Make http-imports faster to load, by hinting persistent connection on request.

runtime/bin/builtin.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library builtin;
 import 'dart:io';
 import 'dart:async';
 // import 'root_library'; happens here from C Code
 
 // The root library (aka the script) is imported into this library. The
@@ skipping 61 matching lines @@
 
 
 void _makeHttpRequest(String uri) {
   var _client = new HttpClient();
   _httpRequestResponseCode = 0;
   _httpRequestStatusString = null;
   _httpRequestResponse = null;
   try {
     Uri requestUri = Uri.parse(uri);
     _client.getUrl(requestUri)
-        .then((HttpClientRequest request) => request.close())
+        .then((HttpClientRequest request) {
+          request.persistentConnection = false;
+          return request.close();
+        })
         .then((HttpClientResponse response) {
-          return response
-              .fold(new BytesBuilder(), (b, d) => b..add(d))
-              .then((builder) {
-                _requestCompleted(builder.takeBytes(), response);
-                // This client is only used for a single request. Force closing
-                // it now otherwise we wait around until it times out.

[Ivan Posva, 2014/03/18 12:13:43]

This comment was crucial in understanding why the client had to be closed.
Please restore it.

[Anders Johnsen, 2014/03/18 12:22:33]

No, it was crucial to why we were using `force: true`.

The comment now could be:

  Close the client to stop any timers currently held alive.

-                _client.close(force:true);
-              });
+          // Only create a ByteBuilder, if multiple chunks is received.

[floitsch, 2014/03/18 12:26:24]

are received.

[Anders Johnsen, 2014/03/18 12:33:24]

Done.

+          var bufferOrBuilder;
+          response.listen(
+            (data) {
+              if (bufferOrBuilder == null) {
+                bufferOrBuilder = data;
+              } else {
+                if (bufferOrBuilder is! BytesBuilder) {
+                  bufferOrBuilder = new BytesBuilder()
+                      ..add(bufferOrBuilder);
+                }
+                bufferOrBuilder.add(data);
+              }
+            },
+            onDone: () {
+              var data = bufferOrBuilder;
+              if (data is BytesBuilder) data = data.takeBytes();
+              _requestCompleted(data, response);
+              _client.close();
+            },
+            onError: _requestFailed);
         }).catchError((error) {
           _requestFailed(error);
         });
   } catch (error) {
     _requestFailed(error);
   }
   // TODO(floitsch): remove this line. It's just here to push an event on the
   // event loop so that we invoke the scheduled microtasks. Also remove the
   // import of dart:async when this line is not needed anymore.
   Timer.run(() {});
@@ skipping 197 matching lines @@
   } else if (Platform.isWindows) {
     filename = '$name.dll';
   } else {
     _logResolution(
         'Native extensions not supported on ${Platform.operatingSystem}');
     throw 'Native extensions not supported on ${Platform.operatingSystem}';
   }
 
   return [path, filename, name];
 }