Ndtyjky

I have a project which need to call Python scripts from C++, because I have many objects which need to call Python, so I write a common class; which like the below:

  PythonTunerIntf * PythonTunerIntf::instance()

    {

        if (instance_ == nullptr)

        {

            instance_ = new PythonTunerIntf();

        }

        return instance_;

    }



    void PythonTunerIntf::release()

    {

        if (instance_)

        {

            delete instance_;

            instance_ = nullptr;

        }

    }



    //the below function is used to get the path accessable from python interpretor

    void PythonTunerIntf::append_path(std::string path)

    {

        PyObject* sysPath = PySys_GetObject((char*)"path");

        PyObject* curDir = PyUnicode_FromString(path.c_str());

        PyList_Append(sysPath, curDir);

        Py_DECREF(curDir);

    }



    //import the module from the path

    void PythonTunerIntf::append_file(std::string file_name)

    {

        PyObject* pName = PyUnicode_FromString(file_name.c_str());

        pModule = PyImport_Import(pName);

        Py_DECREF(pName);

        //assert(pModule != nullptr);

        if (pModule == nullptr)

        {

            printf("not able to load python script %sn", file_name.c_str());

            PyErr_Print();

        }

    }





    //the below two functions set the needed parameters from C++

    void PythonTunerIntf::append_item(std::string key, Python_Intf_Args val)

    {

        m_values.push_back(std::make_pair(key, val));

    }



    void PythonTunerIntf::buildValues()

    {

        for (auto val : m_values)

        {

            PyObject* param_key = Py_BuildValue("s", val.first.c_str());

            PyObject* param_val = (val.second.type == Python_Intf_Args::INT) ? Py_BuildValue("i", val.second.int_arg)

                : Py_BuildValue("s", val.second.str_arg.c_str());

            PyDict_SetItem(pFunc_params, param_key, param_val);

            Py_DECREF(param_key);

            Py_DECREF(param_val);

        }

    }



    //get started to call python, and read the returned values to C++

    std::vector<std::pair<std::string, float> > PythonTunerIntf::call_func(std::string func_name)

    {

        std::vector<std::pair<std::string, float> > returned_data;

        pFunc = PyObject_GetAttrString(pModule, func_name.c_str());

        Py_DECREF(pModule);

        if (pFunc && PyCallable_Check(pFunc))

        {

            PyObject* returned_item = PyObject_CallFunctionObjArgs(pFunc, pFunc_params, NULL);

            Py_DECREF(pFunc);

            Py_DECREF(pFunc_params);

            assert(returned_item != nullptr);

            assert(PyDict_Check(returned_item));

            PyObject *key, *value;

            Py_ssize_t pos = 0;

            while (PyDict_Next(returned_item, &pos, &key, &value))

            {

                assert(PyUnicode_Check(key));

                if (PyFloat_Check(value))

                {

                    double result_value{ PyFloat_AsDouble(value) };

                    float result = static_cast<float>(result_value);

                    ssize_t size{ PyUnicode_GetSize(key) };

                    wchar_t *wstr = (wchar_t*)malloc(sizeof(wchar_t) * size);

                    PyUnicode_AsWideChar(key, wstr, size);

                    std::wstring wide(wstr, size);

                    std::string result_key{ wide.begin(), wide.end() };

                    returned_data.emplace_back(std::make_pair(result_key, result_value));

                    free(wstr);

                }

                else if (PyLong_Check(value))

                {

                    long result_value{ PyLong_AsLong(value) };

                    float result = static_cast<float>(result_value);

                    ssize_t size{ PyUnicode_GetSize(key) };

                    wchar_t *wstr = (wchar_t*)malloc(sizeof(wchar_t) * size);

                    PyUnicode_AsWideChar(key, wstr, size);

                    std::wstring wide(wstr, size);

                    std::string result_key{ wide.begin(), wide.end() };

                    returned_data.emplace_back(std::make_pair(result_key, result_value));

                    free(wstr);

                }

                Py_DECREF(key);

                Py_DECREF(value);

            }

            Py_DECREF(returned_item);

            PyDict_Clear(pFunc_params);

        }

        m_values.clear();

        return returned_data;

    }





    PythonTunerIntf::~PythonTunerIntf()

    {

        Py_XDECREF(pFunc_params);

        Py_Finalize();

    }







    PythonTunerIntf::PythonTunerIntf()

    {

        Py_Initialize();

        if (!Py_IsInitialized())

        {

            std::runtime_error("canot initialize Python interpreter");

        }

        pFunc_params = PyDict_New();

        assert(pFunc_params != nullptr);



        pModule = nullptr;

        pFunc = nullptr;

