Add Popup::parent

The parent defaults to the QML parent object where Popup is declared.
Popup::x/y are relative to the parent, and the popup also automatically
follows the parent as appropriate. QQuickPopupPositioner has been
adapted from Qt Quick Controls 1. It was called QQuickScenePosListener,
and it was implemented for the text selection handle popups.

ComboBox's popup now follows the control eg. when scrolling, but the
below/above positioning feature is temporarily gone missing. It will
be restored in a follow up commit.

Change-Id: I8a6b58cd74e07f33930abc35d0ab9da056685128
Reviewed-by: J-P Nurmi <jpnurmi@theqtcompany.com>

1 files changed, 187 insertions, 4 deletions

diff --git a/src/templates/qquickpopup.cpp b/src/templates/qquickpopup.cpp
index 07310189..caa9f175 100644
--- a/src/templates/qquickpopup.cpp
+++ b/src/templates/qquickpopup.cpp
@@ -59,6 +59,14 @@ QT_BEGIN_NAMESPACE
     \labs
 */
 
+static const QQuickItemPrivate::ChangeTypes AncestorChangeTypes = QQuickItemPrivate::Geometry
+                                                                  | QQuickItemPrivate::Parent
+                                                                  | QQuickItemPrivate::Children;
+
+static const QQuickItemPrivate::ChangeTypes ItemChangeTypes = QQuickItemPrivate::Geometry
+                                                             | QQuickItemPrivate::Parent
+                                                             | QQuickItemPrivate::Destroyed;
+
 QQuickPopupPrivate::QQuickPopupPrivate()
     : QObjectPrivate()
     , focus(false)
@@ -72,12 +80,14 @@ QQuickPopupPrivate::QQuickPopupPrivate()
     , leftPadding(0)
     , rightPadding(0)
     , bottomPadding(0)
+    , parentItem(Q_NULLPTR)
     , background(Q_NULLPTR)
     , contentItem(Q_NULLPTR)
     , overlay(Q_NULLPTR)
     , enter(Q_NULLPTR)
     , exit(Q_NULLPTR)
     , popupItem(Q_NULLPTR)
+    , positioner(this)
     , transitionManager(this)
 {
 }
@@ -87,6 +97,7 @@ void QQuickPopupPrivate::init()
     Q_Q(QQuickPopup);
     popupItem = new QQuickPopupItem(q);
     popupItem->setParent(q);
+    q->setParentItem(qobject_cast<QQuickItem *>(parent));
 }
 
 void QQuickPopupPrivate::finalizeEnterTransition()
@@ -99,6 +110,7 @@ void QQuickPopupPrivate::finalizeExitTransition()
 {
     Q_Q(QQuickPopup);
     overlay = Q_NULLPTR;
+    positioner.setParentItem(Q_NULLPTR);
     popupItem->setParentItem(Q_NULLPTR);
     emit q->visibleChanged();
 }
@@ -244,6 +256,146 @@ void QQuickPopupItem::geometryChanged(const QRectF &newGeometry, const QRectF &o
     popup->geometryChanged(newGeometry, oldGeometry);
 }
 
