Implement fmt::Write for TcpSocket.

whitequark · whitequark · commit 6bc6cc7af7ab · 2017-07-30T06:59:01.000Z
diff --git a/README.md b/README.md
@@ -200,9 +200,9 @@ It responds to:
 
   * pings (`ping 192.168.69.1`);
   * UDP packets on port 6969 (`socat stdio udp4-connect:192.168.69.1:6969 <<<"abcdefg"`),
-    where it will respond "yo dawg" to any incoming packet;
+    where it will respond "hello" to any incoming packet;
   * TCP packets on port 6969 (`socat stdio tcp4-connect:192.168.69.1:6969`),
-    where it will respond "yo dawg" to any incoming connection and immediately close it;
+    where it will respond "hello" to any incoming connection and immediately close it;
   * TCP packets on port 6970 (`socat stdio tcp4-connect:192.168.69.1:6970 <<<"abcdefg"`),
     where it will respond with reversed chunks of the input indefinitely.
   * TCP packets on port 6971 (`cat /dev/urandom | socat stdio tcp4-connect:192.168.69.1:6971`),
diff --git a/examples/server.rs b/examples/server.rs
@@ -7,6 +7,7 @@ extern crate smoltcp;
 mod utils;
 
 use std::str;
+use std::fmt::Write;
 use std::time::Instant;
 use smoltcp::Error;
 use smoltcp::wire::{EthernetAddress, IpAddress};
@@ -60,7 +61,7 @@ fn main() {
 
     let mut tcp_6970_active = false;
     loop {
-        // udp:6969: respond "yo dawg"
+        // udp:6969: respond "hello"
         {
             let socket: &mut UdpSocket = sockets.get_mut(udp_handle).as_socket();
             if !socket.is_open() {
@@ -76,25 +77,23 @@ fn main() {
                 Err(_) => None
             };
             if let Some(endpoint) = client {
-                let data = b"yo dawg\n";
+                let data = b"hello\n";
                 debug!("udp:6969 send data: {:?}",
                        str::from_utf8(data.as_ref()).unwrap());
                 socket.send_slice(data, endpoint).unwrap();
             }
         }
 
-        // tcp:6969: respond "yo dawg"
+        // tcp:6969: respond "hello"
         {
             let socket: &mut TcpSocket = sockets.get_mut(tcp1_handle).as_socket();
             if !socket.is_open() {
                 socket.listen(6969).unwrap();
             }
 
             if socket.can_send() {
-                let data = b"yo dawg\n";
-                debug!("tcp:6969 send data: {:?}",
-                       str::from_utf8(data.as_ref()).unwrap());
-                socket.send_slice(data).unwrap();
+                debug!("tcp:6969 send greeting");
+                write!(socket, "hello\n");
                 debug!("tcp:6969 close");
                 socket.close();
             }
diff --git a/src/socket/tcp.rs b/src/socket/tcp.rs
@@ -1182,6 +1182,17 @@ impl<'a> TcpSocket<'a> {
     }
 }
 
+impl<'a> fmt::Write for TcpSocket<'a> {
+    fn write_str(&mut self, slice: &str) -> fmt::Result {
+        let slice = slice.as_bytes();
+        if self.send_slice(slice) == Ok(slice.len()) {
+            Ok(())
+        } else {
+            Err(fmt::Error)
+        }
+    }
+}
+
 impl<'a> IpPayload for TcpRepr<'a> {
     fn buffer_len(&self) -> usize {
         self.buffer_len()
