TaskScheduler Class Reference

#include <TaskScheduler.h>

Classes
struct	Compare
	Container which provides Task order, insert and reschedule operations. More...
class	Task
class	TaskQueue

Public Member Functions
	TaskScheduler ()
template<typename P >
	TaskScheduler (P &&predicate)
	TaskScheduler (TaskScheduler const &)=delete
	TaskScheduler (TaskScheduler &&)=delete
TaskScheduler &	operator= (TaskScheduler const &)=delete
TaskScheduler &	operator= (TaskScheduler &&)=delete
template<typename P >
TaskScheduler &	SetValidator (P &&predicate)
	Sets a validator which is asked if tasks are allowed to be executed. More...
TaskScheduler &	ClearValidator ()
	Clears the validator which is asked if tasks are allowed to be executed. More...
TaskScheduler &	Update (success_t const &callback=EmptyCallback)
TaskScheduler &	Update (size_t const milliseconds, success_t const &callback=EmptyCallback)
template<class _Rep , class _Period >
TaskScheduler &	Update (std::chrono::duration< _Rep, _Period > const &difftime, success_t const &callback=EmptyCallback)
TaskScheduler &	Async (std::function< void()> const &callable)
template<class _Rep , class _Period >
TaskScheduler &	Schedule (std::chrono::duration< _Rep, _Period > const &time, task_handler_t const &task)
template<class _Rep , class _Period >
TaskScheduler &	Schedule (std::chrono::duration< _Rep, _Period > const &time, group_t const group, task_handler_t const &task)
template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >
TaskScheduler &	Schedule (std::chrono::duration< _RepLeft, _PeriodLeft > const &min, std::chrono::duration< _RepRight, _PeriodRight > const &max, task_handler_t const &task)
template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >
TaskScheduler &	Schedule (std::chrono::duration< _RepLeft, _PeriodLeft > const &min, std::chrono::duration< _RepRight, _PeriodRight > const &max, group_t const group, task_handler_t const &task)
TaskScheduler &	CancelAll ()
TaskScheduler &	CancelGroup (group_t const group)
TaskScheduler &	CancelGroupsOf (std::vector< group_t > const &groups)
template<class _Rep , class _Period >
TaskScheduler &	DelayAll (std::chrono::duration< _Rep, _Period > const &duration)
	Delays all tasks with the given duration. More...
template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >
TaskScheduler &	DelayAll (std::chrono::duration< _RepLeft, _PeriodLeft > const &min, std::chrono::duration< _RepRight, _PeriodRight > const &max)
	Delays all tasks with a random duration between min and max. More...
template<class _Rep , class _Period >
TaskScheduler &	DelayGroup (group_t const group, std::chrono::duration< _Rep, _Period > const &duration)
	Delays all tasks of a group with the given duration. More...
template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >
TaskScheduler &	DelayGroup (group_t const group, std::chrono::duration< _RepLeft, _PeriodLeft > const &min, std::chrono::duration< _RepRight, _PeriodRight > const &max)
	Delays all tasks of a group with a random duration between min and max. More...
template<class _Rep , class _Period >
TaskScheduler &	RescheduleAll (std::chrono::duration< _Rep, _Period > const &duration)
	Reschedule all tasks with a given duration. More...
template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >
TaskScheduler &	RescheduleAll (std::chrono::duration< _RepLeft, _PeriodLeft > const &min, std::chrono::duration< _RepRight, _PeriodRight > const &max)
	Reschedule all tasks with a random duration between min and max. More...
template<class _Rep , class _Period >
TaskScheduler &	RescheduleGroup (group_t const group, std::chrono::duration< _Rep, _Period > const &duration)
	Reschedule all tasks of a group with the given duration. More...
template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >
TaskScheduler &	RescheduleGroup (group_t const group, std::chrono::duration< _RepLeft, _PeriodLeft > const &min, std::chrono::duration< _RepRight, _PeriodRight > const &max)
	Reschedule all tasks of a group with a random duration between min and max. More...

