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// 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 'dart:math' as math;
import 'package:dds/dap.dart' hide PidTracker;
import 'package:meta/meta.dart';
import 'package:vm_service/vm_service.dart' as vm;
import '../base/file_system.dart';
import '../base/io.dart';
import '../base/platform.dart';
import '../cache.dart';
import '../convert.dart';
import 'flutter_adapter_args.dart';
import 'mixins.dart';
/// A DAP Debug Adapter for running and debugging Flutter applications.
class FlutterDebugAdapter extends DartDebugAdapter<FlutterLaunchRequestArguments, FlutterAttachRequestArguments>
with PidTracker {
FlutterDebugAdapter(
super.channel, {
required this.fileSystem,
required this.platform,
super.ipv6,
bool enableDds = true,
super.enableAuthCodes,
super.logger,
super.onError,
}) : _enableDds = enableDds,
// Always disable in the DAP layer as it's handled in the spawned
// 'flutter' process.
super(enableDds: false);
FileSystem fileSystem;
Platform platform;
Process? _process;
/// Whether DDS should be enabled in the Flutter process.
///
/// We never enable DDS in the DAP process for Flutter, so this value is not
/// the same as what is passed to the base class, which is always provided 'false'.
final bool _enableDds;
@override
final FlutterLaunchRequestArguments Function(Map<String, Object?> obj)
parseLaunchArgs = FlutterLaunchRequestArguments.fromJson;
@override
final FlutterAttachRequestArguments Function(Map<String, Object?> obj)
parseAttachArgs = FlutterAttachRequestArguments.fromJson;
/// A completer that completes when the app.started event has been received.
@visibleForTesting
final Completer<void> appStartedCompleter = Completer<void>();
/// Whether or not the app.started event has been received.
bool get _receivedAppStarted => appStartedCompleter.isCompleted;
/// The appId of the current running Flutter app.
@visibleForTesting
String? appId;
/// The ID to use for the next request sent to the Flutter run daemon.
int _flutterRequestId = 1;
/// Outstanding requests that have been sent to the Flutter run daemon and
/// their handlers.
final Map<int, Completer<Object?>> _flutterRequestCompleters = <int, Completer<Object?>>{};
/// Whether or not this adapter can handle the restartRequest.
///
/// For Flutter apps we can handle this with a Hot Restart rather than having
/// the whole debug session stopped and restarted.
@override
bool get supportsRestartRequest => true;
/// Whether the VM Service closing should be used as a signal to terminate the debug session.
///
/// Since we always have a process for Flutter (whether run or attach) we'll
/// always use its termination instead, so this is always false.
@override
bool get terminateOnVmServiceClose => false;
/// Whether or not the user requested debugging be enabled.
///
/// For debugging to be enabled, the user must have chosen "Debug" (and not
/// "Run") in the editor (which maps to the DAP `noDebug` field) _and_ must
/// not have requested to run in Profile or Release mode. Profile/Release
/// modes will always disable debugging.
///
/// This is always `true` for attach requests.
///
/// When not debugging, we will not connect to the VM Service so some
/// functionality (breakpoints, evaluation, etc.) will not be available.
/// Functionality provided via the daemon (hot reload/restart) will still be
/// available.
bool get enableDebugger {
final DartCommonLaunchAttachRequestArguments args = this.args;
if (args is FlutterLaunchRequestArguments) {
// Invert DAP's noDebug flag, treating it as false (so _do_ debug) if not
// provided.
return !(args.noDebug ?? false) && !profileMode && !releaseMode;
}
// Otherwise (attach), always debug.
return true;
}
/// Whether the launch configuration arguments specify `--profile`.
///
/// Always `false` for attach requests.
bool get profileMode {
final DartCommonLaunchAttachRequestArguments args = this.args;
if (args is FlutterLaunchRequestArguments) {
return args.toolArgs?.contains('--profile') ?? false;
}
// Otherwise (attach), always false.
return false;
}
/// Whether the launch configuration arguments specify `--release`.
///
/// Always `false` for attach requests.
bool get releaseMode {
final DartCommonLaunchAttachRequestArguments args = this.args;
if (args is FlutterLaunchRequestArguments) {
return args.toolArgs?.contains('--release') ?? false;
}
// Otherwise (attach), always false.
return false;
}
/// Called by [attachRequest] to request that we actually connect to the app to be debugged.
@override
Future<void> attachImpl() async {
final FlutterAttachRequestArguments args = this.args as FlutterAttachRequestArguments;
final DapProgressReporter progress = startProgressNotification(
'launch',
'Flutter',
message: 'Attaching…',
);
unawaited(appStartedCompleter.future.then((_) => progress.end()));
final String? vmServiceUri = args.vmServiceUri;
final List<String> toolArgs = <String>[
'attach',
'--machine',
if (!_enableDds) '--no-dds',
if (vmServiceUri != null)
...<String>['--debug-uri', vmServiceUri],
];
await _startProcess(
toolArgs: toolArgs,
customTool: args.customTool,
customToolReplacesArgs: args.customToolReplacesArgs,
userToolArgs: args.toolArgs,
);
}
/// [customRequest] handles any messages that do not match standard messages in the spec.
