blob: ab960f50c905b5853e0e2614d118770dcb9196d0 [file] [log] [blame]
// 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 dart_style.benchmark.benchmark;
import 'dart:io';
import 'package:path/path.dart' as p;
import 'package:dart_style/dart_style.dart';
const NUM_TRIALS = 100;
const FORMATS_PER_TRIAL = 30;
/// Note, these files use ".txt" because while they can be *parsed* correctly,
/// they don't resolve without error. That's OK because the formatter doesn't
/// care about that.
final source = loadFile("before.dart.txt");
final expected = loadFile("after.dart.txt");
void main(List<String> args) {
var best = 99999999.0;
// Run the benchmark several times. This ensures the VM is warmed up and lets
// us see how much variance there is.
for (var i = 0; i <= NUM_TRIALS; i++) {
var start = new DateTime.now();
// For a single benchmark, format the source multiple times.
var result;
for (var j = 0; j < FORMATS_PER_TRIAL; j++) {
result = formatSource();
}
var elapsed =
new DateTime.now().difference(start).inMilliseconds / FORMATS_PER_TRIAL;
// Keep track of the best run so far.
if (elapsed >= best) continue;
best = elapsed;
// Sanity check to make sure the output is what we expect and to make sure
// the VM doesn't optimize "dead" code away.
if (result != expected) {
print("Incorrect output:\n$result");
exit(1);
}
// Don't print the first run. It's always terrible since the VM hasn't
// warmed up yet.
if (i == 0) continue;
printResult("Run ${padLeft('#$i', 3)}", elapsed);
}
printResult("Best ", best);
}
String loadFile(String name) {
var path = p.join(p.dirname(p.fromUri(Platform.script)), name);
return new File(path).readAsStringSync();
}
void printResult(String label, double time) {
print("$label: ${padLeft(time.toStringAsFixed(2), 4)}ms "
"${'=' * ((time * 5).toInt())}");
}
String padLeft(input, int length) {
var result = input.toString();
if (result.length < length) {
result = " " * (length - result.length) + result;
}
return result;
}
String formatSource() {
var formatter = new DartFormatter();
return formatter.format(source);
}