Struct Property 

pub struct Property<T: Clone + Send + Sync + 'static> { /* private fields */ }

A value you can .get() or .watch() for changes.

let volume = device.volume.get();

let mut changes = device.volume.watch();
while let Some(vol) = changes.next().await {
    println!("{vol:?}");
}

Implementations

impl<T: Clone + Send + Sync + 'static> Property<T>

pub fn replace(&self, new_value: T)

Unconditional set. Always notifies watchers, and doesn’t require PartialEq.

use wayle_core::Property;

let data = Property::new(vec![1, 2, 3]);
data.replace(vec![1, 2, 3]);
// Watchers fire even though the Vec is equal.
// Use `set` instead if you want to skip duplicates.

pub fn get(&self) -> T

Snapshot of the current value (cloned).

use wayle_core::Property;

let name = Property::new(String::from("default"));
assert_eq!(name.get(), "default");

pub fn watch(&self) -> impl Stream<Item = T> + Send + 'static

Yields the current value immediately, then each subsequent change.

Each call returns an independent stream. Multiple consumers can watch the same property concurrently.

use futures::stream::StreamExt;
use wayle_core::Property;

let score = Property::new(0_u32);

let mut stream = score.watch();
while let Some(points) = stream.next().await {
    println!("score: {points}");
}

pub fn has_subscribers(&self) -> bool

Whether any .watch() streams are alive.

pub async fn wait_for_subscribers(&self)

Suspends until at least one consumer calls .watch().

Pair with has_subscribers in a loop to pause expensive work whenever nobody is listening, and resume when someone subscribes again.

use wayle_core::Property;

let cpu_usage = Property::new(0.0_f64);

loop {
    if !cpu_usage.has_subscribers() {
        cpu_usage.wait_for_subscribers().await;
    }

    let usage = 42.0; // poll_cpu();
    cpu_usage.set(usage);
}

Trait Implementations

impl<T: Clone + Clone + Send + Sync + 'static> Clone for Property<T>

fn clone(&self) -> Property<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Clone + Send + Sync + Debug + 'static> Debug for Property<T>

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

Formats the value using the given formatter.

impl<'de, T: Clone + Send + Sync + Deserialize<'de> + 'static> Deserialize<'de> for Property<T>

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T: Clone + Send + Sync + Serialize + 'static> Serialize for Property<T>

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.