Спринт 7. Сравнение, копирование и присваивание.

#include <cassert>
#include <cstddef>
#include <iterator>
#include <string>
#include <utility>
#include <algorithm>

template <typename Type>
class SingleLinkedList {

    struct Node {
        Node() = default;
        Node(const Type& val, Node* next) : value(val), next_node(next) {}
        Type value;
        Node* next_node = nullptr;
    };

    template <typename ValueType>
    class BasicIterator {

        friend class SingleLinkedList;

        explicit BasicIterator(Node* node) {
            node_ = node;
        }

    public:
        using iterator_category = std::forward_iterator_tag;
        using value_type = Type;
        using difference_type = std::ptrdiff_t;
        using pointer = ValueType*;
        using reference = ValueType&;

        BasicIterator() = default;

        BasicIterator(const BasicIterator<Type>& other) noexcept {
            node_ = other.node_;
        }

        BasicIterator& operator=(const BasicIterator& rhs) = default;

        [[nodiscard]] bool operator==(const BasicIterator<const Type>& rhs) const noexcept {
            return node_ == rhs.node_;
        }

        [[nodiscard]] bool operator!=(const BasicIterator<const Type>& rhs) const noexcept {
            return node_ != rhs.node_;
        }

        [[nodiscard]] bool operator==(const BasicIterator<Type>& rhs) const noexcept {
            return node_ == rhs.node_;
        }

        [[nodiscard]] bool operator!=(const BasicIterator<Type>& rhs) const noexcept {
            return node_ != rhs.node_;
        }

        BasicIterator& operator++() noexcept {
            node_ = node_->next_node;
            return *this;
        }

        BasicIterator operator++(int) noexcept {
            auto old_value(*this);
            ++(*this);
            return old_value;
        }

        [[nodiscard]] reference operator*() const noexcept {
            return node_->value;
        }

        [[nodiscard]] pointer operator->() const noexcept {
            if(node_){
                return &node_->value;
            }else{
                return nullptr;
            }
        }

    private:
        Node* node_ = nullptr;
    };

public:
    SingleLinkedList() {}

    template <typename TypeIt>
    void Init(TypeIt begin, TypeIt end) {
        Node* node = &head_;
        for (TypeIt i= begin;i!=end; ++i) {
            ++size_;
            node->next_node = new Node(*i, nullptr);
            node = node->next_node;
        }
    }

    SingleLinkedList(std::initializer_list<Type> values) {
        SingleLinkedList helper;
        helper.Init(values.begin(), values.end());
        swap(helper);
    }

    SingleLinkedList(const SingleLinkedList& other) {
        SingleLinkedList helper;
        helper.Init(other.begin(), other.end());
        swap(helper);
    }


    SingleLinkedList& operator=(const SingleLinkedList& rhs) {
        if(this!= &rhs){
            SingleLinkedList helper(rhs);
            swap(helper);
        }
        return *this;
    }

    using value_type = Type;
    using reference = value_type&;
    using const_reference = const value_type&;

    using Iterator = BasicIterator<Type>;
    using ConstIterator = BasicIterator<const Type>;

    [[nodiscard]] Iterator begin() noexcept {
        return Iterator{head_.next_node};
    }

    [[nodiscard]] Iterator end() noexcept {
        return Iterator{nullptr};
    }

    [[nodiscard]] ConstIterator begin() const noexcept {
        return ConstIterator{head_.next_node};
    }

    [[nodiscard]] ConstIterator end() const noexcept {
        return ConstIterator{nullptr};
    }

    [[nodiscard]] ConstIterator cbegin() const noexcept {
        return ConstIterator{head_.next_node};
    }

    [[nodiscard]] ConstIterator cend() const noexcept {
        return ConstIterator{nullptr};
    }

    [[nodiscard]] size_t GetSize() const noexcept {
        return size_;
    }

    [[nodiscard]] bool IsEmpty() const noexcept {
        if (!size_) {
        return true;
        }
        return false;
    }

    void PushFront(const Type& value) {
        head_.next_node = new Node(value, head_.next_node);
        ++size_;
    }

    void Clear() noexcept {
        while (head_.next_node) {
            Node* new_head = head_.next_node->next_node;
            delete head_.next_node;
            head_.next_node = new_head;
        }
        size_ = 0;
    }

    void swap(SingleLinkedList& other) noexcept {
        std::swap(head_.next_node, other.head_.next_node);
        std::swap(size_, other.size_);
    }

    ~SingleLinkedList() {
        Clear();
    }

private:
    Node head_;
    size_t size_ = 0;
};

template <typename Type>
void swap(SingleLinkedList<Type>& lhs, SingleLinkedList<Type>& rhs) noexcept {
    lhs.swap(rhs);
}

template <typename Type>
bool operator==(const SingleLinkedList<Type>& lhs, const SingleLinkedList<Type>& rhs) {
    return std::equal(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
}

template <typename Type>
bool operator!=(const SingleLinkedList<Type>& lhs, const SingleLinkedList<Type>& rhs) {
    return !(lhs==rhs);
}

template <typename Type>
bool operator<(const SingleLinkedList<Type>& lhs, const SingleLinkedList<Type>& rhs) {
    return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
}

template <typename Type>
bool operator<=(const SingleLinkedList<Type>& lhs, const SingleLinkedList<Type>& rhs) {
    return !(rhs < lhs);
}

template <typename Type>
bool operator>(const SingleLinkedList<Type>& lhs, const SingleLinkedList<Type>& rhs) {
    return rhs <lhs;
}

template <typename Type>
bool operator>=(const SingleLinkedList<Type>& lhs, const SingleLinkedList<Type>& rhs) {
   return !(lhs <rhs);
}

void Test3() {
    {
        SingleLinkedList<int> list_1;
        list_1.PushFront(1);
        list_1.PushFront(2);

