Object.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2017 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#pragma once
 
#include "MantidPythonInterface/core/ErrorHandling.h"
#include "MantidPythonInterface/core/GlobalInterpreterLock.h"
#include <boost/python/borrowed.hpp>
#include <boost/python/dict.hpp>
#include <boost/python/list.hpp>
#include <boost/python/object.hpp>
 
namespace MantidQt {
namespace Widgets {
namespace Common {
namespace Python {
 
// Alias for boost python object/dict/list wrapper
using Object = boost::python::object;
using Dict = boost::python::dict;
using List = boost::python::list;
 
// Alias for handle wrapping a raw PyObject*
template <typename T = PyObject> using Handle = boost::python::handle<T>;
 
// Alias for type to convert a C++ object to a Python object
template <typename T> using ToPythonValue = boost::python::to_python_value<T>;
 
// Helper to forward to boost python
inline ssize_t Len(const Python::Object &obj) { return boost::python::len(obj); }
 
// Helper to create an Object from a new reference to a raw PyObject*
inline Python::Object NewRef(PyObject *obj) {
  if (!obj) {
    throw Mantid::PythonInterface::PythonException();
  }
  return Python::Object(Python::Handle<>(obj));
}
 
// Helper to create an Object from a borrowed reference to a raw PyObject*
inline Python::Object BorrowedRef(PyObject *obj) {
  if (!obj) {
    throw Mantid::PythonInterface::PythonException();
  }
  return Python::Object(Python::Handle<>(boost::python::borrowed(obj)));
}
 
// Alias for exception indicating Python error handler is set
using ErrorAlreadySet = boost::python::error_already_set;
 
class InstanceHolder {
public:
  explicit InstanceHolder(Object obj) : m_instance(std::move(obj)) {}
 
  InstanceHolder(Object obj, const char *attr) : m_instance(std::move(obj)) {
    Mantid::PythonInterface::GlobalInterpreterLock lock;
    if (PyObject_HasAttrString(pyobj().ptr(), attr) == 0) {
      throw std::invalid_argument(std::string(pyobj().ptr()->ob_type->tp_name) + " has no attribute " + attr);
    }
  }
 
  ~InstanceHolder() {
    Mantid::PythonInterface::GlobalInterpreterLock lock;
    m_instance = Python::Object(); // none
  }
 
  inline const Object &pyobj() const { return m_instance; }
 
private:
  Object m_instance;
};
 
} // namespace Python
} // namespace Common
} // namespace Widgets
} // namespace MantidQt