car_multi/
mailbox.rs

1//! Async channel-based mailbox for inter-agent messaging.
2
3use crate::error::MultiError;
4use crate::types::Message;
5use std::collections::HashMap;
6use tokio::sync::{mpsc, RwLock};
7
8/// Mailbox provides named channels for agent-to-agent messaging.
9///
10/// Each agent registers by name and gets a receiver. Messages are routed
11/// by the `to` field on the Message.
12pub struct Mailbox {
13    senders: RwLock<HashMap<String, mpsc::Sender<Message>>>,
14    buffer_size: usize,
15}
16
17impl Mailbox {
18    pub fn new(buffer_size: usize) -> Self {
19        Self {
20            senders: RwLock::new(HashMap::new()),
21            buffer_size,
22        }
23    }
24
25    /// Register an agent and return its message receiver.
26    pub async fn register(&self, name: &str) -> mpsc::Receiver<Message> {
27        let (tx, rx) = mpsc::channel(self.buffer_size);
28        self.senders.write().await.insert(name.to_string(), tx);
29        rx
30    }
31
32    /// Send a message to a named agent.
33    pub async fn send(&self, msg: Message) -> Result<(), MultiError> {
34        let senders = self.senders.read().await;
35        let tx = senders
36            .get(&msg.to)
37            .ok_or_else(|| MultiError::MailboxSend(format!("no agent '{}'", msg.to)))?;
38        tx.send(msg)
39            .await
40            .map_err(|e| MultiError::MailboxSend(e.to_string()))
41    }
42
43    /// Broadcast a message to all registered agents.
44    pub async fn broadcast(&self, msg: Message) -> Result<(), MultiError> {
45        let senders = self.senders.read().await;
46        for (name, tx) in senders.iter() {
47            if *name != msg.from {
48                let mut m = msg.clone();
49                m.to = name.clone();
50                let _ = tx.send(m).await;
51            }
52        }
53        Ok(())
54    }
55
56    /// Unregister an agent (drops its sender).
57    pub async fn unregister(&self, name: &str) {
58        self.senders.write().await.remove(name);
59    }
60}
61
62impl Default for Mailbox {
63    fn default() -> Self {
64        Self::new(64)
65    }
66}
car_multi/mailbox.rs

car_multi/
mailbox.rs
