ENH: Improve plugin factories

- Remove public setInstance function and do the cleanup in a private cleanup function
- Add PythonQtDecorator classes to be able to use the instance function as static in Python to create the factory class
- Make constructor and destructor private to prevent accidental wrong use (add PythonQtWrapper generated class as friend to allow this)
- Update usage of these factories that used the workaround to fix non-static instance function

Re commontk/CTK#970

Modules/Loadable/Markups/Widgets/qSlicerMarkupsAdditionalOptionsWidgetsFactory.cxx

@@ -38,7 +38,7 @@ class qSlicerMarkupsAdditionalOptionsWidgetsFactoryCleanup
   {
     if (qSlicerMarkupsAdditionalOptionsWidgetsFactory::Instance)
       {
-      qSlicerMarkupsAdditionalOptionsWidgetsFactory::setInstance(nullptr);
+      qSlicerMarkupsAdditionalOptionsWidgetsFactory::cleanup();
       }
   }
 };
@@ -59,23 +59,12 @@ qSlicerMarkupsAdditionalOptionsWidgetsFactory* qSlicerMarkupsAdditionalOptionsWi
 }
 
 //-----------------------------------------------------------------------------
-void qSlicerMarkupsAdditionalOptionsWidgetsFactory::setInstance(qSlicerMarkupsAdditionalOptionsWidgetsFactory* instance)
+void qSlicerMarkupsAdditionalOptionsWidgetsFactory::cleanup()
 {
-  if (qSlicerMarkupsAdditionalOptionsWidgetsFactory::Instance==instance)
-    {
-    return;
-    }
-
-  // Preferably this will be nullptr
   if (qSlicerMarkupsAdditionalOptionsWidgetsFactory::Instance)
     {
     delete qSlicerMarkupsAdditionalOptionsWidgetsFactory::Instance;
-    }
-
-  qSlicerMarkupsAdditionalOptionsWidgetsFactory::Instance = instance;
-  if (!instance)
-    {
-    return;
+    qSlicerMarkupsAdditionalOptionsWidgetsFactory::Instance = nullptr;
     }
 }
 

Modules/Loadable/Markups/Widgets/qSlicerMarkupsAdditionalOptionsWidgetsFactory.h

@@ -46,9 +46,6 @@ class Q_SLICER_MODULE_MARKUPS_WIDGETS_EXPORT qSlicerMarkupsAdditionalOptionsWidg
   /// \return Instance object
   Q_INVOKABLE static qSlicerMarkupsAdditionalOptionsWidgetsFactory* instance();
 
-  /// Allows cleanup of the singleton at application exit
-  static void setInstance(qSlicerMarkupsAdditionalOptionsWidgetsFactory* instance);
-
 public:
   /// Registers an additional options widget.
   Q_INVOKABLE bool registerAdditionalOptionsWidget(qSlicerMarkupsAdditionalOptionsWidget* widget);
@@ -67,17 +64,17 @@ class Q_SLICER_MODULE_MARKUPS_WIDGETS_EXPORT qSlicerMarkupsAdditionalOptionsWidg
 protected:
   QList<QPointer<qSlicerMarkupsAdditionalOptionsWidget>> AdditionalOptionsWidgets;
 
-public:
-  /// Private constructor made public to enable python wrapping
-  /// IMPORTANT: Should not be used for creating effect handler! Use instance() instead.
-  qSlicerMarkupsAdditionalOptionsWidgetsFactory(QObject* parent=nullptr);
+private:
+  /// Allows cleanup of the singleton at application exit
+  static void cleanup();
 
-  /// Private destructor made public to enable python wrapping
+private:
+  qSlicerMarkupsAdditionalOptionsWidgetsFactory(QObject* parent=nullptr);
   ~qSlicerMarkupsAdditionalOptionsWidgetsFactory() override;
 
-private:
   Q_DISABLE_COPY(qSlicerMarkupsAdditionalOptionsWidgetsFactory);
   friend class qSlicerMarkupsAdditionalOptionsWidgetsFactoryCleanup;
+  friend class PythonQtWrapper_qSlicerMarkupsAdditionalOptionsWidgetsFactory; // Allow Python wrapping without enabling direct instantiation
 
