Inheritance diagram for rclcpp::experimental::SubscriptionIntraProcessBase:

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Collaboration diagram for rclcpp::experimental::SubscriptionIntraProcessBase:

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Public Types
enum class	EntityType : std::size_t { Subscription }

Public Member Functions
RCLCPP_PUBLIC	SubscriptionIntraProcessBase (rclcpp::Context::SharedPtr context, const std::string &topic_name, const rclcpp::QoS &qos_profile)

RCLCPP_PUBLIC size_t	get_number_of_ready_guard_conditions () override
	Get the number of ready guard_conditions. More...

RCLCPP_PUBLIC void	add_to_wait_set (rcl_wait_set_t *wait_set) override
	Add the Waitable to a wait set. More...

bool	is_ready (rcl_wait_set_t *wait_set) override=0
	Check if the Waitable is ready. More...

std::shared_ptr< void >	take_data () override=0
	Take the data so that it can be consumed with `execute`. More...

std::shared_ptr< void >	take_data_by_entity_id (size_t id) override
	Take the data so that it can be consumed with `execute`. More...

void	execute (std::shared_ptr< void > &data) override=0
	Execute data that is passed in. More...

virtual bool	use_take_shared_method () const =0

RCLCPP_PUBLIC const char *	get_topic_name () const

RCLCPP_PUBLIC QoS	get_actual_qos () const

void	set_on_ready_callback (std::function< void(size_t, int)> callback) override
	Set a callback to be called when each new message arrives. More...

void	clear_on_ready_callback () override
	Unset the callback registered for new messages, if any.

Public Member Functions inherited from rclcpp::Waitable
virtual RCLCPP_PUBLIC size_t	get_number_of_ready_subscriptions ()
	Get the number of ready subscriptions. More...

virtual RCLCPP_PUBLIC size_t	get_number_of_ready_timers ()
	Get the number of ready timers. More...

virtual RCLCPP_PUBLIC size_t	get_number_of_ready_clients ()
	Get the number of ready clients. More...

virtual RCLCPP_PUBLIC size_t	get_number_of_ready_events ()
	Get the number of ready events. More...

virtual RCLCPP_PUBLIC size_t	get_number_of_ready_services ()
	Get the number of ready services. More...

RCLCPP_PUBLIC bool	exchange_in_use_by_wait_set_state (bool in_use_state)
	Exchange the "in use by wait set" state for this timer. More...

Protected Member Functions
virtual void	trigger_guard_condition ()=0

void	invoke_on_new_message ()

Protected Attributes
std::recursive_mutex	callback_mutex_

std::function< void(size_t)>	on_new_message_callback_ {nullptr}

size_t	unread_count_ {0}

rclcpp::GuardCondition	gc_

Detailed Description

Definition at line 36 of file subscription_intra_process_base.hpp.

Member Function Documentation

◆ add_to_wait_set()

void SubscriptionIntraProcessBase::add_to_wait_set ( rcl_wait_set_t * wait_set )

overridevirtual

Add the Waitable to a wait set.

Parameters

[in] wait_set A handle to the wait set to add the Waitable to.

Exceptions

rclcpp::execptions::RCLError from rcl_wait_set_add_*()

Implements rclcpp::Waitable.

Definition at line 26 of file subscription_intra_process_base.cpp.

◆ execute()

void rclcpp::experimental::SubscriptionIntraProcessBase::execute ( std::shared_ptr< void > & data )

overridepure virtual

Execute data that is passed in.

Before calling this method, the Waitable should be added to a wait set, waited on, and then updated - and the take_data method should be called.

Example usage:

// ... create a wait set and a Waitable
// Add the Waitable to the wait set
waitable.add_to_wait_set(wait_set);
// Wait
rcl_ret_t wait_ret = rcl_wait(wait_set);
// ... error handling
// Update the Waitable
waitable.update(wait_set);
// Execute any entities of the Waitable that may be ready
std::shared_ptr<void> data = waitable.take_data();
waitable.execute(data);

Implements rclcpp::Waitable.

Implemented in rclcpp::experimental::SubscriptionIntraProcess< MessageT, SubscribedType, SubscribedTypeAlloc, SubscribedTypeDeleter, ROSMessageType, Alloc >.

