dpp::detail::task::task_base< R > Class Template Reference

Base class of dpp::task. More...

#include <task.h>

Inheritance diagram for dpp::detail::task::task_base< R >:

Collaboration diagram for dpp::detail::task::task_base< R >:

Public Member Functions
	task_base ()=default
	Default constructor, creates a task not bound to a coroutine. More...
	task_base (const task_base &)=delete
	Copy constructor is disabled. More...
	task_base (task_base &&other) noexcept
	Move constructor, grabs another task's coroutine handle. More...
	~task_base ()
	Destructor. More...
task_base &	operator= (const task_base &)=delete
	Copy assignment is disabled. More...
task_base &	operator= (task_base &&other) noexcept
	Move assignment, grabs another task's coroutine handle. More...
bool	await_ready () const
	Check whether or not a call to co_await will suspend the caller. More...
bool	await_suspend (std_coroutine::coroutine_handle<> caller) noexcept
	Second function called by the standard library when the task is co_await-ed, if await_ready returned false. More...
bool	done () const noexcept
	Function to check if the task has finished its execution entirely. More...
dpp::task< R > &	cancel () &noexcept
	Cancel the task, it will stop the next time it uses co_await. On co_await-ing this task, throws dpp::task_cancelled_exception. More...
dpp::task< R > &&	cancel () &&noexcept
	Cancel the task, it will stop the next time it uses co_await. On co_await-ing this task, throws dpp::task_cancelled_exception. More...
decltype(auto)	await_resume () &
	Function called by the standard library when resuming. More...
decltype(auto)	await_resume () const &
	Function called by the standard library when resuming. More...
decltype(auto)	await_resume () &&
	Function called by the standard library when resuming. More...

Protected Attributes
handle_t< R >	handle
	The coroutine handle of this task. More...

Friends
struct	promise_t< R >
	Promise type of this coroutine. For internal use only, do not use. More...

Detailed Description

template<typename R>
class dpp::detail::task::task_base< R >

Base class of dpp::task.

Warning

This class should not be used directly by a user, use dpp::task instead.

Note

This class contains all the functions used internally by co_await. It is intentionally opaque and a private base of dpp::task so a user cannot call await_suspend() and await_resume() directly.

Constructor & Destructor Documentation

task_base() [1/3]

template<typename R >

dpp::detail::task::task_base< R >::task_base ( )

default

Default constructor, creates a task not bound to a coroutine.

task_base() [2/3]

template<typename R >

dpp::detail::task::task_base< R >::task_base ( const task_base< R > &  )

delete

Copy constructor is disabled.

task_base() [3/3]

template<typename R >

dpp::detail::task::task_base< R >::task_base ( task_base< R > &&  other )

inlinenoexcept

Move constructor, grabs another task's coroutine handle.

Parameters

other

Task to move the handle from

~task_base()

template<typename R >

dpp::detail::task::task_base< R >::~task_base ( )

inline

Destructor.

Destroys the handle.

Warning

The coroutine must be finished before this is called, otherwise it runs the risk of being resumed after it is destroyed, resuming in use-after-free undefined behavior.

Member Function Documentation

await_ready()

template<typename R >

bool dpp::detail::task::task_base< R >::await_ready ( ) const

inline

Check whether or not a call to co_await will suspend the caller.

This function is called by the standard library as a first step when using co_await. If it returns true then the caller is not suspended.

Exceptions

logic_exception

if the task is empty.

Returns

bool Whether not to suspend the caller or not

await_resume() [1/3]

template<typename R >

decltype(auto) dpp::detail::task::task_base< R >::await_resume ( ) &

inline

Function called by the standard library when resuming.

Returns

Return value of the coroutine, handed to the caller of co_await.

await_resume() [2/3]

template<typename R >

decltype(auto) dpp::detail::task::task_base< R >::await_resume ( ) &&

inline

Function called by the standard library when resuming.

Returns

Return value of the coroutine, handed to the caller of co_await.

await_resume() [3/3]

template<typename R >

decltype(auto) dpp::detail::task::task_base< R >::await_resume ( ) const &

inline

Function called by the standard library when resuming.

Returns

Return value of the coroutine, handed to the caller of co_await.

await_suspend()

template<typename R >

bool dpp::detail::task::task_base< R >::await_suspend ( std_coroutine::coroutine_handle<>  caller )

inlinenoexcept

Second function called by the standard library when the task is co_await-ed, if await_ready returned false.

Stores the calling coroutine in the promise to resume when this task suspends.

Remarks

Do not call this manually, use the co_await keyword instead.

Parameters

caller

The calling coroutine, now suspended

Returns

bool Whether to suspend the caller or not

cancel() [1/2]

template<typename R >

dpp::task< R > && dpp::detail::task::task_base< R >::cancel ( ) &&

inlinenoexcept

Cancel the task, it will stop the next time it uses co_await. On co_await-ing this task, throws dpp::task_cancelled_exception.

Returns

*this

cancel() [2/2]

template<typename R >

dpp::task< R > & dpp::detail::task::task_base< R >::cancel ( ) &

inlinenoexcept

Cancel the task, it will stop the next time it uses co_await. On co_await-ing this task, throws dpp::task_cancelled_exception.

Returns

*this

done()

template<typename R >

bool dpp::detail::task::task_base< R >::done ( ) const

inlinenoexcept

Function to check if the task has finished its execution entirely.

Returns

bool Whether the task is finished.

operator=() [1/2]

template<typename R >

task_base & dpp::detail::task::task_base< R >::operator= ( const task_base< R > &  )

delete

Copy assignment is disabled.

operator=() [2/2]

template<typename R >

task_base & dpp::detail::task::task_base< R >::operator= ( task_base< R > &&  other )

inlinenoexcept

Move assignment, grabs another task's coroutine handle.

Parameters

other

Task to move the handle from

Friends And Related Function Documentation

promise_t< R >

template<typename R >

friend struct promise_t< R >

friend

Promise type of this coroutine. For internal use only, do not use.

Member Data Documentation

handle

template<typename R >

handle_t<R> dpp::detail::task::task_base< R >::handle

protected

The coroutine handle of this task.