Alexandria  2.19
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InstOrRefHolder.icpp
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1 /*
2  * Copyright (C) 2012-2021 Euclid Science Ground Segment
3  *
4  * This library is free software; you can redistribute it and/or modify it under
5  * the terms of the GNU Lesser General Public License as published by the Free
6  * Software Foundation; either version 3.0 of the License, or (at your option)
7  * any later version.
8  *
9  * This library is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
12  * details.
13  *
14  * You should have received a copy of the GNU Lesser General Public License
15  * along with this library; if not, write to the Free Software Foundation, Inc.,
16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 /*
20  * @file InstOrRefHolder.icpp
21  * @author nikoapos
22  */
23 
24 #include "AlexandriaKernel/memory_tools.h"
25 #include <type_traits>
26 
27 namespace Euclid {
28 
29 namespace InstOrRefHolder_Impl {
30 
31 template <typename InterfaceType, typename InstanceType>
32 struct InstHolder_Impl : public InstOrRefHolder<InterfaceType> {
33  template <typename... Args>
34  InstHolder_Impl(Args... args) : m_instance(std::forward<Args>(args)...) {}
35  virtual ~InstHolder_Impl() = default;
36  InterfaceType& ref() override {
37  return m_instance;
38  }
39 
40 private:
41  InstanceType m_instance;
42 };
43 
44 template <typename InterfaceType>
45 struct RefHolder_Impl : public InstOrRefHolder<InterfaceType> {
46  RefHolder_Impl(InterfaceType& ref_) : m_reference(ref_) {}
47  virtual ~RefHolder_Impl() = default;
48  InterfaceType& ref() override {
49  return m_reference.get();
50  }
51 
52 private:
53  std::reference_wrapper<InterfaceType> m_reference;
54 };
55 
56 } // end of namespace InstOrRefHolder_Impl
57 
58 template <typename InterfaceType>
59 template <typename InstanceType, typename... Args>
60 std::unique_ptr<InstOrRefHolder<InterfaceType>> InstOrRefHolder<InterfaceType>::create(Args... args) {
61  static_assert(std::is_same<InterfaceType, InstanceType>::value || std::is_base_of<InterfaceType, InstanceType>::value,
62  "InstanceType must be a subtype of InterfaceType");
63  return Euclid::make_unique<InstOrRefHolder_Impl::InstHolder_Impl<InterfaceType, InstanceType>>(std::forward<Args>(args)...);
64 }
65 
66 template <typename InterfaceType>
67 std::unique_ptr<InstOrRefHolder<InterfaceType>> InstOrRefHolder<InterfaceType>::create(InterfaceType& ref) {
68  return Euclid::make_unique<InstOrRefHolder_Impl::RefHolder_Impl<InterfaceType>>(ref);
69 }
70 
71 } // end of namespace Euclid