CRTP base for struct cells that are their own payload. More...

#include <struct.h>

Inheritance diagram for parcel::SelfStructCell< Derived >:

Collaboration diagram for parcel::SelfStructCell< Derived >:

Public Types
using	storage_t = Derived
	Storage-type alias used by descriptors that probe `T::storage_t`.

Public Member Functions
std::string_view	kind () const override
	Wire-stable kind identifier for this cell.

std::string	to_string () const override
	Render the cell's value as a compact human-readable string.

json_t	to_json () const override
	Serialize this cell to its canonical JSON representation.

cell_t	clone () const override
	Deep-copy this cell.

std::partial_ordering	compare (ICell const &other) const override
	Three-way comparison over field values (and `cell_extras_` when `allow_extra_fields` is true); ignores display info.

std::optional< DisplayInfo > const &	overridden_display_info () const override
	Read-only access to this cell's optional display info.

Public Member Functions inherited from parcel::ICell
virtual std::string	to_formatted_string () const
	Render the cell as a multi-line, indented string.

virtual std::size_t	hash_value () const noexcept
	Equality-consistent hash that mirrors `compare`'s display-info-insensitivity.

cell_t	with_display_info (DisplayInfo m) const
	Return a deep copy with the entire display info block replaced.

cell_t	with_name (std::string v) const
	Return a deep copy with `name` set to `v`.

cell_t	with_description (std::string v) const
	Return a deep copy with `description` set to `v`.

cell_t	with_icon (comms::Icon icon) const
	Return a deep copy with `icon` set to the typed `icon`.

cell_t	with_icon (std::string const &v) const
	Return a deep copy with `icon` parsed from an Iconify `set:name` string (e.g.

cell_t	with_color (comms::Color color) const
	Return a deep copy with `color` set to the typed `color`.

cell_t	with_color (std::string const &v) const
	Return a deep copy with `color` parsed from a color string (hex like `"#ffcc00"`, a CSS-functional form, or a CSS color name).

Static Public Member Functions
static cell_t	from_json (json_t const &j, ParcelRegistry const &reg)
	Deserialize the self-payload struct cell from JSON.

static cell_type_descriptor_t	descriptor ()
	Cached descriptor for this self-payload struct cell.

Static Public Attributes
static constexpr bool	allow_extra_fields = false
	Whether unknown JSON keys are tolerated.

Static Public Attributes inherited from parcel::ICell
static constexpr std::string_view	KEY_KIND = "k"
	JSON key for the kind id (`"k"`).

static constexpr std::string_view	KEY_VALUE = "v"
	JSON key for the value payload (`"v"`).

static constexpr std::string_view	KEY_DESCRIPTION = "d"
	JSON key for the optional display info block (`"d"`).

Protected Member Functions
void	inject_display_info (json_t &j) const
	Copy this cell's display info (if any) into the JSON object under `"d"`.

void	set_display_info (std::optional< DisplayInfo > m) override
	Replace this cell's display info in place.

Protected Attributes
std::optional< DisplayInfo >	display_info_
	Optional display info; omitted from JSON when empty.

std::map< std::string, cell_t >	cell_extras_
	Unknown keys retained when `Derived::allow_extra_fields` is true.

Detailed Description

template<typename Derived>
class parcel::SelfStructCell< Derived >

CRTP base for struct cells that are their own payload.

Where StructCell<Derived, Payload, StructId> composes a separate payload struct held in BaseCell::value, SelfStructCell<Derived> inherits ICell directly and treats Derived itself as the payload. Field descriptors are IPayloadFieldDescriptor<Derived> and address members on the cell instance itself — there is no nested value.

Library authors typically introduce a CRTP intermediate (e.g. BaseEvent<Self, EventId>) on top of SelfStructCell to carry common fields and to choose their own wire-namespace prefix:

template <typename Self, parcel::FixedString EventId>
class BaseEvent : public parcel::SelfStructCell<Self> {
public:
    static constexpr std::string_view kind_id =
        parcel::id_join_lit_v<"s:event:", EventId>;
 
protected:
    std::int64_t timestamp_{};
public:
    [[nodiscard]] std::int64_t timestamp() const { return timestamp_; }
 
    static auto field_descriptors() {
        auto builder = parcel::FieldsBuilder<Self>{};
        return Self::event_field_descriptors(builder)
            .template field<&BaseEvent::timestamp_>("timestamp")
            .build();
    }
};

Unlike StructCell, SelfStructCell has no StructId template parameter and does not synthesize a kind_id; the deriving class (or a CRTP intermediate) declares static constexpr std::string_view kind_id directly, which gives library authors freedom to carve out their own sub-namespace (e.g. "s:event:something").

Derived must additionally provide:

static constexpr std::string_view kind_id — wire kind id.
static auto field_descriptors() — built via FieldsBuilder<Derived>.
(optional) static DisplayInfo display_info() — cell-level display info; defaults to an empty DisplayInfo{} when not declared.
(optional) static constexpr bool allow_extra_fields — defaults to false.