+QQuickPopupPositioner::QQuickPopupPositioner(QQuickPopupPrivate *popup) :
+    m_x(0),
+    m_y(0),
+    m_parentItem(Q_NULLPTR),
+    m_popup(popup)
+{
+}
+
+QQuickPopupPositioner::~QQuickPopupPositioner()
+{
+    if (m_parentItem) {
+        QQuickItemPrivate::get(m_parentItem)->removeItemChangeListener(this, ItemChangeTypes);
+        removeAncestorListeners(m_parentItem->parentItem());
+    }
+}
+
+qreal QQuickPopupPositioner::x() const
+{
+    return m_x;
+}
+
+void QQuickPopupPositioner::setX(qreal x)
+{
+    if (m_x != x) {
+        m_x = x;
+        repositionPopup();
+    }
+}
+
+qreal QQuickPopupPositioner::y() const
+{
+    return m_y;
+}
+
+void QQuickPopupPositioner::setY(qreal y)
+{
+    if (m_y != y) {
+        m_y = y;
+        repositionPopup();
+    }
+}
+
+QQuickItem *QQuickPopupPositioner::parentItem() const
+{
+    return m_parentItem;
+}
+
+void QQuickPopupPositioner::setParentItem(QQuickItem *parent)
+{
+    if (m_parentItem == parent)
+        return;
+
+    if (m_parentItem) {
+        QQuickItemPrivate::get(m_parentItem)->removeItemChangeListener(this, ItemChangeTypes);
+        removeAncestorListeners(m_parentItem->parentItem());
+    }
+
+    m_parentItem = parent;
+
+    if (!parent)
+        return;
+
+    QQuickItemPrivate::get(parent)->addItemChangeListener(this, ItemChangeTypes);
+    addAncestorListeners(parent->parentItem());
+
+    repositionPopup();
+}
+
+void QQuickPopupPositioner::itemGeometryChanged(QQuickItem *, const QRectF &, const QRectF &)
+{
+    repositionPopup();
+}
+
+void QQuickPopupPositioner::itemParentChanged(QQuickItem *, QQuickItem *parent)
+{
+    addAncestorListeners(parent);
+}
+
+void QQuickPopupPositioner::itemChildRemoved(QQuickItem *, QQuickItem *child)
+{
+    if (isAncestor(child))
+        removeAncestorListeners(child);
+}
+
+void QQuickPopupPositioner::itemDestroyed(QQuickItem *item)
+{
+    Q_ASSERT(m_parentItem == item);
+
+    m_parentItem = Q_NULLPTR;
+    QQuickItemPrivate::get(item)->removeItemChangeListener(this, ItemChangeTypes);
+    removeAncestorListeners(item->parentItem());
+}
+
+void QQuickPopupPositioner::repositionPopup()
+{
+    QPointF pos(m_x, m_y);
+    if (m_parentItem)
+        pos = m_parentItem->mapToScene(pos);
+    m_popup->popupItem->setPosition(pos);
+}
+
+void QQuickPopupPositioner::removeAncestorListeners(QQuickItem *item)
+{
+    if (item == m_parentItem)
+        return;
+
+    QQuickItem *p = item;
+    while (p) {
+        QQuickItemPrivate::get(p)->removeItemChangeListener(this, AncestorChangeTypes);
+        p = p->parentItem();
+    }
+}
+
+void QQuickPopupPositioner::addAncestorListeners(QQuickItem *item)
+{
+    if (item == m_parentItem)
+        return;
+
+    QQuickItem *p = item;
+    while (p) {
+        QQuickItemPrivate::get(p)->addItemChangeListener(this, AncestorChangeTypes);
+        p = p->parentItem();
+    }
+}
+
+// TODO: use QQuickItem::isAncestorOf() in dev/5.7
+bool QQuickPopupPositioner::isAncestor(QQuickItem *item) const
+{
+    if (!m_parentItem)
+        return false;
+
+    QQuickItem *parent = m_parentItem->parentItem();
+    while (parent) {
+        if (parent == item)
+            return true;
+        parent = parent->parentItem();
+    }
+    return false;
+}
+
 QQuickPopupTransitionManager::QQuickPopupTransitionManager(QQuickPopupPrivate *popup)
     : QQuickTransitionManager()
     , state(Off)
@@ -293,6 +445,12 @@ QQuickPopup::QQuickPopup(QQuickPopupPrivate &dd, QObject *parent)
     d->init();
 }
 
+QQuickPopup::~QQuickPopup()
+{
+    Q_D(QQuickPopup);
+    d->positioner.setParentItem(Q_NULLPTR);
+}
+
 /*!
     \qmlmethod void Qt.labs.controls::Popup::open()
 
@@ -333,6 +491,7 @@ void QQuickPopup::open()
 
     d->overlay = static_cast<QQuickOverlay *>(applicationWindow->overlay());
     d->popupItem->setParentItem(d->overlay);
+    d->positioner.setParentItem(d->parentItem);
     // TODO: add Popup::transformOrigin?
     if (d->contentItem)
         d->popupItem->setTransformOrigin(d->contentItem->transformOrigin());
@@ -368,13 +527,13 @@ void QQuickPopup::close()
 qreal QQuickPopup::x() const
 {
     Q_D(const QQuickPopup);
-    return d->popupItem->x();
+    return d->positioner.x();
 }
 
 void QQuickPopup::setX(qreal x)
 {
     Q_D(QQuickPopup);
-    d->popupItem->setX(x);
+    d->positioner.setX(x);
 }
 
 /*!
@@ -385,13 +544,13 @@ void QQuickPopup::setX(qreal x)
 qreal QQuickPopup::y() const
 {
     Q_D(const QQuickPopup);
-    return d->popupItem->y();
+    return d->positioner.y();
 }
 
 void QQuickPopup::setY(qreal y)
 {
     Q_D(QQuickPopup);
-    d->popupItem->setY(y);
+    d->positioner.setY(y);
 }
 
 /*!
@@ -603,6 +762,28 @@ void QQuickPopup::resetBottomPadding()
 }
 
 /*!
+    \qmlproperty Item Qt.labs.popups::Popup::parent
+
+    This property holds the parent item.
+*/
+QQuickItem *QQuickPopup::parentItem() const
+{
+    Q_D(const QQuickPopup);
+    return d->parentItem;
+}
+
+void QQuickPopup::setParentItem(QQuickItem *parent)
+{
+    Q_D(QQuickPopup);
+    if (d->parentItem != parent) {
+        d->parentItem = parent;
+        if (d->positioner.parentItem())
+            d->positioner.setParentItem(parent);
+        emit parentChanged();
+    }
+}
+
+/*!
     \qmlproperty Item Qt.labs.popups::Popup::background
 
     This property holds the background item.
@@ -787,6 +968,8 @@ void QQuickPopup::componentComplete()
 {
     Q_D(QQuickPopup);
     d->complete = true;
+    if (!parentItem())
+        setParentItem(qobject_cast<QQuickItem *>(parent()));
 }
 
 bool QQuickPopup::isComponentComplete() const