A cooperatively scheduled, event-based actor implementation. More...

#include <scheduled_actor.hpp>

Inheritance diagram for caf::scheduled_actor:

Collaboration diagram for caf::scheduled_actor:

Classes
class	batch_forwarder

struct	stream_source_state

Public Types
enum	message_category { message_category::ordinary, message_category::internal, message_category::skipped }
	Categorizes incoming messages. More...

enum	activation_result { activation_result::success, activation_result::terminated, activation_result::skipped, activation_result::dropped }
	Result of one-shot activations. More...

using	super = abstract_scheduled_actor
	Base type.

using	batch_op_ptr = intrusive_ptr< flow::op::base< async::batch > >

using	pending_response = std::tuple< const message_id, behavior, disposable >
	The message ID of an outstanding response with its callback and timeout.

using	pointer = scheduled_actor *
	A pointer to a scheduled actor.

using	default_handler = std::function< skippable_result(pointer, message &)>
	Function object for handling unmatched messages.

using	error_handler = std::function< void(pointer, error &)>
	Function object for handling error messages.

using	down_handler = std::function< void(pointer, down_msg &)>
	Function object for handling down messages.

using	node_down_handler = std::function< void(pointer, node_down_msg &)>
	Function object for handling node down messages.

using	exit_handler = std::function< void(pointer, exit_msg &)>
	Function object for handling exit messages.

using	idle_handler = std::function< void()>
	Function object for handling timeouts.

using	batch_publisher = flow::multicaster< async::batch >

using	batch_forwarder_ptr = intrusive_ptr< batch_forwarder >

Public Types inherited from caf::abstract_scheduled_actor
using	super = local_actor

Public Types inherited from caf::local_actor
using	clock_type = std::chrono::steady_clock
	Defines a monotonic clock suitable for measuring intervals.

Public Types inherited from caf::resumable
enum	resume_result { resume_later, awaiting_message, done, shutdown_execution_unit }
	Denotes the state in which a `resumable` returned from its last call to `resume`. More...

enum	subtype_t { unspecified, scheduled_actor, io_actor, function_object }
	Denotes common subtypes of `resumable`. More...

Public Types inherited from caf::flow::coordinator
using	steady_time_point = std::chrono::steady_clock::time_point
	A time point of the monotonic clock.

Public Member Functions
	scheduled_actor (actor_config &cfg)

	scheduled_actor (scheduled_actor &&)=delete

	scheduled_actor (const scheduled_actor &)=delete

scheduled_actor &	operator= (scheduled_actor &&)=delete

scheduled_actor &	operator= (const scheduled_actor &)=delete

bool	enqueue (mailbox_element_ptr ptr, scheduler *sched) override
	Enqueues a new message wrapped in a `mailbox_element` to the actor. More...

mailbox_element *	peek_at_next_mailbox_element () override
	Called by the testing DSL to peek at the next element in the mailbox. More...

const char *	name () const override
	Returns an implementation-dependent name for logging purposes, which is only valid as long as the actor is running. More...

void	launch (scheduler *sched, bool lazy, bool hide) override

void	on_cleanup (const error &reason) override
	Called from `cleanup` to perform extra cleanup actions for this actor.

subtype_t	subtype () const noexcept override
	Returns a subtype hint for this object. More...

void	ref_resumable () const noexcept final
	Add a strong reference count to this object.

void	deref_resumable () const noexcept final
	Remove a strong reference count from this object.

resume_result	resume (scheduler *, size_t) override
	Resume any pending computation until it is either finished or needs to be re-scheduled later. More...

virtual proxy_registry *	proxy_registry_ptr ()
	Returns a factory for proxies created and managed by this actor or `nullptr`. More...

void	quit (error x=error{})
	Finishes execution of this actor after any currently running message handler is done. More...

abstract_mailbox &	mailbox () noexcept
	Returns the queue for storing incoming messages.

bool	initialized () const noexcept
	Checks whether this actor is fully initialized.

bool	inactive () const noexcept
	Checks whether this actor is currently inactive, i.e., not ready to run.

void	set_default_handler (default_handler fun)
	Sets a custom handler for unexpected messages.

