BUG: Fix memory leaks in SubjectHierarchy Register and Segment plugins

Since QMenu constructor does not take a QObject as a parent, this commit
introduces a QSharedPointer to manage the menu instance.

This commit fixes the error(s) reported below by valgrind memcheck tool.

Valgrind was used on Ubuntu 14.04 against a Debug build of Slicer. It was
exected doing the following:
 (1) Start a terminal with the appropriate environment: ./Slicer --gnome-terminal
 (2) Start Slicer using valgrind: valgrind --log-file=2015-07-16-Slicer-memcheck.txt --tool=memcheck --leak-check=yes ./bin/SlicerApp-real --disable-python --disable-cli-modules
 (3) Exit Slicer and inspect valgrind log file

Valgrind error:

==29339== 1,160 (40 direct, 1,120 indirect) bytes in 1 blocks are definitely lost in loss record 2,294 of 2,448
==29339==    at 0x4C2B0E0: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==29339==    by 0x10550A4D9: qSlicerSubjectHierarchySegmentPluginPrivate::init() (qSlicerSubjectHierarchySegmentPlugin.cxx:114)
==29339==    by 0x10550A3E7: qSlicerSubjectHierarchySegmentPlugin::qSlicerSubjectHierarchySegmentPlugin(QObject*) (qSlicerSubjectHierarchySegmentPlugin.cxx:103)
==29339==    by 0x1054F1217: qSlicerSubjectHierarchyPluginLogic::registerCorePlugins() (qSlicerSubjectHierarchyPluginLogic.cxx:139)
==29339==    by 0x1054F0DFD: qSlicerSubjectHierarchyPluginLogic::qSlicerSubjectHierarchyPluginLogic(QWidget*) (qSlicerSubjectHierarchyPluginLogic.cxx:117)
==29339==    by 0x1080E2F5C: qSlicerSubjectHierarchyModule::createLogic() (qSlicerSubjectHierarchyModule.cxx:137)
==29339==    by 0x8E715C1: qSlicerAbstractCoreModule::logic() (qSlicerAbstractCoreModule.cxx:280)
==29339==    by 0x8E70BAD: qSlicerAbstractCoreModule::initialize(vtkSlicerApplicationLogic*) (qSlicerAbstractCoreModule.cxx:99)
==29339==    by 0x8EA2A19: qSlicerModuleFactoryManager::loadModule(QString const&, QString const&) (qSlicerModuleFactoryManager.cxx:170)
==29339==    by 0x8EA2586: qSlicerModuleFactoryManager::loadModule(QString const&) (qSlicerModuleFactoryManager.cxx:110)
==29339==    by 0x40672A: (anonymous namespace)::SlicerAppMain(int, char**) (Main.cxx:193)
==29339==    by 0x406D30: main (Main.cxx:254)

==29339==
==29339== 1,176 (40 direct, 1,136 indirect) bytes in 1 blocks are definitely lost in loss record 2,296 of 2,448
==29339==    at 0x4C2B0E0: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==29339==    by 0x105507073: qSlicerSubjectHierarchyRegisterPluginPrivate::init() (qSlicerSubjectHierarchyRegisterPlugin.cxx:120)
==29339==    by 0x105506EC1: qSlicerSubjectHierarchyRegisterPlugin::qSlicerSubjectHierarchyRegisterPlugin(QObject*) (qSlicerSubjectHierarchyRegisterPlugin.cxx:104)
==29339==    by 0x1054F11ED: qSlicerSubjectHierarchyPluginLogic::registerCorePlugins() (qSlicerSubjectHierarchyPluginLogic.cxx:137)
==29339==    by 0x1054F0DFD: qSlicerSubjectHierarchyPluginLogic::qSlicerSubjectHierarchyPluginLogic(QWidget*) (qSlicerSubjectHierarchyPluginLogic.cxx:117)
==29339==    by 0x1080E2F5C: qSlicerSubjectHierarchyModule::createLogic() (qSlicerSubjectHierarchyModule.cxx:137)
==29339==    by 0x8E715C1: qSlicerAbstractCoreModule::logic() (qSlicerAbstractCoreModule.cxx:280)
==29339==    by 0x8E70BAD: qSlicerAbstractCoreModule::initialize(vtkSlicerApplicationLogic*) (qSlicerAbstractCoreModule.cxx:99)
==29339==    by 0x8EA2A19: qSlicerModuleFactoryManager::loadModule(QString const&, QString const&) (qSlicerModuleFactoryManager.cxx:170)
==29339==    by 0x8EA2586: qSlicerModuleFactoryManager::loadModule(QString const&) (qSlicerModuleFactoryManager.cxx:110)
==29339==    by 0x40672A: (anonymous namespace)::SlicerAppMain(int, char**) (Main.cxx:193)
==29339==    by 0x406D30: main (Main.cxx:254)

svn-url: http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=24445
git-svn-id: http://svn.slicer.org/Slicer4/trunk@24445 3bd1e089-480b-0410-8dfb-8563597acbee

