Migrate dart2js stubs for dart:io

tool/input_sdk/lib/io/websocket_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;
+
+const String _webSocketGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+const String _clientNoContextTakeover = "client_no_context_takeover";
+const String _serverNoContextTakeover = "server_no_context_takeover";
+const String _clientMaxWindowBits = "client_max_window_bits";
+const String _serverMaxWindowBits = "server_max_window_bits";
+
+// Matches _WebSocketOpcode.
+class _WebSocketMessageType {
+  static const int NONE = 0;
+  static const int TEXT = 1;
+  static const int BINARY = 2;
+}
+
+class _WebSocketOpcode {
+  static const int CONTINUATION = 0;
+  static const int TEXT = 1;
+  static const int BINARY = 2;
+  static const int RESERVED_3 = 3;
+  static const int RESERVED_4 = 4;
+  static const int RESERVED_5 = 5;
+  static const int RESERVED_6 = 6;
+  static const int RESERVED_7 = 7;
+  static const int CLOSE = 8;
+  static const int PING = 9;
+  static const int PONG = 10;
+  static const int RESERVED_B = 11;
+  static const int RESERVED_C = 12;
+  static const int RESERVED_D = 13;
+  static const int RESERVED_E = 14;
+  static const int RESERVED_F = 15;
+}
+
+/**
+ *  Stores the header and integer value derived from negotiation of
+ *  client_max_window_bits and server_max_window_bits. headerValue will be
+ *  set in the Websocket response headers.
+ */
+class _CompressionMaxWindowBits {
+  String headerValue;
+  int maxWindowBits;
+  _CompressionMaxWindowBits([this.headerValue, this.maxWindowBits]);
+  String toString() => headerValue;
+}
+
+/**
+ * The web socket protocol transformer handles the protocol byte stream
+ * which is supplied through the [:handleData:]. As the protocol is processed,
+ * it'll output frame data as either a List<int> or String.
+ *
+ * Important information about usage: Be sure you use cancelOnError, so the
+ * socket will be closed when the processor encounter an error. Not using it
+ * will lead to undefined behaviour.
+ */
+// TODO(ajohnsen): make this transformer reusable?
+class _WebSocketProtocolTransformer
+    implements StreamTransformer<List<int>, dynamic>, EventSink<Uint8List> {
+  static const int START = 0;
+  static const int LEN_FIRST = 1;
+  static const int LEN_REST = 2;
+  static const int MASK = 3;
+  static const int PAYLOAD = 4;
+  static const int CLOSED = 5;
+  static const int FAILURE = 6;
+  static const int FIN = 0x80;
+  static const int RSV1 = 0x40;
+  static const int RSV2 = 0x20;
+  static const int RSV3 = 0x10;
+  static const int OPCODE = 0xF;
+
+  int _state = START;
+  bool _fin = false;
+  bool _compressed = false;
+  int _opcode = -1;
+  int _len = -1;
+  bool _masked = false;
+  int _remainingLenBytes = -1;
+  int _remainingMaskingKeyBytes = 4;
+  int _remainingPayloadBytes = -1;
+  int _unmaskingIndex = 0;
+  int _currentMessageType = _WebSocketMessageType.NONE;
+  int closeCode = WebSocketStatus.NO_STATUS_RECEIVED;
+  String closeReason = "";
+
+  EventSink _eventSink;
+
+  final bool _serverSide;
+  final List _maskingBytes = new List(4);
+  final BytesBuilder _payload = new BytesBuilder(copy: false);
+
+  _WebSocketPerMessageDeflate _deflate;
+  _WebSocketProtocolTransformer([this._serverSide = false, this._deflate]);
+
+  Stream bind(Stream stream) {
+    return new Stream.eventTransformed(stream, (EventSink eventSink) {
+      if (_eventSink != null) {
+        throw new StateError("WebSocket transformer already used.");
+      }
+      _eventSink = eventSink;
+      return this;
+    });
+  }
+
+  void addError(Object error, [StackTrace stackTrace]) {
+    _eventSink.addError(error, stackTrace);
+  }
+
+  void close() { _eventSink.close(); }
+
+  /**
+   * Process data received from the underlying communication channel.
+   */
+  void add(List<int> bytes) {
+    var buffer = bytes is Uint8List ? bytes : new Uint8List.fromList(bytes);
+    int index = 0;
+    int lastIndex = buffer.length;
+    if (_state == CLOSED) {
+      throw new WebSocketException("Data on closed connection");
+    }
+    if (_state == FAILURE) {
+      throw new WebSocketException("Data on failed connection");
+    }
+    while ((index < lastIndex) && _state != CLOSED && _state != FAILURE) {
+      int byte = buffer[index];
+      if (_state <= LEN_REST) {
+        if (_state == START) {
+          _fin = (byte & FIN) != 0;
+
+          if((byte & (RSV2 | RSV3)) != 0) {
+            // The RSV2, RSV3 bits must both be zero.
