[DLStreamer] Implemented Python's module loader.

libraries/dl-streamer/src/monolithic/gst/elements/gvapython/python_callback.cpp

@@ -54,6 +54,91 @@ gboolean callPython(GstBuffer *buffer, GstCaps *caps, PyObjectWrapper &py_frame_
 }
 } // namespace
 
+// This function safely imports a Python module from a given file path using Python's importlib.
+// It generates and executes Python code to load the module, handling errors and reporting them.
+// Arguments:
+//   module_name - the name to assign to the imported module in sys.modules
+//   file_path   - the path to the Python file (without .py extension)
+// Returns:
+//   A PyObject* pointer to the imported module, or NULL on error.
+PyObject *import_module_full_path(const char *module_name, const char *file_path) {
+    // Allocate memory for the file path with .py extension
+    char *pStr = new char[strlen(file_path) + 3];
+    sprintf(pStr, "%s.py", file_path);
+
+    // Prepare Python code to import the module safely
+    char python_code[4096];
+    snprintf(python_code, sizeof(python_code),
+             "import importlib.util\n"
+             "import sys\n"
+             "import os\n"
+             "\n"
+             "module_name = '%s'\n"
+             "file_path = r'%s'\n"
+             "\n"
+             "try:\n"
+             "    # Check if file exists\n"
+             "    if not os.path.exists(file_path):\n"
+             "        raise FileNotFoundError(f'Python module file not found: {file_path}')\n"
+             "    \n"
+             "    # Create spec\n"
+             "    spec = importlib.util.spec_from_file_location(module_name, file_path)\n"
+             "    if spec is None:\n"
+             "        raise ImportError(f'Cannot create spec for {file_path}')\n"
+             "    \n"
+             "    # Create module\n"
+             "    module = importlib.util.module_from_spec(spec)\n"
+             "    if module is None:\n"
+             "        raise ImportError('Cannot create module from spec')\n"
+             "    \n"
+             "    # Add to sys.modules\n"
+             "    sys.modules[module_name] = module\n"
+             "    \n"
+             "    # Execute module\n"
+             "    spec.loader.exec_module(module)\n"
+             "    \n"
+             "    imported_module = module\n"
+             "    success = True\n"
+             "    error_msg = 'OK'\n"
+             "\n"
+             "except Exception as e:\n"
+             "    imported_module = None\n"
+             "    success = False\n"
+             "    error_msg = f'{type(e).__name__}: {str(e)}'\n",
+             module_name, pStr);
+
+    PyObject *main_module = PyImport_AddModule("__main__");
+    PyObject *main_dict = PyModule_GetDict(main_module);
+
+    if (PyRun_String(python_code, Py_file_input, main_dict, main_dict) == NULL) {
+        printf("Error PyRun_String\n");
+        PyErr_Print();
+        return NULL;
+    }
+
+    // Check result
+    PyObject *success = PyDict_GetItemString(main_dict, "success");
+    if (success && success == Py_True) {
+        PyObject *module = PyDict_GetItemString(main_dict, "imported_module");
+        if (module != NULL) {
+            Py_INCREF(module);
+            if (pStr)
+                delete[] pStr;
+            return module;
+        }
+    } else {
+        PyObject *error = PyDict_GetItemString(main_dict, "error_msg");
+        if (error && PyUnicode_Check(error)) {
+            printf("Error: %s\n", PyUnicode_AsUTF8(error));
+        }
+    }
+
+    if (pStr)
+        delete[] pStr;
+
+    return NULL;
+}
+
 PythonContextInitializer::PythonContextInitializer() {
     state = PyGILState_UNLOCKED;
     if (Py_IsInitialized()) {
@@ -122,7 +207,7 @@ PythonCallback::PythonCallback(const char *module_path, const char *class_name,
         module_name = std::string(filename, extension);
     }
 
-    PyObjectWrapper pluginModule(PyImport_Import(WRAPPER(PyUnicode_FromString(module_name.c_str()))));
+    PyObjectWrapper pluginModule = import_module_full_path(module_name.c_str(), module_path);
     if (!(PyObject *)pluginModule) {
         log_python_error(nullptr, false);
         throw std::runtime_error("Error loading Python module " + std::string(module_path));