    }

When I call this class's instance the second time, will crash, the message in visual studio gives "Exception thrown: read access violation.
bp was 0xFFFFFFFFFFFFFFFF."

the call stack is

python36.dll!_PyObject_Alloc(int use_calloc, void * nelem, unsigned __int64 elsize, unsigned __int64) Line 1258 C

python36.dll!parsetok(tok_state * tok, grammar * g, int start, perrdetail * err_ret, int * flags) Line 229  C

python36.dll!PyParser_ParseStringObject(const char * s, _object * filename, grammar * g, int start, perrdetail * err_ret, int * flags) Line 68  C

python36.dll!PyParser_ASTFromStringObject(const char * s, _object * filename, int start, PyCompilerFlags * flags, _arena * arena) Line 1118 C

python36.dll!Py_CompileStringObject(const char * str, _object * filename, int start, PyCompilerFlags * flags, int optimize) Line 1033   C

python36.dll!builtin_compile_impl(_object * source, _object * filename, _object * mode, const char * flags, int dont_inherit, int optimize, int) Line 774   C

python36.dll!builtin_compile(_object * module, _object * * args, __int64 nargs, _object * kwnames) Line 175 C

python36.dll!_PyCFunction_FastCallDict(_object * func_obj, _object * * args, __int64 nargs, _object * kwargs) Line 250  C

python36.dll!_PyEval_EvalFrameDefault(_frame * f, int throwflag) Line 3377  C

python36.dll!_PyEval_EvalCodeWithName(_object * _co, _object * globals, _object * locals, _object * * args, __int64 argcount, _object * * kwnames, _object * * kwargs, __int64 kwcount, int kwstep, _object * * defs, __int64 defcount, _object * kwdefs, _object * closure, _object * name, _object * qualname) Line 4139  C

python36.dll!call_function(_object * * * pp_stack, __int64 oparg, _object * kwnames) Line 4830  C

python36.dll!_PyEval_EvalFrameDefault(_frame * f, int throwflag) Line 3313  C

python36.dll!_PyEval_EvalCodeWithName(_object * _co, _object * globals, _object * locals, _object * * args, __int64 argcount, _object * * kwnames, _object * * kwargs, __int64 kwcount, int kwstep, _object * * defs, __int64 defcount, _object * kwdefs, _object * closure, _object * name, _object * qualname) Line 4139  C

python36.dll!call_function(_object * * * pp_stack, __int64 oparg, _object * kwnames) Line 4830  C

python36.dll!_PyEval_EvalFrameDefault(_frame * f, int throwflag) Line 3297  C

python36.dll!call_function(_object * * * pp_stack, __int64 oparg, _object * kwnames) Line 4830  C

python36.dll!_PyEval_EvalFrameDefault(_frame * f, int throwflag) Line 3297  C

python36.dll!call_function(_object * * * pp_stack, __int64 oparg, _object * kwnames) Line 4830  C

python36.dll!_PyEval_EvalFrameDefault(_frame * f, int throwflag) Line 3297  C

python36.dll!call_function(_object * * * pp_stack, __int64 oparg, _object * kwnames) Line 4830  C

python36.dll!_PyEval_EvalFrameDefault(_frame * f, int throwflag) Line 3297  C

python36.dll!call_function(_object * * * pp_stack, __int64 oparg, _object * kwnames) Line 4830  C

python36.dll!_PyEval_EvalFrameDefault(_frame * f, int throwflag) Line 3297  C

python36.dll!_PyFunction_FastCallDict(_object * func, _object * * args, __int64 nargs, _object * kwargs) Line 4993  C

python36.dll!_PyObject_FastCallDict(_object * func, _object * * args, __int64 nargs, _object * kwargs) Line 2296    C

python36.dll!_PyObject_CallMethodIdObjArgs(_object * callable, _Py_Identifier * name, ...) Line 2782    C

python36.dll!PyImport_ImportModuleLevelObject(_object * name, _object * globals, _object * locals, _object * fromlist, int level) Line 1592 C

python36.dll!builtin___import__(_object * self, _object * args, _object * kwds) Line 233    C

python36.dll!PyCFunction_Call(_object * func, _object * args, _object * kwds) Line 99   C

python36.dll!PyObject_Call(_object * func, _object * args, _object * kwargs) Line 2246  C

python36.dll!call_function_tail(_object * callable, _object * args) Line 2501   C

python36.dll!PyObject_CallFunction(_object * callable, const char * format, ...) Line 2525  C

python36.dll!PyImport_Import(_object * module_name) Line 1781   C 

Any suggestions on the PythonTunerIntf class implementation? I don't which part will have memory leakage.