+            throw new WebSocketException("Protocol error");
+          }
+
+          _opcode = (byte & OPCODE);
+
+          if (_opcode != _WebSocketOpcode.CONTINUATION) {
+            if ((byte & RSV1) != 0) {
+              _compressed = true;
+            } else {
+              _compressed = false;
+            }
+          }
+
+          if (_opcode <= _WebSocketOpcode.BINARY) {
+            if (_opcode == _WebSocketOpcode.CONTINUATION) {
+              if (_currentMessageType == _WebSocketMessageType.NONE) {
+                throw new WebSocketException("Protocol error");
+              }
+            } else {
+              assert(_opcode == _WebSocketOpcode.TEXT ||
+                  _opcode == _WebSocketOpcode.BINARY);
+              if (_currentMessageType != _WebSocketMessageType.NONE) {
+                throw new WebSocketException("Protocol error");
+              }
+              _currentMessageType = _opcode;
+            }
+          } else if (_opcode >= _WebSocketOpcode.CLOSE &&
+              _opcode <= _WebSocketOpcode.PONG) {
+            // Control frames cannot be fragmented.
+            if (!_fin) throw new WebSocketException("Protocol error");
+          } else {
+            throw new WebSocketException("Protocol error");
+          }
+          _state = LEN_FIRST;
+        } else if (_state == LEN_FIRST) {
+          _masked = (byte & 0x80) != 0;
+          _len = byte & 0x7F;
+          if (_isControlFrame() && _len > 125) {
+            throw new WebSocketException("Protocol error");
+          }
+          if (_len == 126) {
+            _len = 0;
+            _remainingLenBytes = 2;
+            _state = LEN_REST;
+          } else if (_len == 127) {
+            _len = 0;
+            _remainingLenBytes = 8;
+            _state = LEN_REST;
+          } else {
+            assert(_len < 126);
+            _lengthDone();
+          }
+        } else {
+          assert(_state == LEN_REST);
+          _len = _len << 8 | byte;
+          _remainingLenBytes--;
+          if (_remainingLenBytes == 0) {
+            _lengthDone();
+          }
+        }
+      } else {
+        if (_state == MASK) {
+          _maskingBytes[4 - _remainingMaskingKeyBytes--] = byte;
+          if (_remainingMaskingKeyBytes == 0) {
+            _maskDone();
+          }
+        } else {
+          assert(_state == PAYLOAD);
+          // The payload is not handled one byte at a time but in blocks.
+          int payloadLength = min(lastIndex - index, _remainingPayloadBytes);
+          _remainingPayloadBytes -= payloadLength;
+          // Unmask payload if masked.
+          if (_masked) {
+            _unmask(index, payloadLength, buffer);
+          }
+          // Control frame and data frame share _payloads.
+          _payload.add(new Uint8List.view(buffer.buffer, index, payloadLength));
+          index += payloadLength;
+          if (_isControlFrame()) {
+            if (_remainingPayloadBytes == 0) _controlFrameEnd();
+          } else {
+            if (_currentMessageType != _WebSocketMessageType.TEXT &&
+                _currentMessageType != _WebSocketMessageType.BINARY) {
+              throw new WebSocketException("Protocol error");
+            }
+            if (_remainingPayloadBytes == 0) _messageFrameEnd();
+          }
+
+          // Hack - as we always do index++ below.
+          index--;
+        }
+      }
+
+      // Move to the next byte.
+      index++;
+    }
+  }
+
+  void _unmask(int index, int length, Uint8List buffer) {
+    const int BLOCK_SIZE = 16;
+    // Skip Int32x4-version if message is small.
+    if (length >= BLOCK_SIZE) {
+      // Start by aligning to 16 bytes.
+      final int startOffset = BLOCK_SIZE - (index & 15);
+      final int end = index + startOffset;
+      for (int i = index; i < end; i++) {
+        buffer[i] ^= _maskingBytes[_unmaskingIndex++ & 3];
+      }
+      index += startOffset;
+      length -= startOffset;
+      final int blockCount = length ~/ BLOCK_SIZE;
+      if (blockCount > 0) {
+        // Create mask block.
+        int mask = 0;
+        for (int i = 3; i >= 0; i--) {
+          mask = (mask << 8) | _maskingBytes[(_unmaskingIndex + i) & 3];
+        }
+        Int32x4 blockMask = new Int32x4(mask, mask, mask, mask);
+        Int32x4List blockBuffer =
+            new Int32x4List.view(buffer.buffer, index, blockCount);
+        for (int i = 0; i < blockBuffer.length; i++) {
+          blockBuffer[i] ^= blockMask;
+        }
+        final int bytes = blockCount * BLOCK_SIZE;
+        index += bytes;
+        length -= bytes;
+      }
+    }
+    // Handle end.
+    final int end = index + length;
+    for (int i = index; i < end; i++) {
+      buffer[i] ^= _maskingBytes[_unmaskingIndex++ & 3];
+    }
+  }
+
+  void _lengthDone() {
+    if (_masked) {
+      if (!_serverSide) {
+        throw new WebSocketException("Received masked frame from server");
+      }
+      _state = MASK;
+    } else {
+      if (_serverSide) {
+        throw new WebSocketException("Received unmasked frame from client");
+      }
+      _remainingPayloadBytes = _len;
+      _startPayload();
+    }
+  }
+
+  void _maskDone() {
+    _remainingPayloadBytes = _len;
+    _startPayload();
+  }
+
+  void _startPayload() {
+    // If there is no actual payload perform perform callbacks without
+    // going through the PAYLOAD state.