template<class F >
std::enable_if_t< std::is_invocable_r_v< skippable_result, F, message & > >	set_default_handler (F fun)
	Sets a custom handler for unexpected messages.

void	set_error_handler (error_handler fun)
	Sets a custom handler for error messages.

template<class F >
std::enable_if_t< std::is_invocable_v< F, error & > >	set_error_handler (F fun)
	Sets a custom handler for error messages.

void	set_down_handler (down_handler fun)
	Sets a custom handler for down messages.

template<class F >
std::enable_if_t< std::is_invocable_v< F, down_msg & > >	set_down_handler (F fun)
	Sets a custom handler for down messages.

void	set_node_down_handler (node_down_handler fun)
	Sets a custom handler for node down messages.

template<class F >
std::enable_if_t< std::is_invocable_v< F, node_down_msg & > >	set_node_down_handler (F fun)
	Sets a custom handler for down messages.

void	set_exit_handler (exit_handler fun)
	Sets a custom handler for error messages.

template<class F >
std::enable_if_t< std::is_invocable_v< F, exit_msg & > >	set_exit_handler (F fun)
	Sets a custom handler for exit messages.

template<class RefType , class RepeatType >
void	set_idle_handler (timespan delay, RefType, RepeatType, idle_handler fun)
	Sets a custom handler for timeouts that trigger after not receiving a message for a certain amount of time. More...

Public Member Functions inherited from caf::abstract_scheduled_actor
virtual void	add_awaited_response_handler (message_id response_id, behavior bhvr, disposable pending_timeout={})=0
	Adds a callback for an awaited response.

virtual void	add_multiplexed_response_handler (message_id response_id, behavior bhvr, disposable pending_timeout={})=0
	Adds a callback for a multiplexed response.

virtual void	call_error_handler (error &what)=0
	Calls the default error handler.

virtual void	run_actions ()=0
	Runs all pending actions.

template<class... Ts>
auto	response_to_flow_cell (message_id response_id, disposable pending_timeout={})
	Lifts a response message into a flow cell in order to allow the actor to turn a response into an `observable` or `single`. More...

Public Member Functions inherited from caf::local_actor
	local_actor (actor_config &cfg)

void	setup_metrics ()

clock_type::time_point	now () const noexcept
	Returns the current time.

disposable	request_response_timeout (timespan d, message_id mid)
	Requests a new timeout for `mid`. More...

template<class... Args>
void	println (std::string_view fmt, Args &&... args)
	Adds a new line to stdout.

template<class... Args>
void	println (term color, std::string_view fmt, Args &&... args)
	Adds a new line to stdout.

template<class T , spawn_options Os = no_spawn_options, class... Ts>
infer_handle_from_class_t< T >	spawn (Ts &&... xs)

template<spawn_options Options = no_spawn_options, class CustomSpawn , class... Args>
CustomSpawn::handle_type	spawn (CustomSpawn, Args &&... args)

template<spawn_options Os = no_spawn_options, class F , class... Ts>
infer_handle_from_fun_t< F >	spawn (F fun, Ts &&... xs)

void	send_exit (const actor_addr &receiver, error reason)
	Sends an exit message to `receiver`.

void	send_exit (const strong_actor_ptr &receiver, error reason)
	Sends an exit message to `receiver`.

template<class Handle >
void	send_exit (const Handle &receiver, error reason)
	Sends an exit message to `receiver`.

template<message_priority Priority = message_priority::normal, class Handle , class T , class... Ts>
void	anon_send (const Handle &receiver, T &&arg, Ts &&... args)

template<message_priority Priority = message_priority::normal, class Handle , class T , class... Ts>
disposable	scheduled_anon_send (const Handle &receiver, actor_clock::time_point timeout, T &&arg, Ts &&... args)

template<message_priority Priority = message_priority::normal, class Handle , class T , class... Ts>
disposable	delayed_anon_send (const Handle &receiver, actor_clock::duration_type timeout, T &&arg, Ts &&... args)

scheduler *	context () const noexcept
	Returns the execution unit currently used by this actor.

