Add tcp_simple transport crate

unshell-leaves/tcp_simple/src/client/mod.rs

@@ -0,0 +1,44 @@
+use std::{io, net::TcpStream, net::ToSocketAddrs};
+
+use unshell::protocol::{Endpoint, Leaf};
+
+use crate::transport::TcpBridge;
+
+/// TCP client-side transport leaf for one upstream endpoint.
+///
+/// This is the mirror of [`crate::TCPServerLeaf`]: bytes from the connected server
+/// are routed through [`Endpoint::add_inbound_from`], and packets queued for the
+/// parent endpoint are serialized back onto the TCP stream.
+#[derive(Debug)]
+pub struct TCPClientLeaf {
+    bridge: TcpBridge,
+}
+
+impl TCPClientLeaf {
+    /// Connects to an upstream TCP server and registers it as the authority peer.
+    ///
+    /// `parent_endpoint_id` must be the adjacent parent segment in this endpoint's
+    /// path. The connection is made during construction so failed startup is explicit
+    /// instead of being hidden as a permanently idle leaf.
+    pub fn new<A>(connect_addr: A, parent_endpoint_id: u32) -> io::Result<Self>
+    where
+        A: ToSocketAddrs,
+    {
+        let stream = TcpStream::connect(connect_addr)?;
+        let mut bridge = TcpBridge::new(parent_endpoint_id, true);
+        bridge.set_stream(stream)?;
+
+        Ok(Self { bridge })
+    }
+}
+
+impl Leaf for TCPClientLeaf {
+    fn get_id(&self) -> u32 {
+        crate::IDENTIFIER_CLIENT_HASH
+    }
+
+    fn update(&mut self, endpoint: &mut Endpoint) {
+        self.bridge.register(endpoint);
+        self.bridge.update(endpoint);
+    }
+}