Migrate dart2js stubs for dart:io

tool/input_sdk/lib/io/file_impl.dart

Index: tool/input_sdk/lib/io/file_impl.dart
diff --git a/tool/input_sdk/lib/io/file_impl.dart b/tool/input_sdk/lib/io/file_impl.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a6fdde8e4d6e6390d3b5c3081e2f5e1ace3af4b3
--- /dev/null
+++ b/tool/input_sdk/lib/io/file_impl.dart
@@ -0,0 +1,1025 @@
+// 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;
+
+// Read the file in blocks of size 64k.
+const int _BLOCK_SIZE = 64 * 1024;
+
+
+class _FileStream extends Stream<List<int>> {
+  // Stream controller.
+  StreamController<List<int>> _controller;
+
+  // Information about the underlying file.
+  String _path;
+  RandomAccessFile _openedFile;
+  int _position;
+  int _end;
+  final Completer _closeCompleter = new Completer();
+
+  // Has the stream been paused or unsubscribed?
+  bool _unsubscribed = false;
+
+  // Is there a read currently in progress?
+  bool _readInProgress = true;
+  bool _closed = false;
+
+  bool _atEnd = false;
+
+  _FileStream(this._path, this._position, this._end) {
+    if (_position == null) _position = 0;
+  }
+
+  _FileStream.forStdin() : _position = 0;
+
+  StreamSubscription<List<int>> listen(void onData(List<int> event),
+                                       {Function onError,
+                                        void onDone(),
+                                        bool cancelOnError}) {
+    _setupController();
+    return _controller.stream.listen(onData,
+                                     onError: onError,
+                                     onDone: onDone,
+                                     cancelOnError: cancelOnError);
+  }
+
+  void _setupController() {
+    _controller = new StreamController<List<int>>(sync: true,
+        onListen: _start,
+        onResume: _readBlock,
+        onCancel: () {
+          _unsubscribed = true;
+          return _closeFile();
+        });
+  }
+
+  Future _closeFile() {
+    if (_readInProgress || _closed) {
+      return _closeCompleter.future;
+    }
+    _closed = true;
+
+    void done() {
+      _closeCompleter.complete();
+      _controller.close();
+    }
+
+    _openedFile.close()
+        .catchError(_controller.addError)
+        .whenComplete(done);
+    return _closeCompleter.future;
+  }
+
+  void _readBlock() {
+    // Don't start a new read if one is already in progress.
+    if (_readInProgress) return;
+    if (_atEnd) {
+      _closeFile();
+      return;
+    }
+    _readInProgress = true;
+    int readBytes = _BLOCK_SIZE;
+    if (_end != null) {
+      readBytes = min(readBytes, _end - _position);
+      if (readBytes < 0) {
+        _readInProgress = false;
+        if (!_unsubscribed) {
+          _controller.addError(new RangeError("Bad end position: $_end"));
+          _closeFile();
+          _unsubscribed = true;
+        }
+        return;
+      }
+    }
+    _openedFile.read(readBytes)
+      .then((block) {
+        _readInProgress = false;
+        if (_unsubscribed) {
+          _closeFile();
+          return;
+        }
+        _position += block.length;
+        if (block.length < readBytes ||
+            (_end != null && _position == _end)) {
+          _atEnd = true;
+        }
+        if (!_atEnd && !_controller.isPaused) {
+          _readBlock();
+        }
+        _controller.add(block);
+        if (_atEnd) {
+          _closeFile();
+        }
+      })
+      .catchError((e, s) {
+        if (!_unsubscribed) {
+          _controller.addError(e, s);
+          _closeFile();
+          _unsubscribed = true;
+        }
+      });
+  }
+
+  void _start() {
+    if (_position < 0) {
+      _controller.addError(new RangeError("Bad start position: $_position"));
+      _controller.close();
+      _closeCompleter.complete();
+      return;
+    }
+
+    void onReady(RandomAccessFile file) {
+      _openedFile = file;
+      _readInProgress = false;
+      _readBlock();
+    }
+
+    void onOpenFile(RandomAccessFile file) {
+      if (_position > 0) {
+        file.setPosition(_position)
+            .then(onReady, onError: (e, s) {
+              _controller.addError(e, s);
+              _readInProgress = false;
+              _closeFile();
+            });
+      } else {
+        onReady(file);
+      }
+    }
+
+    void openFailed(error, stackTrace) {
+      _controller.addError(error, stackTrace);
+      _controller.close();
+      _closeCompleter.complete();
+    }
+
+    if (_path != null) {
+      new File(_path).open(mode: FileMode.READ)