        SingleLinkedList<int> list_2;
        list_2.PushFront(1);
        list_2.PushFront(2);
        list_2.PushFront(3);

        SingleLinkedList<int> list_1_copy;
        list_1_copy.PushFront(1);
        list_1_copy.PushFront(2);

        SingleLinkedList<int> empty_list;
        SingleLinkedList<int> another_empty_list;

        assert(list_1 == list_1);
        assert(empty_list == empty_list);

        assert(list_1 == list_1_copy);
        assert(list_1 != list_2);
        assert(list_2 != list_1);
        assert(empty_list == another_empty_list);
    }

    {
        SingleLinkedList<int> first;
        first.PushFront(1);
        first.PushFront(2);

        SingleLinkedList<int> second;
        second.PushFront(10);
        second.PushFront(11);
        second.PushFront(15);

        const auto old_first_begin = first.begin();
        const auto old_second_begin = second.begin();
        const auto old_first_size = first.GetSize();
        const auto old_second_size = second.GetSize();

        first.swap(second);

        assert(second.begin() == old_first_begin);
        assert(first.begin() == old_second_begin);
        assert(second.GetSize() == old_first_size);
        assert(first.GetSize() == old_second_size);

        {
            using std::swap;

            swap(first, second);

            assert(first.begin() == old_first_begin);
            assert(second.begin() == old_second_begin);
            assert(first.GetSize() == old_first_size);
            assert(second.GetSize() == old_second_size);
        }
    }

    {
        SingleLinkedList<int> list{1, 2, 3, 4, 5};
        assert(list.GetSize() == 5);
        assert(!list.IsEmpty());
        assert(std::equal(list.begin(), list.end(), std::begin({1, 2, 3, 4, 5})));
    }

    {
        using IntList = SingleLinkedList<int>;

        assert((IntList{1, 2, 3} < IntList{1, 2, 3, 1}));
        assert((IntList{1, 2, 3} <= IntList{1, 2, 3}));
        assert((IntList{1, 2, 4} > IntList{1, 2, 3}));
        assert((IntList{1, 2, 3} >= IntList{1, 2, 3}));
    }

    {
        const SingleLinkedList<int> empty_list{};
        {
            auto list_copy(empty_list);
            assert(list_copy.IsEmpty());
        }

        SingleLinkedList<int> non_empty_list{1, 2, 3, 4};
        {
            auto list_copy(non_empty_list);

            assert(non_empty_list.begin() != list_copy.begin());
            assert(list_copy == non_empty_list);
        }
    }

    {
        const SingleLinkedList<int> source_list{1, 2, 3, 4};

        SingleLinkedList<int> receiver{5, 4, 3, 2, 1};
        receiver = source_list;
        assert(receiver.begin() != source_list.begin());
        assert(receiver == source_list);
    }

    struct ThrowOnCopy {
        ThrowOnCopy() = default;
        explicit ThrowOnCopy(int& copy_counter) noexcept
            : countdown_ptr(&copy_counter) {
        }
        ThrowOnCopy(const ThrowOnCopy& other)
            : countdown_ptr(other.countdown_ptr)  //
        {
            if (countdown_ptr) {
                if (*countdown_ptr == 0) {
                    throw std::bad_alloc();
                } else {
                    --(*countdown_ptr);
                }
            }
        }

        ThrowOnCopy& operator=(const ThrowOnCopy& rhs) = delete;
        int* countdown_ptr = nullptr;
    };

    {
        SingleLinkedList<ThrowOnCopy> src_list;
        src_list.PushFront(ThrowOnCopy{});
        src_list.PushFront(ThrowOnCopy{});
        auto thrower = src_list.begin();
        src_list.PushFront(ThrowOnCopy{});

        int copy_counter = 0;
        thrower->countdown_ptr = &copy_counter;

        SingleLinkedList<ThrowOnCopy> dst_list;
        dst_list.PushFront(ThrowOnCopy{});
        int dst_counter = 10;
        dst_list.begin()->countdown_ptr = &dst_counter;
        dst_list.PushFront(ThrowOnCopy{});

        try {
            dst_list = src_list;
            assert(false);
        } catch (const std::bad_alloc&) {
            assert(dst_list.GetSize() == 2);
            auto it = dst_list.begin();
            assert(it != dst_list.end());
            assert(it->countdown_ptr == nullptr);
            ++it;
            assert(it != dst_list.end());
            assert(it->countdown_ptr == &dst_counter);
            assert(dst_counter == 10);
        } catch (...) {
            assert(false);
        }
    }
}

int main() {
    Test3();
}