WIP

src/proto/settings.rs

@@ -0,0 +1,108 @@
+use ConnectionError;
+use frame::{self, Frame};
+
+use futures::*;
+
+pub struct Settings<T> {
+    inner: T,
+    // Our settings
+    local: frame::SettingSet,
+    // Peer settings
+    remote: frame::SettingSet,
+    // Number of acks remaining to send to the peer
+    remaining_acks: usize,
+    // True when the local settings must be flushed to the remote
+    is_dirty: bool,
+}
+
+impl<T> Settings<T>
+    where T: Stream<Item = Frame, Error = ConnectionError>,
+          T: Sink<SinkItem = Frame, SinkError = ConnectionError>,
+{
+    pub fn new(inner: T) -> Settings<T> {
+        Settings {
+            inner: inner,
+            local: frame::SettingSet::default(),
+            remote: frame::SettingSet::default(),
+            remaining_acks: 0,
+            // Always start in the dirty state as sending the settings frame is
+            // part of the connection handshake
+            is_dirty: true,
+        }
+    }
+
+    fn has_pending_sends(&self) -> bool {
+        self.is_dirty || self.remaining_acks > 0
+    }
+
+    fn try_send_pending(&mut self) -> Poll<(), ConnectionError> {
+        if self.is_dirty {
+            // Create the new frame
+            let frame = frame::Settings::new(self.local.clone()).into();
+            try_ready!(self.try_send(frame));
+
+            self.is_dirty = false;
+        }
+
+        unimplemented!();
+    }
+
+    fn try_send(&mut self, item: frame::Frame) -> Poll<(), ConnectionError> {
+        if let AsyncSink::NotReady(_) = try!(self.inner.start_send(item)) {
+            // Ensure that call to `poll_complete` guarantee is called to satisfied
+            try!(self.inner.poll_complete());
+
+            return Ok(Async::NotReady);
+        }
+
+        Ok(Async::Ready(()))
+    }
+}
+
+impl<T> Stream for Settings<T>
+    where T: Stream<Item = Frame, Error = ConnectionError>,
+          T: Sink<SinkItem = Frame, SinkError = ConnectionError>,
+{
+    type Item = Frame;
+    type Error = ConnectionError;
+
+    fn poll(&mut self) -> Poll<Option<Frame>, ConnectionError> {
+        self.inner.poll()
+    }
+}
+
+impl<T> Sink for Settings<T>
+    where T: Stream<Item = Frame, Error = ConnectionError>,
+          T: Sink<SinkItem = Frame, SinkError = ConnectionError>,
+{
+    type SinkItem = Frame;
+    type SinkError = ConnectionError;
+
+    fn start_send(&mut self, item: Frame) -> StartSend<Frame, ConnectionError> {
+        // Settings frames take priority, so `item` cannot be sent if there are
+        // any pending acks OR the local settings have been changed w/o sending
+        // an associated frame.
+        if self.has_pending_sends() {
+            // Try to flush them
+            try!(self.poll_complete());
+
+            if self.has_pending_sends() {
+                return Ok(AsyncSink::NotReady(item));
+            }
+        }
+
+        self.inner.start_send(item)
+    }
+
+    fn poll_complete(&mut self) -> Poll<(), ConnectionError> {
+        self.inner.poll_complete()
+    }
+
+    fn close(&mut self) -> Poll<(), ConnectionError> {
+        if self.has_pending_sends() {
+            try_ready!(self.poll_complete());
+        }
+
+        self.inner.close()
+    }
+}