+    if (_remainingPayloadBytes == 0) {
+      if (_isControlFrame()) {
+        switch (_opcode) {
+          case _WebSocketOpcode.CLOSE:
+            _state = CLOSED;
+            _eventSink.close();
+            break;
+          case _WebSocketOpcode.PING:
+            _eventSink.add(new _WebSocketPing());
+            break;
+          case _WebSocketOpcode.PONG:
+            _eventSink.add(new _WebSocketPong());
+            break;
+        }
+        _prepareForNextFrame();
+      } else {
+        _messageFrameEnd();
+      }
+    } else {
+      _state = PAYLOAD;
+    }
+  }
+
+  void _messageFrameEnd() {
+    if (_fin) {
+      var bytes = _payload.takeBytes();
+      if (_deflate != null && _compressed) {
+        bytes = _deflate.processIncomingMessage(bytes);
+      }
+
+      switch (_currentMessageType) {
+        case _WebSocketMessageType.TEXT:
+          _eventSink.add(UTF8.decode(bytes));
+          break;
+        case _WebSocketMessageType.BINARY:
+          _eventSink.add(bytes);
+          break;
+      }
+      _currentMessageType = _WebSocketMessageType.NONE;
+    }
+    _prepareForNextFrame();
+  }
+
+  void _controlFrameEnd() {
+    switch (_opcode) {
+      case _WebSocketOpcode.CLOSE:
+        closeCode = WebSocketStatus.NO_STATUS_RECEIVED;
+        var payload = _payload.takeBytes();
+        if (payload.length > 0) {
+          if (payload.length == 1) {
+            throw new WebSocketException("Protocol error");
+          }
+          closeCode = payload[0] << 8 | payload[1];
+          if (closeCode == WebSocketStatus.NO_STATUS_RECEIVED) {
+            throw new WebSocketException("Protocol error");
+          }
+          if (payload.length > 2) {
+            closeReason = UTF8.decode(payload.sublist(2));
+          }
+        }
+        _state = CLOSED;
+        _eventSink.close();
+        break;
+
+      case _WebSocketOpcode.PING:
+        _eventSink.add(new _WebSocketPing(_payload.takeBytes()));
+        break;
+
+      case _WebSocketOpcode.PONG:
+        _eventSink.add(new _WebSocketPong(_payload.takeBytes()));
+        break;
+    }
+    _prepareForNextFrame();
+  }
+
+  bool _isControlFrame() {
+    return _opcode == _WebSocketOpcode.CLOSE ||
+        _opcode == _WebSocketOpcode.PING ||
+        _opcode == _WebSocketOpcode.PONG;
+  }
+
+  void _prepareForNextFrame() {
+    if (_state != CLOSED && _state != FAILURE) _state = START;
+    _fin = false;
+    _opcode = -1;
+    _len = -1;
+    _remainingLenBytes = -1;
+    _remainingMaskingKeyBytes = 4;
+    _remainingPayloadBytes = -1;
+    _unmaskingIndex = 0;
+  }
+}
+
+class _WebSocketPing {
+  final List<int> payload;
+  _WebSocketPing([this.payload = null]);
+}
+
+class _WebSocketPong {
+  final List<int> payload;
+  _WebSocketPong([this.payload = null]);
+}
+
+class _WebSocketTransformerImpl implements WebSocketTransformer {
+  final StreamController<WebSocket> _controller =
+      new StreamController<WebSocket>(sync: true);
+  final Function _protocolSelector;
+  final CompressionOptions _compression;
+
+  _WebSocketTransformerImpl(this._protocolSelector, this._compression);
+
+  Stream<WebSocket> bind(Stream<HttpRequest> stream) {
+    stream.listen((request) {
+      _upgrade(request, _protocolSelector, _compression)
+          .then((WebSocket webSocket) => _controller.add(webSocket))
+          .catchError(_controller.addError);
+    }, onDone: () {
+      _controller.close();
+    });
+
+    return _controller.stream;
+  }
+
+  static Future<WebSocket> _upgrade(
+      HttpRequest request, _protocolSelector, CompressionOptions compression) {
+    var response = request.response;
+    if (!_isUpgradeRequest(request)) {
+      // Send error response.
+      response
+        ..statusCode = HttpStatus.BAD_REQUEST
+        ..close();
+      return new Future.error(
+          new WebSocketException("Invalid WebSocket upgrade request"));
+    }
+
+    Future upgrade(String protocol) {
+      // Send the upgrade response.
+      response
+        ..statusCode = HttpStatus.SWITCHING_PROTOCOLS
+        ..headers.add(HttpHeaders.CONNECTION, "Upgrade")
+        ..headers.add(HttpHeaders.UPGRADE, "websocket");
+      String key = request.headers.value("Sec-WebSocket-Key");
+      _SHA1 sha1 = new _SHA1();
+      sha1.add("$key$_webSocketGUID".codeUnits);
+      String accept = _CryptoUtils.bytesToBase64(sha1.close());
+      response.headers.add("Sec-WebSocket-Accept", accept);
+      if (protocol != null) {
+        response.headers.add("Sec-WebSocket-Protocol", protocol);
+      }
+
+      var deflate = _negotiateCompression(request, response, compression);
+
+      response.headers.contentLength = 0;
+      return response.detachSocket().then((socket) =>
+          new _WebSocketImpl._fromSocket(
+              socket, protocol, compression, true, deflate));
+    }
+
+    var protocols = request.headers['Sec-WebSocket-Protocol'];
+    if (protocols != null && _protocolSelector != null) {
+      // The suggested protocols can be spread over multiple lines, each
+      // consisting of multiple protocols. To unify all of them, first join
+      // the lists with ', ' and then tokenize.
