anchor.diff:  // 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.
   
  +import 'dart:async';
   import 'dart:io';
   import 'dart:convert';
   
  
positive.code: library dart.sdk_sources;
  
  const Map<String, String> SDK_SOURCES = const <String, String>''');
      output.writeStringSync(JSON.encode(map).replaceAll(r'$', r'\$'));
      output.writeStringSync(';\n');
    }
    output.closeSync();
  }
  
negative.code: 
  jsonify(MirrorSystem mirrors) {
    var map = <String, String>{};
    List<Future> futures = <Future>[];
  
    Future mapUri(Uri uri) {
      String filename = relativize(sdkRoot, uri, false);
      return handler.provider.readStringFromUri(uri).then((contents) {
        map['sdk:/$filename'] = contents;
      });
    }
  
    mirrors.libraries.forEach((_, LibraryMirror library) {
      BackDoor.compilationUnitsOf(library).forEach((compilationUnit) {
        futures.add(mapUri(compilationUnit.uri));
      });
    });
  
    libraries.forEach((name, info) {
      var patch = info.dart2jsPatchPath;
      if (patch != null) {
        futures.add(mapUri(sdkRoot.resolve('sdk/lib/$patch')));
      }
    });
  
    for (String filename in ["dart_client.platform",
                             "dart_server.platform",
                             "dart_shared.platform"]) {
      futures.add(mapUri(sdkRoot.resolve('sdk/lib/$filename')));
    }
  
    Future.wait(futures).then((_) {
      if (outputJson) {
        output.writeStringSync(JSON.encode(map));
      } else {
        output.writeStringSync('''
  // 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.
  