vlink::PublisherImpl Class Reference

Transport-agnostic base for publisher node implementations. More...

#include <publisher_impl.h>

Inheritance diagram for vlink::PublisherImpl:

Collaboration diagram for vlink::PublisherImpl:

Public Member Functions
	~PublisherImpl () override
	Destructor.
void	interrupt () override
	Interrupts the publisher, waking any blocked wait_for_subscribers() call.
virtual void	detect_subscribers (ConnectCallback &&callback)
	Registers a callback to be fired when the subscriber presence changes.
virtual bool	wait_for_subscribers (std::chrono::milliseconds timeout)
	Blocks until at least one subscriber is present or the timeout elapses.
virtual bool	has_subscribers () const =0
	Returns true when at least one subscriber is currently connected.
virtual bool	write (const Bytes &msg_data)=0
	Publishes a serialised message to all connected subscribers.
virtual bool	write (const IntraData &intra_data)
	Publishes an in-process zero-copy message.
void	update_subscribers ()
	Notifies the subscriber-detection subsystem that subscriber presence may have changed.
Public Member Functions inherited from vlink::NodeImpl
virtual void	init ()=0
	Initialises the underlying transport channel.
virtual void	deinit ()=0
	Tears down the underlying transport channel.
virtual bool	suspend ()
	Temporarily suspends message delivery without tearing down the channel.
virtual bool	resume ()
	Resumes message delivery after a suspend() call.
virtual bool	is_suspend () const
	Returns true when the node is currently suspended.
virtual bool	is_support_loan () const
	Returns true if the transport supports zero-copy loaning.
virtual Bytes	loan (int64_t size)
	Borrows a write buffer of size bytes from the transport.
virtual bool	return_loan (const Bytes &bytes)
	Returns a previously loaned buffer to the transport.
virtual void	set_manual_unloan (bool manual_unloan)
	Configures manual unloan mode for zero-copy transports.
virtual const struct Conf *	get_conf () const
	Returns a pointer to the associated Conf configuration object.
virtual const AbstractNode *	get_abstract_node () const
	Returns a pointer to the AbstractNode peer (if any).
virtual Status::BasePtr	get_status (Status::Type type) const
	Retrieves a transport-specific status object.
virtual bool	check_version (const Version &version)
	Checks whether version matches the runtime VLink library version.
virtual bool	attach (class MessageLoop *message_loop)
	Attaches the node to a MessageLoop for callback dispatch.
virtual bool	detach ()
	Detaches the node from its MessageLoop.
class MessageLoop *	get_message_loop () const
	Returns the MessageLoop this node is attached to.
template<typename T>
const T *	get_target_conf () const
	Returns a typed pointer to the conf by downcasting to T.
void	register_status_handler (StatusCallback &&callback)
	Registers a callback for DDS status events.
bool	has_register_status () const
	Returns true if a status handler has been registered.
void	call_status (Status::BasePtr ptr)
	Dispatches a status event to the registered status handler.
void	set_property (const std::string &prop, const std::string &value)
	Sets a named transport property on this node.
std::string	get_property (const std::string &prop) const
	Retrieves a named transport property.
Conf::PropertiesMap	get_all_properties () const
	Returns a snapshot of all properties set on this node.
void	set_discovery_enabled (bool enable)
	Enables or disables discovery reporting for this node.
bool	get_discovery_enabled () const
	Returns true if discovery reporting is enabled for this node.
void	set_record_path (const std::string &path)
	Sets the file path for per-node message recording.
void	set_ssl_options (const SslOptions &options)
	Merges SSL/TLS options into the node property map.
void	try_record (ActionType action_type, const Bytes &data)
	Records a message to the global and/or per-node bag writers.
void	reset_interrupted ()
	Clears the interrupted flag set by interrupt().
bool	is_interrupted () const
	Returns true if interrupt() has been called and not yet reset.
void	init_ext ()
	Registers the node with the global DiscoveryReporter.
void	deinit_ext ()
	Deregisters the node from the global DiscoveryReporter.

Protected Member Functions
	PublisherImpl ()
	Protected constructor; initialises the publisher with kPublisher role.
Protected Member Functions inherited from vlink::NodeImpl
	NodeImpl (ImplType type)
virtual	~NodeImpl ()