+      protocols = _HttpParser._tokenizeFieldValue(protocols.join(', '));
+      return new Future(() => _protocolSelector(protocols)).then((protocol) {
+        if (protocols.indexOf(protocol) < 0) {
+          throw new WebSocketException(
+              "Selected protocol is not in the list of available protocols");
+        }
+        return protocol;
+      }).catchError((error) {
+        response
+          ..statusCode = HttpStatus.INTERNAL_SERVER_ERROR
+          ..close();
+        throw error;
+      }).then(upgrade);
+    } else {
+      return upgrade(null);
+    }
+  }
+
+  static _WebSocketPerMessageDeflate _negotiateCompression(HttpRequest request,
+      HttpResponse response, CompressionOptions compression) {
+    var extensionHeader = request.headers.value("Sec-WebSocket-Extensions");
+
+    extensionHeader ??= "";
+
+    var hv = HeaderValue.parse(extensionHeader, valueSeparator: ',');
+    if (compression.enabled && hv.value == _WebSocketImpl.PER_MESSAGE_DEFLATE) {
+      var info = compression._createHeader(hv);
+
+      response.headers.add("Sec-WebSocket-Extensions", info.headerValue);
+      var serverNoContextTakeover =
+          (hv.parameters.containsKey(_serverNoContextTakeover) &&
+            compression.serverNoContextTakeover);
+      var clientNoContextTakeover =
+          (hv.parameters.containsKey(_clientNoContextTakeover) &&
+            compression.clientNoContextTakeover);
+      var deflate = new _WebSocketPerMessageDeflate(
+          serverNoContextTakeover: serverNoContextTakeover,
+          clientNoContextTakeover: clientNoContextTakeover,
+          serverMaxWindowBits: info.maxWindowBits,
+          clientMaxWindowBits: info.maxWindowBits,
+          serverSide: true);
+
+      return deflate;
+    }
+
+    return null;
+  }
+
+  static bool _isUpgradeRequest(HttpRequest request) {
+    if (request.method != "GET") {
+      return false;
+    }
+    if (request.headers[HttpHeaders.CONNECTION] == null) {
+      return false;
+    }
+    bool isUpgrade = false;
+    request.headers[HttpHeaders.CONNECTION].forEach((String value) {
+      if (value.toLowerCase() == "upgrade") isUpgrade = true;
+    });
+    if (!isUpgrade) return false;
+    String upgrade = request.headers.value(HttpHeaders.UPGRADE);
+    if (upgrade == null || upgrade.toLowerCase() != "websocket") {
+      return false;
+    }
+    String version = request.headers.value("Sec-WebSocket-Version");
+    if (version == null || version != "13") {
+      return false;
+    }
+    String key = request.headers.value("Sec-WebSocket-Key");
+    if (key == null) {
+      return false;
+    }
+    return true;
+  }
+}
+
+class _WebSocketPerMessageDeflate {
+  bool serverNoContextTakeover;
+  bool clientNoContextTakeover;
+  int clientMaxWindowBits;
+  int serverMaxWindowBits;
+  bool serverSide;
+
+  _Filter decoder;
+  _Filter encoder;
+
+  _WebSocketPerMessageDeflate(
+      {this.clientMaxWindowBits: _WebSocketImpl.DEFAULT_WINDOW_BITS,
+       this.serverMaxWindowBits: _WebSocketImpl.DEFAULT_WINDOW_BITS,
+       this.serverNoContextTakeover: false,
+       this.clientNoContextTakeover: false,
+       this.serverSide: false});
+
+  void _ensureDecoder() {
+    if (decoder == null) {
+      decoder = _Filter._newZLibInflateFilter(
+          serverSide ? clientMaxWindowBits : serverMaxWindowBits, null, true);
+    }
+  }
+
+  void _ensureEncoder() {
+    if (encoder == null) {
+      encoder = _Filter._newZLibDeflateFilter(
+          false,
+          ZLibOption.DEFAULT_LEVEL,
+          serverSide ? serverMaxWindowBits : clientMaxWindowBits,
+          ZLibOption.DEFAULT_MEM_LEVEL,
+          ZLibOption.STRATEGY_DEFAULT,
+          null,
+          true);
+    }
+  }
+
+  Uint8List processIncomingMessage(List<int> msg) {
+    _ensureDecoder();
+
+    var data = [];
+    data.addAll(msg);
+    data.addAll(const [0x00, 0x00, 0xff, 0xff]);
+
+    decoder.process(data, 0, data.length);
+    var result = [];
+    var out;
+
+    while ((out = decoder.processed()) != null) {
+      result.addAll(out);
+    }
+
+    if ((serverSide && clientNoContextTakeover) ||
+        (!serverSide && serverNoContextTakeover)) {
+      decoder = null;
+    }
+
+    return new Uint8List.fromList(result);
+  }
+
+  List<int> processOutgoingMessage(List<int> msg) {
+    _ensureEncoder();
+    var result = [];
+    Uint8List buffer;
+    var out;
+
+    if (msg is! Uint8List) {
+      for (var i = 0; i < msg.length; i++) {
+        if (msg[i] < 0 || 255 < msg[i]) {
+          throw new ArgumentError("List element is not a byte value "
+              "(value ${msg[i]} at index $i)");
+        }
+      }
+      buffer = new Uint8List.fromList(msg);
+    } else {
+      buffer = msg;
+    }
+
+    encoder.process(buffer, 0, buffer.length);
+
+    while ((out = encoder.processed()) != null) {
+      result.addAll(out);
+    }
+
+    if ((!serverSide && clientNoContextTakeover) ||
+        (serverSide && serverNoContextTakeover)) {
+      encoder = null;
+    }
+
+    if (result.length > 4) {
+      result = result.sublist(0, result.length - 4);
+    }
+
+    return result;
+  }
+}
+
+// TODO(ajohnsen): Make this transformer reusable.
