pkgs/test/lib/src/runner/browser/chrome.dart

// Copyright (c) 2015, 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:async';
import 'dart:io';

import 'package:pedantic/pedantic.dart';
import 'package:test_api/src/backend/runtime.dart'; // ignore: implementation_imports
import 'package:test_core/src/util/io.dart'; // ignore: implementation_imports

import '../executable_settings.dart';
import 'browser.dart';
import 'default_settings.dart';

// TODO(nweiz): move this into its own package?
/// A class for running an instance of Chrome.
///
/// Most of the communication with the browser is expected to happen via HTTP,
/// so this exposes a bare-bones API. The browser starts as soon as the class is
/// constructed, and is killed when [close] is called.
///
/// Any errors starting or running the process are reported through [onExit].
class Chrome extends Browser {
  @override
  final name = 'Chrome';

  @override
  final Future<Uri> remoteDebuggerUrl;

  /// Starts a new instance of Chrome open to the given [url], which may be a
  /// [Uri] or a [String].
  factory Chrome(Uri url, {ExecutableSettings settings, bool debug = false}) {
    settings ??= defaultSettings[Runtime.chrome];
    var remoteDebuggerCompleter = Completer<Uri>.sync();
    return Chrome._(() async {
      var tryPort = ([int port]) async {
        var dir = createTempDir();
        var args = [
          '--user-data-dir=$dir',
          url.toString(),
          '--disable-extensions',
          '--disable-popup-blocking',
          '--bwsi',
          '--no-first-run',
          '--no-default-browser-check',
          '--disable-default-apps',
          '--disable-translate',
          '--disable-dev-shm-usage',
        ];

        if (!debug && settings.headless) {
          args.addAll([
            '--headless',
            '--disable-gpu',
            // We don't actually connect to the remote debugger, but Chrome will
            // close as soon as the page is loaded if we don't turn it on.
            '--remote-debugging-port=0'
          ]);
        }

        args.addAll(settings.arguments);

        // Currently, Chrome doesn't provide any way of ensuring that this port
        // was successfully bound. It produces an error if the binding fails,
        // but without a reliable and fast way to tell if it succeeded that
        // doesn't provide us much. It's very unlikely that this port will fail,
        // though.
        if (port != null) args.add('--remote-debugging-port=$port');

        var process = await Process.start(settings.executable, args);

        if (port != null) {
          remoteDebuggerCompleter.complete(
              getRemoteDebuggerUrl(Uri.parse('http://localhost:$port')));
        } else {
          remoteDebuggerCompleter.complete(null);
        }

        unawaited(process.exitCode
            .then((_) => Directory(dir).deleteSync(recursive: true)));

        return process;
      };

      if (!debug) return tryPort();
      return getUnusedPort<Process>(tryPort);
    }, remoteDebuggerCompleter.future);
  }

  Chrome._(Future<Process> Function() startBrowser, this.remoteDebuggerUrl)
      : super(startBrowser);
}