From b07acdd2b6321689da52cf16cfba5d99103f1303 Mon Sep 17 00:00:00 2001
From: Jean-Christophe Fillion-Robin <jchris.fillionr@kitware.com>
Date: Thu, 25 Apr 2019 10:37:46 -0400
Subject: [PATCH] BUG: Fix crash if layout factory failed to create view from
 XML element

---
 .../Testing/Cpp/ctkLayoutManagerTest1.cpp     | 29 +++++++++++++++++++
 Libs/Widgets/ctkLayoutManager.cpp             | 15 ++++++++--
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/Libs/Widgets/Testing/Cpp/ctkLayoutManagerTest1.cpp b/Libs/Widgets/Testing/Cpp/ctkLayoutManagerTest1.cpp
index 497187421d..393669becb 100644
--- a/Libs/Widgets/Testing/Cpp/ctkLayoutManagerTest1.cpp
+++ b/Libs/Widgets/Testing/Cpp/ctkLayoutManagerTest1.cpp
@@ -77,6 +77,22 @@ QString nestedLayout(
 " <item><view name=\"tab3\"/></item>"
 "</layout>");
 
+namespace
+{
+class ctkNullViewFactory: public ctkLayoutViewFactory
+{
+public:
+  ctkNullViewFactory(QObject* parent = 0) : ctkLayoutViewFactory(parent)
+  {
+    this->setUseCachedViews(true);
+  }
+  virtual QWidget* createViewFromXML(QDomElement layoutElement){
+    Q_UNUSED(layoutElement);
+    return 0;
+    }
+};
+}
+
 /// \ingroup Widgets
 
 //-----------------------------------------------------------------------------
@@ -287,6 +303,19 @@ int ctkLayoutManagerTest1(int argc, char * argv [] )
     return EXIT_FAILURE;
     }
 
+  // Test that factories failing to instantiate view do not lead to a "crash"
+  ctkNullViewFactory* nullViewInstanciator = new ctkNullViewFactory(&viewport);
+  QWidget nullView;
+  nullView.setWindowTitle("Layout with Invalid View");
+  ctkLayoutFactory nullViewLayoutManager;
+  nullViewLayoutManager.registerViewFactory(nullViewInstanciator);
+  nullViewLayoutManager.setLayout(simpleLayoutDoc);
+  nullViewLayoutManager.setViewport(&nullView);
+  nestedToTab.show();
+
+  QTimer::singleShot(200, &app, SLOT(quit()));
+  app.exec();
+
   if (argc < 2 || QString(argv[1]) != "-I" )
     {
     QTimer::singleShot(200, &app, SLOT(quit()));
diff --git a/Libs/Widgets/ctkLayoutManager.cpp b/Libs/Widgets/ctkLayoutManager.cpp
index f072b8e867..93e14b411a 100644
--- a/Libs/Widgets/ctkLayoutManager.cpp
+++ b/Libs/Widgets/ctkLayoutManager.cpp
@@ -415,7 +415,11 @@ void ctkLayoutManager::processItemElement(QDomElement itemElement, QLayoutItem*
     }
   else
     {
-    childrenItem << this->processElement(itemElement.firstChild().toElement());
+    QLayoutItem* layoutItem = this->processElement(itemElement.firstChild().toElement());
+    if (layoutItem)
+      {
+      childrenItem << layoutItem;
+      }
     }
   foreach(QLayoutItem* item, childrenItem)
     {
@@ -475,6 +479,10 @@ QWidgetItem* ctkLayoutManager::widgetItemFromXML(QDomElement viewElement)
 {
   //Q_ASSERT(viewElement.tagName() == "view");
   QWidget* view = this->viewFromXML(viewElement);
+  if (!view)
+    {
+    return 0;
+    }
   this->setupView(viewElement, view);
   return new QWidgetItem(view);
 }
@@ -484,7 +492,10 @@ void ctkLayoutManager::setupView(QDomElement viewElement, QWidget* view)
 {
   Q_UNUSED(viewElement);
   Q_D(ctkLayoutManager);
-  Q_ASSERT(view);
+  if (!view)
+    {
+    return;
+    }
   view->setVisible(true);
   d->Views.insert(view);
 }