| // Copyright 2020 The Dart Authors. 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:io'; |
| import 'dart:math' show Random; |
| |
| import 'package:path/path.dart' as p; |
| |
| final sdkDir = p.dirname(p.dirname(Platform.resolvedExecutable)); |
| final sdkUri = p.toUri(sdkDir).toString(); |
| |
| /// Returns a unique ID in the format: |
| /// |
| /// f47ac10b-58cc-4372-a567-0e02b2c3d479 |
| /// |
| /// The generated uuids are 128 bit numbers encoded in a specific string format. |
| /// For more information, see |
| /// [en.wikipedia.org/wiki/Universally_unique_identifier](http://en.wikipedia.org/wiki/Universally_unique_identifier). |
| String generateUuidV4() { |
| final random = Random(); |
| |
| int _generateBits(int bitCount) => random.nextInt(1 << bitCount); |
| |
| String _printDigits(int value, int count) => |
| value.toRadixString(16).padLeft(count, '0'); |
| String _bitsDigits(int bitCount, int digitCount) => |
| _printDigits(_generateBits(bitCount), digitCount); |
| |
| // Generate xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx / 8-4-4-4-12. |
| var special = 8 + random.nextInt(4); |
| |
| return '${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}-' |
| '${_bitsDigits(16, 4)}-' |
| '4${_bitsDigits(12, 3)}-' |
| '${_printDigits(special, 1)}${_bitsDigits(12, 3)}-' |
| '${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}'; |
| } |