Implemented cloning_ptr (#202)

* Implemented cloning_ptr

* Fixed clang issues

* Another attempt to fix clang issue

* Changes according to review

* ..

include/sparrow_v01/utils/memory.hpp

@@ -14,10 +14,307 @@
 
 #pragma once
 
+#include <compare>
+#include <concepts>
+#include <memory>
+
 namespace sparrow
 {
-    inline int dummy()
+    /**
+     * Matches types that provide a `clone` method.
+     *
+     * This concept checks if a type provides a `clone` method that
+     * returns a pointer convertible to a pointer to the type.
+     *
+     * @tparam T The type to check
+     */
+    template <class T>
+    concept clonable = requires(const T* t)
+    {
+        { t->clone() } -> std::convertible_to<T*>;
+    };
+
+    /**
+     * Smart pointer behaving like a copiable std::unique_ptr.
+     * 
+     * `cloning_ptr` owns and manages another object through a pointer, like
+     * `std::unique_ptr`. The difference with `std::unique_ptr` is that 
+     * `cloning_ptr`calls the `clone` method of the managed object upon copy.
+     * `Therefore, `cloning_ptr` is meant to be used with hierarchies of
+     * classes which provide a `clone` method.
+     * 
+     * @tparam T The type of the object managed by the `cloning_ptr`. It must
+     * satisfy the `clonable` concept.
+     */
+    template <clonable T>
+    class cloning_ptr
+    {
+        using internal_pointer = std::unique_ptr<T>;
+    public:
+
+        using self_type = cloning_ptr<T>;
+        using pointer = typename internal_pointer::pointer;
+        using element_type = typename internal_pointer::element_type;
+
+        // Value semantic
+
+        constexpr cloning_ptr() noexcept = default;
+        constexpr cloning_ptr(std::nullptr_t) noexcept;
+        explicit constexpr cloning_ptr(pointer p) noexcept;
+
+        constexpr ~cloning_ptr() = default;
+
+        constexpr cloning_ptr(const self_type& rhs) noexcept;
+        constexpr cloning_ptr(self_type&& rhs) noexcept = default;
+
+        template <clonable U>
+        requires std::convertible_to<U*, T*>
+        constexpr cloning_ptr(const cloning_ptr<U>& rhs) noexcept;
+
+        template <clonable U>
+        requires std::convertible_to<U*, T*>
+        constexpr cloning_ptr(cloning_ptr<U>&& rhs) noexcept;
+
+        constexpr self_type& operator=(const self_type&) noexcept;
+        constexpr self_type& operator=(self_type&&) noexcept = default;
+        constexpr self_type& operator=(std::nullptr_t) noexcept;
+
+        template <clonable U>
+        requires std::convertible_to<U*, T*>
+        constexpr self_type& operator=(const cloning_ptr<U>& rhs) noexcept;
+
+        template <clonable U>
+        requires std::convertible_to<U*, T*>
+        constexpr self_type& operator=(cloning_ptr<U>&& rhs) noexcept;
+
+        // Modifiers
+
+        constexpr pointer release() noexcept;
+        constexpr void reset(pointer ptr = pointer()) noexcept;
+        void swap(self_type&) noexcept;
+
+        // Observers
+
+        constexpr pointer get() const noexcept;
+
+        constexpr explicit operator bool() const noexcept;
+
+        constexpr std::add_lvalue_reference_t<T>
+        operator*() const noexcept(noexcept(*std::declval<pointer>()));
+
+        constexpr pointer operator->() const noexcept;
+
+    private:
+
+        constexpr internal_pointer& ptr_impl() noexcept;
+        constexpr const internal_pointer& ptr_impl() const noexcept;
+
+        internal_pointer m_data;
+    };
+
+    template <class T>
+    void swap(cloning_ptr<T>& lhs, cloning_ptr<T>& rhs) noexcept;
+
+    template <class T1, class T2>
+    requires std::equality_comparable_with<
+        typename cloning_ptr<T1>::pointer,
+        typename cloning_ptr<T2>::pointer>
+    constexpr
+    bool operator==(const cloning_ptr<T1>& lhs, const cloning_ptr<T2>& rhs) noexcept;
+
+    template <class T1, class T2>
+    requires std::three_way_comparable_with<
+        typename cloning_ptr<T1>::pointer,
+        typename cloning_ptr<T2>::pointer>
+    constexpr
+    std::compare_three_way_result_t<
+        typename cloning_ptr<T1>::pointer,
+        typename cloning_ptr<T2>::pointer>
+    operator<=>(const cloning_ptr<T1>& lhs, const cloning_ptr<T2>& rhs) noexcept;
+
+    template <class T>
+    constexpr
+    bool operator==(const cloning_ptr<T>& lhs, std::nullptr_t) noexcept;
+
+    template <class T>
+    requires std::three_way_comparable<typename cloning_ptr<T>::pointer>
+    constexpr
+    std::compare_three_way_result_t<typename cloning_ptr<T>::pointer>
+    operator<=>(const cloning_ptr<T>& lhs, std::nullptr_t) noexcept;
+
+    /******************************
+     * cloning_ptr implementation *
+     ******************************/
