Better handling of stdin/stdout/stderr

runtime/bin/socket_impl.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 _SocketBase {
   // Bit flags used when communicating between the eventhandler and
   // dart code. The EVENT flags are used to indicate events of
   // interest when sending a message from dart code to the
   // eventhandler. When receiving a message from the eventhandler the
   // EVENT flags indicate the events that actually happened. The
   // COMMAND flags are used to send commands from dart to the
   // eventhandler. COMMAND flags are never received from the
   // eventhandler. Additional flags are used to communicate other
   // information.
   static final int _IN_EVENT = 0;
   static final int _OUT_EVENT = 1;
   static final int _ERROR_EVENT = 2;
   static final int _CLOSE_EVENT = 3;
 
   static final int _CLOSE_COMMAND = 8;
   static final int _SHUTDOWN_READ_COMMAND = 9;
   static final int _SHUTDOWN_WRITE_COMMAND = 10;
 
-  // Flag send to the eventhandler saying that the file descriptor in
-  // question represents a listening socket.
+  // Flag send to the eventhandler providing additional information on
+  // the type of the file descriptor.
   static final int _LISTENING_SOCKET = 16;
+  static final int _PIPE = 17;
 
   static final int _FIRST_EVENT = _IN_EVENT;
   static final int _LAST_EVENT = _CLOSE_EVENT;
 
   static final int _FIRST_COMMAND = _CLOSE_COMMAND;
   static final int _LAST_COMMAND = _SHUTDOWN_WRITE_COMMAND;
 
   _SocketBase () {
-    _handler = new ReceivePort();
     _handlerMap = new List(_LAST_EVENT + 1);
     _handlerMask = 0;
     _canActivateHandlers = true;
     _id = -1;
-    _handler.receive((var message, ignored) {
-      _multiplex(message);
-    });
     EventHandler._start();
   }
 
-  /*
-   * Multiplexes socket events to the right socket handler.
-   */
+  // Multiplexes socket events to the socket handlers.
   void _multiplex(List<int> message) {
     assert(message.length == 1);
     _canActivateHandlers = false;
     int event_mask = message[0];
     for (int i = _FIRST_EVENT; i <= _LAST_EVENT; i++) {
       if (((event_mask & (1 << i)) != 0)) {
         if ((i == _CLOSE_EVENT) && this is _Socket && _id >= 0) {
           _closedRead = true;
           if (_closedWrite) _close();
         }
@@ skipping 16 matching lines @@
     _activateHandlers();
   }
 
   void _setHandler(int event, void callback()) {
     if (callback == null) {
       _handlerMask &= ~(1 << event);
     } else {
       _handlerMask |= (1 << event);
     }
     _handlerMap[event] = callback;
-    _activateHandlers();
+    // If the socket is only for writing then close the receive port
+    // when not waiting for any events.
+    if (this is _Socket &&
+        _closedRead &&
+        _handlerMask == 0 &&
+        _handler != null) {
+      _handler.close();
+      _handler = null;
+    } else {
+      _activateHandlers();
+    }
   }
 
   void _getPort() native "Socket_GetPort";
 
   void set errorHandler(void callback()) {
     _setHandler(_ERROR_EVENT, callback);
   }
 
   void _activateHandlers() {
     if (_canActivateHandlers && (_id >= 0)) {
       int data = _handlerMask;
       if (_isListenSocket()) {
         data |= (1 << _LISTENING_SOCKET);
       } else {
         if (_closedRead) { data &= ~(1 << _IN_EVENT); }
         if (_closedWrite) { data &= ~(1 << _OUT_EVENT); }
-        if (_isListenSocket()) data |= (1 << _LISTENING_SOCKET);

[Mads Ager (google), 2011/11/14 14:14:23]

Good catch. :)

+        if (_isPipe()) data |= (1 << _PIPE);
       }
-      EventHandler._sendData(_id, _handler, data);
+      _sendToEventHandler(data);
     }
   }
 
