vlink::MultiLoop Class Reference

Multi-threaded variant of MessageLoop running tasks on a worker-thread pool. More...

#include <multi_loop.h>

Inheritance diagram for vlink::MultiLoop:

Collaboration diagram for vlink::MultiLoop:

Public Member Functions
	MultiLoop (size_t thread_num=4U)
	Constructs a MultiLoop with the default kNormalType queue and thread_num workers.
	MultiLoop (size_t thread_num, Type type)
	Constructs a MultiLoop with a specific queue type.
	~MultiLoop () override
	Destructor. Quits the loop and joins all worker threads.
bool	is_in_same_thread () const override
	Returns true if the calling thread is one of the worker threads.
Public Member Functions inherited from vlink::MessageLoop
	MessageLoop ()
	Constructs a MessageLoop with kNormalType queue.
	MessageLoop (Type type)
	Constructs a MessageLoop with the specified queue type.
virtual	~MessageLoop ()
	Destructor. Calls quit(true) and waits for the background thread (if any).
void	set_name (const std::string &name)
	Sets a human-readable name for this loop (visible in profiling tools).
const std::string &	get_name () const
	Returns the name set via set_name().
Type	get_type () const
	Returns the queue type this loop was constructed with.
Strategy	get_strategy () const
	Returns the current idle dispatch strategy.
void	set_strategy (Strategy strategy)
	Changes the idle dispatch strategy.
void	register_begin_handler (Callback &&callback)
	Registers a callback invoked once when the loop thread starts.
void	register_end_handler (Callback &&callback)
	Registers a callback invoked once when the loop thread exits.
void	register_idle_handler (Callback &&callback)
	Registers a callback invoked each time the task queue becomes empty.
bool	run ()
	Runs the message loop on the calling thread (blocking).
bool	async_run ()
	Starts the message loop on a new background thread (non-blocking).
bool	spin ()
	Runs the loop continuously in a spin mode (blocking; no background thread).
bool	spin_once (bool block=true)
	Processes one batch of pending tasks and timers.
bool	quit (bool force=false)
	Requests the loop to exit cleanly.
bool	wait_for_idle (int ms=Timer::kInfinite, bool check=true)
	Waits until the task queue is drained.
bool	wait_for_quit (int ms=Timer::kInfinite, bool check=true)
	Waits until the loop has fully exited (after quit() was called).
bool	post_task (Callback &&callback)
	Posts a task to the queue for execution on the loop thread.
bool	post_task_with_priority (Callback &&callback, uint16_t priority)
	Posts a task with an explicit priority (requires kPriorityType loop).
template<typename CallbackT, typename = std::enable_if_t<!std::is_convertible_v<CallbackT, Schedule::RetCallback>>>
Schedule::Status	exec_task (const Schedule::Config &config, CallbackT &&callback)
	Posts a scheduled task and returns a Schedule::Status for chaining callbacks.
template<typename CallbackT, typename = std::enable_if_t<std::is_convertible_v<CallbackT, Schedule::RetCallback>>>
Schedule::RetStatus	exec_task (const Schedule::Config &config, CallbackT &&callback)
	Posts a scheduled task and returns a Schedule::RetStatus for chaining callbacks.
bool	wakeup ()
	Wakes the loop thread if it is sleeping (e.g., in kBlockStrategy).
void	reset_lockfree_capacity ()
	Resets the lock-free queue to its initial capacity.
bool	is_running () const
	Returns true if the loop is currently running (started and not quit).
bool	is_ready_to_quit () const
	Returns true if quit() has been called and the loop is winding down.
bool	is_busy () const
	Returns true if the loop is currently executing a task.
size_t	get_task_count () const
	Returns the number of tasks currently in the queue.
virtual size_t	get_max_task_count () const
	Returns the maximum queue depth.
virtual size_t	get_max_timer_count () const
	Returns the maximum number of timers that can be attached to this loop.
virtual uint32_t	get_max_elapsed_time () const
	Returns the maximum allowed task execution time in milliseconds.
template<class FunctionT, class... ArgsT, typename ResultT = std::invoke_result_t<FunctionT, ArgsT...>>
std::future< ResultT >	invoke_task (FunctionT &&function, ArgsT &&... args)
	Dispatches a callable to the loop thread and returns a std::future for the result.
template<class FunctionT, class... ArgsT, typename ResultT = std::invoke_result_t<FunctionT, ArgsT...>>
std::future< ResultT >	invoke_task_with_priority (FunctionT &&function, uint16_t priority, ArgsT &&... args)
	Dispatches a callable with an explicit priority and returns a std::future.

