BinaryQueryConvertible Interface Reference

#include <ozo/io/binary_query.h>

Description

Concept of a type that is convertible to ozo::binary_query

To be convertible to the ozo::binary_query type should model Query concept or should have a valid ozo::to_binary_query_impl<T> overload.

Customization

A particular query object type may become BinaryQueryConvertible via the specialization of ozo::to_binary_query_impl<T>::apply() template function. By default, it handles any Query model object or binary_query object.

template <typename T>
struct to_binary_query_impl<T> {
    template <typename OidMap, typename Allocator>
    static binary_query apply(const T&, const OidMap&, const Allocator&);
};

Example

E.g., a custom library contains type-erasure interface for its queries.

namespace demo {
 
constexpr auto oidMap = ozo::register_types<...>();
 
using OidMap = decltype(oidMap);
 
struct Query {
    virtual ozo::binary_query toBinaryQuery(const OidMap&, const std::allocator<char>&) const = 0;
    virtual ~Query() = 0;
};
 
} // namespace demo

Then the adaptation should look like this:

namespace ozo {
template <>
struct to_binary_query_impl<demo::Query> {
    template <typename OidMap, typename Alloc>
    static binary_query apply(const demo::Query& query, const demo::OidMap& oid_map, const std::allocator<char>& alloc) {
        return query.toBinaryQuery(oid_map, alloc);
    }
};
} // namespace ozo