53 lines
1.5 KiB
C++
Executable File
53 lines
1.5 KiB
C++
Executable File
// Copyright 2015, Tobias Hermann and the FunctionalPlus contributors.
|
|
// https://github.com/Dobiasd/FunctionalPlus
|
|
// Distributed under the Boost Software License, Version 1.0.
|
|
// (See accompanying file LICENSE_1_0.txt or copy at
|
|
// http://www.boost.org/LICENSE_1_0.txt)
|
|
|
|
#pragma once
|
|
|
|
#include <memory>
|
|
|
|
namespace fplus
|
|
{
|
|
|
|
// A std::shared_ptr expresses
|
|
// optionality of the contained value (can be nullptr)
|
|
// and shared ownership that can be transferred.
|
|
// A std::optional expresses optionality only.
|
|
// The standard does not provide a class to
|
|
// express only shared ownership without optionality.
|
|
// shared_ref fills this gap.
|
|
template <typename T>
|
|
class shared_ref
|
|
{
|
|
public:
|
|
shared_ref(const shared_ref&) = default;
|
|
shared_ref(shared_ref&&) = default;
|
|
shared_ref& operator=(const shared_ref&) = default;
|
|
shared_ref& operator=(shared_ref&&) = default;
|
|
~shared_ref() = default;
|
|
|
|
T* operator->() { return m_ptr.get(); }
|
|
const T* operator->() const { return m_ptr.get(); }
|
|
|
|
T& operator*() { return *m_ptr.get(); }
|
|
const T& operator*() const { return *m_ptr.get(); }
|
|
|
|
template <typename XT, typename...XTypes>
|
|
friend shared_ref<XT> make_shared_ref(XTypes&&...args);
|
|
|
|
private:
|
|
std::shared_ptr<T> m_ptr;
|
|
shared_ref(T* value) :m_ptr(value) { assert(value != nullptr); }
|
|
};
|
|
|
|
// http://stackoverflow.com/a/41976419/1866775
|
|
template <typename T, typename...Types>
|
|
shared_ref<T> make_shared_ref(Types&&...args)
|
|
{
|
|
return shared_ref<T>(new T(std::forward<Types>(args)...));
|
|
}
|
|
|
|
} // namespace fplus
|