Improve the handling of HTTP requests with empty body

sdk/lib/io/http_parser.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.
 
 // Global constants.
 class _Const {
   // Bytes for "HTTP".
   static const HTTP = const [72, 84, 84, 80];
   // Bytes for "HTTP/1.".
   static const HTTP1DOT = const [72, 84, 84, 80, 47, 49, 46];
@@ skipping 308 matching lines @@
               if (byte == _CharCode.CR || byte == _CharCode.LF) {
                 throw new HttpParserException("Invalid response reason phrase");
               }
               _uri_or_reason_phrase.add(byte);
             }
             break;
 
           case _State.RESPONSE_LINE_ENDING:
             _expect(byte, _CharCode.LF);
             _messageType == _MessageType.RESPONSE;
-             _statusCode = parseInt(new String.fromCharCodes(_method_or_status_code));
+             _statusCode = parseInt(
+                 new String.fromCharCodes(_method_or_status_code));
             if (_statusCode < 100 || _statusCode > 599) {
               throw new HttpParserException("Invalid response status code");
-            } else {
-              // Check whether this response will never have a body.
-              _noMessageBody =
-                  _statusCode <= 199 || _statusCode == 204 || _statusCode == 304;
             }
             _state = _State.HEADER_START;
             break;
 
           case _State.HEADER_START:
             if (byte == _CharCode.CR) {
               _state = _State.HEADER_ENDING;
             } else {
               // Start of new header field.
               _headerField.add(_toLowerCase(byte));
@@ skipping 90 matching lines @@
             // Transfer-Encoding the message must not have a body (RFC
             // 2616 section 4.3).
             if (_messageType == _MessageType.REQUEST &&
                 _contentLength < 0 &&
                 _chunked == false) {
               _contentLength = 0;
             }
             if (_connectionUpgrade) {
               _state = _State.UPGRADED;
             }
+            var noBody;
             if (_requestParser) {
+              noBody = _contentLength == 0;
               requestStart(new String.fromCharCodes(_method_or_status_code),
                            new String.fromCharCodes(_uri_or_reason_phrase),
                            version,
-                           _headers);
+                           _headers,
+                           !noBody);
             } else {
+              // Check whether this response will never have a body.
+              noBody = _contentLength == 0 ||
+                       _statusCode <= 199 ||
+                       _statusCode == HttpStatus.NO_CONTENT ||
+                       _statusCode == HttpStatus.NOT_MODIFIED ||
+                       _responseToMethod == "HEAD";
               responseStart(_statusCode,
                             new String.fromCharCodes(_uri_or_reason_phrase),
                             version,
-                            _headers);
+                            _headers,
+                            !noBody);
             }
-            if (_state == _State.CANCELED) continue;
             _method_or_status_code.clear();
             _uri_or_reason_phrase.clear();
+            if (_state == _State.CANCELED) continue;
             if (!_connectionUpgrade) {
-              _method_or_status_code.clear();
-              _uri_or_reason_phrase.clear();
-              if (_chunked) {
+              if (noBody) {
+                _bodyEnd();
+                _reset();
+              } else if (_chunked) {
                 _state = _State.CHUNK_SIZE;
                 _remainingContent = 0;
-              } else if (_contentLength == 0 ||
-                         (_messageType == _MessageType.RESPONSE &&
-                          (_noMessageBody || _responseToMethod == "HEAD"))) {
-                // If there is no message body get ready to process the
-                // next request.
-                _bodyEnd();
-                if (_state == _State.CANCELED) continue;
-                _reset();
               } else if (_contentLength > 0) {
                 _remainingContent = _contentLength;
                 _state = _State.BODY;
               } else {
                 // Neither chunked nor content length. End of body
                 // indicated by close.
                 _state = _State.BODY;
               }
             }
             break;
@@ skipping 200 matching lines @@
     _headerValue = new List();
     _method_or_status_code = new List();
     _uri_or_reason_phrase = new List();
 
     _httpVersion = _HttpVersion.UNDETERMINED;
     _contentLength = -1;
     _persistentConnection = false;
     _connectionUpgrade = false;
     _chunked = false;
 
-    _noMessageBody = false;
     _responseToMethod = null;
     _remainingContent = null;
 
     _headers = new _HttpHeaders();
   }
 
   _releaseBuffer() {
     _buffer = null;
     _index = null;
     _lastIndex = null;
@@ skipping 59 matching lines @@
   List _uri_or_reason_phrase;
   List _headerField;
   List _headerValue;
 
   int _httpVersion;
   int _contentLength;
   bool _persistentConnection;
   bool _connectionUpgrade;
   bool _chunked;
 
-  bool _noMessageBody;
   String _responseToMethod;  // Indicates the method used for the request.
   int _remainingContent;
 
   _HttpHeaders _headers = new _HttpHeaders();
 
   // Callbacks.
   Function requestStart;
   Function responseStart;
   Function dataReceived;
   Function dataEnd;
   Function error;
   Function closed;
 }
 
 
 class HttpParserException implements Exception {
   const HttpParserException([String this.message = ""]);
   String toString() => "HttpParserException: $message";
   final String message;
 }