Speed up web-socket impl by ensuring the optimized compiler is triggered.

sdk/lib/io/websocket_impl.dart

Index: sdk/lib/io/websocket_impl.dart
diff --git a/sdk/lib/io/websocket_impl.dart b/sdk/lib/io/websocket_impl.dart
index 48eeca131d3f6ce888b612521836f4200e59a72b..f499055ac10a472d5358c4ac0b017e29a22cad3c 100644
--- a/sdk/lib/io/websocket_impl.dart
+++ b/sdk/lib/io/websocket_impl.dart
@@ -51,31 +51,26 @@ class _WebSocketProtocolTransformer implements StreamTransformer, EventSink {
   static const int CLOSED = 5;
   static const int FAILURE = 6;
 
-  int _state;
-  bool _fin;
-  int _opcode;
-  int _len;
-  bool _masked;
-  int _maskingKey;
-  int _remainingLenBytes;
-  int _remainingMaskingKeyBytes;
-  int _remainingPayloadBytes;
-  int _unmaskingIndex;
-
-  int _currentMessageType;
-  List<int> _controlPayload;
-  StreamController _controller;
-
+  int _state = START;
+  bool _fin = 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 = "";
 
-  bool _serverSide;
   EventSink _eventSink;
 
-  _WebSocketProtocolTransformer([this._serverSide = false]) {
-    _prepareForNextFrame();
-    _currentMessageType = _WebSocketMessageType.NONE;
-  }
+  final bool _serverSide;
+  final List _maskingBytes = new List(4);
+  final BytesBuilder _payload = new BytesBuilder();
+
+  _WebSocketProtocolTransformer([this._serverSide = false]);
 
   Stream bind(Stream stream) {
     return new Stream.eventTransformed(
@@ -101,163 +96,125 @@ class _WebSocketProtocolTransformer implements StreamTransformer, EventSink {
     int count = buffer.length;
     int index = 0;
     int lastIndex = count;
-    try {
-      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];
-        switch (_state) {
-          case START:
-            _fin = (byte & 0x80) != 0;
-            if ((byte & 0x70) != 0) {
-              // The RSV1, RSV2 bits RSV3 most be all zero.
+    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];
+      switch (_state) {

[kasperl, 2014/01/27 14:40:07]

Is there one of the cases that's way more likely than the others? Consider
measuring if pulling that check out of the switch helps performance. Maybe even
move the uncommon cases to a different helper method?

[Anders Johnsen, 2014/01/28 08:56:10]

Moved the switch in to a binary-like if-hierarchy.

+        case START:
+          _fin = (byte & 0x80) != 0;
+          if ((byte & 0x70) != 0) {
+            // The RSV1, RSV2 bits RSV3 most be all zero.

[kasperl, 2014/01/27 14:40:07]

most -> must

[Anders Johnsen, 2014/01/28 08:56:10]

Done.

+            throw new WebSocketException("Protocol error");
+          }
+          _opcode = (byte & 0xF);
+          switch (_opcode) {
+          case _WebSocketOpcode.CONTINUATION:

[kasperl, 2014/01/27 14:40:07]

Indent the cases.

[Anders Johnsen, 2014/01/28 08:56:10]

Done.

+            if (_currentMessageType == _WebSocketMessageType.NONE) {
               throw new WebSocketException("Protocol error");
             }
-            _opcode = (byte & 0xF);
-            switch (_opcode) {
-            case _WebSocketOpcode.CONTINUATION:
-              if (_currentMessageType == _WebSocketMessageType.NONE) {
-                throw new WebSocketException("Protocol error");
-              }
-              break;
+            break;
 
