PyCore/Sample/ImportMultiLayer: avoid cyclic dependence on MultiLayer module;...

PyCore/Sample/ImportMultiLayer: avoid cyclic dependence on MultiLayer module; rm usage of Result class

GUI/View/Project/PyImportAssistant.cpp

@@ -103,9 +103,12 @@ QString readFile(const QString& fileName)
 std::unique_ptr<MultiLayer> createMultiLayer(const QString& snippet, const QString& funcName)
 {
     QApplication::setOverrideCursor(Qt::WaitCursor);
+    void* result_ptr = nullptr;
+    PyObjectPtr result{PythonInterpreter::createMultiLayerFromPython(
+            snippet.toStdString(), funcName.toStdString(), bornagainDir(), result_ptr)};
 
-    Result<std::unique_ptr<MultiLayer>> result{PythonInterpreter::createMultiLayerFromPython(
-        snippet.toStdString(), funcName.toStdString(), bornagainDir())};
+    std::unique_ptr<MultiLayer> multilayer_ptr(
+        reinterpret_cast<MultiLayer*>(result_ptr)->clone());
 
     if (!result.valid()) {
         QApplication::restoreOverrideCursor();
@@ -116,7 +119,7 @@ std::unique_ptr<MultiLayer> createMultiLayer(const QString& snippet, const QStri
 
     QApplication::restoreOverrideCursor();
 
-    return std::move(result.val);
+    return std::move(multilayer_ptr);
 }
 
 //! Lets user select a function name which generates a MultiLayer.

PyCore/Sample/ImportMultiLayer.cpp

 #ifdef BORNAGAIN_PYTHON
 
-#include "ImportMultiLayer.h"
 #include "PyCore/Embed/PyCore.h"
+#include "ImportMultiLayer.h"
 #include "PyCore/Embed/PythonInterpreter.h" // BornAgain::importScript
-#include "Sample/Multilayer/MultiLayer.h"
+
 // SWIG runtime access for creating a MultiLayer instance from Python
 #include "auto/Wrap/swig_runtime.h"
 
 
 namespace PythonInterpreter {
 
-Result<std::unique_ptr<MultiLayer>> createMultiLayerFromPython(const std::string& script,
-                                                               const std::string& functionName,
-                                                               const std::string& path)
+PyObjectPtr createMultiLayerFromPython(void*& multilayer_ptr,
+                                       const std::string& script,
+                                       const std::string& functionName,
+                                       const std::string& path)
 {
     PyObjectPtr tmpModule{PythonInterpreter::BornAgain::importScript(script, path)};
 
     // locate the `get_simulation` function (it is an attribute of the module)
     PyObject* pAddFn = PyObject_GetAttrString(tmpModule.ptr, functionName.c_str());
     if (!pAddFn) {
-        std::stringstream msg_ss;
-        msg_ss << "PythonInterpreter::BornAgain: "
-               << "Cannot locate the compiled function '" << functionName << "'";
-        return {Status(Status::Type::Error, msg_ss.str())};
+        std::string msg = "PythonInterpreter::BornAgain: "
+            "Cannot locate the compiled function '" + functionName + "'";
+        return {Status(Status::Type::Error, msg)};
     }
 
     // create a `MultiLayer` Python object via calling the function
@@ -32,10 +32,9 @@ Result<std::unique_ptr<MultiLayer>> createMultiLayerFromPython(const std::string
     Py_DecRef(pAddFn);
 
     if (!instance) {
-        std::stringstream msg_ss;
-        msg_ss << "PythonInterpreter::BornAgain: "
-               << "Cannot call the function '" << functionName << "'";
-        return {Status(Status::Type::Error, PythonInterpreter::errorDescription(msg_ss.str()))};
+        std::string msg = "PythonInterpreter::BornAgain: "
+            "Cannot call the function '" + functionName + "'";
+        return {Status(Status::Type::Error, PythonInterpreter::errorDescription(msg))};
     }
 
     // Construct a C++ object from the Python object
@@ -49,20 +48,13 @@ Result<std::unique_ptr<MultiLayer>> createMultiLayerFromPython(const std::string
     const int res = SWIG_ConvertPtr(instance, &argp1, pTypeInfo, 0);
     if (!SWIG_IsOK(res)) {
         Py_DecRef(instance);
-        std::stringstream msg_ss;
-        msg_ss << "PythonInterpreter::BornAgain: "
-               << "SWIG failed to extract a 'MultiLayer' instance "
-               << "via calling the function '" << functionName << "'";
-        return {Status(Status::Type::Error, PythonInterpreter::errorDescription(msg_ss.str()))};
+        std::string msg = "PythonInterpreter::BornAgain: SWIG failed to extract a "
+            "'MultiLayer' instance via calling the function '" + functionName + "'";
+        return {Status(Status::Type::Error, PythonInterpreter::errorDescription(msg))};
     }
 
-    MultiLayer* multilayer = reinterpret_cast<MultiLayer*>(argp1);
-    std::unique_ptr<MultiLayer> result_ptr(multilayer->clone());
-
-    Py_DecRef(instance);
-
-    // TODO: check if it is possible to move a unique_ptr
-    return {std::move(result_ptr)};
+    multilayer_ptr = reinterpret_cast<void*>(argp1);
+    return {instance};
 }
 
 } // namespace PythonInterpreter

PyCore/Sample/ImportMultiLayer.h

+#ifndef BORNAGAIN_PYCORE_MULTILAYER_H
+#define BORNAGAIN_PYCORE_MULTILAYER_H
+
 #ifndef SWIG
 
-#include "PyCore/Embed/PyObjectDecl.h"
-#include "PyCore/Embed/Result.h"
-#include <memory> // unique_ptr
+#include "PyCore/Embed/PyObjectPtr.h"
 #include <string>
 
 class MultiLayer;
@@ -13,10 +14,14 @@ namespace PythonInterpreter {
 //! @param script: Python script
 //! @param functionName: A function name in this script which produces a MultiLayer
 //! @param path: A path to import BornAgain library. If empty, relies on PYTHONPATH
-Result<std::unique_ptr<MultiLayer>> createMultiLayerFromPython(const std::string& script,
-                                                               const std::string& functionName,
-                                                               const std::string& path = "");
+//! @param multilayer_ptr: a void pointer to the resulting MultiLayer instance in C++
+PyObjectPtr createMultiLayerFromPython(void*& multilayer_ptr,
+                                       const std::string& script,
+                                       const std::string& functionName,
+                                       const std::string& path = "");
 
 } // namespace PythonInterpreter
 
 #endif // SWIG
+
+#endif // BORNAGAIN_PYCORE_MULTILAYER_H