aria::Loadable< T > Class Template Reference

Standard loadable view-model. More...

#include <loadable.hpp>

Public Types
using	value_type = T

Public Member Functions
LoadState	state () const noexcept
bool	is_idle () const noexcept
bool	is_loading () const noexcept
bool	is_refreshing () const noexcept
bool	is_success () const noexcept
bool	is_error () const noexcept
bool	in_flight () const noexcept
	True iff a fetch is currently in flight (Loading or Refreshing).
bool	has_value () const noexcept
	True iff the loadable currently has a value to show (Success, Refreshing, or Error+prior).
bool	has_error () const noexcept
	True iff an error is currently surfaced.
const T *	value () const noexcept
	Returns a pointer to the value if has_value(), else nullptr.
template<class U>
T	value_or (U &&fallback) const
	Returns a copy of the value, or constructs T from fallback if absent.
const Error *	error () const noexcept
	Returns a pointer to the error if has_error(), else nullptr.
template<class F>
auto	map (F &&f) const -> Loadable< std::remove_cvref_t< std::invoke_result_t< F, const T & > > >

Static Public Member Functions
static Loadable	idle () noexcept
static Loadable	loading ()
static Loadable	refreshing (T prior)
	Build a Refreshing state from an existing Success payload.
static Loadable	success (T v)
static Loadable	error (Error err)
	Build an Error state.
static Loadable	error (Error err, T prior)

Friends
template<class>
class	Loadable
bool	operator== (const Loadable &a, const Loadable &b)

Detailed Description

template<class T>
class aria::Loadable< T >

Standard loadable view-model.

Stores up to one value (the freshest known good) and up to one error (the last failure). Combined with state() they encode the five-state view-model.

The class is value-typed and equality-comparable so it composes cleanly with Property<Loadable<T>>'s equality-gated set semantics (per lifecycle.md L-21 and error-model.md E-11). It holds no resources of its own.

Member Typedef Documentation

value_type

template<class T>

using aria::Loadable< T >::value_type = T

Member Function Documentation

idle()

template<class T>

Loadable aria::Loadable< T >::idle ( )

inlinestaticnodiscardnoexcept

loading()

template<class T>

Loadable aria::Loadable< T >::loading ( )

inlinestaticnodiscard

refreshing()

template<class T>

Loadable aria::Loadable< T >::refreshing ( T prior )

inlinestaticnodiscard

Build a Refreshing state from an existing Success payload.

prior is the value still on display while the refresh runs.

success()

template<class T>

Loadable aria::Loadable< T >::success ( T v )

inlinestaticnodiscard

error() [1/3]

template<class T>

Loadable aria::Loadable< T >::error ( Error err )

inlinestaticnodiscard

Build an Error state.

If prior is provided the loadable keeps the last good value visible (stale-while-revalidate).

error() [2/3]

template<class T>

Loadable aria::Loadable< T >::error ( Error err, T prior )

inlinestaticnodiscard

state()

template<class T>

LoadState aria::Loadable< T >::state ( ) const

inlinenodiscardnoexcept

is_idle()

template<class T>

bool aria::Loadable< T >::is_idle ( ) const

inlinenodiscardnoexcept

is_loading()

template<class T>

bool aria::Loadable< T >::is_loading ( ) const

inlinenodiscardnoexcept

is_refreshing()

template<class T>

bool aria::Loadable< T >::is_refreshing ( ) const

inlinenodiscardnoexcept

is_success()

template<class T>

bool aria::Loadable< T >::is_success ( ) const

inlinenodiscardnoexcept

is_error()

template<class T>

bool aria::Loadable< T >::is_error ( ) const

inlinenodiscardnoexcept

in_flight()

template<class T>

bool aria::Loadable< T >::in_flight ( ) const

inlinenodiscardnoexcept

True iff a fetch is currently in flight (Loading or Refreshing).

Mirrors AsyncResource's is_loading Property.

has_value()

template<class T>

bool aria::Loadable< T >::has_value ( ) const

inlinenodiscardnoexcept

True iff the loadable currently has a value to show (Success, Refreshing, or Error+prior).

has_error()

template<class T>

bool aria::Loadable< T >::has_error ( ) const

inlinenodiscardnoexcept

True iff an error is currently surfaced.

Only true in Error state (Loading/Refreshing/Success never carry an error per error-model.md – a fresh fetch clears the previous error).

value()

template<class T>

const T * aria::Loadable< T >::value ( ) const

inlinenodiscardnoexcept

Returns a pointer to the value if has_value(), else nullptr.

value_or()

template<class T>

template<class U>

T aria::Loadable< T >::value_or ( U && fallback ) const

inlinenodiscard

Returns a copy of the value, or constructs T from fallback if absent.

error() [3/3]

template<class T>

const Error * aria::Loadable< T >::error ( ) const

inlinenodiscardnoexcept

Returns a pointer to the error if has_error(), else nullptr.

map()

template<class T>

template<class F>

auto aria::Loadable< T >::map ( F && f ) const -> Loadable< std::remove_cvref_t< std::invoke_result_t< F, const T & > > >

inlinenodiscard

Friends And Related Symbol Documentation

Loadable

template<class T>

template<class>

friend class Loadable

friend

operator==

template<class T>

bool operator== ( const Loadable< T > & a, const Loadable< T > & b )

friend

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

• modules/core/include/aria/loadable.hpp