Increase Window Update size

lib/http2.dart

@@ -42,7 +42,7 @@
 ///
 /// A simple example on how to connect to a http/2 capable server and
 /// requesting a resource is available at https://github.com/dart-lang/http2/blob/master/example/display_headers.dart.
-library http2.http2;
+library;
 
 import 'transport.dart';
 export 'transport.dart';

lib/src/flowcontrol/window.dart

@@ -11,13 +11,20 @@ class Window {
   /// streams is 65535).
   ///
   /// NOTE: This value can potentially become negative.
+  final int _initialSize;
   int _size;
 
-  Window({int initialSize = (1 << 16) - 1}) : _size = initialSize;
+  Window({int initialSize = (1 << 16) - 1})
+      : _size = initialSize,
+        _initialSize = initialSize;
 
   /// The current size of the flow control window.
   int get size => _size;
 
+  bool get isTooSmall => size < _initialSize / 2;
+
+  int get updateSize => _initialSize ~/ 2;
+
   void modify(int difference) {
     _size += difference;
   }

lib/src/flowcontrol/window_handler.dart

@@ -152,11 +152,15 @@ class IncomingWindowHandler {
   //  - either stop sending window update frames
   //  - or decreasing the window size
   void dataProcessed(int numberOfBytes) {
-    _localWindow.modify(numberOfBytes);
-
     // TODO: This can be optimized by delaying the window update to
     // send one update with a bigger difference than multiple small update
     // frames.
-    _frameWriter.writeWindowUpdate(numberOfBytes, streamId: _streamId);
+    if (_localWindow.isTooSmall) {
+      _frameWriter.writeWindowUpdate(
+        _localWindow.updateSize,
+        streamId: _streamId,
+      );
+    }
+    _localWindow.modify(_localWindow.updateSize);
   }
 }

lib/src/frames/frames.dart

@@ -2,7 +2,7 @@
 // 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 http2.src.frames;
+library;
 
 import 'dart:async';
 import 'dart:math' show max;

lib/src/hpack/hpack.dart

@@ -5,7 +5,7 @@
 /// Implements a [HPackContext] for encoding/decoding headers according to the
 /// HPACK specificaiton. See here for more information:
 ///   https://tools.ietf.org/html/draft-ietf-httpbis-header-compression-10
-library http2.hpack;
+library;
 
 import 'dart:convert' show ascii;
 import 'dart:typed_data';

pubspec.yaml

@@ -13,6 +13,6 @@ environment:
 
 dev_dependencies:
   build_runner: ^2.3.0
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   mockito: ^5.3.2
   test: ^1.21.4

test/src/flowcontrol/window_handler_test.dart

@@ -102,7 +102,7 @@ void main() {
       const STREAM_ID = 99;
 
       var fw = FrameWriterMock();
-      var window = Window();
+      var window = Window(initialSize: 150);
       var initialSize = window.size;
       var handler = IncomingWindowHandler.stream(fw, window, STREAM_ID);
 
@@ -112,17 +112,18 @@ void main() {
       // If the remote end sends us now 100 bytes, it reduces the local
       // incoming window by 100 bytes. Once we handled these bytes, it,
       // will send a [WindowUpdateFrame] to the remote peer to ACK it.
-      handler.gotData(100);
-      expect(handler.localWindowSize, initialSize - 100);
-      expect(window.size, initialSize - 100);
+      var numberOfBytes = 100;
+      handler.gotData(numberOfBytes);
+      expect(handler.localWindowSize, initialSize - numberOfBytes);
+      expect(window.size, initialSize - numberOfBytes);
 
       // The data might sit in a queue. Once the user drains enough data of
       // the queue, we will start ACKing the data and the window becomes
       // positive again.
-      handler.dataProcessed(100);
-      expect(handler.localWindowSize, initialSize);
-      expect(window.size, initialSize);
-      verify(fw.writeWindowUpdate(100, streamId: STREAM_ID)).called(1);
+      handler.dataProcessed(numberOfBytes);
+      expect(handler.localWindowSize, 125);
+      expect(window.size, 125);
+      verify(fw.writeWindowUpdate(75, streamId: STREAM_ID)).called(1);
       verifyNoMoreInteractions(fw);
     });
   });