query/include/matador/sql/field.hpp

115 lines
2.8 KiB
C++

#ifndef QUERY_FIELD_HPP
#define QUERY_FIELD_HPP
#include "matador/sql/any_type.hpp"
#include "matador/sql/any_type_to_visitor.hpp"
#include "matador/utils/types.hpp"
#include <optional>
#include <string>
namespace matador::sql {
enum class field_type {
Integer,
FloatingPoint,
String,
Boolean,
Blob,
Null
};
template < typename Type, typename Enable = void >
struct field_traits;
template<typename Type>
struct field_traits<Type, typename std::enable_if<std::is_integral<Type>::value && !std::is_same<Type, bool>::value>::type>
{
static field_type type() { return field_type::Integer; }
};
template<typename Type>
struct field_traits<Type, typename std::enable_if<std::is_floating_point<Type>::value>::type>
{
static field_type type() { return field_type::FloatingPoint; }
};
template<typename Type>
struct field_traits<Type, typename std::enable_if<std::is_same<Type, std::string>::value>::type>
{
static field_type type() { return field_type::String; }
};
template<typename Type>
struct field_traits<Type, typename std::enable_if<std::is_same<Type, bool>::value>::type>
{
static field_type type() { return field_type::Boolean; }
};
template<typename Type>
struct field_traits<Type, typename std::enable_if<std::is_same<Type, nullptr_t>::value>::type>
{
static field_type type() { return field_type::Null; }
};
template<typename Type>
struct field_traits<Type, typename std::enable_if<std::is_same<Type, utils::blob>::value>::type>
{
static field_type type() { return field_type::Blob; }
};
class field
{
public:
explicit field(std::string name);
template<typename Type>
field(std::string name, Type value, int index = -1)
: name_(std::move(name))
, index_(index)
, value_(value)
, type_(field_traits<Type>::type()) {}
field(const field &x) = default;
field& operator=(const field &x) = default;
field(field &&x) noexcept;
field& operator=(field &&x) noexcept;
template<typename Type>
field& operator=(Type value) {
value_ = std::move(value);
type_ = field_traits<Type>::type();
return *this;
}
[[nodiscard]] const std::string& name() const;
[[nodiscard]] int index() const;
template<class Type>
std::optional<Type> as() const
{
any_type_to_visitor<Type> visitor;
std::visit(visitor, const_cast<any_type&>(value_));
return visitor.result;
}
[[nodiscard]] std::string str() const;
[[nodiscard]] bool is_integer() const;
[[nodiscard]] bool is_floating_point() const;
[[nodiscard]] bool is_bool() const;
[[nodiscard]] bool is_string() const;
[[nodiscard]] bool is_blob() const;
[[nodiscard]] bool is_null() const;
friend std::ostream& operator<<(std::ostream &out, const field &col);
private:
std::string name_;
int index_{-1};
any_type value_;
field_type type_;
};
}
#endif //QUERY_FIELD_HPP