+          .then(onOpenFile, onError: openFailed);
+    } else {
+      try {
+        onOpenFile(_File._openStdioSync(0));
+      } catch (e, s) {
+        openFailed(e, s);
+      }
+    }
+  }
+}
+
+class _FileStreamConsumer extends StreamConsumer<List<int>> {
+  File _file;
+  Future<RandomAccessFile> _openFuture;
+
+  _FileStreamConsumer(File this._file, FileMode mode) {
+    _openFuture = _file.open(mode: mode);
+  }
+
+  _FileStreamConsumer.fromStdio(int fd) {
+    assert(1 <= fd && fd <= 2);
+    _openFuture = new Future.value(_File._openStdioSync(fd));
+  }
+
+  Future<File> addStream(Stream<List<int>> stream) {
+    Completer<File> completer = new Completer<File>.sync();
+    _openFuture
+      .then((openedFile) {
+        var _subscription;
+        void error(e, [StackTrace stackTrace]) {
+          _subscription.cancel();
+          openedFile.close();
+          completer.completeError(e, stackTrace);
+        }
+        _subscription = stream.listen(
+          (d) {
+            _subscription.pause();
+            try {
+              openedFile.writeFrom(d, 0, d.length)
+                .then((_) => _subscription.resume(),
+                      onError: error);
+            } catch (e, stackTrace) {
+              error(e, stackTrace);
+            }
+          },
+          onDone: () {
+            completer.complete(_file);
+          },
+          onError: error,
+          cancelOnError: true);
+      })
+      .catchError(completer.completeError);
+    return completer.future;
+  }
+
+  Future<File> close() =>
+      _openFuture.then((openedFile) => openedFile.close());
+}
+
+
+// Class for encapsulating the native implementation of files.
+class _File extends FileSystemEntity implements File {
+  final String path;
+
+  // Constructor for file.
+  _File(this.path) {
+    if (path is! String) {
+      throw new ArgumentError('${Error.safeToString(path)} '
+                              'is not a String');
+    }
+  }
+
+  Future<bool> exists() {
+    return _IOService._dispatch(_FILE_EXISTS, [path]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "Cannot check existence", path);
+      }
+      return response;
+    });
+  }
+
+  external static _exists(String path);
+
+  bool existsSync() {
+    var result = _exists(path);
+    throwIfError(result, "Cannot check existence of file", path);
+    return result;
+  }
+
+  File get absolute => new File(_absolutePath);
+
+  Future<FileStat> stat() => FileStat.stat(path);
+
+  FileStat statSync() => FileStat.statSync(path);
+
+  Future<File> create({bool recursive: false}) {
+    var result = recursive ? parent.create(recursive: true)
+                           : new Future.value(null);
+    return result
+      .then((_) => _IOService._dispatch(_FILE_CREATE, [path]))
+      .then((response) {
+        if (_isErrorResponse(response)) {
+          throw _exceptionFromResponse(response, "Cannot create file", path);
+        }
+        return this;
+      });
+  }
+
+  external static _create(String path);
+
+  external static _createLink(String path, String target);
+
+  external static _linkTarget(String path);
+
+  void createSync({bool recursive: false}) {
+    if (recursive) {
+      parent.createSync(recursive: true);
+    }
+    var result = _create(path);
+    throwIfError(result, "Cannot create file", path);
+  }
+
+  Future<File> _delete({bool recursive: false}) {
+    if (recursive) {
+      return new Directory(path).delete(recursive: true).then((_) => this);
+    }
+    return _IOService._dispatch(_FILE_DELETE, [path]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "Cannot delete file", path);
+      }
+      return this;
+    });
+  }
+
+  external static _deleteNative(String path);
+
+  external static _deleteLinkNative(String path);
+
+  void _deleteSync({bool recursive: false}) {
+    if (recursive) {
+      return new Directory(path).deleteSync(recursive: true);
+    }
+    var result = _deleteNative(path);
+    throwIfError(result, "Cannot delete file", path);
+  }
+
+  Future<File> rename(String newPath) {
+    return _IOService._dispatch(_FILE_RENAME, [path, newPath]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(
+            response, "Cannot rename file to '$newPath'", path);
+      }
+      return new File(newPath);
+    });
+  }
+
+  external static _rename(String oldPath, String newPath);
+
+  external static _renameLink(String oldPath, String newPath);
+
+  File renameSync(String newPath) {
+    var result = _rename(path, newPath);
+    throwIfError(result, "Cannot rename file to '$newPath'", path);
