2 files changed, 278 insertions, 0 deletions
diff --git a/karyons_p2p/src/peer/mod.rs b/karyons_p2p/src/peer/mod.rs
new file mode 100644
index 0000000..ee0fdc4
--- /dev/null
+++ b/karyons_p2p/src/peer/mod.rs
@@ -0,0 +1,237 @@
+mod peer_id;
+
+pub use peer_id::PeerID;
+
+use std::sync::Arc;
+
+use log::{error, trace};
+use smol::{
+    channel::{self, Receiver, Sender},
+    lock::RwLock,
+};
+
+use karyons_core::{
+    async_utils::{select, Either, TaskGroup, TaskResult},
+    event::{ArcEventSys, EventListener, EventSys},
+    utils::{decode, encode},
+    Executor,
+};
+
+use karyons_net::Endpoint;
+
+use crate::{
+    io_codec::{CodecMsg, IOCodec},
+    message::{NetMsgCmd, ProtocolMsg, ShutdownMsg},
+    net::ConnDirection,
+    peer_pool::{ArcPeerPool, WeakPeerPool},
+    protocol::{Protocol, ProtocolEvent, ProtocolID},
+    Config, Error, Result,
+};
+
+pub type ArcPeer = Arc<Peer>;
+
+pub struct Peer {
+    /// Peer's ID
+    id: PeerID,
+
+    /// A weak pointer to `PeerPool`
+    peer_pool: WeakPeerPool,
+
+    /// Holds the IOCodec for the peer connection
+    io_codec: IOCodec,
+
+    /// Remote endpoint for the peer
+    remote_endpoint: Endpoint,
+
+    /// The direction of the connection, either `Inbound` or `Outbound`
+    conn_direction: ConnDirection,
+
+    /// A list of protocol IDs
+    protocol_ids: RwLock<Vec<ProtocolID>>,
+
+    /// `EventSys` responsible for sending events to the protocols.
+    protocol_events: ArcEventSys<ProtocolID>,
+
+    /// This channel is used to send a stop signal to the read loop.
+    stop_chan: (Sender<Result<()>>, Receiver<Result<()>>),
+
+    /// Managing spawned tasks.
+    task_group: TaskGroup,
+}
+
+impl Peer {
+    /// Creates a new peer
+    pub fn new(
+        peer_pool: WeakPeerPool,
+        id: &PeerID,
+        io_codec: IOCodec,
+        remote_endpoint: Endpoint,
+        conn_direction: ConnDirection,
+    ) -> ArcPeer {
+        Arc::new(Peer {
+            id: id.clone(),
+            peer_pool,
+            io_codec,
+            protocol_ids: RwLock::new(Vec::new()),
+            remote_endpoint,
+            conn_direction,
+            protocol_events: EventSys::new(),
+            task_group: TaskGroup::new(),
+            stop_chan: channel::bounded(1),
+        })
+    }
+
+    /// Run the peer
+    pub async fn run(self: Arc<Self>, ex: Executor<'_>) -> Result<()> {
+        self.start_protocols(ex.clone()).await;
+        self.read_loop().await
+    }
+
+    /// Send a message to the peer connection using the specified protocol.
+    pub async fn send<T: CodecMsg>(&self, protocol_id: &ProtocolID, msg: &T) -> Result<()> {
+        let payload = encode(msg)?;
+
+        let proto_msg = ProtocolMsg {
+            protocol_id: protocol_id.to_string(),
+            payload: payload.to_vec(),
+        };
+
+        self.io_codec.write(NetMsgCmd::Protocol, &proto_msg).await?;
+        Ok(())
+    }
+
+    /// Broadcast a message to all connected peers using the specified protocol.
+    pub async fn broadcast<T: CodecMsg>(&self, protocol_id: &ProtocolID, msg: &T) {
+        self.peer_pool().broadcast(protocol_id, msg).await;
+    }
+
+    /// Shuts down the peer
+    pub async fn shutdown(&self) {
+        trace!("peer {} start shutting down", self.id);
+
+        // Send shutdown event to all protocols
+        for protocol_id in self.protocol_ids.read().await.iter() {
+            self.protocol_events
+                .emit_by_topic(protocol_id, &ProtocolEvent::Shutdown)
+                .await;
+        }
+
+        // Send a stop signal to the read loop
+        //
+        // No need to handle the error here; a dropped channel and
+        // sending a stop signal have the same effect.
+        let _ = self.stop_chan.0.try_send(Ok(()));
+
+        // No need to handle the error here
+        let _ = self
+            .io_codec
+            .write(NetMsgCmd::Shutdown, &ShutdownMsg(0))
+            .await;
+
+        // Force shutting down
+        self.task_group.cancel().await;
+    }
+
+    /// Check if the connection is Inbound
+    #[inline]
+    pub fn is_inbound(&self) -> bool {
+        match self.conn_direction {
+            ConnDirection::Inbound => true,
+            ConnDirection::Outbound => false,
+        }
+    }
+
+    /// Returns the direction of the connection, which can be either `Inbound`
+    /// or `Outbound`.
