swt::TaskPromise< T > Class Template Reference

Promise type for coroutine-based Task implementation. More...

#include <Task.h>

Collaboration diagram for swt::TaskPromise< T >:

Public Types
using	Handle = std::coroutine_handle< TaskPromise< T > >

Public Member Functions
Task< T >	get_return_object ()
	Create the Task object for this promise.
std::suspend_always	initial_suspend () noexcept
	Initial suspend behavior - always suspend to allow manual start.
auto	final_suspend () noexcept
	Final suspend behavior with continuation chaining.
void	return_value (T value)
	Store the coroutine return value.
void	unhandled_exception ()
	Handle unhandled exceptions in the coroutine.
T	getResult ()
	Get the stored result value.
bool	isReady () const noexcept
	Check if the task has completed.
void	addContinuation (std::coroutine_handle<> continuation)
	Add a continuation to be resumed when task completes.

Detailed Description

template<typename T>
class swt::TaskPromise< T >

Promise type for coroutine-based Task implementation.

TaskPromise manages the coroutine state and provides continuation chaining for proper asynchronous execution. It handles result storage, exception propagation, and thread-safe continuation management.

Template Parameters

T	The return type of the coroutine

Key features:

• Thread-safe completion: Atomic flags and proper memory ordering
• Continuation chaining: Multiple coroutines can await the same task
• Exception safety: Proper exception propagation and resource cleanup
• Memory efficient: Minimal overhead with optimized storage

Note

This class is not intended for direct use - it's managed by Task<T>

Definition at line 45 of file Task.h.

Member Typedef Documentation

Handle

template<typename T >

using swt::TaskPromise< T >::Handle = std::coroutine_handle<TaskPromise<T> >

Definition at line 47 of file Task.h.

Member Function Documentation

addContinuation()

template<typename T >

void swt::TaskPromise< T >::addContinuation ( std::coroutine_handle<>  continuation )

inline

Add a continuation to be resumed when task completes.

Parameters

continuation

Coroutine handle to resume

If the task is already completed, the continuation is resumed immediately. Otherwise, it's added to the continuation list for later resumption.

Definition at line 144 of file Task.h.

final_suspend()

template<typename T >

auto swt::TaskPromise< T >::final_suspend ( )

inlinenoexcept

Final suspend behavior with continuation chaining.

Returns

Custom awaiter that resumes all waiting continuations

Resume all waiting continuations when task completes

Parameters

h	Handle to the completing coroutine

Returns

noop_coroutine to prevent current coroutine resumption

Definition at line 67 of file Task.h.

get_return_object()

template<typename T >

Task< T > swt::TaskPromise< T >::get_return_object ( )

inline

Create the Task object for this promise.

Returns

Task<T> object associated with this promise

Definition at line 467 of file Task.h.

getResult()

template<typename T >

T swt::TaskPromise< T >::getResult ( )

inline

Get the stored result value.

Returns

The result value

Exceptions

std::exception_ptr	if coroutine threw an exception
std::runtime_error	if task not completed

Definition at line 119 of file Task.h.

initial_suspend()

template<typename T >

std::suspend_always swt::TaskPromise< T >::initial_suspend ( )

inlinenoexcept

Initial suspend behavior - always suspend to allow manual start.

Returns

std::suspend_always to require manual task.start() call

Definition at line 59 of file Task.h.

isReady()

template<typename T >

bool swt::TaskPromise< T >::isReady ( ) const

inlinenoexcept

Check if the task has completed.

Returns

true if task completed (successfully or with exception)

Definition at line 133 of file Task.h.

return_value()

template<typename T >

void swt::TaskPromise< T >::return_value ( T  value )

inline

Store the coroutine return value.

Parameters

value

The value returned by co_return

Definition at line 100 of file Task.h.

unhandled_exception()

template<typename T >

void swt::TaskPromise< T >::unhandled_exception ( )

inline

Handle unhandled exceptions in the coroutine.

Definition at line 108 of file Task.h.

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

• include/Task.h