 private:
   /// Instance of the singleton

Modules/Loadable/Markups/Widgets/qSlicerMarkupsModuleWidgetsPythonQtDecorators.h

@@ -0,0 +1,73 @@
+/*=auto=========================================================================
+
+ Portions (c) Copyright 2005 Brigham and Women's Hospital (BWH)
+ All Rights Reserved.
+
+ See COPYRIGHT.txt
+ or http://www.slicer.org/copyright/copyright.txt for details.
+
+ Program:   3D Slicer
+
+=========================================================================auto=*/
+
+#ifndef __qSlicerMarkupsModuleWidgetsPythonQtDecorators_h
+#define __qSlicerMarkupsModuleWidgetsPythonQtDecorators_h
+
+// PythonQt includes
+#include <PythonQt.h>
+
+// Slicer includes
+#include "qSlicerMarkupsAdditionalOptionsWidgetsFactory.h"
+
+#include "qSlicerMarkupsModuleWidgetsExport.h"
+
+// NOTE:
+//
+// For decorators it is assumed that the methods will never be called
+// with the self argument as nullptr.  The self argument is the first argument
+// for non-static methods.
+//
+
+class qSlicerMarkupsModuleWidgetsPythonQtDecorators : public QObject
+{
+  Q_OBJECT
+public:
+
+  qSlicerMarkupsModuleWidgetsPythonQtDecorators()
+    {
+    //PythonQt::self()->registerClass(&qSlicerMarkupsAdditionalOptionsWidgetsFactory::staticMetaObject);
+    // Note: Use registerCPPClassForPythonQt to register pure Cpp classes
+    }
+
+public slots:
+
+  //----------------------------------------------------------------------------
+  // qSlicerMarkupsAdditionalOptionsWidgetsFactory
+
+  //----------------------------------------------------------------------------
+  // static methods
+
+  //----------------------------------------------------------------------------
+  qSlicerMarkupsAdditionalOptionsWidgetsFactory* static_qSlicerMarkupsAdditionalOptionsWidgetsFactory_instance()
+    {
+    return qSlicerMarkupsAdditionalOptionsWidgetsFactory::instance();
+    }
+
+  //----------------------------------------------------------------------------
+  // instance methods
+
+  //----------------------------------------------------------------------------
+  bool registerAdditionalOptionsWidget(qSlicerMarkupsAdditionalOptionsWidgetsFactory* factory,
+                                       PythonQtPassOwnershipToCPP<qSlicerMarkupsAdditionalOptionsWidget*> plugin)
+    {
+    return factory->registerAdditionalOptionsWidget(plugin);
+    }
+};
+
+//-----------------------------------------------------------------------------
+void initqSlicerMarkupsModuleWidgetsPythonQtDecorators()
+{
+  PythonQt::self()->addDecorators(new qSlicerMarkupsModuleWidgetsPythonQtDecorators);
+}
+
+#endif

Modules/Loadable/Segmentations/EditorEffects/Python/AbstractScriptedSegmentEditorEffect.py

@@ -44,10 +44,7 @@ def __init__(self, scriptedEffect):
     self.scriptedEffect = scriptedEffect
 
   def register(self):
-    import qSlicerSegmentationsEditorEffectsPythonQt
-    #TODO: For some reason the instance() function cannot be called as a class function although it's static
-    factory = qSlicerSegmentationsEditorEffectsPythonQt.qSlicerSegmentEditorEffectFactory()
-    effectFactorySingleton = factory.instance()
+    effectFactorySingleton = slicer.qSlicerSegmentEditorEffectFactory.instance()
     effectFactorySingleton.registerEffect(self.scriptedEffect)
 
   #

Modules/Loadable/Segmentations/EditorEffects/qSlicerSegmentEditorEffectFactory.cxx

@@ -41,7 +41,7 @@ class qSlicerSegmentEditorEffectFactoryCleanup
     {
     if (qSlicerSegmentEditorEffectFactory::m_Instance)
       {
-      qSlicerSegmentEditorEffectFactory::setInstance(nullptr);
+      qSlicerSegmentEditorEffectFactory::cleanup();
       }
     }
 };
@@ -60,21 +60,12 @@ qSlicerSegmentEditorEffectFactory* qSlicerSegmentEditorEffectFactory::instance()
 }
 
 //-----------------------------------------------------------------------------
-void qSlicerSegmentEditorEffectFactory::setInstance(qSlicerSegmentEditorEffectFactory* instance)
+void qSlicerSegmentEditorEffectFactory::cleanup()
 {
-  if (qSlicerSegmentEditorEffectFactory::m_Instance==instance)
-    {
-    return;
-    }
-  // Preferably this will be nullptr
   if (qSlicerSegmentEditorEffectFactory::m_Instance)
     {
     delete qSlicerSegmentEditorEffectFactory::m_Instance;
-    }
-  qSlicerSegmentEditorEffectFactory::m_Instance = instance;
-  if (!instance)
-    {
-    return;
+    qSlicerSegmentEditorEffectFactory::m_Instance = nullptr;
     }
 }
 

