Type-safe topic listener for the VLink event communication model. More...

#include <subscriber.h>

Inheritance diagram for vlink::Subscriber< MsgT, SecT >:

Collaboration diagram for vlink::Subscriber< MsgT, SecT >:

Public Types
using	UniquePtr = std::unique_ptr< Subscriber< MsgT, SecT > >
	Owning unique-pointer alias. More...

using	SharedPtr = std::shared_ptr< Subscriber< MsgT, SecT > >
	Owning shared-pointer alias. More...

using	MsgCallback = Function< void(const MsgT &)>
	User callback signature for received messages. More...

Public Types inherited from vlink::Node< SubscriberImpl, SecurityType::kWithoutSecurity >
using	StatusCallback = NodeImpl::StatusCallback
	Handler signature for status-change notifications. More...

Public Member Functions
template<typename ConfT , typename = std::enable_if_t<std::is_base_of_v<Conf, ConfT>>>
	Subscriber (const ConfT &conf, InitType type=InitType::kWithInit)
	Constructs a subscriber from a typed transport configuration object. More...

	Subscriber (const std::string &url_str, InitType type=InitType::kWithInit)
	Constructs a subscriber from a URL string. More...

bool	listen (MsgCallback &&callback)
	Installs the receive callback that runs for every inbound message. More...

void	set_manual_unloan (bool manual_unloan) override
	Enables or disables manual-unloan mode for zero-copy receives. More...

void	set_latency_and_lost_enabled (bool enable)
	Toggles per-message latency and sample-loss measurement. More...

bool	is_latency_and_lost_enabled () const
	Reports whether latency and sample-loss tracking is currently active. More...

int64_t	get_latency () const
	Returns the most recent end-to-end latency measurement. More...

SampleLostInfo	get_lost () const
	Returns cumulative sample-delivery statistics. More...

void	mark_as_getter ()
	Promotes this subscriber to behave as a `Getter` (field-reader) at the transport layer. More...

Public Member Functions inherited from vlink::Node< SubscriberImpl, SecurityType::kWithoutSecurity >
virtual bool	init ()
	Initialises the node and its transport back-end. More...

virtual bool	deinit ()
	Tears the node down and releases all transport resources. More...

virtual void	interrupt ()
	Aborts any blocking wait on this node. More...

bool	has_inited () const
	Reports whether `init()` has been successfully called. More...

bool	is_support_loan () const
	Reports whether the transport supports zero-copy loaned buffers. More...

Bytes	loan (int64_t size)
	Allocates a loaned buffer from the transport memory pool. More...

bool	return_loan (const Bytes &bytes)
	Returns a previously loaned buffer to the transport pool. More...

virtual bool	is_manual_unloan () const
	Reports whether manual-unloan mode is currently active. More...

bool	suspend ()
	Suspends message delivery on this node. More...

bool	resume ()
	Resumes message delivery after a prior `suspend()`. More...

bool	is_suspend () const
	Reports whether the node is currently suspended. More...

bool	attach (class MessageLoop *message_loop)
	Attaches the node to a `MessageLoop` for callback dispatch. More...

bool	detach ()
	Detaches the node from its current `MessageLoop`. More...

class MessageLoop *	get_message_loop () const
	Returns the `MessageLoop` this node is currently attached to. More...

const AbstractNode *	get_abstract_node () const
	Returns the abstract-graph handle for runtime topology inspection. More...

Status::BasePtr	get_status (Status::Type type) const
	Retrieves the current status object for the requested category. More...

void	register_status_handler (StatusCallback &&callback)
	Registers a handler invoked whenever the node's status changes. More...

void	set_property (const std::string &prop, const std::string &value)
	Sets a transport-specific string-keyed property. More...

std::string	get_property (const std::string &prop) const
	Retrieves a previously set transport-specific property value. More...

TransportType	get_transport_type () const
	Returns the `TransportType` this node is bound to. More...

const std::string &	get_url () const
	Returns the URL string used to construct this node. More...

void	set_record_path (const std::string &path)
	Enables recording of inbound or outbound messages to a bag file. More...

void	set_ser_type (const std::string &ser_type, SchemaType schema_type=SchemaType::kUnknown)
	Overrides the runtime wire-metadata identifiers for this node. More...

const std::string &	get_ser_type () const
	Returns the current concrete runtime type identifier. More...

SchemaType	get_schema_type () const
	Returns the current coarse schema family. More...

void	set_discovery_enabled (bool enable)
	Toggles peer-discovery on this node. More...

bool	get_discovery_enabled () const
	Reports whether peer-discovery is currently enabled. More...

void	bind_proto_arena (void *proto_arena)
	Binds a Protobuf Arena for arena-allocated message objects. More...

double	get_cpu_usage () const
	Returns the cumulative CPU-usage ratio sampled by the profiler. More...

bool	get_safety_quit () const
	Reports whether safe-quit mode is currently active. More...

void	set_safety_quit (bool safety_quit)
	Enables or disables safe-quit mode. More...

void	set_ssl_options (const SslOptions &options)
	Configures transport-layer SSL/TLS encryption for this node. More...

