pw::async2::FutureCore Class Reference

Overview

FutureCore provides common functionality for futures that need to be wakeable and stored in a list.

This class provides the core mechanism for:

• Storing a Waker to be woken up.
• Tracking future state.
• Being part of an IntrusiveList.

It is designed to be used as a member of a concrete future class (composition) rather than a base class, to simplify move semantics and object lifetime.

Inheritance diagram for pw::async2::FutureCore:

Public Types
enum	ReadyForCompletion { kReadyForCompletion }
enum	Pending { kPending }
	Tag type to construct an active FutureCore. Pend may be called.

Public Member Functions
	FutureCore (FutureCore &&other) noexcept
FutureCore &	operator= (FutureCore &&other) noexcept
constexpr	FutureCore (Pending)
constexpr	FutureCore (ReadyForCompletion)
	FutureCore (const FutureCore &)=delete
FutureCore &	operator= (const FutureCore &)=delete
bool	is_pendable () const
bool	is_complete () const
bool	is_ready () const
void	Wake ()
void	WakeAndMarkReady ()
void	Unlist ()
	Removes this future from its list, if it is in one.
template<typename FutureType >
auto	DoPend (FutureType &future, Context &cx)
bool	in_list () const

Friends
class	BaseFutureList

Additional Inherited Members
Protected Member Functions inherited from pw::IntrusiveForwardList< T >::Item
constexpr	Item ()=default

Member Enumeration Documentation

ReadyForCompletion

enum pw::async2::FutureCore::ReadyForCompletion

Tag type to construct a FutureCore for which the next call to Pend will return Ready.

Constructor & Destructor Documentation

FutureCore() [1/2]

constexpr pw::async2::FutureCore::FutureCore ( Pending  )

inlineexplicitconstexpr

Constructs a pending FutureCore that represents an async operation. Pend must be called until it returns Ready.

A pending FutureCore must be tracked by its provider (e.g. in a FutureList).

FutureCore() [2/2]

constexpr pw::async2::FutureCore::FutureCore ( ReadyForCompletion  )

inlineexplicitconstexpr

Creates a wakeable future that is ready for completion. The next call to Pend must return Ready.

Member Function Documentation

in_list()

bool pw::async2::FutureCore::in_list ( ) const

inline

Returns

whether the future is currently in a list.

is_complete()

bool pw::async2::FutureCore::is_complete ( ) const

inline

Returns

Whether the future has completed: the future's Pend() returned Ready.

is_pendable()

bool pw::async2::FutureCore::is_pendable ( ) const

inline

Returns

Whether the future's Pend() function can be called.

is_ready()

bool pw::async2::FutureCore::is_ready ( ) const

inline

Returns

true if the next Pend() call is guaranteed to return Ready. Depending on the implementation, Pend() may return Ready while is_ready is false. Future implementations call WakeAndMarkReady to set is_ready to true.

Wake()

void pw::async2::FutureCore::Wake ( )

inline

Wakes the task waiting on the future, if any. The future must be pended in order to make progress.

WakeAndMarkReady()

void pw::async2::FutureCore::WakeAndMarkReady ( )

inline

Wakes the task pending the future and sets is_ready to true. Only call this if the next call to to the future's Pend() will return Ready.

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

• pw_async2/public/pw_async2/future.h