BGE : Standardization of callbacks execution.

A new function (RunPythonCallBackList) to call all python functions
contained in a python list was developed.

This function has:
  - first argument is the python list of callbacks
  - second argument is a python list of arguments
  - third argument is the minimum quantity of arguments
  - forth argument is the maximum quantity of arguments

It improves flexibility and supports *args.

Reviewers: moguri, dfelinto, campbellbarton, sybren

Reviewed By: campbellbarton, sybren

Subscribers: sybren

Projects: #game_engine

Differential Revision: https://developer.blender.org/D1102

source/gameengine/Expressions/CMakeLists.txt

@@ -55,6 +55,7 @@ set(SRC
 	StringValue.cpp
 	Value.cpp
 	VectorValue.cpp
+	KX_PythonCallBack.cpp
 
 	BoolValue.h
 	ConstExpr.h
@@ -77,6 +78,7 @@ set(SRC
 	Value.h
 	VectorValue.h
 	VoidValue.h
+	KX_PythonCallBack.h
 )
 
 blender_add_lib(ge_logic_expressions "${SRC}" "${INC}" "${INC_SYS}")

source/gameengine/Expressions/KX_PythonCallBack.cpp

@@ -0,0 +1,116 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Contributor(s): Porteries Tristan.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file gameengine/Expressions/KX_PythonCallBack.cpp
+ *  \ingroup expressions
+ */
+
+#include "KX_PythonCallBack.h"
+#include <iostream>
+#include <stdarg.h>
+
+/** Check if a python value is a function and have the correct number of arguments.
+ * \param value The python value to check.
+ * \param minargcount The minimum of arguments possible.
+ * \param maxargcount The maximum of arguments possible.
+ * \param r_argcount The number of argument of this function, this variable will be
+ * changed in the function.
+ */
+static PyObject *CheckPythonFunction(PyObject *value, unsigned int minargcount, unsigned int maxargcount, unsigned int &r_argcount)
+{
+	if (PyMethod_Check(value)) {
+		PyCodeObject *code = ((PyCodeObject *)PyFunction_GET_CODE(PyMethod_GET_FUNCTION(value)));
+		// *args support
+		r_argcount = (code->co_flags & CO_VARARGS) ? maxargcount : (code->co_argcount - 1);
+	}
+	else if (PyFunction_Check(value)) {
+		PyCodeObject *code = ((PyCodeObject *)PyFunction_GET_CODE(value));
+		// *args support
+		r_argcount = (code->co_flags & CO_VARARGS) ? maxargcount : code->co_argcount;
+	}
+	else { // is not a methode or a function
+		PyErr_Format(PyExc_TypeError, "items must be functions or methodes, not %s",
+					 Py_TYPE(value)->tp_name);
+		return NULL;
+	}
+
+	if (r_argcount < minargcount || r_argcount >  maxargcount) {
+		// wrong number of arguments
+		PyErr_Format(PyExc_TypeError, "methode or function (%s) has invalid number of arguments (%i) must be between %i and %i",
+					 Py_TYPE(value)->tp_name, r_argcount, minargcount, maxargcount);
+		return NULL;
+	}
+
+	return value;
+}
+
+/** Create a python tuple to call a python function
+ * \param argcount The lenght of the tuple.
+ * \param arglist The fully list of python arguments [size >= argcount].
+ */
+static PyObject *CreatePythonTuple(unsigned int argcount, PyObject **arglist)
+{
+	PyObject *tuple = PyTuple_New(argcount);
+
+	for (unsigned int i = 0; i < argcount; ++i) {
+		PyObject *item = arglist[i];
+		// increment reference and copy it in a new tuple
+		Py_INCREF(item);
+		PyTuple_SET_ITEM(tuple, i, item);
+	}
+
+	return tuple;
+}
+
+void RunPythonCallBackList(PyObject *functionlist, PyObject **arglist, unsigned int minargcount, unsigned int maxargcount)
+{
+	unsigned int size = PyList_Size(functionlist);
+	PyObject *argTuples[(maxargcount - minargcount) + 1] = {NULL};
+
+	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);
+		if (!func) { // this item fails the check
+			PyErr_Print();
+			PyErr_Clear();
+			continue;
+		}
+
+		// get correct argument tuple.
+		PyObject *tuple = argTuples[funcargcount - minargcount];
+		if (!tuple)
+			argTuples[funcargcount - minargcount] = tuple = CreatePythonTuple(funcargcount, arglist);
+
+		PyObject *ret = PyObject_Call(func, tuple, NULL);
+		if (!ret) { // if ret is NULL this seems that the function doesn't work !
+			PyErr_Print();
+			PyErr_Clear();
+		}
+		else
+			Py_DECREF(ret);
+	}
+
+	for (unsigned int i = 0; i <= (maxargcount - minargcount); ++i)
+		Py_XDECREF(argTuples[i]);
+}

source/gameengine/Expressions/KX_PythonCallBack.h

@@ -0,0 +1,40 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Contributor(s): Porteries Tristan.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file KX_PythonCallBack.h
+ *  \ingroup expressions
+ */
+
+#ifndef __KX_PYTHON_CALLBACK_H__
+#define __KX_PYTHON_CALLBACK_H__
+
+#include "KX_Python.h"
+
+/** 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 NULL for no arguments).
+ * \param minargcount The minimum of quantity of arguments possible.
+ * \param maxargcount The maximum of quantity of arguments possible.
+ */
+void RunPythonCallBackList(PyObject *functionlist, PyObject **arglist, unsigned int minargcount, unsigned int maxargcount);
+
+#endif // __KX_PYTHON_CALLBACK_H__

source/gameengine/Ketsji/KX_GameObject.cpp

@@ -69,6 +69,7 @@
 #include "BL_ActionManager.h"
 #include "BL_Action.h"
 