Additional Inherited Members
Public Types inherited from vlink::NodeImpl
using	ConnectCallback = std::function<void(bool)>
	Callback invoked when the peer connection state changes.
using	StatusCallback = std::function<void(const Status::BasePtr& ptr)>
	Callback invoked on DDS status events (e.g. deadline missed).
using	SyncCallback = std::function<void()>
	Callback invoked when a SetterImpl sync completes.
using	ReqRespCallback = std::function<void(uint64_t, const Bytes&, Bytes*)>
	Callback for ServerImpl request/response processing.
using	MsgCallback = std::function<void(const Bytes&)>
	Callback delivering a raw serialised message to a SubscriberImpl or GetterImpl.
using	IntraMsgCallback = std::function<void(const IntraData&)>
	Callback delivering an in-process IntraData message.
Static Public Member Functions inherited from vlink::NodeImpl
static void	global_init ()
	Initialises process-wide VLink singletons.
Public Attributes inherited from vlink::NodeImpl
std::atomic_bool	has_suspend {false}
	Atomic suspend state flag (currently unused by default impls).
std::string	url
	Full URL string of this node (e.g. "dds://my/topic").
std::string	ser_type
	Serialisation type string (e.g. "demo.proto.PointCloud").
ImplType	impl_type {kUnknownImplType}
	Role of this implementation node.
SchemaType	schema_type {SchemaType::kUnknown}
	Coarse schema family reported to discovery and bag/proxy paths.
TransportType	transport_type {TransportType::kUnknown}
	Transport backend of this implementation node.
bool	is_cdr_type {false}
	true when using DDS native CDR serialisation.
bool	is_security_type {false}
	true when security-authenticated transport is enabled.
bool	is_discovery_enabled {true}
	Whether this node is reported to the discovery layer.
std::unique_ptr< class CpuProfiler >	profiler
	Optional per-node CPU profiler (only when global profiling is on).

Detailed Description

Transport-agnostic base for publisher node implementations.

Provides the subscriber-detection infrastructure (condition variable + callback) used by Publisher<T>::wait_for_subscribers() and Publisher<T>::detect_subscribers(). Concrete backends override has_subscribers() to query the transport layer and call update_subscribers() whenever the subscriber count changes.

Constructor & Destructor Documentation

~PublisherImpl()

vlink::PublisherImpl::~PublisherImpl ( )

override

Destructor.

PublisherImpl()

vlink::PublisherImpl::PublisherImpl ( )

protected

Protected constructor; initialises the publisher with kPublisher role.

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Member Function Documentation

detect_subscribers()

virtual void vlink::PublisherImpl::detect_subscribers ( ConnectCallback && callback )

virtual

Registers a callback to be fired when the subscriber presence changes.

The callback is stored and invoked with true when the first subscriber appears and false when the last one disconnects. If subscribers are already present at registration time the callback is fired immediately with true before this function returns.

Parameters

callback

Callable void(bool) to invoke on subscriber change.

has_subscribers()

virtual bool vlink::PublisherImpl::has_subscribers ( ) const

nodiscardpure virtual

Returns true when at least one subscriber is currently connected.

Must be implemented by each concrete transport backend. Called by wait_for_subscribers() and update_subscribers() to determine whether the subscriber presence state has changed.

Returns

true if one or more subscribers are connected; false otherwise.

interrupt()

void vlink::PublisherImpl::interrupt ( )

overridevirtual

Interrupts the publisher, waking any blocked wait_for_subscribers() call.

Calls NodeImpl::interrupt() to set the interrupted flag, then notify_all() on the internal condition variable so that any thread blocked in wait_for_subscribers() returns immediately with false.

Reimplemented from vlink::NodeImpl.

update_subscribers()

void vlink::PublisherImpl::update_subscribers

(

)

Notifies the subscriber-detection subsystem that subscriber presence may have changed.

Called by the concrete transport backend whenever a subscriber connects or disconnects. Compares the current has_subscribers() result against the cached state; if it differs, the condition variable is notified and the registered ConnectCallback is fired.

Note

This method is intended to be called from the transport's internal discovery thread, not from user code.

wait_for_subscribers()

virtual bool vlink::PublisherImpl::wait_for_subscribers ( std::chrono::milliseconds timeout )

virtual

Blocks until at least one subscriber is present or the timeout elapses.

Returns immediately if has_subscribers() is already true. Otherwise waits on an internal condition variable that is notified by update_subscribers() and interrupt().

• timeout < 0 (e.g. Timeout::kInfinite): waits indefinitely.
• timeout >= 0: returns false if no subscriber arrives within the period.

Parameters

timeout

Maximum time to wait; negative value means wait forever.

Returns

true if a subscriber was detected; false on timeout or interruption.

write() [1/2]

virtual bool vlink::PublisherImpl::write ( const Bytes & msg_data )

pure virtual

Publishes a serialised message to all connected subscribers.

Must be implemented by each concrete transport backend. msg_data contains the fully serialised payload produced by Serializer::serialize().

Parameters

msg_data

Serialised message bytes to transmit.

Returns

true if the message was delivered (or queued) successfully; false on error.

write() [2/2]

virtual bool vlink::PublisherImpl::write ( const IntraData & intra_data )

virtual

Publishes an in-process zero-copy message.

Used exclusively on the intra:// transport to pass IntraData directly to subscribers in the same process without serialisation. The default implementation logs a warning and returns false; only IntraPublisherImpl overrides this method.

Parameters

intra_data

Shared pointer to the in-process message payload.

Returns

true if the message was delivered; false if this transport does not support IntraData.

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

• include/vlink/impl/publisher_impl.h