void	context (scheduler *x) noexcept
	Sets the execution unit for this actor.

actor_system &	system () const noexcept
	Returns the hosting actor system.

const actor_system_config &	config () const noexcept
	Returns the config of the hosting actor system.

actor_clock &	clock () const noexcept
	Returns the clock of the actor system.

strong_actor_ptr &	current_sender () noexcept
	Returns a pointer to the sender of the current message. More...

message_id	current_message_id () noexcept
	Returns the ID of the current message.

message_id	take_current_message_id () noexcept
	Returns the ID of the current message and marks the ID stored in the current mailbox element as answered. More...

void	drop_current_message_id () noexcept
	Marks the current message ID as answered.

mailbox_element *	current_mailbox_element () noexcept
	Returns a pointer to the currently processed mailbox element.

void	monitor (const node_id &node)
	Adds a unidirectional `monitor` to `node`. More...

template<message_priority P = message_priority::normal, class Handle >
void	monitor (const Handle &whom)
	Adds a unidirectional `monitor` to `whom`. More...

template<typename Handle , typename Fn >
disposable	monitor (Handle whom, Fn func)
	Adds a unidirectional `monitor` to `whom` with custom callback. More...

void	demonitor (const actor_addr &whom)
	Removes a monitor from `whom`.

void	demonitor (const strong_actor_ptr &whom)
	Removes a monitor from `whom`.

void	demonitor (const node_id &node)
	Removes a monitor from `node`.

template<class Handle >
void	demonitor (const Handle &whom)
	Removes a monitor from `whom`.

virtual void	on_exit ()
	Can be overridden to perform cleanup code after an actor finished execution. More...

template<class... Ts>
detail::response_promise_t< Ts... >	make_response_promise ()
	Creates a `typed_response_promise` to respond to a request later on. More...

response_promise	make_response_promise ()
	Creates a `response_promise` to respond to a request later on.

virtual error	save_state (serializer &sink, unsigned int version)
	Serializes the state of this actor to `sink`. More...

virtual error	load_state (deserializer &source, unsigned int version)
	Deserializes the state of this actor from `source`. More...

const error &	fail_state () const noexcept
	Returns the currently defined fail state. More...

Public Member Functions inherited from caf::abstract_actor
	abstract_actor (const abstract_actor &)=delete

abstract_actor &	operator= (const abstract_actor &)=delete

void	attach (attachable_ptr ptr)
	Attaches `ptr` to this actor. More...

template<class F >
void	attach_functor (F f)
	Convenience function that attaches the functor `f` to this actor. More...

size_t	detach (const attachable::token &what)
	Detaches the first attached object that matches `what`.

void	link_to (const actor_addr &other)
	Links this actor to `other`.

template<class ActorHandle >
void	link_to (const ActorHandle &other)
	Links this actor to `other`.

void	unlink_from (const actor_addr &other)
	Unlinks this actor from `addr`.

template<class ActorHandle >
void	unlink_from (const ActorHandle &other)
	Links this actor to `hdl`.

virtual std::set< std::string >	message_types () const
	Returns the set of accepted messages types as strings or an empty set if this actor is untyped. More...

actor_id	id () const noexcept
	Returns the ID of this actor.

node_id	node () const noexcept
	Returns the node this actor is living on.

actor_system &	home_system () const noexcept
	Returns the system that created this actor (or proxy).

actor_control_block *	ctrl () const
	Returns the control block for this actor.

actor_addr	address () const noexcept
	Returns the logical actor address.

bool	cleanup (error &&reason, scheduler *sched)
	Called by the runtime system to perform cleanup actions for this actor. More...

