.qml"));
+    window->show();
+    window->requestActivate();
+    QVERIFY(QTest::qWaitForWindowActive(window.data()));
+
+    QQuickPathView *pathView = findItem<QQuickPathView>(window->rootObject(), "pathView");
+    QVERIFY(pathView != Q_NULLPTR);
+    const int currentIndex = pathView->currentIndex();
+    QCOMPARE(currentIndex, 8);
+
+    const int pathItemCount = pathView->pathItemCount();
+    int totalCount = 0;
+    foreach (QQuickItem *item, pathView->childItems()) {
+        if (item->objectName().startsWith(QLatin1String("delegate")))
+            ++totalCount;
+    }
+    QCOMPARE(pathItemCount, totalCount);
+}
+
 void tst_QQuickPathView::addCustomAttribute()
 {
     const QScopedPointer<QQuickView> window(createView());