-            case _WebSocketOpcode.TEXT:
-              if (_currentMessageType != _WebSocketMessageType.NONE) {
-                throw new WebSocketException("Protocol error");
-              }
-              _currentMessageType = _WebSocketMessageType.TEXT;
-              _controller = new StreamController(sync: true);
-              _controller.stream
-                  .transform(UTF8.decoder)
-                  .fold(new StringBuffer(), (buffer, str) => buffer..write(str))
-                  .then((buffer) {
-                    _eventSink.add(buffer.toString());
-                  }, onError: _eventSink.addError);
-              break;
-
-            case _WebSocketOpcode.BINARY:
-              if (_currentMessageType != _WebSocketMessageType.NONE) {
-                throw new WebSocketException("Protocol error");
-              }
-              _currentMessageType = _WebSocketMessageType.BINARY;
-              _controller = new StreamController(sync: true);
-              _controller.stream
-                  .fold(new BytesBuilder(), (buffer, data) => buffer..add(data))
-                  .then((buffer) {
-                    _eventSink.add(buffer.takeBytes());
-                  }, onError: _eventSink.addError);
-              break;
-
-            case _WebSocketOpcode.CLOSE:
-            case _WebSocketOpcode.PING:
-            case _WebSocketOpcode.PONG:
-              // Control frames cannot be fragmented.
-              if (!_fin) throw new WebSocketException("Protocol error");
-              break;
-
-            default:
+          case _WebSocketOpcode.TEXT:
+            if (_currentMessageType != _WebSocketMessageType.NONE) {
               throw new WebSocketException("Protocol error");
             }
-            _state = LEN_FIRST;
+            _currentMessageType = _WebSocketMessageType.TEXT;
             break;
 
-          case LEN_FIRST:
-            _masked = (byte & 0x80) != 0;
-            _len = byte & 0x7F;
-            if (_isControlFrame() && _len > 125) {
+          case _WebSocketOpcode.BINARY:
+            if (_currentMessageType != _WebSocketMessageType.NONE) {
               throw new WebSocketException("Protocol error");
             }
-            if (_len < 126) {
-              _lengthDone();
-            } else if (_len == 126) {
-              _len = 0;
-              _remainingLenBytes = 2;
-              _state = LEN_REST;
-            } else if (_len == 127) {
-              _len = 0;
-              _remainingLenBytes = 8;
-              _state = LEN_REST;
-            }
+            _currentMessageType = _WebSocketMessageType.BINARY;
             break;
 
-          case LEN_REST:
-            _len = _len << 8 | byte;
-            _remainingLenBytes--;
-            if (_remainingLenBytes == 0) {
-              _lengthDone();
-            }
+          case _WebSocketOpcode.CLOSE:
+          case _WebSocketOpcode.PING:
+          case _WebSocketOpcode.PONG:
+            // Control frames cannot be fragmented.
+            if (!_fin) throw new WebSocketException("Protocol error");
             break;
 
-          case MASK:
-            _maskingKey = _maskingKey << 8 | byte;
-            _remainingMaskingKeyBytes--;
-            if (_remainingMaskingKeyBytes == 0) {
-              _maskDone();
-            }
-            break;
+          default:
+            throw new WebSocketException("Protocol error");
+          }
+          _state = LEN_FIRST;
+          break;
 
-          case PAYLOAD:
-            // The payload is not handled one byte at a time but in blocks.
-            int payload;
-            if (lastIndex - index <= _remainingPayloadBytes) {
-              payload = lastIndex - index;
-            } else {
-              payload = _remainingPayloadBytes;
-            }
-            _remainingPayloadBytes -= payload;
-
-            // Unmask payload if masked.
-            if (_masked) {
-              for (int i = 0; i < payload; i++) {
-                int maskingByte =
-                    ((_maskingKey >> ((3 - _unmaskingIndex) * 8)) & 0xFF);
-                buffer[index + i] = buffer[index + i] ^ maskingByte;
-                _unmaskingIndex = (_unmaskingIndex + 1) % 4;
-              }
-            }
+        case LEN_FIRST:
+          _masked = (byte & 0x80) != 0;
+          _len = byte & 0x7F;
+          if (_isControlFrame() && _len > 125) {
+            throw new WebSocketException("Protocol error");
+          }
+          if (_len < 126) {
+            _lengthDone();
+          } else if (_len == 126) {
+            _len = 0;
+            _remainingLenBytes = 2;
+            _state = LEN_REST;
+          } else if (_len == 127) {
+            _len = 0;
+            _remainingLenBytes = 8;
+            _state = LEN_REST;
+          }
+          break;
 