Public Member Functions inherited from caf::flow::coordinator
observable_builder	make_observable ()
	Returns a factory object for new observable objects on this coordinator.

template<class Impl , class... Args>
std::enable_if_t< std::is_base_of_v< coordinated, Impl >, intrusive_ptr< Impl > >	add_child (std::in_place_type_t< Impl >, Args &&... args)
	Creates a new coordinated object on this coordinator.

template<class Impl , class... Args>
std::enable_if_t< std::is_base_of_v< coordinated, Impl >, typename Impl::handle_type >	add_child_hdl (std::in_place_type_t< Impl > token, Args &&... args)
	Like add_child, but wraps the result in a handle type. More...

virtual void	release_later (coordinated_ptr &child)=0
	Resets `child` and releases the reference count of the coordinated object at the end of the current cycle. More...

template<class T >
std::enable_if_t< std::is_base_of_v< coordinated, T > >	release_later (intrusive_ptr< T > &child)
	Resets `child` and releases the reference count of the coordinated object at the end of the current cycle. More...

template<class Handle >
std::enable_if< Handle::holds_coordinated >	release_later (Handle &hdl)
	Resets `hdl` and releases the reference count of the coordinated object at the end of the current cycle. More...

virtual steady_time_point	steady_time ()=0
	Returns the current time on the monotonic clock of this coordinator.

virtual void	delay (action what)=0
	Delays execution of an action until all pending actions were executed. More...

template<class F >
void	delay_fn (F &&what)
	Delays execution of an action until all pending actions were executed. More...

virtual disposable	delay_until (steady_time_point abs_time, action what)=0
	Delays execution of an action with an absolute timeout. More...

template<class F >
disposable	delay_until_fn (steady_time_point abs_time, F &&what)
	Delays execution of an action until all pending actions were executed. More...

disposable	delay_for (timespan rel_time, action what)
	Delays execution of an action with a relative timeout. More...

template<class F >
disposable	delay_for_fn (timespan rel_time, F &&what)
	Delays execution of an action with a relative timeout. More...

Public Member Functions inherited from caf::async::execution_context
virtual void	ref_execution_context () const noexcept=0
	Increases the reference count of the execution_context.

virtual void	deref_execution_context () const noexcept=0
	Decreases the reference count of the execution context and destroys the object if necessary. More...

virtual void	schedule (action what)=0
	Schedules `what` to run on the event loop of the execution context. More...

template<class F >
void	schedule_fn (F &&what)
	Schedules `what` to run on the event loop of the execution context. More...

virtual void	watch (disposable what)=0
	Asks the coordinator to keep its event loop running until `what` becomes disposed since it depends on external events or produces events that are visible to outside observers. More...

Static Public Member Functions
static void	default_error_handler (pointer ptr, error &x)

static void	default_down_handler (pointer ptr, down_msg &x)

static void	default_node_down_handler (pointer ptr, node_down_msg &x)

static void	default_exit_handler (pointer ptr, exit_msg &x)

Protected Attributes
abstract_mailbox *	mailbox_
	Stores incoming messages.

detail::behavior_stack	bhvr_stack_
	Stores user-defined callbacks for message handling.

std::forward_list< pending_response >	awaited_responses_
	Stores callbacks for awaited responses.

unordered_flat_map< message_id, std::pair< behavior, disposable > >	multiplexed_responses_
	Stores callbacks for multiplexed responses.

default_handler	default_handler_
	Customization point for setting a default `message` callback.

error_handler	error_handler_
	Customization point for setting a default `error` callback.

down_handler	down_handler_
	Customization point for setting a default `down_msg` callback.

node_down_handler	node_down_handler_
	Customization point for setting a default `down_msg` callback.

exit_handler	exit_handler_
	Customization point for setting a default `exit_msg` callback.

detail::private_thread *	private_thread_
	Pointer to a private thread object associated with a detached actor.

Protected Attributes inherited from caf::local_actor
scheduler *	context_

mailbox_element *	current_element_

message_id	last_request_id_

detail::unique_function< behavior(local_actor *)>	initial_behavior_fac_
	Factory function for returning initial behavior in function-based actors.

metrics_t	metrics_

Protected Attributes inherited from caf::abstract_actor
std::atomic< int >	flags_
	Holds several state and type flags.

std::mutex	mtx_
	Guards members that may be subject to concurrent access . More...

std::condition_variable	cv_
	Allows blocking actors to actively wait for incoming messages.

error	fail_state_
	Stores the user-defined exit reason if this actor has finished execution.

attachable_ptr	attachables_head_
	Points to the first attachable in the linked list of attachables (if any).

