pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy > Class Template Reference

Overview

template<typename T, typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>
requires std::invocable<AllocationErrorHandler>
class pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >

A Task that delegates to a provided Coro<T> and executes an error handler function if coroutine allocation fails.

Inheritance diagram for pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >:

Public Types
using	value_type = std::conditional_t< std::is_void_v< T >, ReadyType, T >

Public Member Functions
template<typename ErrorHandler >
	FallibleCoroTask (Coro< T > &&coro, ErrorHandler &&error_handler)
	FallibleCoroTask (const FallibleCoroTask &)=delete
FallibleCoroTask &	operator= (const FallibleCoroTask &)=delete
	FallibleCoroTask (FallibleCoroTask &&)=delete
FallibleCoroTask &	operator= (FallibleCoroTask &&)=delete
bool	ok () const
bool	has_value () const
value_type &	value ()
const value_type &	value () const
std::optional< value_type > &	Wait ()
Public Member Functions inherited from pw::async2::Task
constexpr	Task (log::Token name=kDefaultName)
	Task (const Task &)=delete
	Task (Task &&)=delete
Task &	operator= (const Task &)=delete
Task &	operator= (Task &&)=delete
virtual	~Task ()
Poll	Pend (Context &cx)
bool	IsRegistered () const
void	Deregister ()
void	Join ()

Private Member Functions
Poll	DoPend (Context &cx) final

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

Constructor & Destructor Documentation

FallibleCoroTask()

template<typename T , typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>

template<typename ErrorHandler >

pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >::FallibleCoroTask ( Coro< T > &&  coro, ErrorHandler &&  error_handler  )

inline

Create a new Task that runs coro, invoking or_else if allocation fails.

Member Function Documentation

DoPend()

template<typename T , typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>

Poll pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >::DoPend ( Context &  )

inlinefinalprivatevirtual

Attempts to advance this Task to completion.

This method should not perform synchronous waiting, as doing so may block the main Dispatcher loop and prevent other Task s from progressing. Because of this, Task s should not invoke blocking Dispatcher methods such as RunUntilComplete.

Tasks should also avoid invoking RunUntilStalled on their own Dispatcher.

Returns Ready if complete, or Pending if the Task was not yet able to complete.

If Pending is returned, the Task must ensure it is woken up when it is able to make progress. To do this, Task::Pend must arrange for Waker::Wake to be called, either by storing a copy of the Waker away to be awoken by another system (such as an interrupt handler).

Implements pw::async2::Task.

has_value()

template<typename T , typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>

bool pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >::has_value ( ) const

inline

Returns whether the task ran and set that value to the function's return value.

ok()

template<typename T , typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>

bool pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >::ok ( ) const

inline

Returns whether this FallibleCoroTask wraps a valid Coro and can be pended. Pending a !ok() FallibleCoroTask calls the error handler.

This will be false if Coro allocation failed.

value() [1/2]

template<typename T , typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>

value_type & pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >::value ( )

inline

The return value from the coroutine.

Precondition

The task must have completed. Call Join to ensure it finished.

value() [2/2]

template<typename T , typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>

const value_type & pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >::value ( ) const

inline

The return value from the coroutine.

Precondition

The task must have completed. Call Join to ensure it finished.

Wait()

template<typename T , typename AllocationErrorHandler = pw::Function<void()>, ReturnValuePolicy policy = std::is_void_v<T> ? ReturnValuePolicy::kDiscard : ReturnValuePolicy::kKeep>

std::optional< value_type > & pw::async2::FallibleCoroTask< T, AllocationErrorHandler, policy >::Wait ( )

inline

Blocks until the task completes and returns the return value in a std::optional. The std::optional is empty if coroutine allocation failed.

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

• pw_async2/public/pw_async2/fallible_coro_task.h