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/*! \file
 * \brief
 * Declares base classes for declaring option sections.
 *
 * This header defines base classes for option section settings that are used
 * with IOptionsContainerWithSections::addSection().  These classes implement
 * the "named parameter" idiom for specifying section properties.
 *
 * \author Teemu Murtola <teemu.murtola@gmail.com>
 * \ingroup module_options
 */
#ifndef GMX_OPTIONS_ABSTRACTSECTION_H
#define GMX_OPTIONS_ABSTRACTSECTION_H

#include <memory>

#include "gromacs/options/ioptionscontainerwithsections.h"
#include "gromacs/utility/classhelpers.h"
#include "gromacs/utility/gmxassert.h"

#include "isectionstorage.h"

namespace gmx
{

class IOptionSectionStorage;

namespace internal
{
class OptionSectionImpl;
}

/*! \brief
 * Base class for specifying option section properties.
 *
 * \ingroup module_options
 */
class AbstractOptionSection
{
protected:
    //! \cond libapi
    //! Initializes option properties with the given name.
    explicit AbstractOptionSection(const char* name) : name_(name) {}
    virtual ~AbstractOptionSection() {}
    /*! \brief
     * Creates a storage object corresponding to this section.
     *
     * Similar to AbstractOption::createStorage().
     */
    virtual std::unique_ptr<IOptionSectionStorage> createStorage() const = 0;
    //! \endcond

private:
    const char* name_;

    friend class internal::OptionSectionImpl;
};

/*! \brief
 * Base class for handles to option sections.
 *
 * This class implements the common functionality for adding options and
 * subsections to option sections.
 *
 * \ingroup module_options
 */
class AbstractOptionSectionHandle : public IOptionsContainerWithSections
{
public:
    // From IOptionsContainer
    //! \copydoc IOptionsContainer::addGroup()
    IOptionsContainer& addGroup() override;

protected:
    //! \cond libapi
    /*! \brief
     * Returns the storage for a particular type of section.
     *
     * This is intended for use in derived class constructors, where the
     * handle needs access to the actual storage.  The handle should know
     * the type of storage created for the section type it deals with, so
     * the cast should always be successful.
     */
    template<typename StorageType>
    static StorageType* getStorage(internal::OptionSectionImpl* section)
    {
        IOptionSectionStorage* storage      = getStorage(section);
        StorageType*           typedStorage = dynamic_cast<StorageType*>(storage);
        GMX_ASSERT(typedStorage != nullptr, "Mismatching section storage type");
        return typedStorage;
    }

    //! Wraps a given section storage object.
    explicit AbstractOptionSectionHandle(internal::OptionSectionImpl* section) : section_(section)
    {
    }
    //! \endcond

private:
    // From IOptionsContainerWithSections
    internal::OptionSectionImpl* addSectionImpl(const AbstractOptionSection& section) override;
    // From IOptionsContainer
    OptionInfo* addOptionImpl(const AbstractOption& settings) override;

    /*! \brief
     * Implementation helper for the template method.
     *
     * This allows encapsulating the implementation within the source file.
     */
    static IOptionSectionStorage* getStorage(internal::OptionSectionImpl* section);

    internal::OptionSectionImpl* section_;
};

class AbstractOptionSectionInfo
{
public:
    //! Wraps a given section storage object.
    explicit AbstractOptionSectionInfo(internal::OptionSectionImpl* section) : section_(*section) {}

    //! Returns the name of the section.
    const std::string& name() const;

    //! Returns the wrapped section storage object.
    internal::OptionSectionImpl& section() { return section_; }
    //! Returns the wrapped section storage object.
    const internal::OptionSectionImpl& section() const { return section_; }

private:
    internal::OptionSectionImpl& section_;

    GMX_DISALLOW_COPY_AND_ASSIGN(AbstractOptionSectionInfo);
};

} // namespace gmx

#endif
