ersa::events::EventBus Class Reference

#include <event_bus.h>

Collaboration diagram for ersa::events::EventBus:

Public Member Functions
	EventBus ()
SubscriptionId	subscribe (EventType type, EventCallback callback, void *userData=nullptr)
SubscriptionId	subscribe (EventType type, IEventListener *listener)
bool	unsubscribe (SubscriptionId id)
void	publish (const Event &event)
bool	post (const Event &event)
size_t	dispatchQueue ()
void	clear ()

Static Public Member Functions
static EventBus &	instance ()

Static Public Attributes
static constexpr size_t	MAX_SUBSCRIBERS = 24
static constexpr size_t	MAX_QUEUE = 32

Private Attributes
Subscription	subscribers_ [MAX_SUBSCRIBERS]
SubscriptionId	nextSubId_ {1}
Event	queue_ [MAX_QUEUE]
size_t	queueHead_ {0}
size_t	queueTail_ {0}
size_t	queueCount_ {0}

Detailed Description

Fixed-memory event distribution for services, HAL adapters, and apps.

publish dispatches synchronously; post copies into a bounded queue for later dispatch by the application task. This split lets interrupt/radio callbacks hand off normalized events without running UI code on their thread, while avoiding heap allocation in the event path.

Constructor & Destructor Documentation

EventBus()

ersa::events::EventBus::EventBus

(

)

Construct an empty bus with an empty queue and fresh subscription IDs.

Member Function Documentation

clear()

void ersa::events::EventBus::clear

(

)

Clear all subscriptions and queued events, primarily for reinitialization/tests.

dispatchQueue()

size_t ersa::events::EventBus::dispatchQueue

(

)

Dispatch queued events in FIFO order and return the number processed.

instance()

EventBus & ersa::events::EventBus::instance ( )

static

Return the process-wide default bus used by system services.

post()

bool ersa::events::EventBus::post

(

const Event &

event

)

Copy an event into the ring queue for later application-task delivery.

Returns

False if the bounded queue is full; callers should handle loss.

publish()

void ersa::events::EventBus::publish

(

const Event &

event

)

Immediately call matching subscribers on the caller's thread.

subscribe() [1/2]

SubscriptionId ersa::events::EventBus::subscribe	(	EventType	type,
		EventCallback	callback,
		void *	userData = nullptr
	)

Register a C-style callback for an event type.

Parameters

type	Event filter; None receives every event.
callback	Function called synchronously during dispatch.
userData	Opaque context forwarded to the callback.

Returns

Nonzero subscription handle, or zero when no slot is available.

subscribe() [2/2]

SubscriptionId ersa::events::EventBus::subscribe	(	EventType	type,
		IEventListener *	listener
	)

Register an object listener for an event type; see callback overload.

unsubscribe()

bool ersa::events::EventBus::unsubscribe

(

SubscriptionId

id

)

Remove a registration by handle; unknown handles return false.

Member Data Documentation

MAX_QUEUE

constexpr size_t ersa::events::EventBus::MAX_QUEUE = 32

staticconstexpr

Maximum queued events awaiting dispatchQueue().

MAX_SUBSCRIBERS

constexpr size_t ersa::events::EventBus::MAX_SUBSCRIBERS = 24

staticconstexpr

Maximum simultaneous callback/listener registrations.

nextSubId_

SubscriptionId ersa::events::EventBus::nextSubId_ {1}

private

queue_

Event ersa::events::EventBus::queue_[MAX_QUEUE]

private

queueCount_

size_t ersa::events::EventBus::queueCount_ {0}

private

queueHead_

size_t ersa::events::EventBus::queueHead_ {0}

private

queueTail_

size_t ersa::events::EventBus::queueTail_ {0}

private

subscribers_

Subscription ersa::events::EventBus::subscribers_[MAX_SUBSCRIBERS]

private

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

• include/ersa/events/event_bus.h
• src/ersa/events/event_bus.cpp