1 files changed, 81 insertions, 0 deletions
diff --git a/third_party/rust/tokio-uds/src/send_dgram.rs b/third_party/rust/tokio-uds/src/send_dgram.rs
new file mode 100644
index 0000000000..59d438b761
--- /dev/null
+++ b/third_party/rust/tokio-uds/src/send_dgram.rs
@@ -0,0 +1,81 @@
+use UnixDatagram;
+
+use futures::{Async, Future, Poll};
+
+use std::io;
+use std::mem;
+use std::path::Path;
+
+/// A future for writing a buffer to a Unix datagram socket.
+#[derive(Debug)]
+pub struct SendDgram<T, P> {
+    st: State<T, P>,
+}
+
+#[derive(Debug)]
+enum State<T, P> {
+    /// current state is Sending
+    Sending {
+        /// the underlying socket
+        sock: UnixDatagram,
+        /// the buffer to send
+        buf: T,
+        /// the destination
+        addr: P,
+    },
+    /// neutral state
+    Empty,
+}
+
+impl<T, P> SendDgram<T, P>
+where
+    T: AsRef<[u8]>,
+    P: AsRef<Path>,
+{
+    pub(crate) fn new(sock: UnixDatagram, buf: T, addr: P) -> SendDgram<T, P> {
+        SendDgram {
+            st: State::Sending {
+                sock,
+                buf,
+                addr,
+            }
+        }
+    }
+}
+
+impl<T, P> Future for SendDgram<T, P>
+where
+    T: AsRef<[u8]>,
+    P: AsRef<Path>,
+{
+    /// Returns the underlying socket and the buffer that was sent.
+    type Item = (UnixDatagram, T);
+    /// The error that is returned when sending failed.
+    type Error = io::Error;
+
+    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+        if let State::Sending {
+            ref mut sock,
+            ref buf,
+            ref addr,
+        } = self.st
+        {
+            let n = try_ready!(sock.poll_send_to(buf.as_ref(), addr));
+            if n < buf.as_ref().len() {
+                return Err(io::Error::new(
+                    io::ErrorKind::Other,
+                    "Couldn't send whole buffer".to_string(),
+                ));
+            }
+        } else {
+            panic!()
+        }
+        if let State::Sending { sock, buf, addr: _ } =
+            mem::replace(&mut self.st, State::Empty)
+        {
+            Ok(Async::Ready((sock, buf)))
+        } else {
+            panic!()
+        }
+    }
+}