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