Improve the error-propagation on socket streams

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;
 
 // The close queue handles graceful closing of HTTP connections. When
 // a connection is added to the queue it will enter a wait state
 // waiting for all data written and possibly socket shutdown from
 // peer.
@@ skipping 733 matching lines @@
     // Register handlers for socket events. All socket events are
     // passed to the HTTP parser.
     _socket.onData = () {
       List<int> buffer = _socket.read();
       if (buffer != null) {
         _httpParser.streamData(buffer);
       }
     };
     _socket.onClosed = _httpParser.streamDone;
     _socket.onError = _httpParser.streamError;
-    // Ignore errors in the socket output stream as this is getting
-    // the same errors as the socket itself.
-    _socket.outputStream.onError = (e) => null;
+    _socket.outputStream.onError = _httpParser.streamError;
   }
 
   bool _write(List<int> data, [bool copyBuffer = false]);
   bool _writeFrom(List<int> buffer, [int offset, int len]);
   bool _flush();
   bool _close();
   bool _destroy();
   DetachedSocket _detachSocket();
 
   HttpConnectionInfo get connectionInfo {
@@ skipping 102 matching lines @@
     _socket.onError = null;
     _socket.outputStream.onNoPendingWrites = null;
     _writeBufferedResponse();
     Socket socket = _socket;
     _socket = null;
     if (onDetach != null) onDetach();
     return new _DetachedSocket(socket, _httpParser.readUnparsedData());
   }
 
   void _onError(e) {
-    onError(e);
+    // Don't report errors for a request parser when HTTP parser is in
+    // idle state. Clients can close the connection and cause a
+    // connection reset by peer error which is OK.
+    _onClosed();
+    if (_state == _HttpConnectionBase.IDLE) return;
+
     // Propagate the error to the streams.
-    if (_request != null && _request._streamErrorHandler != null) {
+    if (_request != null &&
+        !_isRequestDone &&
+        _request._streamErrorHandler != null) {
       _request._streamErrorHandler(e);
-    }
-    if (_response != null && _response._streamErrorHandler != null) {
+    } else if (_response != null &&
+        !_isResponseDone &&
+        _response._streamErrorHandler != null) {
       _response._streamErrorHandler(e);
+    } else {
+      onError(e);
     }
     if (_socket != null) _socket.close();
   }
 
   void _onRequestReceived(String method,
                           String uri,
                           String version,
                           _HttpHeaders headers,
                           bool hasBody) {
     _state = _HttpConnectionBase.ACTIVE;
@@ skipping 1418 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;
 }