scripts/codesize/bin/progress_bar.dart

// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// @dart = 2.8

import 'dart:core';
import 'dart:io';

/// A basic progress indicator that shows `[current/total]`, Ninja-style.
/// Updates in-place using ASCII control characters.
class ProgressBar {
  final int complete;
  int current = 0;
  bool _active = false;

  ProgressBar({this.complete});

  void update(int newValue) {
    if (!_active) {
      stdout.write('[$newValue/$complete]');
      _active = true;
    } else {
      int prevLen = '[$current/$complete]'.length;
      stdout.write('\b' * prevLen);
      stdout.write('[$newValue/$complete]');
    }
    current = newValue;
  }

  void done() {
    stdout.writeln();
  }
}