Add support for sending Websocket continuation frames.

src/ws/client.rs

@@ -275,7 +275,7 @@ impl Client {
 
 enum ContinuationOpCode {
     Binary,
-    Text
+    Text,
 }
 
 struct Continuation {
@@ -454,7 +454,10 @@ impl Future for ClientHandshake {
                 max_size: self.max_size,
                 no_masking: self.no_masking,
             },
-            ClientWriter { inner },
+            ClientWriter {
+                inner,
+                continuation: ClientWriterContinuation::Inactive,
+            },
         )))
     }
 }
@@ -495,7 +498,9 @@ impl Stream for ClientReader {
                             let inner = &mut *inner;
                             match inner.continuation {
                                 Some(ref mut continuation) => {
-                                    continuation.buffer.append(&mut Vec::from(payload.as_ref()));
+                                    continuation
+                                        .buffer
+                                        .append(&mut Vec::from(payload.as_ref()));
                                     Ok(Async::NotReady)
                                 }
                                 None => {
@@ -505,14 +510,17 @@ impl Stream for ClientReader {
                             }
                         } else {
                             match inner.continuation.take() {
-                                Some(Continuation {opcode, mut buffer}) => {
+                                Some(Continuation { opcode, mut buffer }) => {
                                     buffer.append(&mut Vec::from(payload.as_ref()));
                                     match opcode {
-                                        ContinuationOpCode::Binary => 
-                                            Ok(Async::Ready(Some(Message::Binary(Binary::from(buffer))))),
+                                        ContinuationOpCode::Binary => Ok(Async::Ready(
+                                            Some(Message::Binary(Binary::from(buffer))),
+                                        )),
                                         ContinuationOpCode::Text => {
                                             match String::from_utf8(buffer) {
-                                                Ok(s) => Ok(Async::Ready(Some(Message::Text(s)))),
+                                                Ok(s) => Ok(Async::Ready(Some(
+                                                    Message::Text(s),
+                                                ))),
                                                 Err(_) => {
                                                     inner.closed = true;
                                                     Err(ProtocolError::BadEncoding)
@@ -549,7 +557,7 @@ impl Stream for ClientReader {
                         } else {
                             inner.continuation = Some(Continuation {
                                 opcode: ContinuationOpCode::Binary,
-                                buffer: Vec::from(payload.as_ref())
+                                buffer: Vec::from(payload.as_ref()),
                             });
                             Ok(Async::NotReady)
                         }
@@ -567,7 +575,7 @@ impl Stream for ClientReader {
                         } else {
                             inner.continuation = Some(Continuation {
                                 opcode: ContinuationOpCode::Text,
-                                buffer: Vec::from(payload.as_ref())
+                                buffer: Vec::from(payload.as_ref()),
                             });
                             Ok(Async::NotReady)
                         }
@@ -584,9 +592,17 @@ impl Stream for ClientReader {
     }
 }
 
+#[derive(PartialEq)]
+enum ClientWriterContinuation {
+    Inactive,
+    Text,
+    Binary,
+}
+
 /// Websocket writer client
 pub struct ClientWriter {
     inner: Rc<RefCell<Inner>>,
+    continuation: ClientWriterContinuation,
 }
 
 impl ClientWriter {
@@ -604,15 +620,68 @@ impl ClientWriter {
     /// Send text frame
     #[inline]
     pub fn text<T: Into<Binary>>(&mut self, text: T) {
+        assert!(
+            self.continuation == ClientWriterContinuation::Inactive,
+            "Cannot send text frame while continuation is active."
+        );
         self.write(Frame::message(text.into(), OpCode::Text, true, true));
     }
 
+    /// Send a part of a text frame.
+    /// The receiver will concatenate all parts when receiving the final
+    /// frame with `finished == true`.
+    #[inline]
+    pub fn text_part<T: Into<Binary>>(&mut self, text: T, finished: bool) {
+        match self.continuation {
+            ClientWriterContinuation::Inactive => {
+                self.write(Frame::message(text.into(), OpCode::Text, finished, true))
+            }
+            ClientWriterContinuation::Text => self.write(Frame::message(
+                text.into(),
+                OpCode::Continue,
+                finished,
+                true,
+            )),
+            _ => panic!("Cannot send text part while binary continuation is active."),
+        };
+        self.continuation = if !finished {
+            ClientWriterContinuation::Text
+        } else {
+            ClientWriterContinuation::Inactive
+        };
+    }
+
     /// Send binary frame
     #[inline]
     pub fn binary<B: Into<Binary>>(&mut self, data: B) {
+        assert!(
+            self.continuation == ClientWriterContinuation::Inactive,
+            "Cannot send binary frame while continuation is active."
+        );
         self.write(Frame::message(data, OpCode::Binary, true, true));
     }
 
+    /// Send a part of a binary frame.
+    /// The receiver will concatenate all parts when receiving the final
+    /// frame with `finished == true`.
+    #[inline]
+    pub fn binary_part<B: Into<Binary>>(&mut self, data: B, finished: bool) {
+        match self.continuation {
+            ClientWriterContinuation::Inactive => {
+                self.write(Frame::message(data, OpCode::Binary, finished, true))
+            }
+            ClientWriterContinuation::Binary => {
+                self.write(Frame::message(data, OpCode::Continue, finished, true))
+            }
+            _ => panic!("Cannot send binary part while text continuation is active."),
+        };
+        self.continuation = if !finished {
+            ClientWriterContinuation::Binary
+        } else {
+            ClientWriterContinuation::Inactive
+        };
+    }
+
     /// Send ping frame
     #[inline]
     pub fn ping(&mut self, message: &str) {