From 0fecf4184e888b202766210b235fde09a81c5257 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan-Arve=20S=C3=A6ther?= <jan-arve.saether@nokia.com>
Date: Fri, 11 Dec 2009 15:36:13 +0100
Subject: Add a simple check for a common wrong usage to avoid infinite
 recursion

Reviewed-by: Alexis
---
 src/gui/graphicsview/qgraphicsanchorlayout.cpp     | 23 ++++++++++++----------
 src/gui/graphicsview/qgraphicsanchorlayout_p.cpp   |  7 +++++++
 .../tst_qgraphicsanchorlayout.cpp                  | 20 +++++++++++++++++++
 3 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/src/gui/graphicsview/qgraphicsanchorlayout.cpp b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
index 6718a28..f504c54 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
@@ -321,14 +321,14 @@ void QGraphicsAnchorLayout::addCornerAnchors(QGraphicsLayoutItem *firstItem,
     // Horizontal anchor
     Qt::AnchorPoint firstEdge = (firstCorner & 1 ? Qt::AnchorRight: Qt::AnchorLeft);
     Qt::AnchorPoint secondEdge = (secondCorner & 1 ? Qt::AnchorRight: Qt::AnchorLeft);
-    d->addAnchor(firstItem, firstEdge, secondItem, secondEdge);
+    if (d->addAnchor(firstItem, firstEdge, secondItem, secondEdge)) {
+        // Vertical anchor
+        firstEdge = (firstCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop);
+        secondEdge = (secondCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop);
+        d->addAnchor(firstItem, firstEdge, secondItem, secondEdge);
 
-    // Vertical anchor
-    firstEdge = (firstCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop);
-    secondEdge = (secondCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop);
-    d->addAnchor(firstItem, firstEdge, secondItem, secondEdge);
-
-    invalidate();
+        invalidate();
+    }
 }
 
 /*!
@@ -351,11 +351,14 @@ void QGraphicsAnchorLayout::addAnchors(QGraphicsLayoutItem *firstItem,
                                        QGraphicsLayoutItem *secondItem,
                                        Qt::Orientations orientations)
 {
+    bool ok = true;
     if (orientations & Qt::Horizontal) {
-        addAnchor(secondItem, Qt::AnchorLeft, firstItem, Qt::AnchorLeft);
-        addAnchor(firstItem, Qt::AnchorRight, secondItem, Qt::AnchorRight);
+        // Currently, if the first is ok, then the rest of the calls should be ok
+        ok = addAnchor(secondItem, Qt::AnchorLeft, firstItem, Qt::AnchorLeft) != 0;
+        if (ok)
+            addAnchor(firstItem, Qt::AnchorRight, secondItem, Qt::AnchorRight);
     }
-    if (orientations & Qt::Vertical) {
+    if (orientations & Qt::Vertical && ok) {
         addAnchor(secondItem, Qt::AnchorTop, firstItem, Qt::AnchorTop);
         addAnchor(firstItem, Qt::AnchorBottom, secondItem, Qt::AnchorBottom);
     }
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
index 03ed63d..1dc6873 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -1666,6 +1666,13 @@ QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *fi
         return 0;
     }
 
+    const QGraphicsLayoutItem *parentWidget = q->parentLayoutItem();
+    if (firstItem == parentWidget || secondItem == parentWidget) {
+        qWarning("QGraphicsAnchorLayout::addAnchor(): "
+                 "You cannot add the parent of the layout to the layout.");
+        return 0;
+    }
+
     // In QGraphicsAnchorLayout, items are represented in its internal
     // graph as four anchors that connect:
     //  - Left -> HCenter
diff --git a/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp b/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp
index 6e78522..1cb9f0d 100644
--- a/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp
+++ b/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp
@@ -90,6 +90,7 @@ private slots:
     void parallelToHalfLayout();
     void globalSpacing();
     void graphicsAnchorHandling();
+    void invalidHierarchyCheck();
 };
 
 class RectWidget : public QGraphicsWidget
@@ -2058,5 +2059,24 @@ void tst_QGraphicsAnchorLayout::graphicsAnchorHandling()
     delete a;
 }
 
+void tst_QGraphicsAnchorLayout::invalidHierarchyCheck()
+{
+    QGraphicsWidget window(0, Qt::Window);
+    QGraphicsAnchorLayout *l = new QGraphicsAnchorLayout;
+    window.setLayout(l);
+
+    QCOMPARE(l->count(), 0);
+    QTest::ignoreMessage(QtWarningMsg, "QGraphicsAnchorLayout::addAnchor(): "
+                         "You cannot add the parent of the layout to the layout.");
+    QVERIFY(!l->addAnchor(l, Qt::AnchorLeft, &window, Qt::AnchorLeft));
+    QTest::ignoreMessage(QtWarningMsg, "QGraphicsAnchorLayout::addAnchor(): "
+                         "You cannot add the parent of the layout to the layout.");
+    l->addAnchors(l, &window);
+    QTest::ignoreMessage(QtWarningMsg, "QGraphicsAnchorLayout::addAnchor(): "
+                         "You cannot add the parent of the layout to the layout.");
+    l->addCornerAnchors(l, Qt::TopLeftCorner, &window, Qt::TopLeftCorner);
+    QCOMPARE(l->count(), 0);
+}
+
 QTEST_MAIN(tst_QGraphicsAnchorLayout)
 #include "tst_qgraphicsanchorlayout.moc"
-- 
cgit v0.12