Friends
class	detail::batch_forwarder_impl

class	detail::stream_bridge

class	detail::stream_bridge_sub

template<class , class >
class	response_handle

Related Functions
(Note that these are not member functions.)
CAF_CORE_EXPORT skippable_result	reflect (scheduled_actor *, message &)

CAF_CORE_EXPORT skippable_result	reflect_and_quit (scheduled_actor *, message &)

CAF_CORE_EXPORT skippable_result	print_and_drop (scheduled_actor *, message &)

CAF_CORE_EXPORT skippable_result	drop (scheduled_actor *, message &)

Related Functions inherited from caf::local_actor
constexpr keep_behavior_t	keep_behavior = keep_behavior_t{}
	Policy tag that causes event_based_actor::become to keep the current behavior available.

Related Functions inherited from caf::abstract_actor
using	actor_id = uint64_t
	A unique actor ID.

Related Functions inherited from caf::flow::coordinator
using	coordinator_ptr = intrusive_ptr< coordinator >

Related Functions inherited from caf::async::execution_context
using	execution_context_ptr = intrusive_ptr< execution_context >

void	intrusive_ptr_add_ref (const execution_context *ptr) noexcept

void	intrusive_ptr_release (const execution_context *ptr) noexcept

Additional Inherited Members
Protected Member Functions inherited from caf::local_actor
void	do_send (abstract_actor *receiver, message_priority priority, message &&msg)
	Sends `msg` as an asynchronous message to `receiver`. More...

disposable	do_scheduled_send (strong_actor_ptr receiver, message_priority priority, actor_clock::time_point timeout, message &&msg)
	Sends `msg` as an asynchronous message to `receiver` after the timeout. More...

void	do_anon_send (abstract_actor *receiver, message_priority priority, message &&msg)
	Sends `msg` as an asynchronous message to `receiver` without sender information. More...

disposable	do_scheduled_anon_send (strong_actor_ptr receiver, message_priority priority, actor_clock::time_point timeout, message &&msg)
	Sends `msg` as an asynchronous message to `receiver` after the timeout without sender information. More...

Protected Member Functions inherited from caf::abstract_actor
virtual void	on_unreachable ()
	Called on actor if the last strong reference to it expired without a prior call to `quit(exit_reason::not_exited)`. More...

int	flags () const

void	flags (int new_value)

bool	is_terminated () const noexcept
	Checks whether this actor has terminated.

	abstract_actor (actor_config &cfg)

void	attach_impl (attachable_ptr &ptr)

size_t	detach_impl (const attachable::token &what, bool stop_on_hit=false, bool dry_run=false)

void	add_link (abstract_actor *other)
	Causes the actor to establish a link to `other`.

void	remove_link (abstract_actor *other)
	Causes the actor to remove any established link to `other`.

virtual bool	add_backlink (abstract_actor *other)
	Adds an entry to `other` to the link table of this actor. More...

virtual bool	remove_backlink (abstract_actor *other)
	Removes an entry to `other` from the link table of this actor. More...

Detailed Description

A cooperatively scheduled, event-based actor implementation.

Member Enumeration Documentation

◆ activation_result

enum caf::scheduled_actor::activation_result

strong

Result of one-shot activations.

Enumerator
success	Actor is still alive and handled the activation message.
terminated	Actor handled the activation message and terminated.
skipped	Actor skipped the activation message.
dropped	Actor dropped the activation message.

◆ message_category

enum caf::scheduled_actor::message_category

strong

Categorizes incoming messages.

Enumerator
ordinary	Triggers the current behavior.
internal	Triggers handlers for system messages such as `exit_msg` or `down_msg`.
skipped	Delays processing.

Member Function Documentation

◆ enqueue()

bool caf::scheduled_actor::enqueue	(	mailbox_element_ptr	what,
		scheduler *	sched
	)

overridevirtual

Enqueues a new message wrapped in a mailbox_element to the actor.

This enqueue variant allows to define forwarding chains.

Returns: true if the message has added to the mailbox, false otherwise. In the latter case, the actor terminated and the message has been dropped. Once this function returns false, it returns false for all future invocations.