+
+    template <clonable T>
+    constexpr cloning_ptr<T>::cloning_ptr(std::nullptr_t) noexcept
+        : m_data(nullptr)
+    {
+    }
+
+    template <clonable T>
+    constexpr cloning_ptr<T>::cloning_ptr(pointer p) noexcept
+        : m_data(p)
+    {
+    }
+
+    template <clonable T>
+    constexpr cloning_ptr<T>::cloning_ptr(const cloning_ptr& rhs) noexcept
+        : m_data(rhs->clone())
+    {
+    }
+
+    template <clonable T>
+    template <clonable U>
+    requires std::convertible_to<U*, T*>
+    constexpr cloning_ptr<T>::cloning_ptr(const cloning_ptr<U>& rhs) noexcept
+        : m_data(rhs->clone())
+    {
+    }
+
+    template <clonable T>
+    template <clonable U>
+    requires std::convertible_to<U*, T*>
+    constexpr cloning_ptr<T>::cloning_ptr(cloning_ptr<U>&& rhs) noexcept
+        : m_data(rhs.release())
+    {
+    }
+
+    template <clonable T>
+    constexpr auto cloning_ptr<T>::operator=(const self_type& rhs) noexcept -> self_type&
+    {
+        reset(rhs->clone());
+        return *this;
+    }
+
+    template <clonable T>
+    constexpr auto cloning_ptr<T>::operator=(std::nullptr_t) noexcept -> self_type&
+    {
+        reset(nullptr);
+        return *this;
+    }
+
+    template <clonable T>
+    template <clonable U>
+    requires std::convertible_to<U*, T*>
+    constexpr auto cloning_ptr<T>::operator=(const cloning_ptr<U>& rhs) noexcept -> self_type&
+    {
+        reset(rhs->clone());
+        return *this;
+    }
+
+    template <clonable T>
+    template <clonable U>
+    requires std::convertible_to<U*, T*>
+    constexpr auto cloning_ptr<T>::operator=(cloning_ptr<U>&& rhs) noexcept -> self_type&
+    {
+        reset(rhs.release());
+        return *this;
+    }
+
+    template <clonable T>
+    constexpr auto cloning_ptr<T>::release() noexcept -> pointer
+    {
+        return ptr_impl().release();
+    }
+
+    template <clonable T>
+    constexpr void cloning_ptr<T>::reset(pointer ptr) noexcept
+    {
+        ptr_impl().reset(ptr);
+    }
+
+    template <clonable T>
+    void cloning_ptr<T>::swap(self_type& other) noexcept
+    {
+        using std::swap;
+        swap(ptr_impl(), other.ptr_impl());
+    }
+
+    template <clonable T>
+    constexpr auto cloning_ptr<T>::get() const noexcept -> pointer
+    {
+        return ptr_impl().get();
+    }
+
+    template <clonable T>
+    constexpr cloning_ptr<T>::operator bool() const noexcept
+    {
+        return bool(ptr_impl());
+    }
+
+    template <clonable T>
+    constexpr std::add_lvalue_reference_t<T>
+    cloning_ptr<T>::operator*() const noexcept(noexcept(*std::declval<pointer>()))
+    {
+        return *get();
+    }
+
+    template <clonable T>
+    constexpr auto cloning_ptr<T>::operator->() const noexcept -> pointer
+    {
+        return get();
+    }
+
+    template <clonable T>
+    constexpr auto cloning_ptr<T>::ptr_impl() noexcept -> internal_pointer&
+    {
+        return m_data;
+    }
+
+    template <clonable T>
+    constexpr auto cloning_ptr<T>::ptr_impl() const noexcept -> const internal_pointer&
+    {
+        return m_data;
+    }
+
+    /*********************************
+     * Free functions implementation *
+     *********************************/
+
+    template <class T>
+    void swap(cloning_ptr<T>& lhs, cloning_ptr<T>& rhs) noexcept
+    {
+        lhs.swap(rhs);
+    }
+
+    template <class T1, class T2>
+    requires std::equality_comparable_with<
+        typename cloning_ptr<T1>::pointer,
+        typename cloning_ptr<T2>::pointer>
+    constexpr
+    bool operator==(const cloning_ptr<T1>& lhs, const cloning_ptr<T2>& rhs) noexcept
+    {
+        return lhs.get() == rhs.get();
+    }
+
+    template <class T1, class T2>
+    requires std::three_way_comparable_with<
+        typename cloning_ptr<T1>::pointer,
+        typename cloning_ptr<T2>::pointer>
+    constexpr
+    std::compare_three_way_result_t<
+        typename cloning_ptr<T1>::pointer,
+        typename cloning_ptr<T2>::pointer>
+    operator<=>(const cloning_ptr<T1>& lhs, const cloning_ptr<T2>& rhs) noexcept
+    {
+        return lhs.get() <=> rhs.get();
+    }
+
+    template <class T>
+    constexpr
+    bool operator==(const cloning_ptr<T>& lhs, std::nullptr_t) noexcept
+    {
+        return !lhs;
+    }
+
+    template <class T>
+    requires std::three_way_comparable<typename cloning_ptr<T>::pointer>
+    constexpr
+    std::compare_three_way_result_t<typename cloning_ptr<T>::pointer>
+    operator<=>(const cloning_ptr<T>& lhs, std::nullptr_t) noexcept
     {
-        return 0;
+        using pointer = typename cloning_ptr<T>::pointer;
+        return lhs.get() <=> static_cast<pointer>(nullptr);
     }
 }