Private Types
typedef std::chrono::steady_clock	clock_t
typedef clock_t::time_point	timepoint_t
typedef clock_t::duration	duration_t
typedef uint32	group_t
typedef uint32	repeated_t
typedef std::function< void(TaskContext)>	task_handler_t
typedef std::function< bool()>	predicate_t
typedef std::function< void()>	success_t
typedef std::shared_ptr< Task >	TaskContainer
typedef std::queue < std::function< void()> >	AsyncHolder

Private Member Functions
TaskScheduler &	InsertTask (TaskContainer task)
	Insert a new task to the enqueued tasks. More...
template<class _Rep , class _Period >
TaskScheduler &	ScheduleAt (timepoint_t const &end, std::chrono::duration< _Rep, _Period > const &time, task_handler_t const &task)
template<class _Rep , class _Period >
TaskScheduler &	ScheduleAt (timepoint_t const &end, std::chrono::duration< _Rep, _Period > const &time, group_t const group, task_handler_t const &task)
void	Dispatch (success_t const &callback)
	Dispatch remaining tasks. More...

Static Private Member Functions
static bool	EmptyValidator ()
static void	EmptyCallback ()
template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >
static std::chrono::milliseconds	RandomDurationBetween (std::chrono::duration< _RepLeft, _PeriodLeft > const &min, std::chrono::duration< _RepRight, _PeriodRight > const &max)

Private Attributes
std::shared_ptr< TaskScheduler >	self_reference
	Contains a self reference to track if this object was deleted or not. More...
timepoint_t	_now
	The current time point (now) More...
TaskQueue	_task_holder
	The Task Queue which contains all task objects. More...
AsyncHolder	_asyncHolder
predicate_t	_predicate

Friends
class	TaskContext

Detailed Description

The TaskScheduler class provides the ability to schedule std::function's in the near future. Use TaskScheduler::Update to update the scheduler. Popular methods are:

• Schedule (Schedules a std::function which will be executed in the near future).
• Schedules an asynchronous function which will be executed at the next update tick.
• Cancel, Delay & Reschedule (Methods to manipulate already scheduled tasks). Tasks are organized in groups (uint), multiple tasks can have the same group id, you can provide a group or not, but keep in mind that you can only manipulate specific tasks through its group id! Tasks callbacks use the function signature void(TaskContext) where TaskContext provides access to the function schedule plan which makes it possible to repeat the task with the same duration or a new one. It also provides access to the repeat counter which is useful for task that repeat itself often but behave different every time (spoken event dialogs for example).

Member Typedef Documentation

typedef std::queue<std::function<void()> > TaskScheduler::AsyncHolder

private

typedef std::chrono::steady_clock TaskScheduler::clock_t

private

typedef clock_t::duration TaskScheduler::duration_t

private

typedef uint32 TaskScheduler::group_t

private

typedef std::function<bool()> TaskScheduler::predicate_t

private

typedef uint32 TaskScheduler::repeated_t

private

typedef std::function<void()> TaskScheduler::success_t

private

typedef std::function<void(TaskContext)> TaskScheduler::task_handler_t

private

typedef std::shared_ptr<Task> TaskScheduler::TaskContainer

private

typedef clock_t::time_point TaskScheduler::timepoint_t

private

Constructor & Destructor Documentation

TaskScheduler::TaskScheduler ( )

inline

 : self_reference(this, [](TaskScheduler const*) { }), _now(clock_t::now()), _predicate(EmptyValidator) { }

template<typename P >

TaskScheduler::TaskScheduler ( P &&  predicate )

inline

 : self_reference(this, [](TaskScheduler const*) { }), _now(clock_t::now()), _predicate(std::forward<P>(predicate)) { }

TaskScheduler::TaskScheduler ( TaskScheduler const &  )

delete

TaskScheduler::TaskScheduler ( TaskScheduler &&  )

delete

Member Function Documentation

TaskScheduler & TaskScheduler::Async

(

std::function< void()> const &

callable

)

Schedule an callable function that is executed at the next update tick. Its safe to modify the TaskScheduler from within the callable.