Modules/Loadable/Segmentations/EditorEffects/qSlicerSegmentEditorEffectFactory.h

@@ -45,9 +45,6 @@ class Q_SLICER_SEGMENTATIONS_EFFECTS_EXPORT qSlicerSegmentEditorEffectFactory :
   /// \return Instance object
   Q_INVOKABLE static qSlicerSegmentEditorEffectFactory* instance();
 
-  /// Allows cleanup of the singleton at application exit
-  static void setInstance(qSlicerSegmentEditorEffectFactory* instance);
-
 public:
   /// Register a effect
   /// \return True if effect registered successfully, false otherwise
@@ -69,17 +66,17 @@ class Q_SLICER_SEGMENTATIONS_EFFECTS_EXPORT qSlicerSegmentEditorEffectFactory :
   /// List of registered effect instances
   QList<qSlicerSegmentEditorAbstractEffect*> m_RegisteredEffects;
 
-public:
-  /// Private constructor made public to enable python wrapping
-  /// IMPORTANT: Should not be used for creating effect handler! Use instance() instead.
-  qSlicerSegmentEditorEffectFactory(QObject* parent=nullptr);
+private:
+  /// Allows cleanup of the singleton at application exit
+  static void cleanup();
 
-  /// Private destructor made public to enable python wrapping
+private:
+  qSlicerSegmentEditorEffectFactory(QObject* parent=nullptr);
   ~qSlicerSegmentEditorEffectFactory() override;
 
-private:
   Q_DISABLE_COPY(qSlicerSegmentEditorEffectFactory);
   friend class qSlicerSegmentEditorEffectFactoryCleanup;
+  friend class PythonQtWrapper_qSlicerSegmentEditorEffectFactory; // Allow Python wrapping without enabling direct instantiation
 
 private:
   /// Instance of the singleton

Modules/Loadable/Segmentations/EditorEffects/qSlicerSegmentationsEditorEffectsPythonQtDecorators.h

@@ -0,0 +1,73 @@
+/*=auto=========================================================================
+
+ Portions (c) Copyright 2005 Brigham and Women's Hospital (BWH)
+ All Rights Reserved.
+
+ See COPYRIGHT.txt
+ or http://www.slicer.org/copyright/copyright.txt for details.
+
+ Program:   3D Slicer
+
+=========================================================================auto=*/
+
+#ifndef __qSlicerSegmentationsEditorEffectsPythonQtDecorators_h
+#define __qSlicerSegmentationsEditorEffectsPythonQtDecorators_h
+
+// PythonQt includes
+#include <PythonQt.h>
+
+// Slicer includes
+#include "qSlicerSegmentEditorEffectFactory.h"
+
+#include "qSlicerSegmentationsEditorEffectsExport.h"
+
+// NOTE:
+//
+// For decorators it is assumed that the methods will never be called
+// with the self argument as nullptr.  The self argument is the first argument
+// for non-static methods.
+//
+
+class qSlicerSegmentationsEditorEffectsPythonQtDecorators : public QObject
+{
+  Q_OBJECT
+public:
+
+  qSlicerSegmentationsEditorEffectsPythonQtDecorators()
+    {
+    //PythonQt::self()->registerClass(&qSlicerSegmentEditorEffectFactory::staticMetaObject);
+    // Note: Use registerCPPClassForPythonQt to register pure Cpp classes
+    }
+
+public slots:
+
+  //----------------------------------------------------------------------------
+  // qSlicerSegmentEditorEffectFactory
+
+  //----------------------------------------------------------------------------
+  // static methods
+
+  //----------------------------------------------------------------------------
+  qSlicerSegmentEditorEffectFactory* static_qSlicerSegmentEditorEffectFactory_instance()
+    {
+    return qSlicerSegmentEditorEffectFactory::instance();
+    }
+
+  //----------------------------------------------------------------------------
+  // instance methods
+
+  //----------------------------------------------------------------------------
+  bool registerEffect(qSlicerSegmentEditorEffectFactory* factory,
+                      PythonQtPassOwnershipToCPP<qSlicerSegmentEditorAbstractEffect*> plugin)
+    {
+    return factory->registerEffect(plugin);
+    }
+};
+
+//-----------------------------------------------------------------------------
+void initqSlicerSegmentationsEditorEffectsPythonQtDecorators()
+{
+  PythonQt::self()->addDecorators(new qSlicerSegmentationsEditorEffectsPythonQtDecorators);
+}
+
+#endif