+    return new File(newPath);
+  }
+
+  Future<File> copy(String newPath) {
+    return _IOService._dispatch(_FILE_COPY, [path, newPath]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(
+            response, "Cannot copy file to '$newPath'", path);
+      }
+      return new File(newPath);
+    });
+  }
+
+  external static _copy(String oldPath, String newPath);
+
+  File copySync(String newPath) {
+    var result = _copy(path, newPath);
+    throwIfError(result, "Cannot copy file to '$newPath'", path);
+    return new File(newPath);
+  }
+
+  Future<RandomAccessFile> open({FileMode mode: FileMode.READ}) {
+    if (mode != FileMode.READ &&
+        mode != FileMode.WRITE &&
+        mode != FileMode.APPEND &&
+        mode != FileMode.WRITE_ONLY &&
+        mode != FileMode.WRITE_ONLY_APPEND) {
+      return new Future.error(
+          new ArgumentError('Invalid file mode for this operation'));
+    }
+    return _IOService._dispatch(_FILE_OPEN, [path, mode._mode])
+        .then((response) {
+          if (_isErrorResponse(response)) {
+            throw _exceptionFromResponse(response, "Cannot open file", path);
+          }
+          return new _RandomAccessFile(response, path);
+        });
+  }
+
+  Future<int> length() {
+    return _IOService._dispatch(_FILE_LENGTH_FROM_PATH, [path])
+        .then((response) {
+          if (_isErrorResponse(response)) {
+            throw _exceptionFromResponse(response,
+                                         "Cannot retrieve length of file",
+                                         path);
+          }
+          return response;
+        });
+  }
+
+
+  external static _lengthFromPath(String path);
+
+  int lengthSync() {
+    var result = _lengthFromPath(path);
+    throwIfError(result, "Cannot retrieve length of file", path);
+    return result;
+  }
+
+  Future<DateTime> lastModified() {
+    return _IOService._dispatch(_FILE_LAST_MODIFIED, [path]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response,
+                                     "Cannot retrieve modification time",
+                                     path);
+      }
+      return new DateTime.fromMillisecondsSinceEpoch(response);
+    });
+  }
+
+  external static _lastModified(String path);
+
+  DateTime lastModifiedSync() {
+    var ms = _lastModified(path);
+    throwIfError(ms, "Cannot retrieve modification time", path);
+    return new DateTime.fromMillisecondsSinceEpoch(ms);
+  }
+
+  external static _open(String path, int mode);
+
+  RandomAccessFile openSync({FileMode mode: FileMode.READ}) {
+    if (mode != FileMode.READ &&
+        mode != FileMode.WRITE &&
+        mode != FileMode.APPEND &&
+        mode != FileMode.WRITE_ONLY &&
+        mode != FileMode.WRITE_ONLY_APPEND) {
+      throw new ArgumentError('Invalid file mode for this operation');
+    }
+    var id = _open(path, mode._mode);
+    throwIfError(id, "Cannot open file", path);
+    return new _RandomAccessFile(id, path);
+  }
+
+  external static int _openStdio(int fd);
+
+  static RandomAccessFile _openStdioSync(int fd) {
+    var id = _openStdio(fd);
+    if (id == 0) {
+      throw new FileSystemException("Cannot open stdio file for: $fd");
+    }
+    return new _RandomAccessFile(id, "");
+  }
+
+  Stream<List<int>> openRead([int start, int end]) {
+    return new _FileStream(path, start, end);
+  }
+
+  IOSink openWrite({FileMode mode: FileMode.WRITE,
+                    Encoding encoding: UTF8}) {
+    if (mode != FileMode.WRITE &&
+        mode != FileMode.APPEND &&
+        mode != FileMode.WRITE_ONLY &&
+        mode != FileMode.WRITE_ONLY_APPEND) {
+      throw new ArgumentError('Invalid file mode for this operation');
+    }
+    var consumer = new _FileStreamConsumer(this, mode);
+    return new IOSink(consumer, encoding: encoding);
+  }
+
+  Future<List<int>> readAsBytes() {
+    Future<List<int>> readDataChunked(file) {
+      var builder = new BytesBuilder(copy: false);
+      var completer = new Completer();
+      void read() {
+        file.read(_BLOCK_SIZE).then((data) {
+          if (data.length > 0) {
+            builder.add(data);
+            read();
+          } else {
+            completer.complete(builder.takeBytes());
+          }
+        }, onError: completer.completeError);
+      }
+      read();
+      return completer.future;
+    }
+
+    return open().then((file) {
+      return file.length().then((length) {
+        if (length == 0) {
+          // May be character device, try to read it in chunks.
