Timer Class Reference

Basic one shot timer. More...

#include <timer.h>

Inheritance diagram for Timer:

Public Types
using	RegisterHandle = uint64_t
	Handle type.
using	TimerCallback = std::function< void()>
	Timer callback function definition.

Public Member Functions
	Timer () noexcept
	Construct a one-shot timer.
	Timer (const Timer &)=delete
	Timer (std::chrono::milliseconds duration) noexcept
	Construct a one-shot timer with the specified duration.
	Timer (Timer &&)
virtual	~Timer () noexcept
void	cancel ()
	Cancel, or stop, the timer.
void	change_duration (std::chrono::milliseconds duration)
	Change the duration of the timer.
void	clear_handlers ()
	Clear all handlers.
EGT_NODISCARD std::chrono::milliseconds	duration () const
	Return the current duration of the timer.
EGT_NODISCARD const std::string &	name () const
	Get the name of the Timer.
void	name (const std::string &name)
	Set the name of the Timer.
RegisterHandle	on_timeout (TimerCallback callback)
	Add a handler callback to be called with the timer times out.
Timer &	operator= (const Timer &)=delete
Timer &	operator= (Timer &&)
void	remove_handler (RegisterHandle handle)
	Remove an event handler.
EGT_NODISCARD bool	running () const
	Returns true if the timer is currently running.
virtual void	start ()
	Start the timer.
void	start (std::chrono::milliseconds duration)
	Start the timer with the specified duration.
EGT_DEPRECATED void	start_with_duration (std::chrono::milliseconds duration)
	Start the timer with the specified duration.
void	stop ()
	Alias for cancel().
void	timeout ()
	Called when the timer times out.

Protected Types
using	CallbackArray = std::vector< CallbackMeta >
	Type for array of registered callbacks.

Protected Member Functions
void	invoke_handlers ()
	Invoke any registered handlers.

Protected Attributes
CallbackArray	m_callbacks
	Array of registered callbacks.
std::chrono::milliseconds	m_duration {}
	The duration of the timer.
RegisterHandle	m_handle_counter {0}
	Counter used to generate unique handles for each callback registration.
std::unique_ptr< TimerImpl >	m_impl
std::string	m_name
	A user defined name for the Timer.
bool	m_running {false}
	When true, currently running.
asio::steady_timer	m_timer
	Asio timer object.

Detailed Description

Basic one shot timer.

This is a timer that will fire once after the specified duration. To handle the timeout, call on_timeout with a callback.

There are two main use cases for this class. One, is you can derive from this class and overload the Timer::timeout() member function.

struct MyTimer : public Timer
{
    MyTimer()
        : Timer(std::chrono::milliseconds(100))
    {}
 
    void timeout() override
    {
        Timer::timeout();
        ...
    }
};
MyTimer timer;
timer.start();

The other way is to create an instance of this class and connect a handler by calling Timer::on_timeout().

Timer timer(std::chrono::milliseconds(100));
timer.on_timeout([]() {
    ...
});
timer.start();

See also

PeriodicTimer

Member Typedef Documentation

CallbackArray

using CallbackArray = std::vector<CallbackMeta>

protected

Type for array of registered callbacks.

RegisterHandle

using RegisterHandle = uint64_t

Handle type.

TimerCallback

using TimerCallback = std::function<void()>

Timer callback function definition.

Constructor & Destructor Documentation

Timer() [1/4]

Timer ( )

noexcept

Construct a one-shot timer.

The duration of the timer can be specified when calling start_with_duration() when using this constructor.

Timer() [2/4]

Timer ( std::chrono::milliseconds  duration )

explicitnoexcept

Construct a one-shot timer with the specified duration.

Timer() [3/4]

Timer ( const Timer &  )

delete

Timer() [4/4]

Timer

(

Timer &&

)

~Timer()

virtual ~Timer ( )

virtualnoexcept

Member Function Documentation

cancel()

void cancel

(

)

Cancel, or stop, the timer.

change_duration()

void change_duration

(

std::chrono::milliseconds

duration

)

Change the duration of the timer.

This will stop the timer, change the duration, and restart the timer with the new duration if the timer was already running.

clear_handlers()

void clear_handlers

(

)

Clear all handlers.

duration()

EGT_NODISCARD std::chrono::milliseconds duration ( ) const

inline

Return the current duration of the timer.

invoke_handlers()

void invoke_handlers ( )

protected

Invoke any registered handlers.

name() [1/2]

EGT_NODISCARD const std::string & name ( ) const

inline

Get the name of the Timer.

name() [2/2]

void name ( const std::string &  name )

inline

Set the name of the Timer.

Assigns a human readable name to a Timer that can then be used to find timers by name or debug.

Parameters

[in]

name

Name to set for the Object.

on_timeout()

RegisterHandle on_timeout

(

TimerCallback

callback

)

Add a handler callback to be called with the timer times out.

This function can be called any number of times to add handlers.

Parameters

callback

The callback to invoke on event.

Returns

A handle used to identify the registration. This can then be passed to remove_handler().

operator=() [1/2]

Timer & operator= ( const Timer &  )

delete

operator=() [2/2]

Timer & operator=

(

Timer &&

)

remove_handler()

void remove_handler

(

RegisterHandle

handle

)

Remove an event handler.

Parameters

handle

The handle returned from on_timeout().

running()

EGT_NODISCARD bool running ( ) const

inline

Returns true if the timer is currently running.

start() [1/2]

virtual void start ( )

virtual

Start the timer.

It is safe to call start() on an already running timer. It will simply reset and start again.

Note

Assumes a duration is set already.

Reimplemented in PeriodicTimer, and PeriodicTimer.

start() [2/2]

void start ( std::chrono::milliseconds  duration )

inline

Start the timer with the specified duration.

This overwrites any duration specified previously.

start_with_duration()

EGT_DEPRECATED void start_with_duration

(

std::chrono::milliseconds

duration

)

Start the timer with the specified duration.

This overwrites any duration specified previously.

Deprecated:

stop()

void stop ( )

inline

Alias for cancel().

timeout()

void timeout

(

)

Called when the timer times out.

This will invoke any callback registered with add_handler(). If you override this you must make sure to call Timer::timeout() or equivalent if you want callbacks to still be called.

Member Data Documentation

m_callbacks

CallbackArray m_callbacks

protected

Array of registered callbacks.

m_duration

std::chrono::milliseconds m_duration {}

protected

The duration of the timer.

m_handle_counter

RegisterHandle m_handle_counter {0}

protected

Counter used to generate unique handles for each callback registration.

m_impl

std::unique_ptr<TimerImpl> m_impl

protected

m_name

std::string m_name

protected

A user defined name for the Timer.

m_running

bool m_running {false}

protected

When true, currently running.

m_timer

asio::steady_timer m_timer

protected

Asio timer object.