uni20::async::EpochContextReader< T > Class Template Reference

RAII handle representing the writer of a value in an EpochContext. More...

#include <epoch_context.hpp>

Public Member Functions
T const &	data () const
	Access the stored value inside the parent Async<T>.
T const *	data_maybe () const
std::optional< T >	data_option () const
	Optionally retrieves the value stored in this buffer, if available.
std::shared_ptr< EpochContext >	epoch_context_shared () const noexcept
	EpochContextReader ()=delete
	Default-constructed inactive reader (no effect).
	EpochContextReader (EpochContextReader &&other) noexcept
	Move constructor.
	EpochContextReader (EpochContextReader const &other)
	Copy constructor retaining the reader reference count.
	EpochContextReader (shared_storage< T > storage, std::shared_ptr< EpochContext > epoch) noexcept
	Construct a new reader handle for a given parent and epoch.
T const &	get_wait () const
	Wait for the epoch to become available on the global scheduler and return a reference to the value.
T const &	get_wait (IAsyncScheduler &sched) const
	Wait for the epoch to become available on the provided scheduler and return a reference to the value.
void	notify_when_ready (std::function< void()> notify) const
	Register a callback for this reader becoming ready.
EpochContextReader &	operator= (EpochContextReader &&other) noexcept
	Move assignment.
EpochContextReader &	operator= (EpochContextReader const &other)
	Copy assignment retaining the reader reference count.
bool	ready () const noexcept
	Check whether the reader is ready to resume.
void	release () noexcept
	Release the reader.
void	suspend (BasicTask &&t)
	Suspend a coroutine task as a reader of this epoch.
void	wait () const
	Wait for the epoch to become available on the global scheduler.
void	wait (IAsyncScheduler &sched) const
	Wait for the epoch to become available on the provided scheduler.
	~EpochContextReader ()
	Destructor. Signals epoch reader completion if still active.

Detailed Description

template<typename T>
class uni20::async::EpochContextReader< T >

RAII handle representing the writer of a value in an EpochContext.

On construction, this marks the epoch as having a writer. When the buffer is set and the writer releases the value, waiting readers may resume.

EpochContextWriter does not represent a coroutine or suspendable operation. It is a scoped object used to enforce single-writer discipline and ensure writer→readers sequencing.

Note

Writer must eventually call .release() to trigger reader advancement.

See also

EpochContext, EpochContextReader

Constructor & Destructor Documentation

EpochContextReader() [1/4]

template<typename T >

uni20::async::EpochContextReader< T >::EpochContextReader ( )

delete

Default-constructed inactive reader (no effect).

EpochContextReader() [2/4]

template<typename T >

uni20::async::EpochContextReader< T >::EpochContextReader ( EpochContextReader< T > const &  other )

inline

Copy constructor retaining the reader reference count.

EpochContextReader() [3/4]

template<typename T >

uni20::async::EpochContextReader< T >::EpochContextReader ( shared_storage< T >  storage, std::shared_ptr< EpochContext >  epoch  )

inlinenoexcept

Construct a new reader handle for a given parent and epoch.

Parameters

value	Shared pointer to the stored value.
epoch	Pointer to the epoch being tracked.

EpochContextReader() [4/4]

template<typename T >

uni20::async::EpochContextReader< T >::EpochContextReader ( EpochContextReader< T > &&  other )

inlinenoexcept

Move constructor.

Transfers ownership and nulls the source.

Parameters

other

Reader being moved from.

~EpochContextReader()

template<typename T >

uni20::async::EpochContextReader< T >::~EpochContextReader ( )

inline

Destructor. Signals epoch reader completion if still active.

Member Function Documentation

data()

template<typename T >

T const & uni20::async::EpochContextReader< T >::data ( ) const

inline

Access the stored value inside the parent Async<T>.

Returns

Reference to the T value.

Precondition

The value must be ready. Should only be called after await_ready() returns true.

