Improve WebSocket interface by making it implement StreamSink.

sdk/lib/io/io_sink.dart

Index: sdk/lib/io/io_sink.dart
diff --git a/sdk/lib/io/io_sink.dart b/sdk/lib/io/io_sink.dart
index 8001905509676c265355189d1ecebed38dac85ef..c6a82f00338e7fefc4fac78a7828f22c85471c41 100644
--- a/sdk/lib/io/io_sink.dart
+++ b/sdk/lib/io/io_sink.dart
@@ -52,74 +52,20 @@ abstract class IOSink implements StreamSink<List<int>>, StringSink {
   Future get done;
 }
 
-
-class _IOSinkImpl implements IOSink {
-  final StreamConsumer<List<int>> _target;
+class _StreamSinkImpl<T> implements StreamSink<T> {
+  final StreamConsumer<T> _target;
   Completer _doneCompleter = new Completer();
   Future _doneFuture;
-  StreamController<List<int>> _controllerInstance;
+  StreamController<T> _controllerInstance;
   Completer _controllerCompleter;
-  Encoding _encoding;
   bool _isClosed = false;
   bool _isBound = false;
-  bool _encodingMutable = true;
 
-  _IOSinkImpl(StreamConsumer<List<int>> this._target, this._encoding) {
+  _StreamSinkImpl(StreamConsumer<T> this._target) {
     _doneFuture = _doneCompleter.future;
   }
 
-  Encoding get encoding => _encoding;
-
-  void set encoding(Encoding value) {
-    if (!_encodingMutable) {
-      throw new StateError("IOSink encoding is not mutable");
-    }
-    _encoding = value;
-  }
-
-  void write(Object obj) {
-    // This comment is copied from runtime/lib/string_buffer_patch.dart.
-    // TODO(srdjan): The following four lines could be replaced by
-    // '$obj', but apparently this is too slow on the Dart VM.
-    String string;
-    if (obj is String) {
-      string = obj;
-    } else {
-      string = obj.toString();
-      if (string is! String) {
-        throw new ArgumentError('toString() did not return a string');
-      }
-    }
-    if (string.isEmpty) return;
-    add(_encodeString(string, _encoding));
-  }
-
-  void writeAll(Iterable objects, [String separator = ""]) {
-    Iterator iterator = objects.iterator;
-    if (!iterator.moveNext()) return;
-    if (separator.isEmpty) {
-      do {
-        write(iterator.current);
-      } while (iterator.moveNext());
-    } else {
-      write(iterator.current);
-      while (iterator.moveNext()) {
-        write(separator);
-        write(iterator.current);
-      }
-    }
-  }
-
-  void writeln([Object obj = ""]) {
-    write(obj);
-    write("\n");
-  }
-
-  void writeCharCode(int charCode) {
-    write(new String.fromCharCode(charCode));
-  }
-
-  void add(List<int> data) {
+  void add(T data) {
     _controller.add(data);
   }
 
@@ -127,9 +73,9 @@ class _IOSinkImpl implements IOSink {
     _controller.addError(error);
   }
 
-  Future addStream(Stream<List<int>> stream) {
+  Future addStream(Stream<T> stream) {
     if (_isBound) {
-      throw new StateError("IOSink is already bound to a stream");
+      throw new StateError("StreamSink is already bound to a stream");
     }
     _isBound = true;
     // Wait for any sync operations to complete.
@@ -147,7 +93,7 @@ class _IOSinkImpl implements IOSink {
 
   Future close() {
     if (_isBound) {
-      throw new StateError("IOSink is bound to a stream");
+      throw new StateError("StreamSink is bound to a stream");
     }
     if (!_isClosed) {
       _isClosed = true;
@@ -179,15 +125,15 @@ class _IOSinkImpl implements IOSink {
     }
   }
 
-  StreamController<List<int>> get _controller {
+  StreamController<T> get _controller {
     if (_isBound) {
-      throw new StateError("IOSink is bound to a stream");
+      throw new StateError("StreamSink is bound to a stream");
     }
     if (_isClosed) {
-      throw new StateError("IOSink is closed");
+      throw new StateError("StreamSink is closed");
     }
     if (_controllerInstance == null) {
-      _controllerInstance = new StreamController<List<int>>();
+      _controllerInstance = new StreamController<T>();
       _controllerCompleter = new Completer();
       _target.addStream(_controller.stream)
           .then(
@@ -220,3 +166,63 @@ class _IOSinkImpl implements IOSink {
     return _controllerInstance;
   }
 }
+
+
+class _IOSinkImpl extends _StreamSinkImpl<List<int>> implements IOSink {
+  Encoding _encoding;
+  bool _encodingMutable = true;
+
+  _IOSinkImpl(StreamConsumer<List<int>> target, this._encoding)
+      : super(target);
+
+  Encoding get encoding => _encoding;
+
+  void set encoding(Encoding value) {
+    if (!_encodingMutable) {
+      throw new StateError("IOSink encoding is not mutable");
+    }
+    _encoding = value;
+  }
+
+  void write(Object obj) {
+    // This comment is copied from runtime/lib/string_buffer_patch.dart.
+    // TODO(srdjan): The following four lines could be replaced by
+    // '$obj', but apparently this is too slow on the Dart VM.
+    String string;
+    if (obj is String) {
+      string = obj;
+    } else {
+      string = obj.toString();
+      if (string is! String) {
+        throw new ArgumentError('toString() did not return a string');
+      }
+    }
+    if (string.isEmpty) return;
+    add(_encodeString(string, _encoding));
+  }
+
+  void writeAll(Iterable objects, [String separator = ""]) {
+    Iterator iterator = objects.iterator;
+    if (!iterator.moveNext()) return;
+    if (separator.isEmpty) {
+      do {
+        write(iterator.current);
+      } while (iterator.moveNext());
+    } else {
+      write(iterator.current);
+      while (iterator.moveNext()) {
+        write(separator);
+        write(iterator.current);
+      }
+    }
+  }
+
+  void writeln([Object obj = ""]) {
+    write(obj);
+    write("\n");
+  }
+
+  void writeCharCode(int charCode) {
+    write(new String.fromCharCode(charCode));
+  }
+}