a11::Future< T > Class Template Reference

Shared handle to one asynchronous result. More...

#include <cpp/a11/concurrency/future.h>

Public Member Functions
	Future ()=default
bool	valid () const
	Whether this handle refers to shared completion state.
bool	IsReady () const
	Whether the producer has published either a value or an error.
absl::Status	Cancel () const
	Request cancellation from the operation producing this result.
absl::StatusOr< T >	Await (absl::Time deadline=absl::InfiniteFuture()) const
	Wait for and return the result up to an absolute deadline.
void	OnReady (absl::AnyInvocable< void(const absl::StatusOr< T > &)> callback) const
	Run callback once when the result becomes available.

Friends
class	Promise< T >
template<typename U >
Future< U >	Submit (absl::AnyInvocable< absl::StatusOr< U >() && > work, thread::TreeOptions tree_options)
template<typename U >
Future< U >	SubmitWithCancellationHook (absl::AnyInvocable< absl::StatusOr< U >() && > work, std::function< void()> cancellation_hook, thread::TreeOptions tree_options)

Detailed Description

template<typename T>
class a11::Future< T >

Shared handle to one asynchronous result.

Futures are cheap to copy and may have several waiters. Await() integrates with A11 fibers when called inside the runtime and parks an ordinary thread otherwise. OnReady() is the callback-oriented path used by high-cardinality pumps and language bindings.

Cancellation is a request to the producing operation; callers must still observe the future to learn its eventual result.

Constructor & Destructor Documentation

Future()

template<typename T >

a11::Future< T >::Future ( )

default

Member Function Documentation

Await()

template<typename T >

absl::StatusOr< T > a11::Future< T >::Await ( absl::Time  deadline = absl::InfiniteFuture< T >() ) const

inline

Wait for and return the result up to an absolute deadline.

A timeout or cancellation of the waiting fiber does not itself overwrite the producer's result; another observer may continue waiting.

Cancel()

template<typename T >

absl::Status a11::Future< T >::Cancel ( ) const

inline

Request cancellation from the operation producing this result.

Returns

OK when the request was delivered, or Unimplemented when the producer did not install a cancellation source.

IsReady()

template<typename T >

bool a11::Future< T >::IsReady ( ) const

inline

Whether the producer has published either a value or an error.

OnReady()

template<typename T >

void a11::Future< T >::OnReady ( absl::AnyInvocable< void(const absl::StatusOr< T > &)>  callback ) const

inline

Run callback once when the result becomes available.

The callback runs immediately when the future is already ready. It must not retain the referenced StatusOr beyond the callback invocation.

valid()

template<typename T >

bool a11::Future< T >::valid ( ) const

inline

Whether this handle refers to shared completion state.

Friends And Related Symbol Documentation

Promise< T >

template<typename T >

friend class Promise< T >

friend

Submit

template<typename T >

template<typename U >

Future< U > Submit ( absl::AnyInvocable< absl::StatusOr< U >() && >  work, thread::TreeOptions  tree_options  )

friend

SubmitWithCancellationHook

template<typename T >

template<typename U >

Future< U > SubmitWithCancellationHook ( absl::AnyInvocable< absl::StatusOr< U >() && >  work, std::function< void()>  cancellation_hook, thread::TreeOptions  tree_options  )

friend

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

• cpp/a11/concurrency/future.h