Static Public Member Functions
static UniquePtr	create_unique (const std::string &url_str, InitType type=InitType::kWithInit)
	Heap-allocates a `Subscriber` and wraps it in a `std::unique_ptr`. More...

static SharedPtr	create_shared (const std::string &url_str, InitType type=InitType::kWithInit)
	Heap-allocates a `Subscriber` and wraps it in a `std::shared_ptr`. More...

Static Public Attributes
static constexpr ImplType	kImplType = kSubscriber
	Node role tag (`kSubscriber`). More...

static constexpr Serializer::Type	kMsgType = Serializer::get_type_of<MsgT>()
	Codec resolved from `MsgT`. More...

Additional Inherited Members
Protected Member Functions inherited from vlink::Node< SubscriberImpl, SecurityType::kWithoutSecurity >
	Node ()

virtual	~Node ()

bool	enable_security (const Security::Config &cfg)
	Installs a `Security` configuration before transport initialisation. More...

bool	enable_security (Security::Config &&cfg)
	Move overload for construction-time security installation. More...

void	invoke_callback (const CallbackT &callback, ArgsT &&... args)

TypeT	get_default_value ()

Protected Attributes inherited from vlink::Node< SubscriberImpl, SecurityType::kWithoutSecurity >
void *	proto_arena_

bool	is_support_loan_

bool	is_manual_unloan_

std::atomic_bool	has_inited_

std::optional< std::mutex >	quit_mtx_

std::unique_ptr< SubscriberImpl >	impl_

Detailed Description

template<typename MsgT, SecurityType SecT = SecurityType::kWithoutSecurity>
class vlink::Subscriber< MsgT, SecT >

Type-safe topic listener for the VLink event communication model.

Inherits the full Node API and adds receive-specific operations: listen() to register the user callback, manual-unloan control for zero-copy back-ends, and latency / sample-loss tracking. The transport implementation (SubscriberImpl) is selected by the URL scheme or by the typed configuration object supplied at construction time.

Template Parameters

MsgT	C++ message type. Must satisfy `Serializer::is_supported()`.
SecT	Security mode; defaults to `SecurityType::kWithoutSecurity`.

Member Typedef Documentation

◆ MsgCallback

template<typename MsgT , SecurityType SecT = SecurityType::kWithoutSecurity>

using vlink::Subscriber< MsgT, SecT >::MsgCallback = Function<void(const MsgT&)>

User callback signature for received messages.

◆ SharedPtr

template<typename MsgT , SecurityType SecT = SecurityType::kWithoutSecurity>

using vlink::Subscriber< MsgT, SecT >::SharedPtr = std::shared_ptr<Subscriber<MsgT, SecT> >

Owning shared-pointer alias.

◆ UniquePtr

template<typename MsgT , SecurityType SecT = SecurityType::kWithoutSecurity>

using vlink::Subscriber< MsgT, SecT >::UniquePtr = std::unique_ptr<Subscriber<MsgT, SecT> >

Owning unique-pointer alias.

Constructor & Destructor Documentation

◆ Subscriber() [1/2]

template<typename MsgT , SecurityType SecT>

template<typename ConfT , typename >

vlink::Subscriber< MsgT, SecT >::Subscriber	(	const ConfT &	conf,
		InitType	type = `InitType::kWithInit`
	)

inlineexplicit

Constructs a subscriber from a typed transport configuration object.

Accepts any Conf-derived configuration. A compile-time check enforces that the configuration permits the subscriber role.

Template Parameters

ConfT Concrete configuration type derived from Conf.

Parameters

conf	Populated configuration aggregate.
type	Whether to call `init()` inline; default is `InitType::kWithInit`.

◆ Subscriber() [2/2]

template<typename MsgT , SecurityType SecT>

vlink::Subscriber< MsgT, SecT >::Subscriber	(	const std::string &	url_str,
		InitType	type = `InitType::kWithInit`
	)

inlineexplicit

Constructs a subscriber from a URL string.

Parameters

url_str	Topic URL such as `"shm://vehicle/speed"`.
type	Whether to call `init()` inline; default is `InitType::kWithInit`.

Member Function Documentation

◆ create_shared()

template<typename MsgT , SecurityType SecT>

Subscriber< MsgT, SecT >::SharedPtr vlink::Subscriber< MsgT, SecT >::create_shared	(	const std::string &	url_str,
		InitType	type = `InitType::kWithInit`
	)

inlinestatic

Heap-allocates a Subscriber and wraps it in a std::shared_ptr.

Parameters

url_str	Topic URL string.
type	Whether to call `init()` inline; default is `InitType::kWithInit`.

Returns: Owning SharedPtr to the new subscriber.

◆ create_unique()

template<typename MsgT , SecurityType SecT>

Subscriber< MsgT, SecT >::UniquePtr vlink::Subscriber< MsgT, SecT >::create_unique	(	const std::string &	url_str,
		InitType	type = `InitType::kWithInit`
	)

inlinestatic

Heap-allocates a Subscriber and wraps it in a std::unique_ptr.

