concurrent::BackgroundTaskStorageCore Class Reference

#include <userver/concurrent/background_task_storage.hpp>

Detailed Description

A version of concurrent::BackgroundTaskStorage for advanced use cases (e.g. driver internals) that can take the ownership of any kind of task.

Definition at line 21 of file background_task_storage.hpp.

Public Member Functions
	BackgroundTaskStorageCore ()
	Creates an empty BTS.
	BackgroundTaskStorageCore (BackgroundTaskStorageCore &&)=delete
BackgroundTaskStorageCore &	operator= (BackgroundTaskStorageCore &&)=delete
void	CancelAndWait () noexcept
	Explicitly cancel and wait for the tasks. New tasks must not be launched after this call returns.
void	WaitAndDisposeSlow () noexcept
	Wait for the remaining tasks to complete without cancelling them. New tasks must not be launched after this call returns.
void	Detach (engine::Task &&task)
	Detaches task, allowing it to continue execution out of scope. It will be cancelled and waited for on BTS destruction.
std::int64_t	ActiveTasksApprox () const noexcept

Member Function Documentation

ActiveTasksApprox()

std::int64_t concurrent::BackgroundTaskStorageCore::ActiveTasksApprox ( ) const

noexcept

Returns

Approximate number of currently active tasks.

Can be called from a coroutine or a non-coroutine thread. Cannot be called after CancelAndWait or WaitAndDisposeSlow has been called.

CancelAndWait()

void concurrent::BackgroundTaskStorageCore::CancelAndWait ( )

noexcept

Explicitly cancel and wait for the tasks. New tasks must not be launched after this call returns.

More precisely, new tasks must not be launched once this call is completed, but can be launched in the process of waiting for the remaining tasks. This means that one detached task is allowed to spawn another detached task into the same BTS, which will immediately be cancelled and for which this call will wait as well.

Can only be called from a coroutine.

Detach()

void concurrent::BackgroundTaskStorageCore::Detach

(

engine::Task &&

task

)

Detaches task, allowing it to continue execution out of scope. It will be cancelled and waited for on BTS destruction.

Note

After detach, Task becomes invalid

Can be called from a coroutine or a non-coroutine thread. Cannot be called after CancelAndWait or WaitAndDisposeSlow has been called.

WaitAndDisposeSlow()

void concurrent::BackgroundTaskStorageCore::WaitAndDisposeSlow ( )

noexcept

Wait for the remaining tasks to complete without cancelling them. New tasks must not be launched after this call returns.

More precisely, new tasks must not be launched once this call is completed, but can be launched in the process of waiting for the remaining tasks. This means that one detached task is allowed to spawn another detached task into the same BTS, for which this call will wait as well.

Note

Running this method burns some CPU time (a few microseconds). Awaiting the tasks once on service shutdown, or even periodically, is okay, but don't use BackgroundTaskStorage as a substitute for std::vector<Task> in handlers, because it is less efficient.

Can only be called from a coroutine.

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

• userver/concurrent/background_task_storage.hpp