events, observers & happy new year 🎆

crates/livekit-utils/Cargo.toml

@@ -6,3 +6,5 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+parking_lot = "0.12.1"
+tokio = { version = "1", features = ["full"] }

crates/livekit-utils/src/lib.rs

@@ -1 +1,2 @@
 pub mod enum_dispatch;
+pub mod observer;

crates/livekit-utils/src/observer.rs

@@ -0,0 +1,39 @@
+// Really basic implementation of the observer pattern using mpsc channels.
+// Currently unbounded channels
+
+use tokio::sync::mpsc;
+
+#[derive(Debug)]
+pub struct Dispatcher<T>
+where
+    T: Clone,
+{
+    senders: Vec<mpsc::UnboundedSender<T>>,
+}
+
+impl<T> Default for Dispatcher<T>
+where
+    T: Clone,
+{
+    fn default() -> Self {
+        Self {
+            senders: Default::default(),
+        }
+    }
+}
+
+impl<T> Dispatcher<T>
+where
+    T: Clone,
+{
+    pub fn register(&mut self) -> mpsc::UnboundedReceiver<T> {
+        let (tx, rx) = mpsc::unbounded_channel();
+        self.senders.push(tx);
+        rx
+    }
+
+    pub fn dispatch(&mut self, msg: &T) {
+        self.senders
+            .retain(|sender| sender.send(msg.clone()).is_err());
+    }
+}