pkg/vm_snapshot_analysis/test/utils.dart

// Copyright (c) 2020, 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.

import 'dart:convert';
import 'dart:io';

import 'package:path/path.dart' as path;
import 'package:test/test.dart';

final dart2native = () {
  final sdkBin = path.dirname(Platform.executable);
  final dart2native =
      path.join(sdkBin, Platform.isWindows ? 'dart2native.bat' : 'dart2native');

  if (!File(dart2native).existsSync()) {
    throw 'Failed to locate dart2native in the SDK';
  }

  return path.canonicalize(dart2native);
}();

Future withFlag(String prefix, Map<String, String> source, String flag,
    Future Function(String sizesJson) f) {
  return withTempDir(prefix, (dir) async {
    final outputBinary = path.join(dir, 'output.exe');
    final sizesJson = path.join(dir, 'sizes.json');
    final packages = path.join(dir, '.packages');
    final mainDart = path.join(dir, 'main.dart');

    // Create test input.
    for (var file in source.entries) {
      await File(path.join(dir, file.key)).writeAsString(file.value);
    }
    await File(packages).writeAsString('''
input:./
''');
    await File(mainDart).writeAsString('''
import 'package:input/input.dart' as input;

void main(List<String> args) => input.main(args);
''');

    // Compile input.dart to native and output instruction sizes.
    final result = await Process.run(dart2native, [
      '-o',
      outputBinary,
      '--packages=$packages',
      '--extra-gen-snapshot-options=--dwarf-stack-traces,$flag=$sizesJson',
      mainDart,
    ]);

    expect(result.exitCode, equals(0), reason: '''
Compilation completed successfully.

stdout: ${result.stdout}
stderr: ${result.stderr}
''');
    expect(File(outputBinary).existsSync(), isTrue,
        reason: 'Output binary exists');
    expect(File(sizesJson).existsSync(), isTrue,
        reason: 'Instruction sizes output exists');

    await f(sizesJson);
  });
}

Future withTempDir(String prefix, Future Function(String dir) f) async {
  final tempDir =
      Directory.systemTemp.createTempSync('instruction-sizes-test-${prefix}');
  try {
    await f(tempDir.path);
  } finally {
    tempDir.deleteSync(recursive: true);
  }
}

Future<Object> loadJson(File input) async {
  return await input
      .openRead()
      .transform(utf8.decoder)
      .transform(json.decoder)
      .first;
}