Note: The returned value is purely informational and may be used to discard actor handles early. Messages may still get dropped later even if this function returns true. In particular when dealing with remote actors.

Implements caf::abstract_actor.

Reimplemented in caf::io::abstract_broker.

◆ name()

const char * caf::scheduled_actor::name ( ) const

overridevirtual

Returns an implementation-dependent name for logging purposes, which is only valid as long as the actor is running.

The default implementation simply returns "actor".

Reimplemented from caf::local_actor.

Reimplemented in caf::io::abstract_broker, caf::io::basp_broker, and caf::detail::prometheus_broker.

◆ peek_at_next_mailbox_element()

mailbox_element * caf::scheduled_actor::peek_at_next_mailbox_element ( )

overridevirtual

Called by the testing DSL to peek at the next element in the mailbox.

Do not call this function in production code! The default implementation always returns nullptr.

Returns: A pointer to the next mailbox element or nullptr if the mailbox is empty or the actor does not have a mailbox.

Reimplemented from caf::abstract_actor.

◆ proxy_registry_ptr()

proxy_registry * caf::scheduled_actor::proxy_registry_ptr ( )

virtual

Returns a factory for proxies created and managed by this actor or nullptr.

Reimplemented in caf::io::basp_broker.

◆ quit()

void caf::scheduled_actor::quit ( error x = error{} )

Finishes execution of this actor after any currently running message handler is done.

This member function clears the behavior stack of the running actor and invokes on_exit(). The actors does not finish execution if the implementation of on_exit() sets a new behavior. When setting a new behavior in on_exit(), one has to make sure to not produce an infinite recursion.

If on_exit() did not set a new behavior, the actor sends an exit message to all of its linked actors, sets its state to exited and finishes execution.

◆ resume()

resumable::resume_result caf::scheduled_actor::resume	(	scheduler *	,
		size_t	max_throughput
	)

overridevirtual

Resume any pending computation until it is either finished or needs to be re-scheduled later.

Implements caf::resumable.

Reimplemented in caf::io::abstract_broker, and caf::io::basp_broker.

◆ set_idle_handler()

template<class RefType , class RepeatType >

void caf::scheduled_actor::set_idle_handler	(	timespan	delay,
		RefType	,
		RepeatType	,
		idle_handler	fun
	)

inline

Sets a custom handler for timeouts that trigger after not receiving a message for a certain amount of time.

◆ subtype()

resumable::subtype_t caf::scheduled_actor::subtype ( ) const

overridevirtualnoexcept

Returns a subtype hint for this object.

This allows an execution unit to limit processing to a specific set of resumables and delegate other subtypes to dedicated workers.

Reimplemented from caf::resumable.

Reimplemented in caf::io::abstract_broker.

Friends And Related Function Documentation

◆ drop()

CAF_CORE_EXPORT skippable_result drop	(	scheduled_actor *	,
		message &
	)

◆ print_and_drop()

CAF_CORE_EXPORT skippable_result print_and_drop	(	scheduled_actor *	,
		message &
	)

◆ reflect()

CAF_CORE_EXPORT skippable_result reflect	(	scheduled_actor *	,
		message &
	)

◆ reflect_and_quit()

CAF_CORE_EXPORT skippable_result reflect_and_quit	(	scheduled_actor *	,
		message &
	)

Member Data Documentation

◆ default_mailbox_

detail::default_mailbox caf::scheduled_actor::default_mailbox_

The default mailbox instance that we use if the user does not configure a mailbox via the ::actor_config.

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

libcaf_core/caf/scheduled_actor.hpp
libcaf_core/caf/scheduled_actor/flow.hpp
libcaf_core/caf/scheduled_actor.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Protected Attributes

Friends

Related Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ activation_result

◆ message_category

Member Function Documentation

◆ enqueue()

◆ name()

◆ peek_at_next_mailbox_element()

◆ proxy_registry_ptr()

◆ quit()

◆ resume()

◆ set_idle_handler()

◆ subtype()

Friends And Related Function Documentation

◆ drop()

◆ print_and_drop()

◆ reflect()

◆ reflect_and_quit()

Member Data Documentation

◆ default_mailbox_