{
 _asyncHolder.push(callable);
 return *this;
}

Here is the caller graph for this function:

TaskScheduler & TaskScheduler::CancelAll

(

)

Cancels all tasks. Never call this from within a task context! Use TaskContext::CancelAll instead!

Clear the task holder

{
 _task_holder.Clear();
 _asyncHolder = AsyncHolder();
 return *this;
}

Here is the call graph for this function:

Here is the caller graph for this function:

TaskScheduler & TaskScheduler::CancelGroup

(

group_t const

group

)

Cancel all tasks of a single group. Never call this from within a task context! Use TaskContext::CancelGroup instead!

{
 _task_holder.RemoveIf([group](TaskContainer const& task) -> bool
 {
 return task->IsInGroup(group);
 });
 return *this;
}

Here is the call graph for this function:

Here is the caller graph for this function:

TaskScheduler & TaskScheduler::CancelGroupsOf

(

std::vector< group_t > const &

groups

)

Cancels all groups in the given std::vector. Hint: Use std::initializer_list for this: "{1, 2, 3, 4}"

{
 std::for_each(groups.begin(), groups.end(),
 std::bind(&TaskScheduler::CancelGroup, this, std::placeholders::_1));

 return *this;
}

Here is the call graph for this function:

Here is the caller graph for this function:

TaskScheduler & TaskScheduler::ClearValidator

(

)

Clears the validator which is asked if tasks are allowed to be executed.

{
 _predicate = EmptyValidator;
 return *this;
}

Here is the call graph for this function:

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::DelayAll ( std::chrono::duration< _Rep, _Period > const &  duration )

inline

Delays all tasks with the given duration.

 {
 _task_holder.ModifyIf([&duration](TaskContainer const& task) -> bool
 {
 task->_end += duration;
 return true;
 });
 return *this;
 }

Here is the call graph for this function:

Here is the caller graph for this function:

template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >

TaskScheduler& TaskScheduler::DelayAll ( std::chrono::duration< _RepLeft, _PeriodLeft > const &  min, std::chrono::duration< _RepRight, _PeriodRight > const &  max  )

inline

Delays all tasks with a random duration between min and max.

 {
 return DelayAll(RandomDurationBetween(min, max));
 }

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::DelayGroup ( group_t const  group, std::chrono::duration< _Rep, _Period > const &  duration  )

inline

Delays all tasks of a group with the given duration.

 {
 _task_holder.ModifyIf([&duration, group](TaskContainer const& task) -> bool
 {
 if (task->IsInGroup(group))
 {
 task->_end += duration;
 return true;
 }
 else
 return false;
 });
 return *this;
 }

Here is the call graph for this function:

Here is the caller graph for this function:

template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >

TaskScheduler& TaskScheduler::DelayGroup ( group_t const  group, std::chrono::duration< _RepLeft, _PeriodLeft > const &  min, std::chrono::duration< _RepRight, _PeriodRight > const &  max  )

inline

Delays all tasks of a group with a random duration between min and max.

 {
 return DelayGroup(group, RandomDurationBetween(min, max));
 }

void TaskScheduler::Dispatch ( success_t const &  callback )

private

Dispatch remaining tasks.

