Better handling of stdin/stdout/stderr

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;
-  }
+  SocketInputStream(Socket socket) : _socket = socket;
 
   List<int> read([int len]) {
     int bytesToRead = available();
     if (bytesToRead == 0) return null;
     if (len !== null) {
       if (len <= 0) {
         throw new StreamException("Illegal length $len");
       } else if (bytesToRead > len) {
         bytesToRead = len;
       }
@@ skipping 30 matching lines @@
   void set errorHandler(void callback()) {
     _socket.errorHandler = callback;
   }
 
   Socket _socket;
 }
 
 
 class SocketOutputStream implements OutputStream {
   SocketOutputStream(Socket socket)
-      : _socket = socket, _pendingWrites = new _BufferList() {
-    _socket.writeHandler = _writeHandler;
-    _socket.errorHandler = _errorHandler;
-  }
+      : _socket = socket, _pendingWrites = new _BufferList();
 
     bool write(List<int> buffer, [bool copyBuffer = true]) {
     return _write(buffer, 0, buffer.length, copyBuffer);
   }
 
   bool writeFrom(List<int> buffer, [int offset = 0, int len]) {
     return _write(
         buffer, offset, (len == null) ? buffer.length - offset : len, true);
   }
 
@@ skipping 11 matching lines @@
 
   void destroy() {
     _socket.writeHandler = null;
     _pendingWrites.clear();
     _socket.close();
     _closed = true;
   }
 
   void set noPendingWriteHandler(void callback()) {
     _noPendingWriteHandler = callback;
-    _socket.writeHandler = _writeHandler;
+    if (_noPendingWriteHandler != null) {
+      _socket.writeHandler = _writeHandler;
+    }
   }
 
   void set closeHandler(void callback()) {
     _socket.closeHandler = callback;
   }
 
   void set errorHandler(void callback()) {
     _streamErrorHandler = callback;
+    if (_streamErrorHandler != null) {
+      _socket.errorHandler = _errorHandler;
+    } else {
+      _socket.errorHandler = null;
+    }
   }
 
   bool _write(List<int> buffer, int offset, int len, bool copyBuffer) {
     if (_closing || _closed) throw new StreamException("Stream closed");
     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;
     }
 
     // Place remaining data on the pending writes queue.
     int notWrittenOffset = offset + bytesWritten;
     if (copyBuffer) {
       List<int> newBuffer =
           buffer.getRange(notWrittenOffset, len - bytesWritten);
       _pendingWrites.add(newBuffer);
     } else {
       assert(offset + len == buffer.length);
       _pendingWrites.add(buffer, notWrittenOffset);
     }
+    _socket.writeHandler = _writeHandler;
   }
 
   void _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) {
         _socket.writeHandler = _writeHandler;
         return;
       }
     }
 
     // All buffered data was written.
     if (_closing) {
       _socket._closeWrite();
       _closed = true;
     } else {
       if (_noPendingWriteHandler != null) _noPendingWriteHandler();
     }
+    if (_noPendingWriteHandler == null) _socket.writeHandler = null;
   }
 
   void _errorHandler() {
     close();
     if (_streamErrorHandler != null) _streamErrorHandler();
   }
 
   Socket _socket;
   _BufferList _pendingWrites;
   var _noPendingWriteHandler;
   var _streamErrorHandler;
   bool _closing = false;
   bool _closed = false;
 }