parcel::MemberFieldDescriptor< Payload, FieldT, CellT > Class Template Reference

Concrete payload field descriptor backed by a member pointer. More...

#include <struct.h>

Inheritance diagram for parcel::MemberFieldDescriptor< Payload, FieldT, CellT >:

Collaboration diagram for parcel::MemberFieldDescriptor< Payload, FieldT, CellT >:

Public Member Functions
	MemberFieldDescriptor (FieldT Payload::*member_ptr, std::string key, DisplayInfo info)
	Construct with the member pointer, JSON key, and (initial) display info.
std::string_view	key () const override
	JSON key under which this field appears in "v".
std::string_view	kind () const override
	Cell kind id for the field's value type.
DisplayInfo	display_info () const override
	Display info for this field.
bool	is_required () const override
	Whether the field must be present on deserialization.
json_t	to_json () const override
	Serialize the field descriptor itself.
DisplayInfo &	mutable_display_info () override
	Mutable access to this field's display info — used by FieldsBuilder.
void	set_required (const bool r) override
	Override the field's required flag.
void	to_json_into (json_t &v_obj, Payload const &p) const override
	Serialize this field from p into the value object v_obj.
void	from_json_into (json_t const &field_json, Payload &p, ParcelRegistry const &reg) const override
	Deserialize this field from field_json into p.
std::partial_ordering	compare (Payload const &a, Payload const &b) const override
	Three-way compare this field across two payload instances.
void	to_string_into (std::string &out, Payload const &p) const override
	Append key: value for this field to the rendered string.

Detailed Description

template<typename Payload, typename FieldT, CellLike CellT>
class parcel::MemberFieldDescriptor< Payload, FieldT, CellT >

Concrete payload field descriptor backed by a member pointer.

The required flag defaults to false for std::optional<T> fields and true otherwise — matching the natural reading of "optional means may be absent".

The member pointer is held at runtime (not as a non-type template parameter) so it can be a FieldT Base::* implicitly converted to FieldT Payload::*. This keeps FieldsBuilder<Derived>::field<&Base::x> usable for redeclaring/overriding inherited fields after extend<>.

Template Parameters

Payload	The struct type being described.
FieldT	The type of the member pointed at by member_ptr.
CellT	The cell type used to wrap FieldT on the wire.

Constructor & Destructor Documentation

MemberFieldDescriptor()

template<typename Payload , typename FieldT , CellLike CellT>

parcel::MemberFieldDescriptor< Payload, FieldT, CellT >::MemberFieldDescriptor ( FieldT Payload::*  member_ptr, std::string  key, DisplayInfo  info  )

inline

Construct with the member pointer, JSON key, and (initial) display info.

Parameters

member_ptr	Pointer-to-member into Payload.
key	JSON key under which this field appears.
info	Initial display info.

Member Function Documentation

compare()

template<typename Payload , typename FieldT , CellLike CellT>

std::partial_ordering parcel::MemberFieldDescriptor< Payload, FieldT, CellT >::compare ( Payload const &  a, Payload const &  b  ) const

inlineoverridevirtual

Three-way compare this field across two payload instances.

StructCell::compare walks fields in declaration order and short- circuits on the first non-equal result; ignores display info. Optional fields follow std::optional's <=>: absent < present, both absent is equal.

Implements parcel::IPayloadFieldDescriptor< Payload >.

from_json_into()

template<typename Payload , typename FieldT , CellLike CellT>

void parcel::MemberFieldDescriptor< Payload, FieldT, CellT >::from_json_into ( json_t const &  field_json, Payload &  p, ParcelRegistry const &  reg  ) const

inlineoverridevirtual

Deserialize this field from field_json into p.

Parameters

field_json	JSON value for this field (already a wrapped cell).
p	Payload instance to write into.
reg	Registry forwarded to nested cell deserializers.

Implements parcel::IPayloadFieldDescriptor< Payload >.

to_json()

template<typename Payload , typename FieldT , CellLike CellT>

json_t parcel::MemberFieldDescriptor< Payload, FieldT, CellT >::to_json ( ) const

inlineoverridevirtual

Serialize the field descriptor itself.

Returns

JSON object with key, kind, display_info, required.

Implements parcel::IFieldDescriptor.

to_json_into()

template<typename Payload , typename FieldT , CellLike CellT>

void parcel::MemberFieldDescriptor< Payload, FieldT, CellT >::to_json_into ( json_t &  v_obj, Payload const &  p  ) const

inlineoverridevirtual

Serialize this field from p into the value object v_obj.

Parameters

v_obj	Target JSON object (the "v" block of the cell).
p	Payload instance to read from.

Implements parcel::IPayloadFieldDescriptor< Payload >.

to_string_into()

template<typename Payload , typename FieldT , CellLike CellT>

void parcel::MemberFieldDescriptor< Payload, FieldT, CellT >::to_string_into ( std::string &  out, Payload const &  p  ) const

inlineoverridevirtual

Append key: value for this field to the rendered string.

Parameters

out	String buffer to append to.
p	Payload instance to read from.

Implements parcel::IPayloadFieldDescriptor< Payload >.

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The documentation for this class was generated from the following file:

• include/parcel/struct.h