+    #[inline]
+    pub fn direction(&self) -> &ConnDirection {
+        &self.conn_direction
+    }
+
+    /// Returns the remote endpoint for the peer
+    #[inline]
+    pub fn remote_endpoint(&self) -> &Endpoint {
+        &self.remote_endpoint
+    }
+
+    /// Return the peer's ID
+    #[inline]
+    pub fn id(&self) -> &PeerID {
+        &self.id
+    }
+
+    /// Returns the `Config` instance.
+    pub fn config(&self) -> Arc<Config> {
+        self.peer_pool().config.clone()
+    }
+
+    /// Registers a listener for the given Protocol `P`.
+    pub async fn register_listener<P: Protocol>(&self) -> EventListener<ProtocolID, ProtocolEvent> {
+        self.protocol_events.register(&P::id()).await
+    }
+
+    /// Start a read loop to handle incoming messages from the peer connection.
+    async fn read_loop(&self) -> Result<()> {
+        loop {
+            let fut = select(self.stop_chan.1.recv(), self.io_codec.read()).await;
+            let result = match fut {
+                Either::Left(stop_signal) => {
+                    trace!("Peer {} received a stop signal", self.id);
+                    return stop_signal?;
+                }
+                Either::Right(result) => result,
+            };
+
+            let msg = result?;
+
+            match msg.header.command {
+                NetMsgCmd::Protocol => {
+                    let msg: ProtocolMsg = decode(&msg.payload)?.0;
+
+                    if !self.protocol_ids.read().await.contains(&msg.protocol_id) {
+                        return Err(Error::UnsupportedProtocol(msg.protocol_id));
+                    }
+
+                    let proto_id = &msg.protocol_id;
+                    let msg = ProtocolEvent::Message(msg.payload);
+                    self.protocol_events.emit_by_topic(proto_id, &msg).await;
+                }
+                NetMsgCmd::Shutdown => {
+                    return Err(Error::PeerShutdown);
+                }
+                command => return Err(Error::InvalidMsg(format!("Unexpected msg {:?}", command))),
+            }
+        }
+    }
+
+    /// Start running the protocols for this peer connection.
+    async fn start_protocols(self: &Arc<Self>, ex: Executor<'_>) {
+        for (protocol_id, constructor) in self.peer_pool().protocols.read().await.iter() {
+            trace!("peer {} start protocol {protocol_id}", self.id);
+            let protocol = constructor(self.clone());
+
+            self.protocol_ids.write().await.push(protocol_id.clone());
+
+            let selfc = self.clone();
+            let exc = ex.clone();
+            let proto_idc = protocol_id.clone();
+
+            let on_failure = |result: TaskResult<Result<()>>| async move {
+                if let TaskResult::Completed(res) = result {
+                    if res.is_err() {
+                        error!("protocol {} stopped", proto_idc);
+                    }
+                    // Send a stop signal to read loop
+                    let _ = selfc.stop_chan.0.try_send(res);
+                }
+            };
+
+            self.task_group
+                .spawn(ex.clone(), protocol.start(exc), on_failure);
+        }
+    }
+
+    fn peer_pool(&self) -> ArcPeerPool {
+        self.peer_pool.upgrade().unwrap()
+    }
+}
diff --git a/karyons_p2p/src/peer/peer_id.rs b/karyons_p2p/src/peer/peer_id.rs
new file mode 100644
index 0000000..c8aec7d
--- /dev/null
+++ b/karyons_p2p/src/peer/peer_id.rs
@@ -0,0 +1,41 @@
+use bincode::{Decode, Encode};
+use rand::{rngs::OsRng, RngCore};
+use sha2::{Digest, Sha256};
+
+/// Represents a unique identifier for a peer.
+#[derive(Clone, Debug, Eq, PartialEq, Hash, Decode, Encode)]
+pub struct PeerID(pub [u8; 32]);
+
+impl std::fmt::Display for PeerID {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        let id = self.0[0..8]
+            .iter()
+            .map(|b| format!("{:x}", b))
+            .collect::<Vec<String>>()
+            .join("");
+
+        write!(f, "{}", id)
+    }
+}
+
+impl PeerID {
+    /// Creates a new PeerID.
+    pub fn new(src: &[u8]) -> Self {
+        let mut hasher = Sha256::new();
+        hasher.update(src);
+        Self(hasher.finalize().into())
+    }
+
+    /// Generates a random PeerID.
+    pub fn random() -> Self {
+        let mut id: [u8; 32] = [0; 32];
+        OsRng.fill_bytes(&mut id);
+        Self(id)
+    }
+}
+
+impl From<[u8; 32]> for PeerID {
+    fn from(b: [u8; 32]) -> Self {
+        PeerID(b)
+    }
+}