Don't report unuseful SocketIOExceptions on HttpServer.

sdk/lib/io/http_impl.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 class _HttpIncoming extends Stream<List<int>> {
   final int _transferLength;
   final Completer _dataCompleter = new Completer();
   Stream<List<int>> _stream;
@@ skipping 524 matching lines @@
   void _writeHeader();  // TODO(ajohnsen): Better name.
 }
 
 
 class _HttpOutboundConsumer implements StreamConsumer {
   final _HttpOutboundMessage _outbound;
   StreamController _controller;
   StreamSubscription _subscription;
   Completer _closeCompleter = new Completer();
   Completer _completer;
+  bool _socketError = false;
 
   _HttpOutboundConsumer(_HttpOutboundMessage this._outbound);
 
-  void _onPause() {
-    if (_controller.isPaused) {
-      _subscription.pause();
-    } else {
-      _subscription.resume();
-    }
-  }
-
-  void _onListen() {
-    if (!_controller.hasListener && _subscription != null) {
+  void _cancel() {
+    if (_subscription != null) {
       _subscription.cancel();
     }
   }
 
   _ensureController() {
     if (_controller != null) return;
-    _controller = new StreamController(onPause: _onPause,
-                                       onResume: _onPause,
-                                       onListen: _onListen,
-                                       onCancel: _onListen);
+    _controller = new StreamController(onPause: () => _subscription.pause(),
+                                       onResume: () => _subscription.resume(),
+                                       onCancel: _cancel);
     _outbound._addStream(_controller.stream)
         .then((_) {
-                _onListen();  // Make sure we unsubscribe.
+                _cancel();
                 _done();
                 _closeCompleter.complete(_outbound);
               },
               onError: (error) {
-                if (!_done(error)) {
-                  _closeCompleter.completeError(error);
+                _socketError = true;
+                if (error is SocketIOException &&
+                    _outbound is HttpResponse) {
+                  _cancel();
+                  _done();
+                  _closeCompleter.complete(_outbound);
+                } else {
+                  if (!_done(error)) {
+                    _closeCompleter.completeError(error);
+                  }
                 }
               });
   }
 
   bool _done([error]) {
     if (_completer == null) return false;
     if (error != null) {
       _completer.completeError(error);
     } else {
       _completer.complete(_outbound);
     }
     _completer = null;
     return true;
   }
 
   Future addStream(var stream) {
-    _ensureController();
+    // If we saw a socket error subscribe and then cancel, to ignore any data
+    // on the stream.
+    if (_socketError) {
+      stream.listen(null).cancel();
+      return new Future.value(_outbound);
+    }
     _completer = new Completer();
     _subscription = stream.listen(
         (data) {
           _controller.add(data);
         },
         onDone: () {
           _done();
         },
         onError: (error) {
           _done(error);
         },
         cancelOnError: true);
+    _ensureController();
     return _completer.future;
   }
 
   Future close() {
     Future closeOutbound() {
+      if (_socketError) return new Future.value(_outbound);
       return _outbound._close().then((_) => _outbound);
     }
     if (_controller == null) return closeOutbound();
     _controller.close();
     return _closeCompleter.future.then((_) => closeOutbound());
   }
 }
 
 
 class _BufferTransformer extends StreamEventTransformer<List<int>, List<int>> {
@@ skipping 1131 matching lines @@
                 destroy();
               });
           response._ignoreBody = request.method == "HEAD";
           response._httpRequest = request;
           _httpServer._handleRequest(request);
         },
         onDone: () {
           destroy();
         },
         onError: (error) {
-          _httpServer._handleError(error);
+          // Ignore failed requests that was closed before headers was received.
           destroy();
         });
   }
 
   void destroy() {
     if (_state == _CLOSING || _state == _DETACHED) return;
     _state = _CLOSING;
     _socket.destroy();
     _httpServer._connectionClosed(this);
   }
@@ skipping 539 matching lines @@
 
 
 class _RedirectInfo implements RedirectInfo {
   const _RedirectInfo(int this.statusCode,
                       String this.method,
                       Uri this.location);
   final int statusCode;
   final String method;
   final Uri location;
 }