Derived must also be default-constructible with access from parcel-internal code — from_json calls std::make_shared<Derived>(). Keeping the default constructor public while making data members protected/private is the standard pattern.

Template Parameters

Derived The concrete struct cell, which is also its own payload.

Member Typedef Documentation

◆ storage_t

template<typename Derived >

using parcel::SelfStructCell< Derived >::storage_t = Derived

Storage-type alias used by descriptors that probe T::storage_t.

SelfStructCell does not own a separate payload — the cell is its own payload — so storage_t resolves to Derived itself. Lets the existing BaseCellTypeDescriptor<Derived>::storage_type() keep working unchanged.

Member Function Documentation

◆ clone()

template<typename Derived >

cell_t parcel::SelfStructCell< Derived >::clone ( ) const

inlineoverridevirtual

Deep-copy this cell.

Returns: A new cell_t whose state is independent of the original.

Implements parcel::ICell.

◆ compare()

template<typename Derived >

std::partial_ordering parcel::SelfStructCell< Derived >::compare ( ICell const & other ) const

inlineoverridevirtual

Three-way comparison over field values (and cell_extras_ when allow_extra_fields is true); ignores display info.

Walks declared fields in the order returned by field_descriptors() and short-circuits on the first non-equal result. Optional fields follow std::optional's <=>. When allow_extra_fields is true, after declared fields agree the cell_extras_ maps are compared lexicographically by key, with ICell <=> resolving each value pair.

Implements parcel::ICell.

◆ descriptor()

template<typename Derived >

static cell_type_descriptor_t parcel::SelfStructCell< Derived >::descriptor ( )

inlinestatic

Cached descriptor for this self-payload struct cell.

Returns: Shared StructCellTypeDescriptor<Derived, Derived> instance.

◆ from_json()

template<typename Derived >

static cell_t parcel::SelfStructCell< Derived >::from_json	(	json_t const &	j,
		ParcelRegistry const &	reg
	)

inlinestatic

Deserialize the self-payload struct cell from JSON.

Mirrors StructCell::from_json, but field descriptors target Derived itself rather than a separate payload type.

Parameters

j	Input JSON object — must match `{"k": kind_id, "v": {…}}`.
reg	Registry used to dispatch nested cells.

Returns: Newly built cell handle.

Exceptions

std::runtime_error on shape or kind mismatch, missing required field, or unknown key when extras are not allowed.

◆ inject_display_info()

template<typename Derived >

void parcel::SelfStructCell< Derived >::inject_display_info ( json_t & j ) const

inlineprotected

Copy this cell's display info (if any) into the JSON object under "d".

Mirrors BaseCell::inject_display_info — re-declared here because SelfStructCell inherits ICell directly, not BaseCell.

Parameters

j	JSON object to mutate.

◆ kind()

template<typename Derived >

std::string_view parcel::SelfStructCell< Derived >::kind ( ) const

inlineoverridevirtual

Wire-stable kind identifier for this cell.

Returns: The same value as the static kind_id on the concrete type.

Implements parcel::ICell.

◆ overridden_display_info()

template<typename Derived >

std::optional< DisplayInfo > const & parcel::SelfStructCell< Derived >::overridden_display_info ( ) const

inlineoverridevirtual

Read-only access to this cell's optional display info.

Returns: Reference to the held optional; empty when no display info is set.

Implements parcel::ICell.

◆ set_display_info()

template<typename Derived >

void parcel::SelfStructCell< Derived >::set_display_info ( std::optional< DisplayInfo > m )

inlineoverrideprotectedvirtual

Replace this cell's display info in place.

Used by with_* builders on freshly cloned receivers and by JSON deserializers; no other public path mutates display info.

Parameters

m	New display info value (may be empty to clear).

Implements parcel::ICell.

◆ to_json()

template<typename Derived >

json_t parcel::SelfStructCell< Derived >::to_json ( ) const

inlineoverridevirtual

Serialize this cell to its canonical JSON representation.

Returns: JSON object of shape {"k", "v", optional "d"}.

Implements parcel::ICell.

◆ to_string()

template<typename Derived >

std::string parcel::SelfStructCell< Derived >::to_string ( ) const

inlineoverridevirtual

Render the cell's value as a compact human-readable string.

Returns: String form — implementation-defined per cell type.

Implements parcel::ICell.

Member Data Documentation

◆ allow_extra_fields

template<typename Derived >

constexpr bool parcel::SelfStructCell< Derived >::allow_extra_fields = false

staticconstexpr

Whether unknown JSON keys are tolerated.

Concrete Derived types may shadow this with true to opt into lenient deserialization; the default is strict (false).

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

include/parcel/struct.h

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Member Typedef Documentation

◆ storage_t

Member Function Documentation

◆ clone()

◆ compare()

◆ descriptor()

◆ from_json()

◆ inject_display_info()

◆ kind()

◆ overridden_display_info()

◆ set_display_info()

◆ to_json()

◆ to_string()

Member Data Documentation

◆ allow_extra_fields