RAII handle for reading the value from an Async container at a given epoch. More...

#include <buffers.hpp>

Public Types
using	value_type = T

Public Member Functions
bool	await_ready () const noexcept
	Check if the value is already ready to be read.

OwningReadAccessProxy< T >	await_resume () &&
	Resume execution and return an owning read proxy.

T const &	await_resume () const &
	Resume execution and return the stored value.

void	await_suspend (BasicTask &&t) noexcept
	Suspend this coroutine and enqueue for resumption.

std::shared_ptr< EpochContext >	epoch_context_shared () const noexcept
	Returns the epoch context used for exception propagation.

T const &	get_wait () const
	Block until the read value is available.

T const &	get_wait (IAsyncScheduler &sched) const
	Block using an explicit scheduler until the read value is available.

ReadMaybeAwaiter< T const & >	maybe () &
	Returns a `ReadMaybeAwaiter`.

ReadMaybeAwaiter< T >	maybe () &&
	Returns a `ReadMaybeAwaiter` consuming this read buffer.

auto	operator co_await () &&noexcept -> OwningReadAwaiter< T >
	Enable co_await on rvalue ReadBuffer and transfer ownership to an owning read proxy.

auto	operator co_await () &noexcept -> ReadBuffer &
	Enable co_await on lvalue ReadBuffer and return a borrowed reference.

auto	operator co_await () const &noexcept -> ReadBuffer const &

ReadBuffer &	operator= (ReadBuffer &&other) noexcept
	Move assignment.

ReadBuffer &	operator= (ReadBuffer const &)=delete

ReadOrCancelAwaiter< T const & >	or_cancel () &
	Returns a `ReadOrCancelAwaiter`.

ReadOrCancelAwaiter< T >	or_cancel () &&
	Returns a `ReadOrCancelAwaiter` consuming this read buffer.

	ReadBuffer (EpochContextReader< T > reader)
	Construct a read buffer tied to a reader context.

	ReadBuffer (ReadBuffer &&other) noexcept
	Move constructor.

	ReadBuffer (ReadBuffer const &other)
	Copy constructor; duplicates read handle and exception sink registration.

void	register_exception_sink (TaskPromiseBase &promise, bool explicit_sink) const
	Register this buffer as an exception sink with a promise.

void	release () noexcept
	Manually release the epoch reader before awaitable destruction.

ReadBuffer &&	transfer () &&noexcept
	Transfer this read buffer into the owning-await path.

ReadBuffer &&	transfer () &noexcept
	Transfer this read buffer into the owning-await path.

void	wait () const
	Block until the read value is available.

void	wait (IAsyncScheduler &sched) const
	Block using an explicit scheduler until the read value is available.

	~ReadBuffer () noexcept
	Destructor unregisters any attached exception sink.

Detailed Description

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

RAII handle for reading the value from an Async container at a given epoch.

A ReadBuffer<T> represents a read-only access to the value of an Async<T> at a specific epoch. It is awaitable, and yields either a borrowed reference or an owning proxy depending on value category:

co_await buf yields T const&: shared read access.
co_await buf.transfer() yields an owning proxy that keeps the read epoch alive.

Note: transfer() is the explicit owning form for named buffers. Direct co_await on a temporary buffer still uses the owning rvalue path.; A ReadBuffer<T> can be co_awaited multiple times, but buf.transfer() transfers ownership semantics and should only be used once. After moving, further use is undefined.

Template Parameters

T	The underlying value type.

Member Typedef Documentation

◆ value_type

template<typename T >

using uni20::async::ReadBuffer< T >::value_type = T

Constructor & Destructor Documentation

◆ ReadBuffer() [1/3]

template<typename T >

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

inline

Construct a read buffer tied to a reader context.

Parameters

reader The RAII epoch reader handle for this operation.

◆ ReadBuffer() [2/3]

template<typename T >

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

inline

Copy constructor; duplicates read handle and exception sink registration.

Parameters

◆ ReadBuffer() [3/3]

template<typename T >

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

inlinenoexcept

Move constructor.

Parameters

◆ ~ReadBuffer()

template<typename T >

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

inlinenoexcept

Destructor unregisters any attached exception sink.

Member Function Documentation

◆ await_ready()

template<typename T >

bool uni20::async::ReadBuffer< T >::await_ready ( ) const

inlinenoexcept

Check if the value is already ready to be read.

Returns: True if the epoch is ready and no suspension is needed.

◆ await_resume() [1/2]

template<typename T >

OwningReadAccessProxy< T > uni20::async::ReadBuffer< T >::await_resume ( ) &&

Resume execution and return an owning read proxy.

◆ await_resume() [2/2]

template<typename T >

T const & uni20::async::ReadBuffer< T >::await_resume ( ) const &

inline

Resume execution and return the stored value.

Returns: Reference to the stored T inside Async<T>.

◆ await_suspend()

template<typename T >

void uni20::async::ReadBuffer< T >::await_suspend ( BasicTask && t )

inlinenoexcept

Suspend this coroutine and enqueue for resumption.

Parameters

t	Coroutine task to enqueue.

◆ epoch_context_shared()

template<typename T >

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

inlinenoexcept

Returns the epoch context used for exception propagation.

Returns: Shared pointer to the epoch context.

◆ get_wait() [1/2]

template<typename T >

T const & uni20::async::ReadBuffer< T >::get_wait ( ) const

inline

Block until the read value is available.

