Alginment is off after newline

main.dart

// Copyright (c) 2014, 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.

library services.analyzer;

import 'package:analyzer/analyzer.dart';
import 'package:analyzer/src/generated/element.dart';
import 'package:analyzer/src/generated/engine.dart' hide Logger;
import 'package:analyzer/src/generated/java_io.dart';
import 'package:analyzer/src/generated/sdk.dart';
import 'package:analyzer/src/generated/sdk_io.dart';
import 'package:analyzer/src/generated/source.dart';


import 'package:cli_util/cli_util.dart' as cli_util;

main() async {
  var b = await dartdoc("void main() => print('hello world');", 20);
  print(b);
}


Map<String, String> dartdoc(String source, int offset) {
  String _sdkPath = cli_util.getSdkDir([]).path;

  DartSdk sdk = new DirectoryBasedDartSdk(new JavaFile(_sdkPath), true);
  AnalysisContext _context = AnalysisEngine.instance.createAnalysisContext();

  List<UriResolver> resolvers = [
    new DartUriResolver(sdk)
  ];
  _context.sourceFactory = new SourceFactory(resolvers);

  var _source = new StringSource(source, "main.dart");

  ChangeSet changeSet = new ChangeSet();
  changeSet.addedSource(_source);
  _context.applyChanges(changeSet);

  LibraryElement library = _context.computeLibraryElement(_source);
  CompilationUnit unit = _context.resolveCompilationUnit(_source, library);

  AstNode node = new NodeLocator(offset).searchWithin(unit);

  if (node == null) return null;

  if (node.parent is TypeName &&
      node.parent.parent is ConstructorName &&
      node.parent.parent.parent is InstanceCreationExpression) {
    node = node.parent.parent.parent;
  }

  if (node.parent is ConstructorName &&
      node.parent.parent is InstanceCreationExpression) {
    node = node.parent.parent;
  }

  if (node is Expression) {
    Expression expression = node;
    Map info = {};

    // element
    Element element = ElementLocator.locateWithOffset(expression, offset);

    if (element != null) {
      // variable, if synthetic accessor
      if (element is PropertyAccessorElement) {
        PropertyAccessorElement accessor = element;
        if (accessor.isSynthetic) element = accessor.variable;
      }

      // documentation
      String dartDoc = element.computeDocumentationComment();
      dartDoc = cleanDartDoc(dartDoc);
      if (dartDoc != null) info['dartdoc'] = dartDoc;
    }
    return info;
  }
  return null;
}


/// An implementation of [Source] that is based on an in-memory string.
class StringSource implements Source {
  final String fullName;

  int _modificationStamp;
  String _contents;

  StringSource(this._contents, this.fullName)
      : _modificationStamp = new DateTime.now().millisecondsSinceEpoch;

  void updateSource(String newSource) {
    _contents = newSource;
    _modificationStamp = new DateTime.now().millisecondsSinceEpoch;
  }

  int get modificationStamp => _modificationStamp;

  bool operator ==(Object object) {
    if (object is StringSource) {
      StringSource ssObject = object;
      return ssObject._contents == _contents && ssObject.fullName == fullName;
    }
    return false;
  }

  bool exists() => true;

  TimestampedData<String> get contents =>
      new TimestampedData(modificationStamp, _contents);

  String get encoding => 'utf-8';

  String get shortName => fullName;

  UriKind get uriKind => UriKind.FILE_URI;

  int get hashCode => fullName.hashCode;

  bool get isInSystemLibrary => false;

  Uri get uri {
    throw new UnsupportedError("StringSource doesn't support uri.");
  }

  // TODO: I don't think this is generally sufficent, but it meets our purposes
  // here.
  Uri resolveRelativeUri(Uri relativeUri) {
    return relativeUri;
  }

  @override
  Source get source => this;
}

/**
 * Converts [str] from a Dartdoc string with slashes and stars to a plain text
 * representation of the comment.
 */
String cleanDartDoc(String str) {
  if (str == null) return null;

  // Remove /** */.
  str = str.trim();
  if (str.startsWith('/**')) str = str.substring(3);
  if (str.endsWith("*/")) str = str.substring(0, str.length - 2);
  str = str.trim();

  // Remove leading '* '.
  StringBuffer sb = new StringBuffer();
  bool firstLine = true;

  for (String line in str.split('\n')) {
    line = line.trim();

    // Remove leading '* ' and '///'; don't remove a leading '*' if there is a
    // matching '*' in the line.
    if (line.startsWith('* ')) {
      line = line.substring(2);
    } else if (line.startsWith("*") && line.lastIndexOf('*') == 0) {
      line = line.substring(1);
      if (line.startsWith(" ")) line = line.substring(1);
    } else if (line.startsWith("///")) {
      line = line.substring(3);
      if (line.startsWith(" ")) line = line.substring(1);
    }

    if (!firstLine) sb.write('\n');
    firstLine = false;
    sb.write(line);
  }

  return sb.toString();
}