+class _WebSocketOutgoingTransformer
+    implements StreamTransformer<dynamic, List<int>>, EventSink {
+  final _WebSocketImpl webSocket;
+  EventSink<List<int>> _eventSink;
+
+  _WebSocketPerMessageDeflate _deflateHelper;
+
+  _WebSocketOutgoingTransformer(this.webSocket) {
+    _deflateHelper = webSocket._deflate;
+  }
+
+  Stream<List<int>> bind(Stream stream) {
+    return new Stream.eventTransformed(stream, (eventSink) {
+      if (_eventSink != null) {
+        throw new StateError("WebSocket transformer already used");
+      }
+      _eventSink = eventSink;
+      return this;
+    });
+  }
+
+  void add(message) {
+    if (message is _WebSocketPong) {
+      addFrame(_WebSocketOpcode.PONG, message.payload);
+      return;
+    }
+    if (message is _WebSocketPing) {
+      addFrame(_WebSocketOpcode.PING, message.payload);
+      return;
+    }
+    List<int> data;
+    int opcode;
+    if (message != null) {
+      if (message is String) {
+        opcode = _WebSocketOpcode.TEXT;
+        data = UTF8.encode(message);
+      } else {
+        if (message is List<int>) {
+          data = message;
+          opcode = _WebSocketOpcode.BINARY;
+        } else {
+          throw new ArgumentError(message);
+        }
+      }
+
+      if (_deflateHelper != null) {
+        data = _deflateHelper.processOutgoingMessage(data);
+      }
+    } else {
+      opcode = _WebSocketOpcode.TEXT;
+    }
+    addFrame(opcode, data);
+  }
+
+  void addError(Object error, [StackTrace stackTrace]) {
+    _eventSink.addError(error, stackTrace);
+  }
+
+  void close() {
+    int code = webSocket._outCloseCode;
+    String reason = webSocket._outCloseReason;
+    List<int> data;
+    if (code != null) {
+      data = new List<int>();
+      data.add((code >> 8) & 0xFF);
+      data.add(code & 0xFF);
+      if (reason != null) {
+        data.addAll(UTF8.encode(reason));
+      }
+    }
+    addFrame(_WebSocketOpcode.CLOSE, data);
+    _eventSink.close();
+  }
+
+  void addFrame(int opcode, List<int> data) => createFrame(
+          opcode,
+          data,
+          webSocket._serverSide,
+          _deflateHelper != null &&
+              (opcode == _WebSocketOpcode.TEXT ||
+                  opcode == _WebSocketOpcode.BINARY)).forEach((e) {
+        _eventSink.add(e);
+      });
+
+  static Iterable<List<int>> createFrame(
+      int opcode, List<int> data, bool serverSide, bool compressed) {
+    bool mask = !serverSide; // Masking not implemented for server.
+    int dataLength = data == null ? 0 : data.length;
+    // Determine the header size.
+    int headerSize = (mask) ? 6 : 2;
+    if (dataLength > 65535) {
+      headerSize += 8;
+    } else if (dataLength > 125) {
+      headerSize += 2;
+    }
+    Uint8List header = new Uint8List(headerSize);
+    int index = 0;
+
+    // Set FIN and opcode.
+    var hoc = _WebSocketProtocolTransformer.FIN
+              | (compressed ? _WebSocketProtocolTransformer.RSV1 : 0)
+              | (opcode & _WebSocketProtocolTransformer.OPCODE);
+
+    header[index++] = hoc;
+    // Determine size and position of length field.
+    int lengthBytes = 1;
+    if (dataLength > 65535) {
+      header[index++] = 127;
+      lengthBytes = 8;
+    } else if (dataLength > 125) {
+      header[index++] = 126;
+      lengthBytes = 2;
+    }
+    // Write the length in network byte order into the header.
+    for (int i = 0; i < lengthBytes; i++) {
+      header[index++] = dataLength >> (((lengthBytes - 1) - i) * 8) & 0xFF;
+    }
+    if (mask) {
+      header[1] |= 1 << 7;
+      var maskBytes = _IOCrypto.getRandomBytes(4);
+      header.setRange(index, index + 4, maskBytes);
+      index += 4;
+      if (data != null) {
+        Uint8List list;
+        // If this is a text message just do the masking inside the
+        // encoded data.
+        if (opcode == _WebSocketOpcode.TEXT && data is Uint8List) {
+          list = data;
+        } else {
+          if (data is Uint8List) {
+            list = new Uint8List.fromList(data);
+          } else {
+            list = new Uint8List(data.length);
+            for (int i = 0; i < data.length; i++) {
+              if (data[i] < 0 || 255 < data[i]) {
+                throw new ArgumentError("List element is not a byte value "
+                    "(value ${data[i]} at index $i)");
+              }
+              list[i] = data[i];
+            }
+          }
+        }
+        const int BLOCK_SIZE = 16;
+        int blockCount = list.length ~/ BLOCK_SIZE;
+        if (blockCount > 0) {
+          // Create mask block.
+          int mask = 0;
+          for (int i = 3; i >= 0; i--) {
+            mask = (mask << 8) | maskBytes[i];
+          }
+          Int32x4 blockMask = new Int32x4(mask, mask, mask, mask);
+          Int32x4List blockBuffer =
+              new Int32x4List.view(list.buffer, 0, blockCount);
+          for (int i = 0; i < blockBuffer.length; i++) {
+            blockBuffer[i] ^= blockMask;
+          }
+        }
+        // Handle end.
