1 /*
2  * PImpl.hpp
3  *
4  * Copyright (C) 2021 by RStudio, PBC
5  *
6  * Unless you have received this program directly from RStudio pursuant to the terms of a commercial license agreement
7  * with RStudio, then this program is licensed to you under the following terms:
8  *
9  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
10  * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
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12  * permit persons to whom the Software is furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
18  * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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22  */
23 
24 #ifndef SHARED_CORE_P_IMPL_HPP
25 #define SHARED_CORE_P_IMPL_HPP
26 
27 #include <memory>
28 
29 /**
30  * @brief Shared start of the macro to define a private implementation for a class.
31  */
32 #define PRIVATE_IMPL_START                            \
33    struct Impl;
34 
35 /**
36  * @brief Macro to define a private implementation for a non-copyable class.
37  *
38  * Class which use this macro must either be non-copyable or define a custom deep-copy constructor and operator which
39  * performs a deep copy of the impl.
40  *
41  * This macro should be included in the private or protected section of a classes declaration.
42  * The PRIVATE_IMPL_DELETER_IMPL macro must be used in the definition file, after the definition of the Impl struct.
43  * struct OwningClass::Impl should be defined in the definition file before defining OwningClass.
44  *
45  * @param in_memberName    The name of the private implementation member variable (e.g. m_impl).
46  */
47 #define PRIVATE_IMPL(in_memberName)                      \
48    PRIVATE_IMPL_START                                    \
49    struct ImplDeleter { void operator()(Impl*); };       \
50    std::unique_ptr<Impl, ImplDeleter> in_memberName;
51 
52 /**
53  * @brief Macro to define a private implementation which would be shared with copied instances.
54  *
55  * This macro should be included in the private or protected section of a classes declaration.
56  * struct OwningClass::Impl should be defined in the definition file before defining OwningClass.
57  *
58  * @param in_memeberName    The name of the private implementation member variable (e.g. m_impl).
59  */
60 #define PRIVATE_IMPL_SHARED(in_memberName)   \
61    PRIVATE_IMPL_START                        \
62    std::shared_ptr<Impl> in_memberName;
63 
64 /**
65  * @brief Macro which implements the deleter for the class's private implementation. This macro must be used after the
66  *        implementation of the Impl struct in the definition file.
67  *
68  * @param in_owningClass    The name of the class which owns the private implementation (e.g. Error).
69  */
70 #define PRIVATE_IMPL_DELETER_IMPL(in_owningClass)                                   \
71 void in_owningClass::ImplDeleter::operator()(in_owningClass::Impl* io_toDelete)     \
72 {                                                                                   \
73    delete io_toDelete;                                                              \
74 }
75 
76 #endif
77