-  void _scheduleEvent(int event) {
-    _handler.toSendPort().send([1 << event], null);
-  }
-
   int get port() {
     if (_port === null) {
       _port = _getPort();
     }
     return _port;
   }
 
   void close([bool halfClose = false]) {
     if (_id >= 0) {
       if (halfClose) {
         _closeWrite();
       } else {
         _close();
       }
     } else if (_handler != null) {
       // This is to support closing sockets created but never assigned
       // any actual socket.
       _handler.close();
       _handler = null;
     }
   }
 
   void _closeWrite() {
     if (_closedRead) {
       _close();
     } else {
-      EventHandler._sendData(_id, _handler, 1 << _SHUTDOWN_WRITE_COMMAND);
+      _sendToEventHandler(1 << _SHUTDOWN_WRITE_COMMAND);
     }
     _closedWrite = true;
   }
 
   void _closeRead() {
     if (_closedWrite) {
       _close();
     } else {
-      EventHandler._sendData(_id, _handler, 1 << _SHUTDOWN_READ_COMMAND);
+      _sendToEventHandler(1 << _SHUTDOWN_READ_COMMAND);
     }
     _closedRead = true;
   }
 
   void _close() {
-    EventHandler._sendData(_id, _handler, 1 << _CLOSE_COMMAND);
+    _sendToEventHandler(1 << _CLOSE_COMMAND);
     _handler.close();
     _handler = null;
     _id = -1;
   }
 
+  void _sendToEventHandler(int data) {
+    if (_handler === null) {
+      _handler = new ReceivePort();
+      _handler.receive((var message, ignored) { _multiplex(message); });
+    }
+    EventHandler._sendData(_id, _handler, data);
+  }
+
   abstract bool _isListenSocket();
+  abstract bool _isPipe();
 
   /*
    * Socket id is set from native. -1 indicates that the socket was closed.
    */
   int _id;
 
   /*
    * Dedicated ReceivePort for socket events.
    */
   ReceivePort _handler;
@@ skipping 57 matching lines @@
   bool _accept(Socket socket) native "ServerSocket_Accept";
 
   bool _createBindListen(String bindAddress, int port, int backlog)
       native "ServerSocket_CreateBindListen";
 
   void set connectionHandler(void callback()) {
     _setHandler(_IN_EVENT, callback);
   }
 
   bool _isListenSocket() => true;
+  bool _isPipe() => false;
 }
 
 
 class _Socket extends _SocketBase implements Socket {
   /*
    * Constructor for socket. First a socket object is allocated
    * in which the native socket is stored. After that _createConnect is
    * called which creates a file discriptor and connects to the given
    * host on the given port. Null is returned if file descriptor creation
    * or connect failed.
    */
   factory _Socket(String host, int port) {
     Socket socket = new _Socket._internal();
     if (!socket._createConnect(host, port)) {
       socket.close();
       return null;
     }
     return socket;
   }
 
   _Socket._internal();
-  _Socket._internalReadOnly() : _closedWrite = true;
-  _Socket._internalWriteOnly() : _closedRead = true;
+  _Socket._internalReadOnly() : _closedWrite = true, _pipe = true;
+  _Socket._internalWriteOnly() : _closedRead = true, _pipe = true;
 
   int available() {
     if (_id >= 0) {
       return _available();
     }
     throw new
         SocketIOException("Error: available failed - invalid socket handle");
   }
 
   int _available() native "Socket_Available";
@@ skipping 58 matching lines @@
 
   void set dataHandler(void callback()) {
     _setHandler(_IN_EVENT, callback);
   }
 
   void set closeHandler(void callback()) {
     _setHandler(_CLOSE_EVENT, callback);
   }
 
   bool _isListenSocket() => false;
+  bool _isPipe() => _pipe;
 
   InputStream get inputStream() {
     if (_inputStream === null) {
       _inputStream = new SocketInputStream(this);
     }
     return _inputStream;
   }
 
   OutputStream get outputStream() {
     if (_outputStream === null) {
       _outputStream = new SocketOutputStream(this);
     }
     return _outputStream;
   }
 
   bool _closedRead = false;
   bool _closedWrite = false;
+  bool _pipe = false;
   SocketInputStream _inputStream;
   SocketOutputStream _outputStream;
 }