Revert "Revert "Make stdout/stderr async""

sdk/lib/io/stdio.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 const int _STDIO_HANDLE_TYPE_TERMINAL = 0;
 const int _STDIO_HANDLE_TYPE_PIPE = 1;
 const int _STDIO_HANDLE_TYPE_FILE = 2;
 const int _STDIO_HANDLE_TYPE_SOCKET = 3;
@@ skipping 131 matching lines @@
    * Synchronously read a byte from stdin. This call will block until a byte is
    * available.
    *
    * If at end of file, -1 is returned.
    */
   external int readByteSync();
 }
 
 
 /**
- * [Stdout] represents the [IOSink] for either `stdout` or `stderr`.
+ * [Stdout] exposes methods to query the terminal for properties.
  *
- * It provides a *blocking* `IOSink`, so using this to write will block until
- * the output is written.
- *
- * In some situations this blocking behavior is undesirable as it does not
- * provide the same non-blocking behavior as dart:io in general exposes.
- * Use the property [nonBlocking] to get an `IOSink` which has the non-blocking
- * behavior.
- *
- * This class can also be used to check whether `stdout` or `stderr` is
- * connected to a terminal and query some terminal properties.
+ * Use [hasTerminal] to test if there is a terminal associated to stdout.
  */
 class Stdout extends _StdSink implements IOSink {
-  final int _fd;
-  IOSink _nonBlocking;
-
-  Stdout._(IOSink sink, this._fd) : super(sink);
+  Stdout._(IOSink sink) : super(sink);
 
   /**
    * Returns true if there is a terminal attached to stdout.
    */
-  bool get hasTerminal => _hasTerminal(_fd);
+  external bool get hasTerminal;
 
   /**
    * Get the number of columns of the terminal.
    *
    * If no terminal is attached to stdout, a [StdoutException] is thrown. See
    * [hasTerminal] for more info.
    */
-  int get terminalColumns => _terminalColumns(_fd);
+  external int get terminalColumns;
 
   /**
    * Get the number of lines of the terminal.
    *
    * If no terminal is attached to stdout, a [StdoutException] is thrown. See
    * [hasTerminal] for more info.
    */
-  int get terminalLines => _terminalLines(_fd);
-
-  external bool _hasTerminal(int fd);
-  external int _terminalColumns(int fd);
-  external int _terminalLines(int fd);
-
-  /**
-   * Get a non-blocking `IOSink`.
-   */
-  IOSink get nonBlocking {
-    if (_nonBlocking == null) {
-      _nonBlocking = new IOSink(new _FileStreamConsumer.fromStdio(_fd));
-    }
-    return _nonBlocking;
-  }
+  external int get terminalLines;
 }
 
 
 class StdoutException implements IOException {
   final String message;
   final OSError osError;
 
   const StdoutException(this.message, [this.osError]);
 
   String toString() {
     return "StdoutException: $message${osError == null ? "" : ", $osError"}";
   }
 }
 
-class _StdConsumer implements StreamConsumer<List<int>> {
-  final _file;
-
-  _StdConsumer(int fd) : _file = _File._openStdioSync(fd);
-
-  Future addStream(Stream<List<int>> stream) {
-    var completer = new Completer();
-    var sub;
-    sub = stream.listen(
-        (data) {
-          try {
-            _file.writeFromSync(data);
-          } catch (e, s) {
-            sub.cancel();
-            completer.completeError(e, s);
-          }
-        },
-        onError: completer.completeError,
-        onDone: completer.complete,
-        cancelOnError: true);
-    return completer.future;
-  }
-
-  Future close() {
-    _file.closeSync();
-    return new Future.value();
-  }
-}
 
 class _StdSink implements IOSink {
   final IOSink _sink;
 
   _StdSink(this._sink);
 
   Encoding get encoding => _sink.encoding;
   void set encoding(Encoding encoding) {
     _sink.encoding = encoding;
   }
@@ skipping 17 matching lines @@
   static const StdioType FILE = const StdioType._("file");
   static const StdioType OTHER = const StdioType._("other");
   final String name;
   const StdioType._(this.name);
   String toString() => "StdioType: $name";
 }
 
 
 Stdin _stdin;
 Stdout _stdout;
-Stdout _stderr;
+IOSink _stderr;
 
 
 /// The standard input stream of data read by this program.
 Stdin get stdin {
   if (_stdin == null) {
     _stdin = _StdIOUtils._getStdioInputStream();
   }
   return _stdin;
 }
 
 
 /// The standard output stream of data written by this program.
 Stdout get stdout {
   if (_stdout == null) {
     _stdout = _StdIOUtils._getStdioOutputStream(1);
   }
   return _stdout;
 }
 
 
 /// The standard output stream of errors written by this program.
-Stdout get stderr {
+IOSink get stderr {
   if (_stderr == null) {
     _stderr = _StdIOUtils._getStdioOutputStream(2);
   }
   return _stderr;
 }
 
 
 /// For a stream, returns whether it is attached to a file, pipe, terminal, or
 /// something else.
 StdioType stdioType(object) {
@@ skipping 28 matching lines @@
   return StdioType.OTHER;
 }
 
 
 class _StdIOUtils {
   external static _getStdioOutputStream(int fd);
   external static Stdin _getStdioInputStream();
   external static int _socketType(nativeSocket);
   external static _getStdioHandleType(int fd);
 }