resource.h

#ifndef RESOURCE_H
#define RESOURCE_H
 
#include <memory>
#include "value.h"
 
namespace Runtime
{
    class Resource
    {
    public:
        virtual ~Resource() = default;
        virtual Value GetProperties() const = 0;
    };
 
    class ResourceIterator
    {
    public:
        virtual ~ResourceIterator() = default;
        virtual void Step() const = 0;
        virtual std::shared_ptr<const Resource> Get() const = 0;
        std::shared_ptr<Resource> Get()
        {
            return std::const_pointer_cast<Resource>(const_cast<const ResourceIterator *>(this)->Get());
        }
        virtual bool SameAs(const ResourceIterator * other) const = 0;
        virtual void Erase() = 0;
    };
 
    class ResourceIterable
    {
    public:
        struct Iterator
        {
            std::shared_ptr<ResourceIterator> iterator_object;
 
            std::shared_ptr<Resource> operator *()
            {
                return iterator_object->Get();
            }
 
            Iterator& operator ++()
            {
                iterator_object->Step();
                return *this;
            }
 
            bool operator !=(const Iterator& other) const
            {
                return !iterator_object->SameAs(other.iterator_object.get());
            }
        };
 
        struct ConstIterator
        {
            std::shared_ptr<const ResourceIterator> iterator_object;
 
            std::shared_ptr<const Resource> operator *()
            {
                return iterator_object->Get();
            }
 
            ConstIterator& operator ++()
            {
                iterator_object->Step();
                return *this;
            }
 
            bool operator !=(const ConstIterator& other) const
            {
                return !iterator_object->SameAs(other.iterator_object.get());
            }
        };
 
        virtual std::shared_ptr<ResourceIterator> BeginIteration() = 0;
        std::shared_ptr<const ResourceIterator> BeginIteration() const
        {
            return std::const_pointer_cast<const ResourceIterator>(const_cast<ResourceIterable *>(this)->BeginIteration());
        }
        virtual std::shared_ptr<ResourceIterator> EndOfIteration() = 0;
        std::shared_ptr<const ResourceIterator> EndOfIteration() const
        {
            return std::const_pointer_cast<const ResourceIterator>(const_cast<ResourceIterable *>(this)->EndOfIteration());
        }
 
        ConstIterator begin() const
        {
            return ConstIterator{BeginIteration()};
        }
 
        ConstIterator end() const
        {
            return ConstIterator{EndOfIteration()};
        }
 
        Iterator begin()
        {
            return Iterator{BeginIteration()};
        }
 
        Iterator end()
        {
            return Iterator{EndOfIteration()};
        }
    };
 
    class ResourceManager
    {
    public:
        virtual ~ResourceManager() = default;
 
        virtual ResourceIterable& Iterate() = 0;
        const ResourceIterable& Iterate() const
        {
            return const_cast<const ResourceIterable&>(const_cast<ResourceManager *>(this)->Iterate());
        }
 
        virtual std::shared_ptr<ResourceIterator> FindResource(const Value& value) = 0;
        std::shared_ptr<const ResourceIterator> FindResource(const Value& value) const
        {
            return std::const_pointer_cast<const ResourceIterator>(const_cast<ResourceManager *>(this)->FindResource(value));
        }
 
        virtual bool UpdateResource(std::shared_ptr<Resource> resource) = 0;
    };
}
 
#endif /* RESOURCE_H */