{
 // If the validation failed abort the dispatching here.
 if (!_predicate())
 return;

 // Process all asyncs
 while (!_asyncHolder.empty())
 {
 _asyncHolder.front()();
 _asyncHolder.pop();

 // If the validation failed abort the dispatching here.
 if (!_predicate())
 return;
 }

 while (!_task_holder.IsEmpty())
 {
 if (_task_holder.First()->_end > _now)
 break;

 // Perfect forward the context to the handler
 // Use weak references to catch destruction before callbacks.
 TaskContext context(_task_holder.Pop(), std::weak_ptr<TaskScheduler>(self_reference));

 // Invoke the context
 context.Invoke();

 // If the validation failed abort the dispatching here.
 if (!_predicate())
 return;
 }

 // On finish call the final callback
 callback();
}

Here is the call graph for this function:

Here is the caller graph for this function:

static void TaskScheduler::EmptyCallback ( )

inlinestaticprivate

 {
 }

static bool TaskScheduler::EmptyValidator ( )

inlinestaticprivate

 {
 return true;
 }

Here is the caller graph for this function:

TaskScheduler & TaskScheduler::InsertTask ( TaskContainer  task )

private

Insert a new task to the enqueued tasks.

{
 _task_holder.Push(std::move(task));
 return *this;
}

Here is the call graph for this function:

Here is the caller graph for this function:

TaskScheduler& TaskScheduler::operator= ( TaskScheduler const &  )

delete

TaskScheduler& TaskScheduler::operator= ( TaskScheduler &&  )

delete

template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >

static std::chrono::milliseconds TaskScheduler::RandomDurationBetween ( std::chrono::duration< _RepLeft, _PeriodLeft > const &  min, std::chrono::duration< _RepRight, _PeriodRight > const &  max  )

inlinestaticprivate

 {
 auto const milli_min = std::chrono::duration_cast<std::chrono::milliseconds>(min);
 auto const milli_max = std::chrono::duration_cast<std::chrono::milliseconds>(max);

 // TC specific: use SFMT URandom
 return std::chrono::milliseconds(urand(uint32(milli_min.count()), uint32(milli_max.count())));
 }

Here is the call graph for this function:

Here is the caller graph for this function:

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::RescheduleAll ( std::chrono::duration< _Rep, _Period > const &  duration )

inline

Reschedule all tasks with a given duration.

 {
 auto const end = _now + duration;
 _task_holder.ModifyIf([end](TaskContainer const& task) -> bool
 {
 task->_end = end;
 return true;
 });
 return *this;
 }

Here is the call graph for this function:

Here is the caller graph for this function:

template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >

TaskScheduler& TaskScheduler::RescheduleAll ( std::chrono::duration< _RepLeft, _PeriodLeft > const &  min, std::chrono::duration< _RepRight, _PeriodRight > const &  max  )

inline

Reschedule all tasks with a random duration between min and max.

 {
 return RescheduleAll(RandomDurationBetween(min, max));
 }

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::RescheduleGroup ( group_t const  group, std::chrono::duration< _Rep, _Period > const &  duration  )

inline

Reschedule all tasks of a group with the given duration.

 {
 auto const end = _now + duration;
 _task_holder.ModifyIf([end, group](TaskContainer const& task) -> bool
 {
 if (task->IsInGroup(group))
 {
 task->_end = end;
 return true;
 }
 else
 return false;
 });
 return *this;
 }

Here is the call graph for this function:

Here is the caller graph for this function:

template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >

TaskScheduler& TaskScheduler::RescheduleGroup ( group_t const  group, std::chrono::duration< _RepLeft, _PeriodLeft > const &  min, std::chrono::duration< _RepRight, _PeriodRight > const &  max  )

inline

Reschedule all tasks of a group with a random duration between min and max.

 {
 return RescheduleGroup(group, RandomDurationBetween(min, max));
 }

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::Schedule ( std::chrono::duration< _Rep, _Period > const &  time, task_handler_t const &  task  )

inline

Schedule an event with a fixed rate. Never call this from within a task context! Use TaskContext::Schedule instead!

 {
 return ScheduleAt(_now, time, task);
 }

Here is the caller graph for this function:

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::Schedule ( std::chrono::duration< _Rep, _Period > const &  time, group_t const  group, task_handler_t const &  task  )

inline

Schedule an event with a fixed rate. Never call this from within a task context! Use TaskContext::Schedule instead!