+#include "KX_PythonCallBack.h"
 #include "PyObjectPlus.h" /* python stuff */
 #include "BLI_utildefines.h"
 #include "python_utildefines.h"
@@ -1565,67 +1566,14 @@ void KX_GameObject::RegisterCollisionCallbacks()
 void KX_GameObject::RunCollisionCallbacks(KX_GameObject *collider, const MT_Vector3 &point, const MT_Vector3 &normal)
 {
 #ifdef WITH_PYTHON
-	Py_ssize_t len;
+	if (!m_collisionCallbacks || PyList_GET_SIZE(m_collisionCallbacks) == 0)
-	PyObject* collision_callbacks = m_collisionCallbacks;
+		return;
 
-	if (collision_callbacks && (len=PyList_GET_SIZE(collision_callbacks)))
+	PyObject *args[] = {collider->GetProxy(), PyObjectFrom(point), PyObjectFrom(normal)};
-	{
+	RunPythonCallBackList(m_collisionCallbacks, args, 1, ARRAY_SIZE(args));
-		// Argument tuples are created lazily, only when they are needed.
-		PyObject *args_3 = NULL;
-		PyObject *args_1 = NULL; // Only for compatibility with pre-2.74 callbacks that take 1 argument.
 
-		PyObject *func;
+	for (unsigned int i = 0; i < ARRAY_SIZE(args); ++i) {
-		PyObject *ret;
+		Py_DECREF(args[i]);
-		int co_argcount;
-
-		// Iterate the list and run the callbacks
-		for (Py_ssize_t pos=0; pos < len; pos++)
-		{
-			func = PyList_GET_ITEM(collision_callbacks, pos);
-
-			// Get the number of arguments, supporting functions, methods and generic callables.
-			if (PyMethod_Check(func)) {
-				// Take away the 'self' argument for methods.
-				co_argcount = ((PyCodeObject *)PyFunction_GET_CODE(PyMethod_GET_FUNCTION(func)))->co_argcount - 1;
-			} else if (PyFunction_Check(func)) {
-				co_argcount = ((PyCodeObject *)PyFunction_GET_CODE(func))->co_argcount;
-			} else {
-				// We'll just assume the callable takes the correct number of arguments.
-				co_argcount = 3;
-			}
-
-			// Check whether the function expects the colliding object only,
-			// or also the point and normal.
-			if (co_argcount <= 1) {
-				// One argument, or *args (which gives co_argcount == 0)
-				if (args_1 == NULL) {
-					args_1 = PyTuple_New(1);
-					PyTuple_SET_ITEMS(args_1, collider->GetProxy());
-				}
-				ret = PyObject_Call(func, args_1, NULL);
-			} else {
-				// More than one argument, assume we can give point & normal.
-				if (args_3 == NULL) {
-					args_3 = PyTuple_New(3);
-					PyTuple_SET_ITEMS(args_3,
-					                  collider->GetProxy(),
-					                  PyObjectFrom(point),
-					                  PyObjectFrom(normal));
-				}
-				ret = PyObject_Call(func, args_3, NULL);
-			}
-
-			if (ret == NULL) {
-				PyErr_Print();
-				PyErr_Clear();
-			}
-			else {
-				Py_DECREF(ret);
-			}
-		}
-
-		if (args_3) Py_DECREF(args_3);
-		if (args_1) Py_DECREF(args_1);
 	}
 #endif
 }

source/gameengine/Ketsji/KX_Scene.cpp

@@ -43,6 +43,7 @@
 #include "KX_FontObject.h"
 #include "RAS_IPolygonMaterial.h"
 #include "ListValue.h"
+#include "KX_PythonCallBack.h"
 #include "SCA_LogicManager.h"
 #include "SCA_TimeEventManager.h"
 //#include "SCA_AlwaysEventManager.h"
@@ -2132,30 +2133,10 @@ void KX_Scene::Render2DFilters(RAS_ICanvas* canvas)
 
 void KX_Scene::RunDrawingCallbacks(PyObject *cb_list)
 {
-	Py_ssize_t len;
+	if (!cb_list || PyList_GET_SIZE(cb_list) == 0)
+		return;
 
-	if (cb_list && (len=PyList_GET_SIZE(cb_list)))
+	RunPythonCallBackList(cb_list, NULL, 0, 0);
-	{
-		PyObject *args = PyTuple_New(0); // save python creating each call
-		PyObject *func;
-		PyObject *ret;
-
-		// Iterate the list and run the callbacks
-		for (Py_ssize_t pos=0; pos < len; pos++)
-		{
-			func= PyList_GET_ITEM(cb_list, pos);
-			ret= PyObject_Call(func, args, NULL);
-			if (ret==NULL) {
-				PyErr_Print();
-				PyErr_Clear();
-			}
-			else {
-				Py_DECREF(ret);
-			}
-		}
-
-		Py_DECREF(args);
-	}
 }
 
 //----------------------------------------------------------------------------