Struct Topic

#[repr(align(64))]
pub struct Topic<T> { /* private fields */ }

A message topic that delivers only the latest published message to subscribers.

Implementations

impl<T> Topic<T>

where T: Clone,

pub fn publish(&self, message: T)

Publishes a message to this topic.

Examples

let bus = Bus::<Bytes>::new();
let topic = bus.topic("events");
topic.publish(Bytes::from("Hello, World!"));

pub fn subscribe(self: &Arc<Self>) -> Sub<T>

Creates a new subscriber for this topic.

Subscribers receive only messages published after they subscribe. The subscriber will receive the latest published message and all subsequent messages until it’s dropped.

Examples

let bus = Bus::<String>::new();
let topic = bus.topic("events");
let mut subscriber = topic.subscribe();

pub fn subscriber_count(&self) -> usize

Returns the number of active subscribers.

This count includes all subscribers that haven’t been dropped yet.

Examples

let bus = Bus::<String>::new();
let topic = bus.topic("events");

assert_eq!(topic.subscriber_count(), 0);

let _sub1 = topic.subscribe();
let _sub2 = topic.subscribe();
assert_eq!(topic.subscriber_count(), 2);

pub fn name(&self) -> &str

Returns the topic name.

Examples

let bus = Bus::<String>::new();
let topic = bus.topic("events");

assert_eq!(topic.name(), "events");

pub fn has_subscribers(&self) -> bool

Returns true if the topic has any subscribers.

This is equivalent to topic.subscriber_count() > 0 but more efficient.

Examples

let bus = Bus::<String>::new();
let topic = bus.topic("events");

assert!(!topic.has_subscribers());

let _subscriber = topic.subscribe();
assert!(topic.has_subscribers());

impl Topic<Bytes>

Zero-copy bytes operations for Topics.

pub fn publish_slice(&self, data: &[u8])

Publishes a byte slice to this topic.

This method copies the slice into a Bytes object for publishing. For true zero-copy, use publish_vec with a Vec<u8>.

Arguments

• data - Byte slice to publish

Examples

let bus = Bus::<Bytes>::new();
let topic = bus.topic("events");

let data = b"Hello, World!";
topic.publish_slice(data);

pub fn publish_vec(&self, data: Vec<u8>)

Publishes a Vec<u8> to this topic.

This method provides zero-copy publishing by converting the Vec<u8> directly into a Bytes object without copying the data.

Arguments

• data - Vector of bytes to publish

Examples

let bus = Bus::<Bytes>::new();
let topic = bus.topic("events");

let data = vec![72, 101, 108, 108, 111]; // "Hello"
topic.publish_vec(data);

Trait Implementations

impl<T: Debug> Debug for Topic<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.