+        for (int i = blockCount * BLOCK_SIZE; i < list.length; i++) {
+          list[i] ^= maskBytes[i & 3];
+        }
+        data = list;
+      }
+    }
+    assert(index == headerSize);
+    if (data == null) {
+      return [header];
+    } else {
+      return [header, data];
+    }
+  }
+}
+
+class _WebSocketConsumer implements StreamConsumer {
+  final _WebSocketImpl webSocket;
+  final Socket socket;
+  StreamController _controller;
+  StreamSubscription _subscription;
+  bool _issuedPause = false;
+  bool _closed = false;
+  Completer _closeCompleter = new Completer();
+  Completer _completer;
+
+  _WebSocketConsumer(this.webSocket, this.socket);
+
+  void _onListen() {
+    if (_subscription != null) {
+      _subscription.cancel();
+    }
+  }
+
+  void _onPause() {
+    if (_subscription != null) {
+      _subscription.pause();
+    } else {
+      _issuedPause = true;
+    }
+  }
+
+  void _onResume() {
+    if (_subscription != null) {
+      _subscription.resume();
+    } else {
+      _issuedPause = false;
+    }
+  }
+
+  void _cancel() {
+    if (_subscription != null) {
+      var subscription = _subscription;
+      _subscription = null;
+      subscription.cancel();
+    }
+  }
+
+  _ensureController() {
+    if (_controller != null) return;
+    _controller = new StreamController(
+        sync: true,
+        onPause: _onPause,
+        onResume: _onResume,
+        onCancel: _onListen);
+    var stream = _controller.stream
+        .transform(new _WebSocketOutgoingTransformer(webSocket));
+    socket.addStream(stream).then((_) {
+      _done();
+      _closeCompleter.complete(webSocket);
+    }, onError: (error, StackTrace stackTrace) {
+      _closed = true;
+      _cancel();
+      if (error is ArgumentError) {
+        if (!_done(error, stackTrace)) {
+          _closeCompleter.completeError(error, stackTrace);
+        }
+      } else {
+        _done();
+        _closeCompleter.complete(webSocket);
+      }
+    });
+  }
+
+  bool _done([error, StackTrace stackTrace]) {
+    if (_completer == null) return false;
+    if (error != null) {
+      _completer.completeError(error, stackTrace);
+    } else {
+      _completer.complete(webSocket);
+    }
+    _completer = null;
+    return true;
+  }
+
+  Future addStream(var stream) {
+    if (_closed) {
+      stream.listen(null).cancel();
+      return new Future.value(webSocket);
+    }
+    _ensureController();
+    _completer = new Completer();
+    _subscription = stream.listen((data) {
+      _controller.add(data);
+    }, onDone: _done, onError: _done, cancelOnError: true);
+    if (_issuedPause) {
+      _subscription.pause();
+      _issuedPause = false;
+    }
+    return _completer.future;
+  }
+
+  Future close() {
+    _ensureController();
+    Future closeSocket() {
+      return socket.close().catchError((_) {}).then((_) => webSocket);
+    }
+    _controller.close();
+    return _closeCompleter.future.then((_) => closeSocket());
+  }
+
+  void add(data) {
+    if (_closed) return;
+    _ensureController();
+    _controller.add(data);
+  }
+
+  void closeSocket() {
+    _closed = true;
+    _cancel();
+    close();
+  }
+}
+
+class _WebSocketImpl extends Stream with _ServiceObject implements WebSocket {
+  // Use default Map so we keep order.
+  static Map<int, _WebSocketImpl> _webSockets = new Map<int, _WebSocketImpl>();
+  static const int DEFAULT_WINDOW_BITS = 15;
+  static const String PER_MESSAGE_DEFLATE = "permessage-deflate";
+
+  final String protocol;
+
+  StreamController _controller;
+  StreamSubscription _subscription;
+  StreamSink _sink;
+
+  final _socket;
+  final bool _serverSide;
+  int _readyState = WebSocket.CONNECTING;
+  bool _writeClosed = false;
+  int _closeCode;
+  String _closeReason;
+  Duration _pingInterval;
+  Timer _pingTimer;
+  _WebSocketConsumer _consumer;
+
+  int _outCloseCode;
+  String _outCloseReason;
+  Timer _closeTimer;
+  _WebSocketPerMessageDeflate _deflate;
+
+  static final HttpClient _httpClient = new HttpClient();
+
+  static Future<WebSocket> connect(
+      String url, Iterable<String> protocols, Map<String, dynamic> headers,
+      {CompressionOptions compression: CompressionOptions.DEFAULT}) {
+    Uri uri = Uri.parse(url);
+    if (uri.scheme != "ws" && uri.scheme != "wss") {
+      throw new WebSocketException("Unsupported URL scheme '${uri.scheme}'");
+    }
+
+    Random random = new Random();
+    // Generate 16 random bytes.
+    Uint8List nonceData = new Uint8List(16);
+    for (int i = 0; i < 16; i++) {
+      nonceData[i] = random.nextInt(256);
+    }
+    String nonce = _CryptoUtils.bytesToBase64(nonceData);
+
+    uri = new Uri(
+        scheme: uri.scheme == "wss" ? "https" : "http",
+        userInfo: uri.userInfo,
+        host: uri.host,
+        port: uri.port,
+        path: uri.path,
+        query: uri.query,
+        fragment: uri.fragment);
+    return _httpClient.openUrl("GET", uri).then((request) {
+      if (uri.userInfo != null && !uri.userInfo.isEmpty) {
+        // If the URL contains user information use that for basic
+        // authorization.
