UPBGE: Allow KX_LibLoadStatus.onFinish to call python method. (#896)

Previously KX_LibLoadStatus finish callback was only permitted to be
python function not method.

To allow calling a method, work from EXP_RunPythonCallBackList is reused
and the calling of a python function is moved into new function
EXP_RunPythonCallback. This function is in charge of checking that the
python object is callable and construct a tuple of the arguments.

EXP_RunPythonCallback is now called into KX_LibLoadStatus::RunFinishCallback.

source/gameengine/Expressions/EXP_PythonCallBack.h

@@ -29,6 +29,14 @@
 
 #include "EXP_Python.h"
 
+/** Check and call a python callable object.
+ * \param value Callable object candidate.
+ * \param arglist The first item in the tuple to execute callbacks (can be nullptr for no arguments).
+ * \param minargcount The minimum of arguments possible.
+ * \param maxargcount The maximum of arguments possible.
+ */
+void EXP_RunPythonCallback(PyObject *value, PyObject **arglist, unsigned int minargcount, unsigned int maxargcount);
+
 /** Execute each functions with at least one argument
  * \param functionlist The python list which contains callbacks.
  * \param arglist The first item in the tuple to execute callbacks (can be nullptr for no arguments).

source/gameengine/Expressions/intern/PythonCallBack.cpp

@@ -84,29 +84,20 @@ static PyObject *CreatePythonTuple(unsigned int argcount, PyObject **arglist)
 	return tuple;
 }
 
-void EXP_RunPythonCallBackList(PyObject *functionlist, PyObject **arglist, unsigned int minargcount, unsigned int maxargcount)
+void EXP_RunPythonCallback(PyObject *value, PyObject **arglist, unsigned int minargcount, unsigned int maxargcount)
 {
-	unsigned int size = PyList_Size(functionlist);
-	PyObject **argTuples = (PyObject **)BLI_array_alloca(argTuples, maxargcount - minargcount + 1);
-	memset(argTuples, 0, sizeof(PyObject *) * (maxargcount - minargcount + 1));
-
-	for (unsigned int i = 0; i < size; ++i) {
 		unsigned int funcargcount = 0;
 
-		PyObject *item = PyList_GET_ITEM(functionlist, i);
-		PyObject *func = CheckPythonFunction(item, minargcount, maxargcount, funcargcount);
-		// This item fails the check.
+		PyObject *func = CheckPythonFunction(value, minargcount, maxargcount, funcargcount);
+		// This value fails the check.
 		if (!func) {
 			PyErr_Print();
 			PyErr_Clear();
-			continue;
+			return;
 		}
 
 		// Get correct argument tuple.
-		PyObject *tuple = argTuples[funcargcount - minargcount];
-		if (!tuple) {
-			argTuples[funcargcount - minargcount] = tuple = CreatePythonTuple(funcargcount, arglist);
-		}
+		PyObject *tuple = CreatePythonTuple(funcargcount, arglist);
 
 		PyObject *ret = PyObject_Call(func, tuple, nullptr);
 		if (!ret) { // If ret is nullptr this seems that the function doesn't work.
@@ -116,9 +107,14 @@ void EXP_RunPythonCallBackList(PyObject *functionlist, PyObject **arglist, unsig
 		else {
 			Py_DECREF(ret);
 		}
-	}
+}
+
+void EXP_RunPythonCallBackList(PyObject *functionlist, PyObject **arglist, unsigned int minargcount, unsigned int maxargcount)
+{
+	const unsigned int size = PyList_Size(functionlist);
 
-	for (unsigned int i = 0; i <= (maxargcount - minargcount); ++i) {
-		Py_XDECREF(argTuples[i]);
+	for (unsigned int i = 0; i < size; ++i) {
+		PyObject *item = PyList_GET_ITEM(functionlist, i);
+		EXP_RunPythonCallback(item, arglist, minargcount, maxargcount);
 	}
 }

source/gameengine/Ketsji/KX_LibLoadStatus.cpp

@@ -25,6 +25,9 @@
  */
 
 #include "KX_LibLoadStatus.h"
+
+#include "EXP_PythonCallBack.h"
+
 #include "PIL_time.h"
 
 KX_LibLoadStatus::KX_LibLoadStatus(BL_Converter *converter, KX_KetsjiEngine *engine, KX_Scene *merge_scene, const std::string& path)
@@ -57,14 +60,11 @@ void KX_LibLoadStatus::RunFinishCallback()
 {
 #ifdef WITH_PYTHON
 	if (m_finish_cb) {
-		PyObject *args = Py_BuildValue("(O)", GetProxy());
+		PyObject *args[] = {GetProxy()};
 
-		if (!PyObject_Call(m_finish_cb, args, nullptr)) {
-			PyErr_Print();
-			PyErr_Clear();
-		}
+		EXP_RunPythonCallback(m_finish_cb, args, 0, 1);
 
-		Py_DECREF(args);
+		Py_DECREF(args[0]);
 	}
 #endif
 }