Returns: Const reference to the available value.

◆ get_wait() [2/2]

template<typename T >

T const & uni20::async::ReadBuffer< T >::get_wait ( IAsyncScheduler & sched ) const

inline

Block using an explicit scheduler until the read value is available.

Parameters

sched Scheduler used to drive progress.

Returns: Const reference to the available value.

◆ maybe() [1/2]

template<typename T >

ReadMaybeAwaiter< T const & > uni20::async::ReadBuffer< T >::maybe ( ) &

Returns a ReadMaybeAwaiter.

Lvalue reads return T const*; moved reads return std::optional<OwningReadAccessProxy<T>>.

◆ maybe() [2/2]

template<typename T >

ReadMaybeAwaiter< T > uni20::async::ReadBuffer< T >::maybe ( ) &&

Returns a ReadMaybeAwaiter consuming this read buffer.

Build a maybe-awaiter from an rvalue read buffer.

Moved reads return std::optional<OwningReadAccessProxy<T>>.

Template Parameters

T	Stored value type.

Returns: Awaiter yielding optional owning read access.

◆ operator co_await() [1/3]

template<typename T >

auto uni20::async::ReadBuffer< T >::operator co_await ( ) && -> OwningReadAwaiter<T>

inlinenoexcept

Enable co_await on rvalue ReadBuffer and transfer ownership to an owning read proxy.

◆ operator co_await() [2/3]

template<typename T >

auto uni20::async::ReadBuffer< T >::operator co_await ( ) & -> ReadBuffer&

inlinenoexcept

Enable co_await on lvalue ReadBuffer and return a borrowed reference.

◆ operator co_await() [3/3]

template<typename T >

auto uni20::async::ReadBuffer< T >::operator co_await ( ) const & -> ReadBuffer const&

inlinenoexcept

◆ operator=() [1/2]

template<typename T >

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

inlinenoexcept

Move assignment.

Parameters

◆ operator=() [2/2]

template<typename T >

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

delete

◆ or_cancel() [1/2]

template<typename T >

ReadOrCancelAwaiter< T const & > uni20::async::ReadBuffer< T >::or_cancel ( ) &

Returns a ReadOrCancelAwaiter.

Lvalue reads return T const& and throw task_cancelled when no value was written. Exceptions stored by a failed writer propagate unchanged.

◆ or_cancel() [2/2]

template<typename T >

ReadOrCancelAwaiter< T > uni20::async::ReadBuffer< T >::or_cancel ( ) &&

Returns a ReadOrCancelAwaiter consuming this read buffer.

Build an or-cancel awaiter from an rvalue read buffer.

Moved reads return OwningReadAccessProxy<T> and throw task_cancelled when no value was written. Exceptions stored by a failed writer propagate unchanged.

Template Parameters

T	Stored value type.

Returns: Awaiter yielding owning read access or throwing on cancellation.

◆ register_exception_sink()

template<typename T >

void uni20::async::ReadBuffer< T >::register_exception_sink	(	TaskPromiseBase &	promise,
		bool	explicit_sink
	)		const

inline

Register this buffer as an exception sink with a promise.

Parameters

promise	Promise that owns the sink list.
explicit_sink	Whether this sink came from `propagate_exceptions_to`.

◆ release()

template<typename T >

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

inlinenoexcept

Manually release the epoch reader before awaitable destruction.

This allows the coroutine to relinquish its reader role earlier than its full lifetime.

Postcondition: The ReadBuffer becomes inert and idempotent; calling release() more than once has no effect.

◆ transfer() [1/2]

template<typename T >

ReadBuffer && uni20::async::ReadBuffer< T >::transfer ( ) &&

inlinenoexcept

Transfer this read buffer into the owning-await path.

Returns: Rvalue reference to *this.

◆ transfer() [2/2]

template<typename T >

ReadBuffer && uni20::async::ReadBuffer< T >::transfer ( ) &

inlinenoexcept

Transfer this read buffer into the owning-await path.

Returns: Rvalue reference to *this.

◆ wait() [1/2]

template<typename T >

void uni20::async::ReadBuffer< T >::wait ( ) const

inline

Block until the read value is available.

◆ wait() [2/2]

template<typename T >

void uni20::async::ReadBuffer< T >::wait ( IAsyncScheduler & sched ) const

inline

Block using an explicit scheduler until the read value is available.

Parameters

sched Scheduler used to drive progress.

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

buffers.hpp

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

◆ value_type

Constructor & Destructor Documentation

◆ ReadBuffer() [1/3]

◆ ReadBuffer() [2/3]

◆ ReadBuffer() [3/3]

◆ ~ReadBuffer()

Member Function Documentation

◆ await_ready()

◆ await_resume() [1/2]

◆ await_resume() [2/2]

◆ await_suspend()

◆ epoch_context_shared()

◆ get_wait() [1/2]

◆ get_wait() [2/2]

◆ maybe() [1/2]

◆ maybe() [2/2]

◆ operator co_await() [1/3]

◆ operator co_await() [2/3]

◆ operator co_await() [3/3]

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ or_cancel() [1/2]

◆ or_cancel() [2/2]

◆ register_exception_sink()

◆ release()

◆ transfer() [1/2]

◆ transfer() [2/2]

◆ wait() [1/2]

◆ wait() [2/2]