+          return readDataChunked(file);
+        }
+        return file.read(length);
+      }).whenComplete(file.close);
+    });
+  }
+
+  List<int> readAsBytesSync() {
+    var opened = openSync();
+    try {
+      var data;
+      var length = opened.lengthSync();
+      if (length == 0) {
+        // May be character device, try to read it in chunks.
+        var builder = new BytesBuilder(copy: false);
+        do {
+          data = opened.readSync(_BLOCK_SIZE);
+          if (data.length > 0) builder.add(data);
+        } while (data.length > 0);
+        data = builder.takeBytes();
+      } else {
+        data = opened.readSync(length);
+      }
+      return data;
+    } finally {
+      opened.closeSync();
+    }
+  }
+
+  String _tryDecode(List<int> bytes, Encoding encoding) {
+    try {
+      return encoding.decode(bytes);
+    } catch (_) {
+      throw new FileSystemException(
+          "Failed to decode data using encoding '${encoding.name}'", path);
+    }
+  }
+
+  Future<String> readAsString({Encoding encoding: UTF8}) =>
+    readAsBytes().then((bytes) => _tryDecode(bytes, encoding));
+
+  String readAsStringSync({Encoding encoding: UTF8}) =>
+    _tryDecode(readAsBytesSync(), encoding);
+
+  Future<List<String>> readAsLines({Encoding encoding: UTF8}) =>
+    readAsString(encoding: encoding).then(const LineSplitter().convert);
+
+  List<String> readAsLinesSync({Encoding encoding: UTF8}) =>
+    const LineSplitter().convert(readAsStringSync(encoding: encoding));
+
+  Future<File> writeAsBytes(List<int> bytes,
+                            {FileMode mode: FileMode.WRITE,
+                             bool flush: false}) {
+    return open(mode: mode).then((file) {
+      return file.writeFrom(bytes, 0, bytes.length)
+          .then((_) {
+            if (flush) return file.flush().then((_) => this);
+            return this;
+          })
+          .whenComplete(file.close);
+    });
+  }
+
+  void writeAsBytesSync(List<int> bytes,
+                        {FileMode mode: FileMode.WRITE,
+                         bool flush: false}) {
+    RandomAccessFile opened = openSync(mode: mode);
+    try {
+      opened.writeFromSync(bytes, 0, bytes.length);
+      if (flush) opened.flushSync();
+    } finally {
+      opened.closeSync();
+    }
+  }
+
+  Future<File> writeAsString(String contents,
+                             {FileMode mode: FileMode.WRITE,
+                              Encoding encoding: UTF8,
+                              bool flush: false}) {
+    try {
+      return writeAsBytes(encoding.encode(contents), mode: mode, flush: flush);
+    } catch (e) {
+      return new Future.error(e);
+    }
+  }
+
+  void writeAsStringSync(String contents,
+                         {FileMode mode: FileMode.WRITE,
+                          Encoding encoding: UTF8,
+                          bool flush: false}) {
+    writeAsBytesSync(encoding.encode(contents), mode: mode, flush: flush);
+  }
+
+  String toString() => "File: '$path'";
+
+  static throwIfError(Object result, String msg, String path) {
+    if (result is OSError) {
+      throw new FileSystemException(msg, path, result);
+    }
+  }
+}
+
+abstract class _RandomAccessFileOps {
+  external factory _RandomAccessFileOps(int pointer);
+
+  int getPointer();
+  int close();
+  readByte();
+  read(int bytes);
+  readInto(List<int> buffer, int start, int end);
+  writeByte(int value);
+  writeFrom(List<int> buffer, int start, int end);
+  position();
+  setPosition(int position);
+  truncate(int length);
+  length();
+  flush();
+  lock(int lock, int start, int end);
+}
+
+class _RandomAccessFile implements RandomAccessFile {
+  static bool _connectedResourceHandler = false;
+
+  final String path;
+
+  bool _asyncDispatched = false;
+  SendPort _fileService;
+
+  _FileResourceInfo _resourceInfo;
+  _RandomAccessFileOps _ops;
+
+  _RandomAccessFile(int pointer, this.path) {
+    _ops = new _RandomAccessFileOps(pointer);
+    _resourceInfo = new _FileResourceInfo(this);
+    _maybeConnectHandler();
+  }
+
+  void _maybePerformCleanup() {
+    if (closed) {
+      _FileResourceInfo.FileClosed(_resourceInfo);
+    }
+  }
+
+  _maybeConnectHandler() {
+    if (!_connectedResourceHandler) {
+      // TODO(ricow): We probably need to set these in some initialization code.
