BGE Python API

This changes how the BGE classes and Python work together, which hasnt changed since blender went opensource.
The main difference is PyObjectPlus - the base class for most game engine classes, no longer inherit from PyObject, and cannot be cast to a PyObject.

This has the advantage that the BGE does not have to keep 2 reference counts valid for C++ and Python.

Previously C++ classes would never be freed while python held a reference, however this reference could be problematic eg: a GameObject that isnt in a scene anymore should not be used by python, doing so could even crash blender in some cases.

Instead PyObjectPlus has a member "PyObject *m_proxy" which is lazily initialized when python needs it. m_proxy reference counts are managed by python, though it should never be freed while the C++ class exists since it holds a reference to avoid making and freeing it all the time.
When the C++ class is free'd it sets the m_proxy reference to NULL, If python accesses this variable it will raise a RuntimeError, (check the isValid attribute to see if its valid without raising an error).
- This replaces the m_zombie bool and IsZombie() tests added recently.

In python return values that used to be..
 return value->AddRef();
Are now
 return value->GetProxy();
or...
 return value->NewProxy(true); // true means python owns this C++ value which will be deleted when the PyObject is freed

1 files changed, 4 insertions, 5 deletions

diff --git a/source/gameengine/Ketsji/KX_SCA_AddObjectActuator.cpp b/source/gameengine/Ketsji/KX_SCA_AddObjectActuator.cpp
index 65b654ccba4..975e6d9d6cc 100644
--- a/source/gameengine/Ketsji/KX_SCA_AddObjectActuator.cpp
+++ b/source/gameengine/Ketsji/KX_SCA_AddObjectActuator.cpp
@@ -223,7 +223,7 @@ PyObject* KX_SCA_AddObjectActuator::pyattr_get_object(void *self, const struct K
 	if (!actuator->m_OriginalObject)	
 		Py_RETURN_NONE;
 	else
-		return actuator->m_OriginalObject->AddRef();
+		return actuator->m_OriginalObject->GetProxy();
 }
 
 int KX_SCA_AddObjectActuator::pyattr_set_object(void *self, const struct KX_PYATTRIBUTE_DEF *attrdef, PyObject *value)
@@ -251,7 +251,7 @@ PyObject* KX_SCA_AddObjectActuator::pyattr_get_objectLastCreated(void *self, con
 	if (!actuator->m_lastCreatedObject)
 		Py_RETURN_NONE;
 	else
-		return actuator->m_lastCreatedObject->AddRef();
+		return actuator->m_lastCreatedObject->GetProxy();
 }
 
 
@@ -350,7 +350,7 @@ PyObject* KX_SCA_AddObjectActuator::PyGetObject(PyObject* self, PyObject* args)
 	if (ret_name_only)
 		return PyString_FromString(m_OriginalObject->GetName());
 	else
-		return m_OriginalObject->AddRef();
+		return m_OriginalObject->GetProxy();
 }
 
 
@@ -492,8 +492,7 @@ PyObject* KX_SCA_AddObjectActuator::PyGetLastCreatedObject(PyObject* self)
 	// it means the object has ended, The BGE python api crashes in many places if the object is returned.
 	if (result && (static_cast<KX_GameObject *>(result))->GetSGNode()) 
 	{
-		result->AddRef();
-		return result;
+		return result->GetProxy();
 	}
 	// don't return NULL to python anymore, it gives trouble in the scripts
 	Py_RETURN_NONE;