| //===-- Cloneable.h ---------------------------------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLDB_UTILITY_CLONEABLE_H |
| #define LLDB_UTILITY_CLONEABLE_H |
| |
| #include <memory> |
| #include <type_traits> |
| |
| namespace lldb_private { |
| |
| /// \class Cloneable Cloneable.h "lldb/Utility/Cloneable.h" |
| /// A class that implements CRTP-based "virtual constructor" idiom. |
| /// |
| /// Example: |
| /// @code |
| /// class Base { |
| /// using TopmostBase = Base; |
| /// public: |
| /// virtual std::shared_ptr<Base> Clone() const = 0; |
| /// }; |
| /// @endcode |
| /// |
| /// To define a class derived from the Base with overridden Clone: |
| /// @code |
| /// class Intermediate : public Cloneable<Intermediate, Base> {}; |
| /// @endcode |
| /// |
| /// To define a class at the next level of inheritance with overridden Clone: |
| /// @code |
| /// class Derived : public Cloneable<Derived, Intermediate> {}; |
| /// @endcode |
| |
| template <typename Derived, typename Base> |
| class Cloneable : public Base { |
| public: |
| using Base::Base; |
| |
| std::shared_ptr<typename Base::TopmostBase> Clone() const override { |
| // std::is_base_of requires derived type to be complete, that's why class |
| // scope static_assert cannot be used. |
| static_assert(std::is_base_of<Cloneable, Derived>::value, |
| "Derived class must be derived from this."); |
| |
| return std::make_shared<Derived>(static_cast<const Derived &>(*this)); |
| } |
| }; |
| |
| } // namespace lldb_private |
| |
| #endif // LLDB_UTILITY_CLONEABLE_H |