Exceptions

buffer_read_uninitialized

if no value was constructed for this epoch.

data_maybe()

template<typename T >

T const * uni20::async::EpochContextReader< T >::data_maybe ( ) const

inline

Returns

A pointer to the value, if it is written, otherwise returns nullptr.

Exceptions

Any	exception stored in the writer, if the buffer is in an exception state.

Precondition

The buffer must be ready for reading (i.e., the write gate is closed).

data_option()

template<typename T >

std::optional< T > uni20::async::EpochContextReader< T >::data_option ( ) const

inline

Optionally retrieves the value stored in this buffer, if available.

Returns

A copy of the value if it was written; std::nullopt if the buffer was cancelled.

Exceptions

Any	exception stored in the writer, if the write failed exceptionally.

Precondition

The buffer must be ready for reading (i.e., the write gate is closed).

Postcondition

If a value is returned, it is a full copy and independent of the internal buffer.

epoch_context_shared()

template<typename T >

std::shared_ptr< EpochContext > uni20::async::EpochContextReader< T >::epoch_context_shared ( ) const

inlinenoexcept

get_wait() [1/2]

template<typename T >

T const & uni20::async::EpochContextReader< T >::get_wait

(

)

const

Wait for the epoch to become available on the global scheduler and return a reference to the value.

Wait for a reader context using the global scheduler.

Template Parameters

T	Stored value type.

Returns

Reference to the ready value.

get_wait() [2/2]

template<typename T >

T const & uni20::async::EpochContextReader< T >::get_wait

(

IAsyncScheduler &

sched

)

const

Wait for the epoch to become available on the provided scheduler and return a reference to the value.

Wait for a reader context using an explicit scheduler.

Parameters

sched

Scheduler used to drive readiness.

Template Parameters

T	Stored value type.

Parameters

sched

Scheduler used to drive progress.

Returns

Reference to the ready value.

notify_when_ready()

template<typename T >

void uni20::async::EpochContextReader< T >::notify_when_ready ( std::function< void()>  notify ) const

inline

Register a callback for this reader becoming ready.

Parameters

notify

Non-throwing callback invoked when the epoch reaches Reading.

operator=() [1/2]

template<typename T >

EpochContextReader & uni20::async::EpochContextReader< T >::operator= ( EpochContextReader< T > &&  other )

inlinenoexcept

Move assignment.

Releases prior ownership and transfers.

Parameters

other

Reader being moved from.

Returns

Reference to *this after transfer.

operator=() [2/2]

template<typename T >

EpochContextReader & uni20::async::EpochContextReader< T >::operator= ( EpochContextReader< T > const &  other )

inline

Copy assignment retaining the reader reference count.

Parameters

other

Reader being copied from.

Returns

Reference to *this after copy.

ready()

template<typename T >

bool uni20::async::EpochContextReader< T >::ready ( ) const

inlinenoexcept

Check whether the reader is ready to resume.

Returns

True if all prerequisites for this epoch are satisfied.

release()

template<typename T >

void uni20::async::EpochContextReader< T >::release ( )

inlinenoexcept

Release the reader.

suspend()

template<typename T >

void uni20::async::EpochContextReader< T >::suspend ( BasicTask &&  t )

inline

Suspend a coroutine task as a reader of this epoch.

Parameters

t	The coroutine task to register.

wait() [1/2]

template<typename T >

void uni20::async::EpochContextReader< T >::wait

(

)

const

Wait for the epoch to become available on the global scheduler.

Wait for a reader context using the global scheduler.

Template Parameters

T	Stored value type.

wait() [2/2]

template<typename T >

void uni20::async::EpochContextReader< T >::wait

(

IAsyncScheduler &

sched

)

const

Wait for the epoch to become available on the provided scheduler.

Wait for a reader context using an explicit scheduler.

Parameters

sched

Scheduler used to drive readiness.

Template Parameters

T	Stored value type.

Parameters

sched

Scheduler used to drive progress.

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

• epoch_context.hpp
• debug_scheduler.hpp