SmartPtrs.h

/*
 * MIT License
 *
 * Copyright (c) 2025 Adriano dos Santos Fernandes
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
 
#ifndef FBCPP_SMART_PTRS_H
#define FBCPP_SMART_PTRS_H
 
#include "fb-api.h"
#include <memory>
 
 
namespace fbcpp
{
    namespace impl
    {
        struct FbDisposeDeleter final
        {
            void operator()(fb::IDisposable* obj) noexcept
            {
                if (obj)
                    obj->dispose();
            }
        };
    }  // namespace impl
 
    template <typename T>
    using FbUniquePtr = std::unique_ptr<T, impl::FbDisposeDeleter>;
 
    template <typename T>
    FbUniquePtr<T> fbUnique(T* obj) noexcept
    {
        return FbUniquePtr<T>{obj};
    }
 
    // FIXME: Review every usage to see if is not leaking one reference count.
    template <typename T>
    class FbRef final
    {
        template <typename Y>
        friend class FbRef;
 
    public:
        FbRef() noexcept
            : ptr{nullptr}
        {
        }
 
        FbRef(std::nullptr_t) noexcept
            : ptr{nullptr}
        {
        }
 
        explicit FbRef(T* p) noexcept
            : ptr{p}
        {
        }
 
        template <typename Y>
        explicit FbRef(Y* p) noexcept
            : ptr{p}
        {
        }
 
        FbRef(FbRef& r) noexcept
            : ptr{nullptr}
        {
            assign(r.ptr, true);
        }
 
        template <typename Y>
        FbRef(FbRef<Y>& r) noexcept
            : ptr{nullptr}
        {
            assign(r.ptr, true);
        }
 
        FbRef(FbRef&& r) noexcept
            : ptr{r.ptr}
        {
            r.ptr = nullptr;
        }
 
        ~FbRef() noexcept
        {
            if (ptr)
                ptr->release();
        }
 
        void reset(T* p = nullptr) noexcept
        {
            assign(p, false);
        }
 
        FbRef& operator=(FbRef& r) noexcept
        {
            assign(r.ptr, true);
            return *this;
        }
 
        template <typename Y>
        FbRef& operator=(FbRef<Y>& r) noexcept
        {
            assign(r.ptr, true);
            return *this;
        }
 
        FbRef& operator=(FbRef&& r) noexcept
        {
            if (ptr != r.ptr)
            {
                if (ptr)
                    assign(nullptr, false);
 
                ptr = r.ptr;
                r.ptr = nullptr;
            }
 
            return *this;
        }
 
        T* operator->() noexcept
        {
            return ptr;
        }
 
        const T* operator->() const noexcept
        {
            return ptr;
        }
 
        explicit operator bool() const noexcept
        {
            return ptr != nullptr;
        }
 
        bool operator!() const noexcept
        {
            return ptr == nullptr;
        }
 
        bool operator==(const FbRef& other) const noexcept
        {
            return ptr == other.ptr;
        }
 
        bool operator==(const T* other) const noexcept
        {
            return ptr == other;
        }
 
        bool operator!=(const FbRef& other) const noexcept
        {
            return ptr != other.ptr;
        }
 
        bool operator!=(const T* other) const noexcept
        {
            return ptr != other;
        }
 
        T* get() noexcept
        {
            return ptr;
        }
 
        const T* get() const noexcept
        {
            return ptr;
        }
 
    private:
        T* assign(T* const p, bool addRef) noexcept
        {
            if (ptr != p)
            {
                if (p && addRef)
                    p->addRef();
 
                T* tmp = ptr;
                ptr = p;
 
                if (tmp)
                    tmp->release();
            }
 
            return p;
        }
 
    private:
        T* ptr;
    };
 
    template <typename T>
    FbRef<T> fbRef(T* arg) noexcept
    {
        return FbRef<T>{arg};
    }
}  // namespace fbcpp
 
 
#endif  // FBCPP_SMART_PTRS_H