 {
 return ScheduleAt(_now, time, group, task);
 }

template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >

TaskScheduler& TaskScheduler::Schedule ( std::chrono::duration< _RepLeft, _PeriodLeft > const &  min, std::chrono::duration< _RepRight, _PeriodRight > const &  max, task_handler_t const &  task  )

inline

Schedule an event with a randomized rate between min and max rate. Never call this from within a task context! Use TaskContext::Schedule instead!

 {
 return Schedule(RandomDurationBetween(min, max), task);
 }

template<class _RepLeft , class _PeriodLeft , class _RepRight , class _PeriodRight >

TaskScheduler& TaskScheduler::Schedule ( std::chrono::duration< _RepLeft, _PeriodLeft > const &  min, std::chrono::duration< _RepRight, _PeriodRight > const &  max, group_t const  group, task_handler_t const &  task  )

inline

Schedule an event with a fixed rate. Never call this from within a task context! Use TaskContext::Schedule instead!

 {
 return Schedule(RandomDurationBetween(min, max), group, task);
 }

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::ScheduleAt ( timepoint_t const &  end, std::chrono::duration< _Rep, _Period > const &  time, task_handler_t const &  task  )

inlineprivate

 {
 return InsertTask(TaskContainer(new Task(end + time, time, task)));
 }

Here is the caller graph for this function:

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::ScheduleAt ( timepoint_t const &  end, std::chrono::duration< _Rep, _Period > const &  time, group_t const  group, task_handler_t const &  task  )

inlineprivate

Schedule an event with a fixed rate. Never call this from within a task context! Use TaskContext::schedule instead!

 {
 static repeated_t const DEFAULT_REPEATED = 0;
 return InsertTask(TaskContainer(new Task(end + time, time, group, DEFAULT_REPEATED, task)));
 }

template<typename P >

TaskScheduler& TaskScheduler::SetValidator ( P &&  predicate )

inline

Sets a validator which is asked if tasks are allowed to be executed.

 {
 _predicate = std::forward<P>(predicate);
 return *this;
 }

Here is the caller graph for this function:

TaskScheduler & TaskScheduler::Update

(

success_t const &

callback = EmptyCallback

)

Update the scheduler to the current time. Calls the optional callback on successfully finish.

{
 _now = clock_t::now();
 Dispatch(callback);
 return *this;
}

Here is the call graph for this function:

Here is the caller graph for this function:

TaskScheduler & TaskScheduler::Update	(	size_t const	milliseconds,
		success_t const &	callback = EmptyCallback
	)

Update the scheduler with a difftime in ms. Calls the optional callback on successfully finish.

{
 return Update(std::chrono::milliseconds(milliseconds), callback);
}

Here is the call graph for this function:

template<class _Rep , class _Period >

TaskScheduler& TaskScheduler::Update ( std::chrono::duration< _Rep, _Period > const &  difftime, success_t const &  callback = EmptyCallback  )

inline

Update the scheduler with a difftime. Calls the optional callback on successfully finish.

 {
 _now += difftime;
 Dispatch(callback);
 return *this;
 }

Friends And Related Function Documentation

friend class TaskContext

friend

Member Data Documentation

AsyncHolder TaskScheduler::_asyncHolder

private

Contains all asynchronous tasks which will be invoked at the next update tick.

timepoint_t TaskScheduler::_now

private

The current time point (now)

predicate_t TaskScheduler::_predicate

private

TaskQueue TaskScheduler::_task_holder

private

The Task Queue which contains all task objects.

std::shared_ptr<TaskScheduler> TaskScheduler::self_reference

private

Contains a self reference to track if this object was deleted or not.

---

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

• src/common/Utilities/TaskScheduler.h
• src/common/Utilities/TaskScheduler.cpp