feat(server): add upgrade support to lower-level Connection API (#1459)

Closes #1323

src/proto/h1/conn.rs

@@ -500,6 +500,8 @@ where I: AsyncRead + AsyncWrite,
             Ok(encoder) => {
                 if !encoder.is_eof() {
                     Writing::Body(encoder)
+                } else if encoder.is_last() {
+                    Writing::Closed
                 } else {
                     Writing::KeepAlive
                 }
@@ -566,7 +568,11 @@ where I: AsyncRead + AsyncWrite,
                     self.io.buffer(encoded);
 
                     if encoder.is_eof() {
-                        Writing::KeepAlive
+                        if encoder.is_last() {
+                            Writing::Closed
+                        } else {
+                            Writing::KeepAlive
+                        }
                     } else {
                         return Ok(AsyncSink::Ready);
                     }
@@ -577,7 +583,11 @@ where I: AsyncRead + AsyncWrite,
                             if let Some(end) = end {
                                 self.io.buffer(end);
                             }
-                            Writing::KeepAlive
+                            if encoder.is_last() {
+                                Writing::Closed
+                            } else {
+                                Writing::KeepAlive
+                            }
                         },
                         Err(_not_eof) => Writing::Closed,
                     }

src/proto/h1/encode.rs

@@ -9,6 +9,7 @@ use iovec::IoVec;
 #[derive(Debug, Clone)]
 pub struct Encoder {
     kind: Kind,
+    is_last: bool,
 }
 
 #[derive(Debug)]
@@ -43,22 +44,22 @@ enum BufKind<B> {
 }
 
 impl Encoder {
-    pub fn chunked() -> Encoder {
+    fn new(kind: Kind) -> Encoder {
         Encoder {
-            kind: Kind::Chunked,
+            kind: kind,
+            is_last: false,
         }
     }
+    pub fn chunked() -> Encoder {
+        Encoder::new(Kind::Chunked)
+    }
 
     pub fn length(len: u64) -> Encoder {
-        Encoder {
-            kind: Kind::Length(len),
-        }
+        Encoder::new(Kind::Length(len))
     }
 
     pub fn eof() -> Encoder {
-        Encoder {
-            kind: Kind::Eof,
-        }
+        Encoder::new(Kind::Eof)
     }
 
     pub fn is_eof(&self) -> bool {
@@ -68,6 +69,14 @@ impl Encoder {
         }
     }
 
+    pub fn set_last(&mut self) {
+        self.is_last = true;
+    }
+
+    pub fn is_last(&self) -> bool {
+        self.is_last
+    }
+
     pub fn end<B>(&self) -> Result<Option<EncodedBuf<B>>, NotEof> {
         match self.kind {
             Kind::Length(0) => Ok(None),

src/proto/h1/role.rs

@@ -132,7 +132,11 @@ where
         // replying with the latter status code response.
         let ret = if ::StatusCode::SwitchingProtocols == head.subject {
             T::on_encode_upgrade(&mut head)
-                .map(|_| Server::set_length(&mut head, has_body, method.as_ref()))
+                .map(|_| {
+                    let mut enc = Server::set_length(&mut head, has_body, method.as_ref());
+                    enc.set_last();
+                    enc
+                })
         } else if head.subject.is_informational() {
             error!("response with 1xx status code not supported");
             head = MessageHead::default();