1 | //===-- Cloneable.h ---------------------------------------------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | |
9 | #ifndef LLDB_UTILITY_CLONEABLE_H |
10 | #define LLDB_UTILITY_CLONEABLE_H |
11 | |
12 | #include <memory> |
13 | #include <type_traits> |
14 | |
15 | namespace lldb_private { |
16 | |
17 | /// \class Cloneable Cloneable.h "lldb/Utility/Cloneable.h" |
18 | /// A class that implements CRTP-based "virtual constructor" idiom. |
19 | /// |
20 | /// Example: |
21 | /// @code |
22 | /// class Base { |
23 | /// using TopmostBase = Base; |
24 | /// public: |
25 | /// virtual std::shared_ptr<Base> Clone() const = 0; |
26 | /// }; |
27 | /// @endcode |
28 | /// |
29 | /// To define a class derived from the Base with overridden Clone: |
30 | /// @code |
31 | /// class Intermediate : public Cloneable<Intermediate, Base> {}; |
32 | /// @endcode |
33 | /// |
34 | /// To define a class at the next level of inheritance with overridden Clone: |
35 | /// @code |
36 | /// class Derived : public Cloneable<Derived, Intermediate> {}; |
37 | /// @endcode |
38 | |
39 | template <typename Derived, typename Base> |
40 | class Cloneable : public Base { |
41 | public: |
42 | using Base::Base; |
43 | |
44 | std::shared_ptr<typename Base::TopmostBase> Clone() const override { |
45 | // std::is_base_of requires derived type to be complete, that's why class |
46 | // scope static_assert cannot be used. |
47 | static_assert(std::is_base_of<Cloneable, Derived>::value, |
48 | "Derived class must be derived from this." ); |
49 | |
50 | return std::make_shared<Derived>(static_cast<const Derived &>(*this)); |
51 | } |
52 | }; |
53 | |
54 | } // namespace lldb_private |
55 | |
56 | #endif // LLDB_UTILITY_CLONEABLE_H |
57 | |