-            if (_isControlFrame()) {
-              if (payload > 0) {
-                // Allocate a buffer for collecting the control frame
-                // payload if any.
-                if (_controlPayload == null) {
-                  _controlPayload = new List<int>();
-                }
-                _controlPayload.addAll(buffer.sublist(index, index + payload));
-                index += payload;
-              }
-
-              if (_remainingPayloadBytes == 0) {
-                _controlFrameEnd();
-              }
-            } else {
-              if (_currentMessageType != _WebSocketMessageType.TEXT &&
-                  _currentMessageType != _WebSocketMessageType.BINARY) {
-                  throw new WebSocketException("Protocol error");
-              }
-              _controller.add(
-                  new Uint8List.view(buffer.buffer, index, payload));
-              index += payload;
-              if (_remainingPayloadBytes == 0) {
-                _messageFrameEnd();
-              }
-            }
+        case LEN_REST:
+          _len = _len << 8 | byte;
+          _remainingLenBytes--;
+          if (_remainingLenBytes == 0) {
+            _lengthDone();
+          }
+          break;
 
-            // Hack - as we always do index++ below.
-            index--;
-            break;
-        }
+        case MASK:
+          _maskingBytes[4 - _remainingMaskingKeyBytes--] = byte;
+          if (_remainingMaskingKeyBytes == 0) {
+            _maskDone();
+          }
+          break;
+
+        case PAYLOAD:
+          // The payload is not handled one byte at a time but in blocks.
+          int payload;
+          if (lastIndex - index <= _remainingPayloadBytes) {
+            payload = lastIndex - index;
+          } else {
+            payload = _remainingPayloadBytes;
+          }
+          _remainingPayloadBytes -= payload;
+          // Unmask payload if masked.
+          if (_masked) {
+            for (int i = index; i < index + payload; i++) {
+              buffer[i] ^= _maskingBytes[_unmaskingIndex++ & 3];
+            }
+          }
+          // Control frame and data frame share _payload builder.
+          _payload.add(new Uint8List.view(buffer.buffer, index, payload));
+          index += payload;
+          if (_isControlFrame()) {
+            if (_remainingPayloadBytes == 0) _controlFrameEnd();
+          } else {
+            if (_currentMessageType != _WebSocketMessageType.TEXT &&
+                _currentMessageType != _WebSocketMessageType.BINARY) {
+                throw new WebSocketException("Protocol error");
+            }
+            if (_remainingPayloadBytes == 0) _messageFrameEnd();
+          }
 
-        // Move to the next byte.
-        index++;
+          // Hack - as we always do index++ below.
+          index--;
+          break;
       }
-    } catch (e, stackTrace) {
-      _state = FAILURE;
-      _eventSink.addError(e, stackTrace);
+
+      // Move to the next byte.
+      index++;
     }
   }
 