◆ get_number_of_ready_guard_conditions()

RCLCPP_PUBLIC size_t rclcpp::experimental::SubscriptionIntraProcessBase::get_number_of_ready_guard_conditions ( )

inlineoverridevirtual

Get the number of ready guard_conditions.

Returns a value of 0 by default. This should be overridden if the Waitable contains one or more guard_conditions.

Returns: The number of guard_conditions associated with the Waitable.

Reimplemented from rclcpp::Waitable.

Definition at line 59 of file subscription_intra_process_base.hpp.

◆ is_ready()

bool rclcpp::experimental::SubscriptionIntraProcessBase::is_ready ( rcl_wait_set_t * wait_set )

overridepure virtual

Check if the Waitable is ready.

The input wait set should be the same that was used in a previously call to add_to_wait_set(). The wait set should also have been previously waited on with rcl_wait().

Parameters

[in] wait_set A handle to the wait set the Waitable was previously added to and that has been waited on.

Returns: true if the Waitable is ready, false otherwise.

Implements rclcpp::Waitable.

Implemented in rclcpp::experimental::SubscriptionIntraProcessBuffer< SubscribedType, Alloc, Deleter, ROSMessageType >, and rclcpp::experimental::SubscriptionIntraProcessBuffer< SubscribedType, std::allocator< SubscribedType >, std::default_delete< SubscribedType >, SubscribedType >.

◆ set_on_ready_callback()

void rclcpp::experimental::SubscriptionIntraProcessBase::set_on_ready_callback ( std::function< void(size_t, int)> callback )

inlineoverridevirtual

Set a callback to be called when each new message arrives.

The callback receives a size_t which is the number of messages received since the last time this callback was called. Normally this is 1, but can be > 1 if messages were received before any callback was set.

The callback also receives an int identifier argument. This is needed because a Waitable may be composed of several distinct entities, such as subscriptions, services, etc. The application should provide a generic callback function that will be then forwarded by the waitable to all of its entities. Before forwarding, a different value for the identifier argument will be bound to the function. This implies that the provided callback can use the identifier to behave differently depending on which entity triggered the waitable to become ready.

Calling it again will clear any previously set callback.

An exception will be thrown if the callback is not callable.

This function is thread-safe.

If you want more information available in the callback, like the subscription or other information, you may use a lambda with captures or std::bind.

Parameters

[in] callback functor to be called when a new message is received.

Reimplemented from rclcpp::Waitable.

Definition at line 122 of file subscription_intra_process_base.hpp.

References rclcpp::QoS::depth(), rclcpp::get_logger(), and rclcpp::QoS::history().

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◆ take_data()

std::shared_ptr<void> rclcpp::experimental::SubscriptionIntraProcessBase::take_data ( )

overridepure virtual

Take the data so that it can be consumed with execute.

NOTE: take_data is a partial fix to a larger design issue with the multithreaded executor. This method is likely to be removed when a more permanent fix is implemented. A longterm fix is currently being discussed here: https://github.com/ros2/rclcpp/pull/1276

This method takes the data from the underlying data structure and writes it to the void shared pointer data that is passed into the method. The data can then be executed with the execute method.

Before calling this method, the Waitable should be added to a wait set, waited on, and then updated.

Example usage:

// ... create a wait set and a Waitable
// Add the Waitable to the wait set
waitable.add_to_wait_set(wait_set);
// Wait
rcl_ret_t wait_ret = rcl_wait(wait_set);
// ... error handling
// Update the Waitable
waitable.update(wait_set);
// Execute any entities of the Waitable that may be ready
std::shared_ptr<void> data = waitable.take_data();

Implements rclcpp::Waitable.

Implemented in rclcpp::experimental::SubscriptionIntraProcess< MessageT, SubscribedType, SubscribedTypeAlloc, SubscribedTypeDeleter, ROSMessageType, Alloc >.

Referenced by take_data_by_entity_id().

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◆ take_data_by_entity_id()

std::shared_ptr<void> rclcpp::experimental::SubscriptionIntraProcessBase::take_data_by_entity_id ( size_t id )

inlineoverridevirtual

Take the data so that it can be consumed with execute.

This function allows to specify an entity ID to take the data from. Entity IDs are identifiers that can be defined by waitable-derived classes that are composed of several distinct entities. The main use-case is in conjunction with the listener APIs.

Parameters

[in] id the id of the entity from which to take