New OutputStream interface

runtime/bin/socket_stream.dart

 // Copyright (c) 2011, 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.
 
 class SocketInputStream implements InputStream {
   SocketInputStream(Socket socket) {
     _socket = socket;
   }
 
   List<int> read([int len]) {
@@ skipping 38 matching lines @@
   }
 
   void set errorHandler(void callback()) {
     _socket.setErrorHandler(callback);
   }
 
   Socket _socket;
 }
 
 
+class _BufferList2 {
+  _BufferList2() {
+    clear();
+  }
+
+  // Adds a new buffer to the list possibly with an offset of the
+  // first byte of interest. The offset can only be specified if the
+  // buffer list is empty.
+  void add(List<int> buffer, [int offset = 0]) {
+    assert(offset == 0 || _buffers.isEmpty());
+    _buffers.addLast(buffer);
+    _length += buffer.length;
+    if (offset != 0) _index = offset;
+  }
+
+  List<int> get first() => _buffers.first();
+  int get index() => _index;
+
+  void removeBytes(int count) {
+    int firstRemaining = first.length - _index;
+    assert(count <= firstRemaining);
+    if (count == firstRemaining) {
+      _buffers.removeFirst();
+      _index = 0;
+    } else {
+      _index += count;
+    }
+    _length -= count;
+  }
+
+  int get length() => _length;
+
+  bool isEmpty() => _buffers.isEmpty();
+
+  void clear() {
+    _index = 0;
+    _length = 0;
+    _buffers = new Queue();
+  }
+
+  int _length;  // Total length of pending data.
+  Queue<List<int>> _buffers;
+  int _index;  // Offset into the first buffer of next write position.
+}
+
+
 class SocketOutputStream implements OutputStream {
-  SocketOutputStream(Socket socket) : _socket = socket;
+  SocketOutputStream(Socket socket)
+      : _socket = socket, _pendingWrites = new _BufferList2() {
+    _socket.setWriteHandler(_writeHandler);
+    _socket.setErrorHandler(_errorHandler);
+  }
 
-  bool write(List<int> buffer, int offset, int len, void callback()) {
-    int bytesWritten = _socket.writeList(buffer, offset, len);
+  bool write(List<int> buffer) {
+    return _write(buffer, 0, buffer.length, false);
+  }
 
-    void finishWrite() {
-      bytesWritten += _socket.writeList(
-          buffer, offset + bytesWritten, len - bytesWritten);
-      if (bytesWritten < len) {
-        _socket.setWriteHandler(finishWrite);
-      } else {
-        assert(bytesWritten == len);
-        if (callback !== null) {
-          callback();
-        }
-      }
+  bool writeFrom(List<int> buffer, [int offset = 0, int len]) {
+    return _write(buffer, offset, (len == null) ? buffer.length : len, true);
+  }
+
+  void end() {
+    if (_ending || _ended) throw new StreamException("Stream ended");
+    _ending = true;
+    if (_pendingWrites.isEmpty()) {
+      close();
+    }
+  }
+
+  void close() {
+    _socket.setWriteHandler(null);
+    _pendingWrites.clear();
+    _socket.close();
+    _ended = true;
+  }
+
+  void set noPendingWriteHandler(void callback()) {
+    _noPendingWriteHandler = callback;
+    _socket.setWriteHandler(_writeHandler);
+  }
+
+  void set closeHandler(void callback()) {
+    _socket.setCloseHandler(callback());
+  }
+
+  void set errorHandler(void callback()) {
+    _streamErrorHandler = callback();
+  }
+
+  bool _write(List<int> buffer, int offset, int len, bool copyBuffer) {
+    if (_ending || _ended) throw new StreamException("Stream ended");
+    if (len == null) len = buffer.length;
+    int bytesWritten = 0;
+    if (_pendingWrites.isEmpty()) {
+      // If nothing is buffered write as much as possible and buffer
+      // the rest.
+      bytesWritten = _socket.writeList(buffer, offset, len);
+      if (bytesWritten == len) return true;
     }
 
-    if (bytesWritten == len) {
-      return true;
+    // Place remaining data on the pending writes queue.
+    if (copyBuffer) {
+      List<int> newBuffer =
+          new List.fromList(buffer, offset + bytesWritten, buffer.length);
+      _pendingWrites.add(newBuffer);
+    } else {
+      _pendingWrites.add(buffer, bytesWritten);
     }
-    _socket.setWriteHandler(finishWrite);
-    return false;
+  }
+
+  void _writeHandler() {
+    _socket.setWriteHandler(_writeHandler);
+    // Write as much buffered data to the socket as possible.
+    while (!_pendingWrites.isEmpty()) {
+      List<int> buffer = _pendingWrites.first;
+      int offset = _pendingWrites.index;
+      int bytesToWrite = buffer.length - offset;
+      int bytesWritten = _socket.writeList(buffer, offset, bytesToWrite);
+      _pendingWrites.removeBytes(bytesWritten);
+      if (bytesWritten < bytesToWrite) return;
+    }
+
+    // All buffered data was written.
+    if (_ending) {
+      _socket.close();
+      _ended = true;
+    } else {
+      if (_noPendingWriteHandler != null) _noPendingWriteHandler();
+    }
+  }
+
+  void _errorHandler() {
+    close();
+    if (_streamErrorHandler != null) _streamErrorHandler();
   }
 
   Socket _socket;
+  _BufferList2 _pendingWrites;
+  bool _ending = false;
+  bool _ended = false;
+  var _noPendingWriteHandler;
+  var _streamErrorHandler;
 }