http: use FixedQueue for incoming

Author: ronag

lib/_http_server.js

@@ -111,6 +111,7 @@ const {
   startPerf,
   stopPerf,
 } = require('internal/perf/observe');
+const FixedQueue = require('internal/fixed_queue');
 
 const STATUS_CODES = {
   100: 'Continue',                   // RFC 7231 6.2.1
@@ -724,7 +725,7 @@ function connectionListenerInternal(server, socket) {
     onClose: null,
     onDrain: null,
     outgoing: [],
-    incoming: [],
+    incoming: new FixedQueue(),
     // `outgoingData` is an approximate amount of bytes queued through all
     // inactive responses. If more data than the high watermark is queued - we
     // need to pause TCP socket/HTTP parser, and wait until the data will be
@@ -822,7 +823,7 @@ function socketOnClose(socket, state) {
 }
 
 function abortIncoming(incoming) {
-  while (incoming.length) {
+  while (!incoming.isEmpty()) {
     const req = incoming.shift();
     req.destroy(new ConnResetException('aborted'));
   }
@@ -1003,15 +1004,15 @@ function resOnFinish(req, res, socket, state, server) {
     });
   }
 
+  const head = state.incoming.shift();
+
   // Usually the first incoming element should be our request.  it may
   // be that in the case abortIncoming() was called that the incoming
   // array will be empty.
-  if (state.incoming.length > 0 && state.incoming[0] !== req) {
+  if (head !== null && head !== req) {
     throw new Error('Out of order response finish');
   }
 
-  state.incoming.shift();
-
   // If the user never called req.read(), and didn't pipe() or
   // .resume() or .on('data'), then we call req._dump() so that the
   // bytes will be pulled off the wire.