Modules/Loadable/SubjectHierarchy/Widgets/qSlicerSubjectHierarchyPluginHandler.cxx

@@ -55,7 +55,7 @@ class qSlicerSubjectHierarchyPluginHandlerCleanup
     {
     if (qSlicerSubjectHierarchyPluginHandler::m_Instance)
       {
-      qSlicerSubjectHierarchyPluginHandler::setInstance(nullptr);
+      qSlicerSubjectHierarchyPluginHandler::cleanup();
       }
     }
 };
@@ -74,21 +74,12 @@ qSlicerSubjectHierarchyPluginHandler* qSlicerSubjectHierarchyPluginHandler::inst
 }
 
 //-----------------------------------------------------------------------------
-void qSlicerSubjectHierarchyPluginHandler::setInstance(qSlicerSubjectHierarchyPluginHandler* instance)
+void qSlicerSubjectHierarchyPluginHandler::cleanup()
 {
-  if (qSlicerSubjectHierarchyPluginHandler::m_Instance==instance)
-    {
-    return;
-    }
-  // Preferably this will be nullptr
   if (qSlicerSubjectHierarchyPluginHandler::m_Instance)
     {
     delete qSlicerSubjectHierarchyPluginHandler::m_Instance;
-    }
-  qSlicerSubjectHierarchyPluginHandler::m_Instance = instance;
-  if (!instance)
-    {
-    return;
+    qSlicerSubjectHierarchyPluginHandler::m_Instance = nullptr;
     }
 }
 

Modules/Loadable/SubjectHierarchy/Widgets/qSlicerSubjectHierarchyPluginHandler.h

@@ -83,9 +83,6 @@ class Q_SLICER_MODULE_SUBJECTHIERARCHY_WIDGETS_EXPORT qSlicerSubjectHierarchyPlu
   /// \return Instance object
   Q_INVOKABLE static qSlicerSubjectHierarchyPluginHandler* instance();
 
-  /// Allows cleanup of the singleton at application exit
-  static void setInstance(qSlicerSubjectHierarchyPluginHandler* instance);
-
   /// Get subject hierarchy node
   Q_INVOKABLE vtkMRMLSubjectHierarchyNode* subjectHierarchyNode()const;
   /// Set MRML scene
@@ -226,19 +223,20 @@ class Q_SLICER_MODULE_SUBJECTHIERARCHY_WIDGETS_EXPORT qSlicerSubjectHierarchyPlu
   vtkSmartPointer<vtkCallbackCommand> m_CallBack;
 
 public:
-  /// Private constructor made public to enable python wrapping
-  /// IMPORTANT: Should not be used for creating plugin handler! Use instance() instead.
-  qSlicerSubjectHierarchyPluginHandler(QObject* parent=nullptr);
-
-  /// Private destructor made public to enable python wrapping
-  ~qSlicerSubjectHierarchyPluginHandler() override;
-
   /// Timestamp of the last plugin registration. Used to allow context menus be repopulated if needed.
   QDateTime LastPluginRegistrationTime;
 
 private:
+  /// Allows cleanup of the singleton at application exit
+  static void cleanup();
+
+private:
+  qSlicerSubjectHierarchyPluginHandler(QObject* parent=nullptr);
+  ~qSlicerSubjectHierarchyPluginHandler() override;
+
   Q_DISABLE_COPY(qSlicerSubjectHierarchyPluginHandler);
   friend class qSlicerSubjectHierarchyPluginHandlerCleanup;
+  friend class PythonQtWrapper_qSlicerSubjectHierarchyPluginHandler; // Allow Python wrapping without enabling direct instantiation
 
 private:
   /// Instance of the singleton

Modules/Scripted/SegmentEditor/SegmentEditor.py

@@ -64,10 +64,7 @@ def setup(self):
     # Observe editor effect registrations to make sure that any effects that are registered
     # later will show up in the segment editor widget. For example, if Segment Editor is set
     # as startup module, additional effects are registered after the segment editor widget is created.
-    import qSlicerSegmentationsEditorEffectsPythonQt
-    #TODO: For some reason the instance() function cannot be called as a class function although it's static
-    factory = qSlicerSegmentationsEditorEffectsPythonQt.qSlicerSegmentEditorEffectFactory()
-    self.effectFactorySingleton = factory.instance()
+    self.effectFactorySingleton = slicer.qSlicerSegmentEditorEffectFactory.instance()
     self.effectFactorySingleton.connect('effectRegistered(QString)', self.editorEffectRegistered)
 
     # Connect observers to scene events