+      // We need to make sure that these are always available from the
+      // observatory even if no files (or sockets for the socket ones) are
+      // open.
+      registerExtension('ext.dart.io.getOpenFiles',
+                        _FileResourceInfo.getOpenFiles);
+      registerExtension('ext.dart.io.getFileByID',
+                        _FileResourceInfo.getFileInfoMapByID);
+      _connectedResourceHandler = true;
+    }
+  }
+
+  Future<RandomAccessFile> close() {
+    return _dispatch(_FILE_CLOSE, [null], markClosed: true).then((result) {
+      if (result != -1) {
+        closed = closed || (result == 0);
+        _maybePerformCleanup();
+        return this;
+      } else {
+        throw new FileSystemException("Cannot close file", path);
+      }
+    });
+  }
+
+  void closeSync() {
+    _checkAvailable();
+    var id = _ops.close();
+    if (id == -1) {
+      throw new FileSystemException("Cannot close file", path);
+    }
+    closed = closed || (id == 0);
+    _maybePerformCleanup();
+  }
+
+  Future<int> readByte() {
+    return _dispatch(_FILE_READ_BYTE, [null]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "readByte failed", path);
+      }
+      _resourceInfo.addRead(1);
+      return response;
+    });
+  }
+
+  int readByteSync() {
+    _checkAvailable();
+    var result = _ops.readByte();
+    if (result is OSError) {
+      throw new FileSystemException("readByte failed", path, result);
+    }
+    _resourceInfo.addRead(1);
+    return result;
+  }
+
+  Future<List<int>> read(int bytes) {
+    if (bytes is !int) {
+      throw new ArgumentError(bytes);
+    }
+    return _dispatch(_FILE_READ, [null, bytes]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "read failed", path);
+      }
+      _resourceInfo.addRead(response[1].length);
+      return response[1];
+    });
+  }
+
+  List<int> readSync(int bytes) {
+    _checkAvailable();
+    if (bytes is !int) {
+      throw new ArgumentError(bytes);
+    }
+    var result = _ops.read(bytes);
+    if (result is OSError) {
+      throw new FileSystemException("readSync failed", path, result);
+    }
+    _resourceInfo.addRead(result.length);
+    return result;
+  }
+
+  Future<int> readInto(List<int> buffer, [int start = 0, int end]) {
+    if ((buffer is !List) ||
+        ((start != null) && (start is !int)) ||
+        ((end != null) && (end is !int))) {
+      throw new ArgumentError();
+    }
+    end = RangeError.checkValidRange(start, end, buffer.length);
+    if (end == start) {
+      return new Future.value(0);
+    }
+    int length = end - start;
+    return _dispatch(_FILE_READ_INTO, [null, length]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "readInto failed", path);
+      }
+      var read = response[1];
+      var data = response[2];
+      buffer.setRange(start, start + read, data);
+      _resourceInfo.addRead(read);
+      return read;
+    });
+  }
+
+  int readIntoSync(List<int> buffer, [int start = 0, int end]) {
+    _checkAvailable();
+    if ((buffer is !List) ||
+        ((start != null) && (start is !int)) ||
+        ((end != null) && (end is !int))) {
+      throw new ArgumentError();
+    }
+    end = RangeError.checkValidRange(start, end, buffer.length);
+    if (end == start) {
+      return 0;
+    }
+    var result = _ops.readInto(buffer, start, end);
+    if (result is OSError) {
+      throw new FileSystemException("readInto failed", path, result);
+    }
+    _resourceInfo.addRead(result);
+    return result;
+  }
+
+  Future<RandomAccessFile> writeByte(int value) {
+    if (value is !int) {
+      throw new ArgumentError(value);
+    }
+    return _dispatch(_FILE_WRITE_BYTE, [null, value]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "writeByte failed", path);
+      }
+      _resourceInfo.addWrite(1);
+      return this;
+    });
+  }
+
+  int writeByteSync(int value) {
+    _checkAvailable();
+    if (value is !int) {
+      throw new ArgumentError(value);
+    }
+    var result = _ops.writeByte(value);
+    if (result is OSError) {
+      throw new FileSystemException("writeByte failed", path, result);
+    }
+    _resourceInfo.addWrite(1);