Protected Member Functions
void	on_begin () override
	Called once on each worker thread immediately after it starts.
void	on_end () override
	Called once on each worker thread just before it exits.
void	on_task_changed (Callback &&callback, uint32_t start_time) override
	Called on the worker thread executing the task, before the task runs.
Protected Member Functions inherited from vlink::MessageLoop
virtual void	on_idle ()
	Called from the loop thread each time the queue becomes empty.
virtual void	on_task_timeout (Callback &&callback, uint32_t elapsed_time)
	Called when a task's execution time exceeds get_max_elapsed_time().

Additional Inherited Members
Public Types inherited from vlink::MessageLoop
enum	Type : uint8_t { kNormalType = 0 , kLockfreeType = 1 , kPriorityType = 2 }
	Queue implementation type. More...
enum	Strategy : uint8_t { kOptimizationStrategy = 0 , kPopStrategy = 1 , kBlockStrategy = 2 }
	Idle strategy controlling CPU and latency trade-offs. More...
enum	Priority : uint16_t {   kNoPriority = 0 , kLowestPriority = 1 , kTimerPriority = 50 , kNormalPriority = 100 ,   kHighestPriority = std::numeric_limits<uint16_t>::max() }
	Pre-defined task priority levels for kPriorityType loops. More...
using	Callback = std::function<void()>
	Callback type for tasks and event handlers.

Detailed Description

Multi-threaded variant of MessageLoop running tasks on a worker-thread pool.

All threads share the same task queue. Tasks are not guaranteed to execute in order.

Constructor & Destructor Documentation

MultiLoop() [1/2]

vlink::MultiLoop::MultiLoop ( size_t thread_num = 4U )

explicit

Constructs a MultiLoop with the default kNormalType queue and thread_num workers.

Parameters

thread_num

Number of worker threads. Default: 4.

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MultiLoop() [2/2]

vlink::MultiLoop::MultiLoop ( size_t thread_num, Type type )

explicit

Constructs a MultiLoop with a specific queue type.

Parameters

thread_num	Number of worker threads.
type	Queue implementation type (see MessageLoop::Type).

~MultiLoop()

vlink::MultiLoop::~MultiLoop ( )

override

Destructor. Quits the loop and joins all worker threads.

Member Function Documentation

is_in_same_thread()

bool vlink::MultiLoop::is_in_same_thread ( ) const

nodiscardoverridevirtual

Returns true if the calling thread is one of the worker threads.

Returns

true if called from any thread owned by this MultiLoop.

Reimplemented from vlink::MessageLoop.

on_begin()

void vlink::MultiLoop::on_begin ( )

overrideprotectedvirtual

Called once on each worker thread immediately after it starts.

Override to perform per-thread initialisation (e.g., setting thread name or affinity).

Reimplemented from vlink::MessageLoop.

on_end()

void vlink::MultiLoop::on_end ( )

overrideprotectedvirtual

Called once on each worker thread just before it exits.

Override to perform per-thread cleanup.

Reimplemented from vlink::MessageLoop.

on_task_changed()

void vlink::MultiLoop::on_task_changed ( Callback && callback, uint32_t start_time )

overrideprotectedvirtual

Called on the worker thread executing the task, before the task runs.

Parameters

callback	The task about to be executed.
start_time	Millisecond timestamp at which the task was dequeued.

Reimplemented from vlink::MessageLoop.

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

• include/vlink/base/multi_loop.h