From 20becca336caae61cd24f7afba0e177c0a210c70 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Mon, 9 Apr 2018 11:36:06 +0100
Subject: [PATCH 1/2] read queue of 1 message

---
 tornado/websocket.py | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/tornado/websocket.py b/tornado/websocket.py
index 91c5f1ff9e..b536c3ced9 100644
--- a/tornado/websocket.py
+++ b/tornado/websocket.py
@@ -34,6 +34,7 @@
 from tornado.iostream import StreamClosedError
 from tornado.log import gen_log, app_log
 from tornado import simple_httpclient
+from tornado.queues import Queue
 from tornado.tcpclient import TCPClient
 from tornado.util import _websocket_mask, PY3
 
@@ -1096,8 +1097,7 @@ def __init__(self, request, on_message_callback=None,
         self.compression_options = compression_options
         self.connect_future = Future()
         self.protocol = None
-        self.read_future = None
-        self.read_queue = collections.deque()
+        self.read_queue = Queue(1)
         self.key = base64.b64encode(os.urandom(16))
         self._on_message_callback = on_message_callback
         self.close_code = self.close_reason = None
@@ -1207,12 +1207,8 @@ def read_message(self, callback=None):
         is given it will be called with the future when it is
         ready.
         """
-        assert self.read_future is None
-        future = Future()
-        if self.read_queue:
-            future_set_result_unless_cancelled(future, self.read_queue.popleft())
-        else:
-            self.read_future = future
+
+        future = self.read_queue.get()
         if callback is not None:
             self.io_loop.add_future(future, callback)
         return future
@@ -1220,11 +1216,8 @@ def read_message(self, callback=None):
     def on_message(self, message):
         if self._on_message_callback:
             self._on_message_callback(message)
-        elif self.read_future is not None:
-            future_set_result_unless_cancelled(self.read_future, message)
-            self.read_future = None
         else:
-            self.read_queue.append(message)
+            return self.read_queue.put(message)
 
     def ping(self, data=b''):
         """Send ping frame to the remote end.

From 3f62e7e678de314c28d14978513a470e56b46fbc Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Mon, 9 Apr 2018 13:47:37 +0100
Subject: [PATCH 2/2] Remove unused import

---
 tornado/websocket.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tornado/websocket.py b/tornado/websocket.py
index b536c3ced9..738a9ccb80 100644
--- a/tornado/websocket.py
+++ b/tornado/websocket.py
@@ -19,7 +19,6 @@
 from __future__ import absolute_import, division, print_function
 
 import base64
-import collections
 import hashlib
 import os
 import struct