QQuickItem: added isAncestorOf()

[ChangeLog][QtQuick][QQuickItem] added isAncestorOf()

Change-Id: I9f6e0574db787c6c9d2311223c6a3ae7fd820bab
Reviewed-by: J-P Nurmi <jpnurmi@theqtcompany.com>

3 files changed, 60 insertions, 0 deletions

diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index b89482fb90..ae7b197619 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -6825,6 +6825,26 @@ QQuickItem *QQuickItem::scopedFocusItem() const
 }
 
 /*!
+    Returns \c true if this item is an ancestor of \a child (i.e., if this item
+    is \a child's parent, or one of \a child's parent's ancestors).
+
+    \since 5.7
+
+    \sa parentItem()
+  */
+bool QQuickItem::isAncestorOf(const QQuickItem *child) const
+{
+    if (!child || child == this)
+        return false;
+    const QQuickItem *ancestor = child;
+    while ((ancestor = ancestor->parentItem())) {
+        if (ancestor == this)
+            return true;
+    }
+    return false;
+}
+
+/*!
     Returns the mouse buttons accepted by this item.
 
     The default value is Qt::NoButton; that is, no mouse buttons are accepted.
diff --git a/src/quick/items/qquickitem.h b/src/quick/items/qquickitem.h
index d92910ce9c..50d691b1b6 100644
--- a/src/quick/items/qquickitem.h
+++ b/src/quick/items/qquickitem.h
@@ -278,6 +278,8 @@ public:
     bool isFocusScope() const;
     QQuickItem *scopedFocusItem() const;
 
+    bool isAncestorOf(const QQuickItem *child) const;
+
     Qt::MouseButtons acceptedMouseButtons() const;
     void setAcceptedMouseButtons(Qt::MouseButtons buttons);
     bool acceptHoverEvents() const;
diff --git a/tests/auto/quick/qquickitem2/tst_qquickitem.cpp b/tests/auto/quick/qquickitem2/tst_qquickitem.cpp
index c7717b9cca..518e248207 100644
--- a/tests/auto/quick/qquickitem2/tst_qquickitem.cpp
+++ b/tests/auto/quick/qquickitem2/tst_qquickitem.cpp
@@ -117,6 +117,7 @@ private slots:
     void contains_data();
     void contains();
     void childAt();
+    void isAncestorOf();
 
     void grab();
 
@@ -2959,6 +2960,43 @@ void tst_QQuickItem::grab()
 
 }
 
+void tst_QQuickItem::isAncestorOf()
+{
+    QQuickItem parent;
+
+    QQuickItem sub1;
+    sub1.setParentItem(&parent);
+
+    QQuickItem child1;
+    child1.setParentItem(&sub1);
+    QQuickItem child2;
+    child2.setParentItem(&sub1);
+
+    QQuickItem sub2;
+    sub2.setParentItem(&parent);
+
+    QQuickItem child3;
+    child3.setParentItem(&sub2);
+    QQuickItem child4;
+    child4.setParentItem(&sub2);
+
+    QVERIFY(parent.isAncestorOf(&sub1));
+    QVERIFY(parent.isAncestorOf(&sub2));
+    QVERIFY(parent.isAncestorOf(&child1));
+    QVERIFY(parent.isAncestorOf(&child2));
+    QVERIFY(parent.isAncestorOf(&child3));
+    QVERIFY(parent.isAncestorOf(&child4));
+    QVERIFY(sub1.isAncestorOf(&child1));
+    QVERIFY(sub1.isAncestorOf(&child2));
+    QVERIFY(!sub1.isAncestorOf(&child3));
+    QVERIFY(!sub1.isAncestorOf(&child4));
+    QVERIFY(sub2.isAncestorOf(&child3));
+    QVERIFY(sub2.isAncestorOf(&child4));
+    QVERIFY(!sub2.isAncestorOf(&child1));
+    QVERIFY(!sub2.isAncestorOf(&child2));
+    QVERIFY(!sub1.isAncestorOf(&sub1));
+    QVERIFY(!sub2.isAncestorOf(&sub2));
+}
 
 QTEST_MAIN(tst_QQuickItem)