v1::observer< T > Class Template Reference

#include <hikogui/observer.hpp>

Data Structures
class	_proxy
	A proxy object of the observer. More...

Public Types
using	value_type = T
using	notifier_type = notifier<void(value_type)>
using	callback_token = notifier_type::callback_token
using	callback_proto = notifier_type::callback_proto
using	awaiter_type = notifier_type::awaiter_type
using	path_type = observable_msg::path_type
using	proxy = _proxy<true>
using	const_proxy = _proxy<false>

Public Member Functions
	observer (forward_of< std::shared_ptr< observable > > auto &&observed) noexcept
	Create an observer from an observable.
constexpr	observer () noexcept
	Create a observer linked to an anonymous default initialized observed-value.
constexpr	observer (std::convertible_to< value_type > auto &&value) noexcept
	Create a observer linked to an anonymous observed-value.
constexpr	observer (observer const &other) noexcept
	Copy construct.
constexpr	observer (observer &&other) noexcept
	Move construct.
constexpr observer &	operator= (observer const &other) noexcept
	Copy assign.
constexpr observer &	operator= (observer &&other) noexcept
	Move assign.
void	reset () noexcept
	Reset the observer.
const_proxy	read () const &noexcept
	Read the observed value.
const_proxy	read () &&=delete
proxy	copy () const &noexcept
	Make a copy of the observed value for modification.
callback_token	subscribe (forward_of< callback_proto > auto &&function, callback_flags flags=callback_flags::synchronous) noexcept
	Subscribe a callback to this observer.
awaiter_type	operator co_await () const noexcept
auto	get (auto const &index) const noexcept
	Create a sub-observer by indexing into the value.
template<fixed_string Name>
auto	get () const noexcept
	Create a sub-observer by selecting a member-variable of the value.
template<typename Rhs > requires requires (value_type &a, Rhs &&b) { a = std::forward<Rhs>(b); }
observer &	operator= (Rhs &&rhs) noexcept
	Assign a new value to the observed value.
value_type	operator* () const noexcept
	Get a copy of the value being observed.
const_proxy	operator-> () const &noexcept
	Constant pointer-to-member of the value being observed.
const_proxy	operator-> () &&=delete
	X (++) X(--) X(++) X(--) X(+
	observer (forward_of< observed_type > auto &&observed, forward_of< path_type > auto &&path, forward_of< void *(void *)> auto &&converter) noexcept
	Construct an observer from an observable.
void	read_unlock () const noexcept
void	commit (void *base) const noexcept
void	abort (void *base) const noexcept
value_type *	convert (void *base) const noexcept
value_type const *	convert (void const *base) const noexcept
void	update_state_callback () noexcept

Data Fields
observed_type	_observed = {}
path_type	_path = {}
std::function< void *(void *)	_convert ) = {}
notifier_type	_notifier
value_type	_value

Detailed Description

template<typename T>
class v1::observer< T >

A observer pointing to the whole or part of a observable.

A observer will point to a observable that was created, or possibly an anonymous observable, which is created when a observer is created as empty.

Template Parameters

T	The type of observer.

Constructor & Destructor Documentation

observer() [1/6]

template<typename T >

v1::observer< T >::observer ( forward_of< std::shared_ptr< observable > > auto && observed )

inlinenoexcept

Create an observer from an observable.

Parameters

observed

The observable which will be observed by this observer.

observer() [2/6]

template<typename T >

constexpr v1::observer< T >::observer ( )

inlineexplicitconstexprnoexcept

Create a observer linked to an anonymous default initialized observed-value.

Note

marked 'explicit' so that accidental assignment with {} is not allowed.

observer() [3/6]

template<typename T >

constexpr v1::observer< T >::observer ( std::convertible_to< value_type > auto && value )

inlineconstexprnoexcept

Create a observer linked to an anonymous observed-value.

observer() [4/6]

template<typename T >

constexpr v1::observer< T >::observer ( observer< T > const & other )

inlineconstexprnoexcept

Copy construct.

Note

callback subscriptions are not copied.

Parameters

other

The other observer.

observer() [5/6]

template<typename T >

constexpr v1::observer< T >::observer ( observer< T > && other )

inlineconstexprnoexcept

Move construct.

Note

callback subscriptions are not copied.

Parameters

other

The other observer.

observer() [6/6]

template<typename T >

v1::observer< T >::observer ( forward_of< observed_type > auto && observed, forward_of< path_type > auto && path, forward_of< void *(void *)> auto && converter )

inlinenoexcept

Construct an observer from an observable.

Member Function Documentation

copy()

template<typename T >

proxy v1::observer< T >::copy ( ) const &

inlinenoexcept

Make a copy of the observed value for modification.

Returns

A proxy object used to modify the data being observed.

get() [1/2]

template<typename T >

template<fixed_string Name>

auto v1::observer< T >::get ( ) const

inlinenoexcept

Create a sub-observer by selecting a member-variable of the value.

Note

This function requires the hi::selector type-trait to be implemented for value_type.

Template Parameters

Name	The name of the member-variable of value.

Returns

A new sub-observer which monitors the member of value.

get() [2/2]

template<typename T >

auto v1::observer< T >::get ( auto const & index ) const

inlinenoexcept

Create a sub-observer by indexing into the value.

Parameters

index

The index into the value being observed.

Returns

A new sub-observer which monitors the selected sub-value.

operator*()

template<typename T >

value_type v1::observer< T >::operator* ( ) const

inlinenoexcept

Get a copy of the value being observed.

operator->()

template<typename T >

const_proxy v1::observer< T >::operator-> ( ) const &

inlinenoexcept

Constant pointer-to-member of the value being observed.

operator=() [1/3]

template<typename T >

constexpr observer & v1::observer< T >::operator= ( observer< T > && other )

inlineconstexprnoexcept

Move assign.

Note

Callback subscriptions remain unchanged and are not moved.

The other shared observer will be attached to the anonymous state.

Parameters

other

The other observer.

Returns

this

operator=() [2/3]

template<typename T >

constexpr observer & v1::observer< T >::operator= ( observer< T > const & other )

inlineconstexprnoexcept

Copy assign.

Note

callback subscriptions remain unchanged and are not copied.

Parameters

other

The other observer.

Returns

this

operator=() [3/3]

template<typename T >

template<typename Rhs >
requires requires (value_type &a, Rhs &&b) { a = std::forward<Rhs>(b); }

observer & v1::observer< T >::operator= ( Rhs && rhs )

inlinenoexcept

Assign a new value to the observed value.

read()

template<typename T >

const_proxy v1::observer< T >::read ( ) const &

inlinenoexcept

Read the observed value.

Returns

A const-proxy object used to access the data being observed.

reset()

template<typename T >

void v1::observer< T >::reset ( )

inlinenoexcept

Reset the observer.

This will link the observer with an anonymous observable with a default initialized value.

subscribe()

template<typename T >

callback_token v1::observer< T >::subscribe ( forward_of< callback_proto > auto && function, callback_flags flags = callback_flags::synchronous )

inlinenoexcept

Subscribe a callback to this observer.

Parameters

flags	The callback flags on how to call the function.
function	The function used as callback in the form void(value_type const &old_value, value_type const &new_value)

Returns

A callback-token used to extend the lifetime of the callback function.

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

• hikogui/src/hikogui/observable_value.hpp
• hikogui/src/hikogui/observer.hpp