// Copyright 2019 The Chromium 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:convert';

import 'dart:io';

/// Outputs the time intervals between adjacent cpu samples.

///

/// A json file path is required as a command line argument.

/// Ex: dart cpu_sample_intervals.dart ~/Downloads/example_json.dart

void main(List<String> arguments) async {

if (arguments.isEmpty) {

print('You must specify a json input file path.\n'

'Ex: dart cpu_sample_intervals.dart ~/Downloads/example.json');

return;

}

final File file = File(arguments.first);

final Map<String, dynamic> timelineDump =

(jsonDecode(await file.readAsString()) as Map).cast<String, dynamic>();

final List<dynamic> cpuSampleTraceEvents =

timelineDump['cpuProfile']['traceEvents'] as List;

final List<int> deltas = [];

for (int i = 0; i < cpuSampleTraceEvents.length - 1; i++) {

final Map<String, dynamic> current =

(cpuSampleTraceEvents[i] as Map).cast<String, dynamic>();

final Map<String, dynamic> next =

(cpuSampleTraceEvents[i + 1] as Map).cast<String, dynamic>();

deltas.add((next['ts'] as int) - (current['ts'] as int));

}

print(deltas);

}