+        String auth = _CryptoUtils.bytesToBase64(UTF8.encode(uri.userInfo));
+        request.headers.set(HttpHeaders.AUTHORIZATION, "Basic $auth");
+      }
+      if (headers != null) {
+        headers.forEach((field, value) => request.headers.add(field, value));
+      }
+      // Setup the initial handshake.
+      request.headers
+        ..set(HttpHeaders.CONNECTION, "Upgrade")
+        ..set(HttpHeaders.UPGRADE, "websocket")
+        ..set("Sec-WebSocket-Key", nonce)
+        ..set("Cache-Control", "no-cache")
+        ..set("Sec-WebSocket-Version", "13");
+      if (protocols != null) {
+        request.headers.add("Sec-WebSocket-Protocol", protocols.toList());
+      }
+
+      if (compression.enabled) {
+        request.headers
+            .add("Sec-WebSocket-Extensions", compression._createHeader());
+      }
+
+      return request.close();
+    }).then((response) {
+
+      void error(String message) {
+        // Flush data.
+        response.detachSocket().then((socket) {
+          socket.destroy();
+        });
+        throw new WebSocketException(message);
+      }
+
+      if (response.statusCode != HttpStatus.SWITCHING_PROTOCOLS ||
+          response.headers[HttpHeaders.CONNECTION] == null ||
+          !response.headers[HttpHeaders.CONNECTION]
+              .any((value) => value.toLowerCase() == "upgrade") ||
+          response.headers.value(HttpHeaders.UPGRADE).toLowerCase() !=
+              "websocket") {
+        error("Connection to '$uri' was not upgraded to websocket");
+      }
+      String accept = response.headers.value("Sec-WebSocket-Accept");
+      if (accept == null) {
+        error("Response did not contain a 'Sec-WebSocket-Accept' header");
+      }
+      _SHA1 sha1 = new _SHA1();
+      sha1.add("$nonce$_webSocketGUID".codeUnits);
+      List<int> expectedAccept = sha1.close();
+      List<int> receivedAccept = _CryptoUtils.base64StringToBytes(accept);
+      if (expectedAccept.length != receivedAccept.length) {
+        error("Reasponse header 'Sec-WebSocket-Accept' is the wrong length");
+      }
+      for (int i = 0; i < expectedAccept.length; i++) {
+        if (expectedAccept[i] != receivedAccept[i]) {
+          error("Bad response 'Sec-WebSocket-Accept' header");
+        }
+      }
+      var protocol = response.headers.value('Sec-WebSocket-Protocol');
+
+      _WebSocketPerMessageDeflate deflate =
+          negotiateClientCompression(response, compression);
+
+      return response.detachSocket().then/*<WebSocket>*/((socket) =>
+          new _WebSocketImpl._fromSocket(
+              socket, protocol, compression, false, deflate));
+    });
+  }
+
+  static _WebSocketPerMessageDeflate negotiateClientCompression(
+      HttpClientResponse response, CompressionOptions compression) {
+    String extensionHeader = response.headers.value('Sec-WebSocket-Extensions');
+
+    if (extensionHeader == null) {
+      extensionHeader = "";
+    }
+
+    var hv = HeaderValue.parse(extensionHeader, valueSeparator: ',');
+
+    if (compression.enabled && hv.value == PER_MESSAGE_DEFLATE) {
+      var serverNoContextTakeover =
+          hv.parameters.containsKey(_serverNoContextTakeover);
+      var clientNoContextTakeover =
+          hv.parameters.containsKey(_clientNoContextTakeover);
+
+      int getWindowBits(String type) {
+        var o = hv.parameters[type];
+        if (o == null) {
+          return DEFAULT_WINDOW_BITS;
+        }
+
+        return int.parse(o, onError: (s) => DEFAULT_WINDOW_BITS);
+      }
+
+      return new _WebSocketPerMessageDeflate(
+          clientMaxWindowBits: getWindowBits(_clientMaxWindowBits),
+          serverMaxWindowBits: getWindowBits(_serverMaxWindowBits),
+          clientNoContextTakeover: clientNoContextTakeover,
+          serverNoContextTakeover: serverNoContextTakeover);
+    }
+
+    return null;
+  }
+
+  _WebSocketImpl._fromSocket(
+      this._socket, this.protocol, CompressionOptions compression,
+      [this._serverSide = false, _WebSocketPerMessageDeflate deflate]) {
+    _consumer = new _WebSocketConsumer(this, _socket);
+    _sink = new _StreamSinkImpl(_consumer);
+    _readyState = WebSocket.OPEN;
+    _deflate = deflate;
+
+    var transformer = new _WebSocketProtocolTransformer(_serverSide, _deflate);
+    _subscription = _socket.transform(transformer).listen((data) {
+      if (data is _WebSocketPing) {
+        if (!_writeClosed) _consumer.add(new _WebSocketPong(data.payload));
+      } else if (data is _WebSocketPong) {
+        // Simply set pingInterval, as it'll cancel any timers.
