QGraphicsAnchorLayout: Testing for existing anchors before adding new ones

The layout was not aware of the fact an anchor could already exist when it
was added. This commit ensures that only one anchor exists between two
vertices to avoid unwanted behavior and memory leaks (AnchorData's and
Vertices would leak otherwise).

Signed-off-by: Eduardo M. Fleury <eduardo.fleury@openbossa.org>
Reviewed-by: Anselmo Lacerda S. de Melo <anselmo.melo@openbossa.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
index 63179ef..9d145a2 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -642,6 +642,11 @@ void QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *firstItem,
     AnchorVertex *v1 = addInternalVertex(firstItem, firstEdge);
     AnchorVertex *v2 = addInternalVertex(secondItem, secondEdge);
 
+    // Remove previous anchor
+    // ### Could we update the existing edgeData rather than creating a new one?
+    if (graph[edgeOrientation(firstEdge)].edgeData(v1, v2))
+        removeAnchor(firstItem, firstEdge, secondItem, secondEdge);
+
     // Create a bi-directional edge in the sense it can be transversed both
     // from v1 or v2. "data" however is shared between the two references
     // so we still know that the anchor direction is from 1 to 2.