@@ -267,7 +224,6 @@ class _WebSocketProtocolTransformer implements StreamTransformer, EventSink {
         throw new WebSocketException("Received masked frame from server");
       }
       _state = MASK;
-      _remainingMaskingKeyBytes = 4;
     } else {
       if (_serverSide) {
         throw new WebSocketException("Received unmasked frame from client");
@@ -312,13 +268,12 @@ class _WebSocketProtocolTransformer implements StreamTransformer, EventSink {
     if (_fin) {
       switch (_currentMessageType) {
         case _WebSocketMessageType.TEXT:
-          _controller.close();
+          _eventSink.add(UTF8.decode(_payload.takeBytes()));
           break;
         case _WebSocketMessageType.BINARY:
-          _controller.close();
+          _eventSink.add(_payload.takeBytes());
           break;
       }
-      _controller = null;
       _currentMessageType = _WebSocketMessageType.NONE;
     }
     _prepareForNextFrame();
@@ -328,16 +283,17 @@ class _WebSocketProtocolTransformer implements StreamTransformer, EventSink {
     switch (_opcode) {
       case _WebSocketOpcode.CLOSE:
         closeCode = WebSocketStatus.NO_STATUS_RECEIVED;
-        if (_controlPayload.length > 0) {
-          if (_controlPayload.length == 1) {
+        if (_payload.length > 0) {
+          var bytes = _payload.takeBytes();
+          if (bytes.length == 1) {
             throw new WebSocketException("Protocol error");
           }
-          closeCode = _controlPayload[0] << 8 | _controlPayload[1];
+          closeCode = bytes[0] << 8 | bytes[1];
           if (closeCode == WebSocketStatus.NO_STATUS_RECEIVED) {
             throw new WebSocketException("Protocol error");
           }
-          if (_controlPayload.length > 2) {
-            closeReason = UTF8.decode(_controlPayload.sublist(2));
+          if (bytes.length > 2) {
+            closeReason = UTF8.decode(bytes.sublist(2));
           }
         }
         _state = CLOSED;
@@ -345,11 +301,11 @@ class _WebSocketProtocolTransformer implements StreamTransformer, EventSink {
         break;
 
       case _WebSocketOpcode.PING:
-        _eventSink.add(new _WebSocketPing(_controlPayload));
+        _eventSink.add(new _WebSocketPing(_payload.takeBytes()));
         break;
 
       case _WebSocketOpcode.PONG:
-        _eventSink.add(new _WebSocketPong(_controlPayload));
+        _eventSink.add(new _WebSocketPong(_payload.takeBytes()));
         break;
     }
     _prepareForNextFrame();
@@ -363,16 +319,13 @@ class _WebSocketProtocolTransformer implements StreamTransformer, EventSink {
 
   void _prepareForNextFrame() {
     if (_state != CLOSED && _state != FAILURE) _state = START;
-    _fin = null;
-    _opcode = null;
-    _len = null;
-    _masked = null;
-    _maskingKey = 0;
-    _remainingLenBytes = null;
-    _remainingMaskingKeyBytes = null;
-    _remainingPayloadBytes = null;
+    _fin = false;
+    _opcode = -1;
+    _len = -1;
+    _remainingLenBytes = -1;
+    _remainingMaskingKeyBytes = 4;
+    _remainingPayloadBytes = -1;
     _unmaskingIndex = 0;
-    _controlPayload = null;
   }
 }
 
@@ -571,7 +524,7 @@ class _WebSocketOutgoingTransformer implements StreamTransformer, EventSink {
     } else if (dataLength > 125) {
       headerSize += 2;
     }
-    List<int> header = new List<int>(headerSize);
+    Uint8List header = new Uint8List(headerSize);
     int index = 0;
     // Set FIN and opcode.
     header[index++] = 0x80 | opcode;
@@ -605,7 +558,7 @@ class _WebSocketOutgoingTransformer implements StreamTransformer, EventSink {
         }
         if (data is Uint8List) {
           for (int i = 0; i < data.length; i++) {
-            list[i] = data[i] ^ maskBytes[i % 4];
+            list[i] = data[i] ^ maskBytes[i & 3];
           }
         } else {
           for (int i = 0; i < data.length; i++) {
@@ -786,7 +739,7 @@ class _WebSocketImpl extends Stream implements WebSocket {
 
     Random random = new Random();
     // Generate 16 random bytes.
-    List<int> nonceData = new List<int>(16);
+    Uint8List nonceData = new Uint8List(16);
     for (int i = 0; i < 16; i++) {
       nonceData[i] = random.nextInt(256);
     }