+        pingInterval = _pingInterval;
+      } else {
+        _controller.add(data);
+      }
+    }, onError: (error, stackTrace) {
+      if (_closeTimer != null) _closeTimer.cancel();
+      if (error is FormatException) {
+        _close(WebSocketStatus.INVALID_FRAME_PAYLOAD_DATA);
+      } else {
+        _close(WebSocketStatus.PROTOCOL_ERROR);
+      }
+      // An error happened, set the close code set above.
+      _closeCode = _outCloseCode;
+      _closeReason = _outCloseReason;
+      _controller.close();
+    }, onDone: () {
+      if (_closeTimer != null) _closeTimer.cancel();
+      if (_readyState == WebSocket.OPEN) {
+        _readyState = WebSocket.CLOSING;
+        if (!_isReservedStatusCode(transformer.closeCode)) {
+          _close(transformer.closeCode, transformer.closeReason);
+        } else {
+          _close();
+        }
+        _readyState = WebSocket.CLOSED;
+      }
+      // Protocol close, use close code from transformer.
+      _closeCode = transformer.closeCode;
+      _closeReason = transformer.closeReason;
+      _controller.close();
+    }, cancelOnError: true);
+    _subscription.pause();
+    _controller = new StreamController(
+        sync: true, onListen: _subscription.resume, onCancel: () {
+      _subscription.cancel();
+      _subscription = null;
+    }, onPause: _subscription.pause, onResume: _subscription.resume);
+
+    _webSockets[_serviceId] = this;
+    try {
+      _socket._owner = this;
+    } catch (_) {}
+  }
+
+  StreamSubscription listen(void onData(message),
+      {Function onError, void onDone(), bool cancelOnError}) {
+    return _controller.stream.listen(onData,
+        onError: onError, onDone: onDone, cancelOnError: cancelOnError);
+  }
+
+  Duration get pingInterval => _pingInterval;
+
+  void set pingInterval(Duration interval) {
+    if (_writeClosed) return;
+    if (_pingTimer != null) _pingTimer.cancel();
+    _pingInterval = interval;
+
+    if (_pingInterval == null) return;
+
+    _pingTimer = new Timer(_pingInterval, () {
+      if (_writeClosed) return;
+      _consumer.add(new _WebSocketPing());
+      _pingTimer = new Timer(_pingInterval, () {
+        // No pong received.
+        _close(WebSocketStatus.GOING_AWAY);
+      });
+    });
+  }
+
+  int get readyState => _readyState;
+
+  String get extensions => null;
+  int get closeCode => _closeCode;
+  String get closeReason => _closeReason;
+
+  void add(data) { _sink.add(data); }
+  void addError(error, [StackTrace stackTrace]) {
+    _sink.addError(error, stackTrace);
+  }
+  Future addStream(Stream stream) => _sink.addStream(stream);
+  Future get done => _sink.done;
+
+  Future close([int code, String reason]) {
+    if (_isReservedStatusCode(code)) {
+      throw new WebSocketException("Reserved status code $code");
+    }
+    if (_outCloseCode == null) {
+      _outCloseCode = code;
+      _outCloseReason = reason;
+    }
+    if (!_controller.isClosed) {
+      // If a close has not yet been received from the other end then
+      //   1) make sure to listen on the stream so the close frame will be
+      //      processed if received.
+      //   2) set a timer terminate the connection if a close frame is
+      //      not received.
+      if (!_controller.hasListener && _subscription != null) {
+        _controller.stream.drain().catchError((_) => {});
+      }
+      if (_closeTimer == null) {
+        // When closing the web-socket, we no longer accept data.
+        _closeTimer = new Timer(const Duration(seconds: 5), () {
+          // Reuse code and reason from the local close.
+          _closeCode = _outCloseCode;
+          _closeReason = _outCloseReason;
+          if (_subscription != null) _subscription.cancel();
+          _controller.close();
+          _webSockets.remove(_serviceId);
+        });
+      }
+    }
+    return _sink.close();
+  }
+
+  void _close([int code, String reason]) {
+    if (_writeClosed) return;
+    if (_outCloseCode == null) {
+      _outCloseCode = code;
+      _outCloseReason = reason;
+    }
+    _writeClosed = true;
+    _consumer.closeSocket();
+    _webSockets.remove(_serviceId);
+  }
+
+  String get _serviceTypePath => 'io/websockets';
+  String get _serviceTypeName => 'WebSocket';
+
+  Map<String, dynamic> _toJSON(bool ref) {
+    var name = '${_socket.address.host}:${_socket.port}';
+    var r = <String, dynamic>{
+      'id': _servicePath,
+      'type': _serviceType(ref),
+      'name': name,
+      'user_name': name,
+    };
+    if (ref) {
+      return r;
+    }
+    try {
+      r['socket'] = _socket._toJSON(true);
+    } catch (_) {
+      r['socket'] = {
+        'id': _servicePath,
+        'type': '@Socket',
+        'name': 'UserSocket',
+        'user_name': 'UserSocket',
+      };
+    }
+    return r;
+  }
+
+  static bool _isReservedStatusCode(int code) {
+    return code != null &&
+        (code < WebSocketStatus.NORMAL_CLOSURE ||
+            code == WebSocketStatus.RESERVED_1004 ||
+            code == WebSocketStatus.NO_STATUS_RECEIVED ||
+            code == WebSocketStatus.ABNORMAL_CLOSURE ||
+            (code > WebSocketStatus.INTERNAL_SERVER_ERROR &&
+                code < WebSocketStatus.RESERVED_1015) ||
+            (code >= WebSocketStatus.RESERVED_1015 && code < 3000));
+  }
+}