blob: a13878e47e41c8f4ff17c700716c131360a31e7d [file] [log] [blame]
// Copyright 2014 The Flutter 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:async';
import 'package:meta/meta.dart';
import 'base/io.dart';
import 'device.dart';
import 'globals.dart' as globals;
/// Discovers a specific service protocol on a device, and forwards the service
/// protocol device port to the host.
class ProtocolDiscovery {
ProtocolDiscovery._(
this.logReader,
this.serviceName, {
this.portForwarder,
this.throttleDuration,
this.hostPort,
this.devicePort,
this.ipv6,
}) : assert(logReader != null)
{
_deviceLogSubscription = logReader.logLines.listen(
_handleLine,
onDone: _stopScrapingLogs,
);
_uriStreamController = _BufferedStreamController<Uri>();
}
factory ProtocolDiscovery.observatory(
DeviceLogReader logReader, {
DevicePortForwarder portForwarder,
Duration throttleDuration = const Duration(milliseconds: 200),
@required int hostPort,
@required int devicePort,
@required bool ipv6,
}) {
const String kObservatoryService = 'Observatory';
return ProtocolDiscovery._(
logReader,
kObservatoryService,
portForwarder: portForwarder,
throttleDuration: throttleDuration,
hostPort: hostPort,
devicePort: devicePort,
ipv6: ipv6,
);
}
final DeviceLogReader logReader;
final String serviceName;
final DevicePortForwarder portForwarder;
final int hostPort;
final int devicePort;
final bool ipv6;
/// The time to wait before forwarding a new observatory URIs from [logReader].
final Duration throttleDuration;
StreamSubscription<String> _deviceLogSubscription;
_BufferedStreamController<Uri> _uriStreamController;
/// The discovered service URL.
/// Use [uris] instead.
// TODO(egarciad): replace `uri` for `uris`.
Future<Uri> get uri {
return uris.first;
}
/// The discovered service URLs.
///
/// When a new observatory URL: is available in [logReader],
/// the URLs are forwarded at most once every [throttleDuration].
///
/// Port forwarding is only attempted when this is invoked,
/// for each observatory URL in the stream.
Stream<Uri> get uris {
return _uriStreamController.stream
.transform(_throttle<Uri>(
waitDuration: throttleDuration,
))
.asyncMap<Uri>(_forwardPort);
}
Future<void> cancel() => _stopScrapingLogs();
Future<void> _stopScrapingLogs() async {
await _uriStreamController?.close();
await _deviceLogSubscription?.cancel();
_deviceLogSubscription = null;
}
Match _getPatternMatch(String line) {
final RegExp r = RegExp('${RegExp.escape(serviceName)} listening on ((http|\/\/)[a-zA-Z0-9:/=_\\-\.\\[\\]]+)');
return r.firstMatch(line);
}
Uri _getObservatoryUri(String line) {
final Match match = _getPatternMatch(line);
if (match != null) {
return Uri.parse(match[1]);
}
return null;
}
void _handleLine(String line) {
Uri uri;
try {
uri = _getObservatoryUri(line);
} on FormatException catch(error, stackTrace) {
_uriStreamController.addError(error, stackTrace);
}
if (uri == null) {
return;
}
if (devicePort != null && uri.port != devicePort) {
globals.printTrace('skipping potential observatory $uri due to device port mismatch');
return;
}
_uriStreamController.add(uri);
}
Future<Uri> _forwardPort(Uri deviceUri) async {
globals.printTrace('$serviceName URL on device: $deviceUri');
Uri hostUri = deviceUri;
if (portForwarder != null) {
final int actualDevicePort = deviceUri.port;
final int actualHostPort = await portForwarder.forward(actualDevicePort, hostPort: hostPort);
globals.printTrace('Forwarded host port $actualHostPort to device port $actualDevicePort for $serviceName');
hostUri = deviceUri.replace(port: actualHostPort);
}
assert(InternetAddress(hostUri.host).isLoopback);
if (ipv6) {
hostUri = hostUri.replace(host: InternetAddress.loopbackIPv6.host);
}
return hostUri;
}
}
/// Provides a broadcast stream controller that buffers the events
/// if there isn't a listener attached.
/// The events are then delivered when a listener is attached to the stream.
class _BufferedStreamController<T> {
_BufferedStreamController() : _events = <dynamic>[];
/// The stream that this controller is controlling.
Stream<T> get stream {
return _streamController.stream;
}
StreamController<T> _streamControllerInstance;
StreamController<T> get _streamController {
_streamControllerInstance ??= StreamController<T>.broadcast(onListen: () {
for (final dynamic event in _events) {
assert(T is! List);
if (event is T) {
_streamControllerInstance.add(event);
} else {
_streamControllerInstance.addError(
event.first as Object,
event.last as StackTrace,
);
}
}
_events.clear();
});
return _streamControllerInstance;
}
final List<dynamic> _events;
/// Sends [event] if there is a listener attached to the broadcast stream.
/// Otherwise, it enqueues [event] until a listener is attached.
void add(T event) {
if (_streamController.hasListener) {
_streamController.add(event);
} else {
_events.add(event);
}
}
/// Sends or enqueues an error event.
void addError(Object error, [StackTrace stackTrace]) {
if (_streamController.hasListener) {
_streamController.addError(error, stackTrace);
} else {
_events.add(<dynamic>[error, stackTrace]);
}
}
/// Closes the stream.
Future<void> close() {
return _streamController.close();
}
}
/// This transformer will produce an event at most once every [waitDuration].
///
/// For example, consider a `waitDuration` of `10ms`, and list of event names
/// and arrival times: `a (0ms), b (5ms), c (11ms), d (21ms)`.
/// The events `c` and `d` will be produced as a result.
StreamTransformer<S, S> _throttle<S>({
@required Duration waitDuration,
}) {
assert(waitDuration != null);
S latestLine;
int lastExecution;
Future<void> throttleFuture;
return StreamTransformer<S, S>
.fromHandlers(
handleData: (S value, EventSink<S> sink) {
latestLine = value;
final int currentTime = DateTime.now().millisecondsSinceEpoch;
lastExecution ??= currentTime;
final int remainingTime = currentTime - lastExecution;
final int nextExecutionTime = remainingTime > waitDuration.inMilliseconds
? 0
: waitDuration.inMilliseconds - remainingTime;
throttleFuture ??= Future<void>
.delayed(Duration(milliseconds: nextExecutionTime))
.whenComplete(() {
sink.add(latestLine);
throttleFuture = null;
lastExecution = DateTime.now().millisecondsSinceEpoch;
});
}
);
}