abstract_factory.hpp

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#ifndef GKO_CORE_BASE_ABSTRACT_FACTORY_HPP_
#define GKO_CORE_BASE_ABSTRACT_FACTORY_HPP_


#include <ginkgo/core/base/polymorphic_object.hpp>


namespace gko {


template <typename AbstractProductType, typename ComponentsType>
class AbstractFactory
    : public EnableAbstractPolymorphicObject<
          AbstractFactory<AbstractProductType, ComponentsType>> {
public:
    using abstract_product_type = AbstractProductType;
    using components_type = ComponentsType;

    template <typename... Args>
    std::unique_ptr<AbstractProductType> generate(Args &&... args) const
    {
        auto product = this->generate_impl({std::forward<Args>(args)...});
        for (auto logger : this->loggers_) {
            product->add_logger(logger);
        }
        return product;
    }

protected:
    AbstractFactory(std::shared_ptr<const Executor> exec)
        : EnableAbstractPolymorphicObject<AbstractFactory>(std::move(exec))
    {}

    virtual std::unique_ptr<AbstractProductType> generate_impl(
        ComponentsType args) const = 0;
};


template <typename ConcreteFactory, typename ProductType,
          typename ParametersType, typename PolymorphicBase>
class EnableDefaultFactory
    : public EnablePolymorphicObject<ConcreteFactory, PolymorphicBase>,
      public EnablePolymorphicAssignment<ConcreteFactory> {
public:
    friend class EnablePolymorphicObject<ConcreteFactory, PolymorphicBase>;

    using product_type = ProductType;
    using parameters_type = ParametersType;
    using polymorphic_base = PolymorphicBase;
    using abstract_product_type =
        typename PolymorphicBase::abstract_product_type;
    using components_type = typename PolymorphicBase::components_type;

    template <typename... Args>
    std::unique_ptr<ProductType> generate(Args &&... args) const
    {
        auto product = std::unique_ptr<ProductType>(static_cast<ProductType *>(
            this->generate_impl({std::forward<Args>(args)...}).release()));
        propagate_loggers<ConcreteFactory, ProductType>(product.get());
        return product;
    }

    const parameters_type &get_parameters() const noexcept
    {
        return parameters_;
    };

    static parameters_type create() { return {}; }

protected:
    template <typename TheFactory, typename TheType>
    typename std::enable_if<
        std::is_base_of<log::Loggable, TheType>::value &&
            std::is_base_of<log::Loggable, TheFactory>::value,
        void>::type
    propagate_loggers(TheType *product) const
    {
        for (auto logger : this->loggers_) {
            product->add_logger(logger);
        }
    }

    template <typename TheFactory, typename TheType>
    typename std::enable_if<
        not std::is_base_of<log::Loggable, TheType>::value ||
            not std::is_base_of<log::Loggable, TheFactory>::value,
        void>::type
    propagate_loggers(TheType *product) const
    {}

    explicit EnableDefaultFactory(std::shared_ptr<const Executor> exec,
                                  const parameters_type &parameters = {})
        : EnablePolymorphicObject<ConcreteFactory, PolymorphicBase>(
              std::move(exec)),
          parameters_{parameters}
    {}

    std::unique_ptr<abstract_product_type> generate_impl(
        components_type args) const override
    {
        return std::unique_ptr<abstract_product_type>(
            new ProductType(self(), args));
    }

private:
    GKO_ENABLE_SELF(ConcreteFactory);

    ParametersType parameters_;
};


template <typename ConcreteParametersType, typename Factory>
struct enable_parameters_type {
    using factory = Factory;

    std::unique_ptr<Factory> on(std::shared_ptr<const Executor> exec) const
    {
        return std::unique_ptr<Factory>(new Factory(exec, *self()));
    }

protected:
    GKO_ENABLE_SELF(ConcreteParametersType);
};


}  // namespace gko


#endif  // GKO_CORE_BASE_ABSTRACT_FACTORY_HPP_