Modules/Loadable/SubjectHierarchy/Widgets/qSlicerSubjectHierarchyRegisterPlugin.cxx

@@ -74,6 +74,7 @@ class qSlicerSubjectHierarchyRegisterPluginPrivate: public QObject
 public:
   QAction* RegisterThisAction;
   QAction* RegisterToAction;
+  QSharedPointer<QMenu> RegistrationMethodsSubMenu;
 };
 
 //-----------------------------------------------------------------------------
@@ -117,20 +118,20 @@ void qSlicerSubjectHierarchyRegisterPluginPrivate::init()
   this->RegisterToAction = new QAction("Register * to this using...",q);
 
   // Actions for the registration methods
-  QMenu* registrationMethodsSubMenu = new QMenu();
-  this->RegisterToAction->setMenu(registrationMethodsSubMenu);
+  this->RegistrationMethodsSubMenu = QSharedPointer<QMenu>(new QMenu());
+  this->RegisterToAction->setMenu(this->RegistrationMethodsSubMenu.data());
 
   QAction* imageBasedRigidAction = new QAction("Rigid image-based registration",q);
   QObject::connect(imageBasedRigidAction, SIGNAL(triggered()), q, SLOT(registerImageBasedRigid()));
-  registrationMethodsSubMenu->addAction(imageBasedRigidAction);
+  this->RegistrationMethodsSubMenu->addAction(imageBasedRigidAction);
 
   QAction* imageBasedBSplineAction = new QAction("BSpline image-based registration",q);
   QObject::connect(imageBasedBSplineAction, SIGNAL(triggered()), q, SLOT(registerImageBasedBSpline()));
-  registrationMethodsSubMenu->addAction(imageBasedBSplineAction);
+  this->RegistrationMethodsSubMenu->addAction(imageBasedBSplineAction);
 
   QAction* interactiveLandmarkAction = new QAction("Interactive landmark registration",q);
   QObject::connect(interactiveLandmarkAction, SIGNAL(triggered()), q, SLOT(registerInteractiveLandmark()));
-  registrationMethodsSubMenu->addAction(interactiveLandmarkAction);
+  this->RegistrationMethodsSubMenu->addAction(interactiveLandmarkAction);
 }
 
 //-----------------------------------------------------------------------------

Modules/Loadable/SubjectHierarchy/Widgets/qSlicerSubjectHierarchySegmentPlugin.cxx

@@ -73,7 +73,7 @@ class qSlicerSubjectHierarchySegmentPluginPrivate: public QObject
   void init();
 public:
   QAction* SegmentWithMenuAction;
-  QMenu* SegmentWithMenu;
+  QSharedPointer<QMenu> SegmentWithMenu;
 };
 
 //-----------------------------------------------------------------------------
@@ -84,7 +84,6 @@ qSlicerSubjectHierarchySegmentPluginPrivate::qSlicerSubjectHierarchySegmentPlugi
 : q_ptr(&object)
 {
   this->SegmentWithMenuAction = NULL;
-  this->SegmentWithMenu = NULL;
 }
 
 //-----------------------------------------------------------------------------
@@ -111,8 +110,8 @@ void qSlicerSubjectHierarchySegmentPluginPrivate::init()
   // Create top-level segment action and add it to menu
   this->SegmentWithMenuAction = new QAction("Segment this using...",q);
 
-  this->SegmentWithMenu = new QMenu();
-  this->SegmentWithMenuAction->setMenu(this->SegmentWithMenu);
+  this->SegmentWithMenu = QSharedPointer<QMenu>(new QMenu());
+  this->SegmentWithMenuAction->setMenu(this->SegmentWithMenu.data());
 
   QAction* editorAction = new QAction("Editor",q);
   QObject::connect(editorAction, SIGNAL(triggered()), q, SLOT(segmentCurrentNodeWithEditor()));
@@ -167,7 +166,7 @@ QMenu* qSlicerSubjectHierarchySegmentPlugin::segmentWithMenu()
 {
   Q_D(qSlicerSubjectHierarchySegmentPlugin);
 
-  return d->SegmentWithMenu;
+  return d->SegmentWithMenu.data();
 }
 
 //---------------------------------------------------------------------------