+    return result;
+  }
+
+  Future<RandomAccessFile> writeFrom(
+      List<int> buffer, [int start = 0, int end]) {
+    if ((buffer is !List) ||
+        ((start != null) && (start is !int)) ||
+        ((end != null) && (end is !int))) {
+      throw new ArgumentError("Invalid arguments to writeFrom");
+    }
+    end = RangeError.checkValidRange(start, end, buffer.length);
+    if (end == start) {
+      return new Future.value(this);
+    }
+    _BufferAndStart result;
+    try {
+      result = _ensureFastAndSerializableByteData(buffer, start, end);
+    } catch (e) {
+      return new Future.error(e);
+    }
+
+    List request = new List(4);
+    request[0] = null;
+    request[1] = result.buffer;
+    request[2] = result.start;
+    request[3] = end - (start - result.start);
+    return _dispatch(_FILE_WRITE_FROM, request).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "writeFrom failed", path);
+      }
+      _resourceInfo.addWrite(end - (start - result.start));
+      return this;
+    });
+  }
+
+  void writeFromSync(List<int> buffer, [int start = 0, int end]) {
+    _checkAvailable();
+    if ((buffer is !List) ||
+        ((start != null) && (start is !int)) ||
+        ((end != null) && (end is !int))) {
+      throw new ArgumentError("Invalid arguments to writeFromSync");
+    }
+    end = RangeError.checkValidRange(start, end, buffer.length);
+    if (end == start) {
+      return;
+    }
+    _BufferAndStart bufferAndStart =
+        _ensureFastAndSerializableByteData(buffer, start, end);
+    var result = _ops.writeFrom(bufferAndStart.buffer,
+                                bufferAndStart.start,
+                                end - (start - bufferAndStart.start));
+    if (result is OSError) {
+      throw new FileSystemException("writeFrom failed", path, result);
+    }
+    _resourceInfo.addWrite(end - (start - bufferAndStart.start));
+  }
+
+  Future<RandomAccessFile> writeString(String string,
+                                       {Encoding encoding: UTF8}) {
+    if (encoding is! Encoding) {
+      throw new ArgumentError(encoding);
+    }
+    var data = encoding.encode(string);
+    return writeFrom(data, 0, data.length);
+  }
+
+  void writeStringSync(String string, {Encoding encoding: UTF8}) {
+    if (encoding is! Encoding) {
+      throw new ArgumentError(encoding);
+    }
+    var data = encoding.encode(string);
+    writeFromSync(data, 0, data.length);
+  }
+
+  Future<int> position() {
+    return _dispatch(_FILE_POSITION, [null]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "position failed", path);
+      }
+      return response;
+    });
+  }
+
+  int positionSync() {
+    _checkAvailable();
+    var result = _ops.position();
+    if (result is OSError) {
+      throw new FileSystemException("position failed", path, result);
+    }
+    return result;
+  }
+
+  Future<RandomAccessFile> setPosition(int position) {
+    return _dispatch(_FILE_SET_POSITION, [null, position])
+        .then((response) {
+          if (_isErrorResponse(response)) {
+            throw _exceptionFromResponse(response, "setPosition failed", path);
+          }
+          return this;
+        });
+  }
+
+  void setPositionSync(int position) {
+    _checkAvailable();
+    var result = _ops.setPosition(position);
+    if (result is OSError) {
+      throw new FileSystemException("setPosition failed", path, result);
+    }
+  }
+
+  Future<RandomAccessFile> truncate(int length) {
+    return _dispatch(_FILE_TRUNCATE, [null, length]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "truncate failed", path);
+      }
+      return this;
+    });
+  }
+
+  void truncateSync(int length) {
+    _checkAvailable();
+    var result = _ops.truncate(length);
+    if (result is OSError) {
+      throw new FileSystemException("truncate failed", path, result);
+    }
+  }
+
+  Future<int> length() {
+    return _dispatch(_FILE_LENGTH, [null]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "length failed", path);
+      }
+      return response;
+    });
+  }
+
+  int lengthSync() {
+    _checkAvailable();
+    var result = _ops.length();
+    if (result is OSError) {
