DataServiceExporter.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2014 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 "MantidKernel/DataService.h"
#include "MantidKernel/Exception.h"
#include "MantidPythonInterface/core/ReleaseGlobalInterpreterLock.h"
#include "MantidPythonInterface/core/WeakPtr.h"
 
#include <boost/python/class.hpp>
#include <boost/python/extract.hpp>
#include <boost/python/list.hpp>
#include <boost/python/str.hpp>
 
#include <memory>
#include <set>
 
namespace Mantid {
namespace PythonInterface {
template <typename SvcType, typename SvcPtrType> struct DataServiceExporter {
  // typedef the type created by boost.python
  using PythonType = boost::python::class_<SvcType, boost::noncopyable>;
  using WeakPtr = std::weak_ptr<typename SvcPtrType::element_type>;
 
  static PythonType define(const char *pythonClassName) {
    using namespace boost::python;
    using namespace Mantid::Kernel;
 
    auto classType =
        PythonType(pythonClassName, no_init)
            .def("add", &DataServiceExporter::addItem, (arg("self"), arg("name"), arg("item")),
                 "Adds the given object to the service with the given name. If "
                 "the name/object exists it will raise an error.")
            .def("addOrReplace", &DataServiceExporter::addOrReplaceItem, (arg("self"), arg("name"), arg("item")),
                 "Adds the given object to the service with the given name. "
                 "The the name exists the object is replaced.")
            .def("doesExist", &SvcType::doesExist, (arg("self"), arg("name")),
                 "Returns True if the object is found in the service.")
            .def("retrieve", &DataServiceExporter::retrieveOrKeyError, (arg("self"), arg("name")),
                 "Retrieve the named object. Raises an exception if the name "
                 "does not exist")
            .def("remove", &DataServiceExporter::removeItem, (arg("self"), arg("name")), "Remove a named object")
            .def("clear", &DataServiceExporter::clearItems, arg("self"), "Removes all objects managed by the service.")
            .def("size", &SvcType::size, arg("self"), "Returns the number of objects within the service")
            .def("getObjectNames", &DataServiceExporter::getObjectNamesAsList, (arg("self"), arg("contain") = ""),
                 "Return the list of names currently known to the ADS")
 
            // Make it act like a dictionary
            .def("__len__", &SvcType::size, arg("self"))
            .def("__getitem__", &DataServiceExporter::retrieveOrKeyError, (arg("self"), arg("name")))
            .def("__setitem__", &DataServiceExporter::addOrReplaceItem, (arg("self"), arg("name"), arg("item")))
            .def("__contains__", &SvcType::doesExist, (arg("self"), arg("name")))
            .def("__delitem__", &DataServiceExporter::removeItem, (arg("self"), arg("name")));
 
    return classType;
  }
 
  static void addItem(SvcType &self, const std::string &name, const boost::python::object &item) {
    ReleaseGlobalInterpreterLock releaseGIL;
    self.add(name, extractCppValue(item));
  }
 
  static void addOrReplaceItem(SvcType &self, const std::string &name, const boost::python::object &item) {
    ReleaseGlobalInterpreterLock releaseGIL;
    self.addOrReplace(name, extractCppValue(item));
  }
 
  static void removeItem(SvcType &self, const std::string &name) {
    ReleaseGlobalInterpreterLock releaseGIL;
    self.remove(name);
  }
 
  static void clearItems(SvcType &self) {
    ReleaseGlobalInterpreterLock releaseGIL;
    self.clear();
  }
 
  static SvcPtrType extractCppValue(const boost::python::object &pyvalue) {
    // Test for a weak pointer first
    boost::python::extract<WeakPtr &> extractWeak(pyvalue);
    if (extractWeak.check()) {
      return extractWeak().lock();
    }
    boost::python::extract<SvcPtrType &> extractRefShared(pyvalue);
    if (extractRefShared.check()) {
      return extractRefShared();
    } else {
      throw std::invalid_argument("Cannot extract pointer from Python object argument. Incorrect type");
    }
  }
 
  static WeakPtr retrieveOrKeyError(SvcType &self, const std::string &name) {
    using namespace Mantid::Kernel;
 
    SvcPtrType item;
    try {
      item = self.retrieve(name);
    } catch (Exception::NotFoundError &) {
      // Translate into a Python KeyError
      std::string err = "'" + name + "' does not exist.";
      PyErr_SetString(PyExc_KeyError, err.c_str());
      throw boost::python::error_already_set();
    }
    return WeakPtr(item);
  }
 
  static boost::python::list getObjectNamesAsList(SvcType const *const self, const std::string &contain) {
    boost::python::list names;
    const auto keys = self->getObjectNames(Mantid::Kernel::DataServiceSort::Unsorted,
                                           Mantid::Kernel::DataServiceHidden::Auto, contain);
    for (auto itr = keys.begin(); itr != keys.end(); ++itr) {
      names.append(*itr);
    }
    assert(names.attr("__len__")() == keys.size());
    return names;
  }
};
} // namespace PythonInterface
} // namespace Mantid