1 files changed, 54 insertions, 0 deletions
diff --git a/src/pipe.rs b/src/pipe.rs
new file mode 100644
index 0000000..09ca580
--- /dev/null
+++ b/src/pipe.rs
@@ -0,0 +1,54 @@
+//! Define an adapter to implement `std::io::Write` on `Sender<Bytes>`.
+use bytes::{Bytes, BytesMut};
+use futures::sink::{Sink, Wait};
+use futures::sync::mpsc::Sender;
+use std::io::{Error, ErrorKind, Result, Write};
+
+/// Adapter to implement the `std::io::Write` trait on a `Sender<Bytes>` from a futures channel.
+///
+/// It uses an intermediate buffer to transfer packets.
+pub struct Pipe {
+    // Wrapping the sender in `Wait` makes it blocking, so we can implement blocking-style
+    // io::Write over the async-style Sender.
+    dest: Wait<Sender<Bytes>>,
+    bytes: BytesMut,
+}
+
+impl Pipe {
+    /// Wrap the given sender in a `Pipe`.
+    pub fn new(destination: Sender<Bytes>) -> Self {
+        Pipe {
+            dest: destination.wait(),
+            bytes: BytesMut::new(),
+        }
+    }
+}
+
+impl Drop for Pipe {
+    fn drop(&mut self) {
+        // This is the correct thing to do, but is not super important since the `Sink`
+        // implementation of `Sender` just returns `Ok` without doing anything else.
+        let _ = self.dest.close();
+    }
+}
+
+impl Write for Pipe {
+    fn write(&mut self, buf: &[u8]) -> Result<usize> {
+        // We are given a slice of bytes we do not own, so we must start by copying it.
+        self.bytes.extend_from_slice(buf);
+
+        // Then, take the buffer and send it in the channel.
+        self.dest
+            .send(self.bytes.take().into())
+            .map_err(|e| Error::new(ErrorKind::UnexpectedEof, e))?;
+
+        // Return how much we sent - all of it.
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> Result<()> {
+        self.dest
+            .flush()
+            .map_err(|e| Error::new(ErrorKind::UnexpectedEof, e))
+    }
+}