Parameters

url_str	Topic URL string.
type	Whether to call `init()` inline; default is `InitType::kWithInit`.

Returns: Owning UniquePtr to the new subscriber.

◆ get_latency()

template<typename MsgT , SecurityType SecT>

int64_t vlink::Subscriber< MsgT, SecT >::get_latency

inline

Returns the most recent end-to-end latency measurement.

Computed as receive-timestamp minus source-timestamp on the last delivered message. Returns 0 when tracking is not enabled.

Returns: Latency in nanoseconds; 0 if disabled.

◆ get_lost()

template<typename MsgT , SecurityType SecT>

SampleLostInfo vlink::Subscriber< MsgT, SecT >::get_lost

inline

Returns cumulative sample-delivery statistics.

Returns: SampleLostInfo with total expected and total lost counts.

◆ is_latency_and_lost_enabled()

template<typename MsgT , SecurityType SecT>

bool vlink::Subscriber< MsgT, SecT >::is_latency_and_lost_enabled

inline

Reports whether latency and sample-loss tracking is currently active.

Returns: true if set_latency_and_lost_enabled(true) was invoked.

◆ listen()

template<typename MsgT , SecurityType SecT>

bool vlink::Subscriber< MsgT, SecT >::listen ( MsgCallback && callback )

inline

Installs the receive callback that runs for every inbound message.

The callback is invoked on the transport delivery thread by default; if the subscriber is attach()ed to a MessageLoop the callback is posted onto that loop instead. For intra:// transports carrying an IntraDataType shared pointer the value is forwarded zero-copy and no deserialisation occurs.

Warning: The argument reference points at thread_local scratch memory that is reused across invocations. Copy the data before stashing it outside the callback. This restriction does not apply to Bytes or IntraData payloads.

Note: Calling listen() more than once is fatal. The subscriber must be initialised before the first call to listen().

Parameters

callback void(const MsgT&) invoked for each received message.

Returns: true if the callback was installed successfully.

◆ mark_as_getter()

template<typename MsgT , SecurityType SecT>

void vlink::Subscriber< MsgT, SecT >::mark_as_getter

inline

Promotes this subscriber to behave as a Getter (field-reader) at the transport layer.

Switches impl_type from kSubscriber to kGetter so that latest-value delivery semantics are activated. Reinitialises the transport extension if called post-init(). Used internally by Getter.

◆ set_latency_and_lost_enabled()

template<typename MsgT , SecurityType SecT>

void vlink::Subscriber< MsgT, SecT >::set_latency_and_lost_enabled ( bool enable )

inline

Toggles per-message latency and sample-loss measurement.

Parameters

enable true to begin tracking; false to stop.

◆ set_manual_unloan()

template<typename MsgT , SecurityType SecT>

void vlink::Subscriber< MsgT, SecT >::set_manual_unloan ( bool manual_unloan )

inlineoverridevirtual

Enables or disables manual-unloan mode for zero-copy receives.

In manual-unloan mode the user must call return_loan() after consuming each delivered buffer. Only relevant on loan-capable transports (shm://, Zenoh with SHM, etc.).

Parameters

manual_unloan true to enable manual return; false for auto-return.

Reimplemented from vlink::Node< SubscriberImpl, SecurityType::kWithoutSecurity >.

Member Data Documentation

◆ kImplType

template<typename MsgT , SecurityType SecT = SecurityType::kWithoutSecurity>

constexpr ImplType vlink::Subscriber< MsgT, SecT >::kImplType = kSubscriber

staticconstexpr

Node role tag (kSubscriber).

◆ kMsgType

template<typename MsgT , SecurityType SecT = SecurityType::kWithoutSecurity>

constexpr Serializer::Type vlink::Subscriber< MsgT, SecT >::kMsgType = Serializer::get_type_of<MsgT>()

staticconstexpr

Codec resolved from MsgT.

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

include/vlink/subscriber.h
include/vlink/internal/subscriber-inl.h

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Additional Inherited Members

Detailed Description

template<typename MsgT, SecurityType SecT = SecurityType::kWithoutSecurity> class vlink::Subscriber< MsgT, SecT >

Member Typedef Documentation

◆ MsgCallback

◆ SharedPtr

◆ UniquePtr

Constructor & Destructor Documentation

◆ Subscriber() [1/2]

◆ Subscriber() [2/2]

Member Function Documentation

◆ create_shared()

◆ create_unique()

◆ get_latency()

◆ get_lost()

◆ is_latency_and_lost_enabled()

◆ listen()

◆ mark_as_getter()

◆ set_latency_and_lost_enabled()

◆ set_manual_unloan()

Member Data Documentation

◆ kImplType

◆ kMsgType

template<typename MsgT, SecurityType SecT = SecurityType::kWithoutSecurity>
class vlink::Subscriber< MsgT, SecT >