+      throw new FileSystemException("length failed", path, result);
+    }
+    return result;
+  }
+
+  Future<RandomAccessFile> flush() {
+    return _dispatch(_FILE_FLUSH, [null]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response,
+                                     "flush failed",
+                                     path);
+      }
+      return this;
+    });
+  }
+
+  void flushSync() {
+    _checkAvailable();
+    var result = _ops.flush();
+    if (result is OSError) {
+      throw new FileSystemException("flush failed", path, result);
+    }
+  }
+
+  static final int LOCK_UNLOCK = 0;
+  static final int LOCK_SHARED = 1;
+  static final int LOCK_EXCLUSIVE = 2;
+
+  Future<RandomAccessFile> lock(
+      [FileLock mode = FileLock.EXCLUSIVE, int start = 0, int end = -1]) {
+    if ((mode is !FileLock) || (start is !int) || (end is !int)) {
+      throw new ArgumentError();
+    }
+    if ((start < 0) || (end < -1) || ((end != -1) && (start >= end))) {
+      throw new ArgumentError();
+    }
+    int lock = (mode == FileLock.EXCLUSIVE) ? LOCK_EXCLUSIVE : LOCK_SHARED;
+    return _dispatch(_FILE_LOCK, [null, lock, start, end])
+        .then((response) {
+          if (_isErrorResponse(response)) {
+            throw _exceptionFromResponse(response, 'lock failed', path);
+          }
+          return this;
+        });
+  }
+
+  Future<RandomAccessFile> unlock([int start = 0, int end = -1]) {
+    if ((start is !int) || (end is !int)) {
+      throw new ArgumentError();
+    }
+    if (start == end) {
+      throw new ArgumentError();
+    }
+    return _dispatch(_FILE_LOCK, [null, LOCK_UNLOCK, start, end])
+        .then((response) {
+          if (_isErrorResponse(response)) {
+            throw _exceptionFromResponse(response, 'unlock failed', path);
+          }
+          return this;
+        });
+  }
+
+  void lockSync(
+      [FileLock mode = FileLock.EXCLUSIVE, int start = 0, int end = -1]) {
+    _checkAvailable();
+    if ((mode is !FileLock) || (start is !int) || (end is !int)) {
+      throw new ArgumentError();
+    }
+    if ((start < 0) || (end < -1) || ((end != -1) && (start >= end))) {
+      throw new ArgumentError();
+    }
+    int lock = (mode == FileLock.EXCLUSIVE) ? LOCK_EXCLUSIVE : LOCK_SHARED;
+    var result = _ops.lock(lock, start, end);
+    if (result is OSError) {
+      throw new FileSystemException('lock failed', path, result);
+    }
+  }
+
+  void unlockSync([int start = 0, int end = -1]) {
+    _checkAvailable();
+    if ((start is !int) || (end is !int)) {
+      throw new ArgumentError();
+    }
+    if (start == end) {
+      throw new ArgumentError();
+    }
+    var result = _ops.lock(LOCK_UNLOCK, start, end);
+    if (result is OSError) {
+      throw new FileSystemException('unlock failed', path, result);
+    }
+  }
+
+  bool closed = false;
+
+  // Calling this function will increase the reference count on the native
+  // object that implements the file operations. It should only be called to
+  // pass the pointer to the IO Service, which will decrement the reference
+  // count when it is finished with it.
+  int _pointer() => _ops.getPointer();
+
+  Future _dispatch(int request, List data, { bool markClosed: false }) {
+    if (closed) {
+      return new Future.error(new FileSystemException("File closed", path));
+    }
+    if (_asyncDispatched) {
+      var msg = "An async operation is currently pending";
+      return new Future.error(new FileSystemException(msg, path));
+    }
+    if (markClosed) {
+      // Set closed to true to ensure that no more async requests can be issued
+      // for this file.
+      closed = true;
+    }
+    _asyncDispatched = true;
+    data[0] = _pointer();
+    return _IOService._dispatch(request, data)
+        .whenComplete(() {
+          _asyncDispatched = false;
+        });
+  }
+
+  void _checkAvailable() {
+    if (_asyncDispatched) {
+      throw new FileSystemException("An async operation is currently pending",
+                                    path);
+    }
+    if (closed) {
+      throw new FileSystemException("File closed", path);
+    }
+  }
+}