{

/// Callbacks for events related to this subscription.

SubscriptionEventCallbacks event_callbacks;

/// Whether or not to use default callbacks when user doesn't supply any in event_callbacks

bool use_default_callbacks = true;

/// True to ignore local publications.

bool ignore_local_publications = false;

/// Require middleware to generate unique network flow endpoints

/// Disabled by default

rmw_unique_network_flow_endpoints_requirement_t require_unique_network_flow_endpoints =

RMW_UNIQUE_NETWORK_FLOW_ENDPOINTS_NOT_REQUIRED;

/// The callback group for this subscription. NULL to use the default callback group.

rclcpp::CallbackGroup::SharedPtr callback_group = nullptr;

/// Setting to explicitly set intraprocess communications.

IntraProcessSetting use_intra_process_comm = IntraProcessSetting::NodeDefault;

/// Setting the data-type stored in the intraprocess buffer

IntraProcessBufferType intra_process_buffer_type = IntraProcessBufferType::CallbackDefault;

/// Optional RMW implementation specific payload to be used during creation of the subscription.

std::shared_ptr<rclcpp::detail::RMWImplementationSpecificSubscriptionPayload>

rmw_implementation_payload = nullptr;

// Options to configure topic statistics collector in the subscription.

struct TopicStatisticsOptions

{

// Enable and disable topic statistics calculation and publication. Defaults to disabled.

TopicStatisticsState state = TopicStatisticsState::NodeDefault;

// Topic to which topic statistics get published when enabled. Defaults to /statistics.

std::string publish_topic = "/statistics";

// Topic statistics publication period in ms. Defaults to one second.

// Only values greater than zero are allowed.

std::chrono::milliseconds publish_period{std::chrono::seconds(1)};

// An optional QoS which can provide topic_statistics with a stable QoS separate from

// the subscription's current QoS settings which could be unstable.

// Explicitly set the enough depth to avoid missing the statistics messages.

rclcpp::QoS qos = SystemDefaultsQoS().keep_last(10);

};

TopicStatisticsOptions topic_stats_options;

QosOverridingOptions qos_overriding_options;

ContentFilterOptions content_filter_options;

{

static_assert(

std::is_void_v<typename std::allocator_traits<Allocator>::value_type>,

"Subscription allocator value type must be void");

/// Optional custom allocator.

std::shared_ptr<Allocator> allocator = nullptr;

SubscriptionOptionsWithAllocator() {}

/// Constructor using base class as input.

explicit SubscriptionOptionsWithAllocator(

const SubscriptionOptionsBase & subscription_options_base)

: SubscriptionOptionsBase(subscription_options_base)

{}

/// Convert this class, with a rclcpp::QoS, into an rcl_subscription_options_t.

/**

rcl_subscription_options_t

to_rcl_subscription_options(const rclcpp::QoS & qos) const

{

rcl_subscription_options_t result = rcl_subscription_get_default_options();

result.allocator = this->get_rcl_allocator();

result.qos = qos.get_rmw_qos_profile();

result.rmw_subscription_options.ignore_local_publications = this->ignore_local_publications;

result.rmw_subscription_options.require_unique_network_flow_endpoints =

this->require_unique_network_flow_endpoints;

// Apply payload to rcl_subscription_options if necessary.

if (rmw_implementation_payload && rmw_implementation_payload->has_been_customized()) {

rmw_implementation_payload->modify_rmw_subscription_options(result.rmw_subscription_options);

}

// Copy content_filter_options into rcl_subscription_options.

if (!content_filter_options.filter_expression.empty()) {

std::vector<const char *> cstrings =

get_c_vector_string(content_filter_options.expression_parameters);

rcl_ret_t ret = rcl_subscription_options_set_content_filter_options(

get_c_string(content_filter_options.filter_expression),

cstrings.size(),

cstrings.data(),

&result);

if (RCL_RET_OK != ret) {

rclcpp::exceptions::throw_from_rcl_error(

ret, "failed to set content_filter_options");

}

}

return result;

}

std::shared_ptr<Allocator>

get_allocator() const

{

if (!this->allocator) {

if (!allocator_storage_) {

allocator_storage_ = std::make_shared<Allocator>();

}

return allocator_storage_;

}

return this->allocator;

}

using PlainAllocator =

typename std::allocator_traits<Allocator>::template rebind_alloc<char>;

rcl_allocator_t

get_rcl_allocator() const

{

if constexpr (std::is_same_v<Allocator, std::allocator<void>>) {

return rcl_get_default_allocator();

} else {

if constexpr (rclcpp::allocator::has_get_rcl_allocator_v<Allocator>) {

return get_allocator()->get_rcl_allocator();

} else {

if (!plain_allocator_storage_) {

plain_allocator_storage_ =

std::make_shared<PlainAllocator>(*this->get_allocator());

}

return rclcpp::allocator::get_rcl_allocator<char>(*plain_allocator_storage_);

}

}

}

// This is a temporal workaround, to make sure that get_allocator()

// always returns a copy of the same allocator.

mutable std::shared_ptr<Allocator> allocator_storage_;

// This is a temporal workaround, to keep the plain allocator that backs

// up the rcl allocator returned in rcl_subscription_options_t alive.

mutable std::shared_ptr<PlainAllocator> plain_allocator_storage_;