///
/// This is used to allow a client/DA to have custom methods outside of the
/// spec. It is up to the client/DA to negotiate which custom messages are
/// allowed.
///
/// [sendResponse] must be called when handling a message, even if it is with
/// a null response. Otherwise the client will never be informed that the
/// request has completed.
///
/// Any requests not handled must call super which will respond with an error
/// that the message was not supported.
///
/// Unless they start with _ to indicate they are private, custom messages
/// should not change in breaking ways if client IDEs/editors may be calling
/// them.
@override
Future<void> customRequest(
Request request,
RawRequestArguments? args,
void Function(Object?) sendResponse,
) async {
switch (request.command) {
case 'hotRestart':
case 'hotReload':
final bool isFullRestart = request.command == 'hotRestart';
await _performRestart(isFullRestart, args?.args['reason'] as String?);
sendResponse(null);
break;
default:
await super.customRequest(request, args, sendResponse);
}
}
@override
Future<void> debuggerConnected(vm.VM vmInfo) async {
// Usually we'd capture the pid from the VM here and record it for
// terminating, however for Flutter apps it may be running on a remote
// device so it's not valid to terminate a process with that pid locally.
// For attach, pids should never be collected as terminateRequest() should
// not terminate the debugee.
}
/// Called by [disconnectRequest] to request that we forcefully shut down the app being run (or in the case of an attach, disconnect).
///
/// Client IDEs/editors should send a terminateRequest before a
/// disconnectRequest to allow a graceful shutdown. This method must terminate
/// quickly and therefore may leave orphaned processes.
@override
Future<void> disconnectImpl() async {
if (isAttach) {
await preventBreakingAndResume();
}
terminatePids(ProcessSignal.sigkill);
}
@override
Future<void> handleExtensionEvent(vm.Event event) async {
await super.handleExtensionEvent(event);
switch (event.kind) {
case vm.EventKind.kExtension:
switch (event.extensionKind) {
case 'Flutter.ServiceExtensionStateChanged':
_sendServiceExtensionStateChanged(event.extensionData);
break;
case 'Flutter.Error':
_handleFlutterErrorEvent(event.extensionData);
break;
}
break;
}
}
/// Sends OutputEvents to the client for a Flutter.Error event.
void _handleFlutterErrorEvent(vm.ExtensionData? data) {
final Map<String, dynamic>? errorData = data?.data;
if (errorData == null) {
return;
}
final String errorText = (errorData['renderedErrorText'] as String?)
?? (errorData['description'] as String?)
// We should never not error text, but if we do at least send something
// so it's not just completely silent.
?? 'Unknown error in Flutter.Error event';
sendOutput('stderr', '$errorText\n');
}
/// Called by [launchRequest] to request that we actually start the app to be run/debugged.
///
/// For debugging, this should start paused, connect to the VM Service, set
/// breakpoints, and resume.
@override
Future<void> launchImpl() async {
final FlutterLaunchRequestArguments args = this.args as FlutterLaunchRequestArguments;
final DapProgressReporter progress = startProgressNotification(
'launch',
'Flutter',
message: 'Launching…',
);
unawaited(appStartedCompleter.future.then((_) => progress.end()));
final List<String> toolArgs = <String>[
'run',
'--machine',
if (!_enableDds) '--no-dds',
if (enableDebugger) '--start-paused',
// Structured errors are enabled by default, but since we don't connect
// the VM Service for noDebug, we need to disable them so that error text
// is sent to stderr. Otherwise the user will not see any exception text
// (because nobody is listening for Flutter.Error events).
if (!enableDebugger)
'--dart-define=flutter.inspector.structuredErrors=false',
];
await _startProcess(
toolArgs: toolArgs,
customTool: args.customTool,
customToolReplacesArgs: args.customToolReplacesArgs,
targetProgram: args.program,
userToolArgs: args.toolArgs,
userArgs: args.args,
);
}
/// Starts the `flutter` process to run/attach to the required app.
Future<void> _startProcess({
required String? customTool,
required int? customToolReplacesArgs,
required List<String> toolArgs,
required List<String>? userToolArgs,
String? targetProgram,
List<String>? userArgs,
}) async {
// Handle customTool and deletion of any arguments for it.
final String executable = customTool ?? fileSystem.path.join(Cache.flutterRoot!, 'bin', platform.isWindows ? 'flutter.bat' : 'flutter');
final int? removeArgs = customToolReplacesArgs;
if (customTool != null && removeArgs != null) {
toolArgs.removeRange(0, math.min(removeArgs, toolArgs.length));
}
final List<String> processArgs = <String>[
...toolArgs,
...?userToolArgs,
if (targetProgram != null) ...<String>[
'--target',
targetProgram,
],
...?userArgs,
];
await launchAsProcess(
executable: executable,
processArgs: processArgs,
env: args.env,
);
}
@visibleForOverriding
Future<void> launchAsProcess({
required String executable,
required List<String> processArgs,
required Map<String, String>? env,
}) async {
logger?.call('Spawning $executable with $processArgs in ${args.cwd}');
final Process process = await Process.start(
executable,
processArgs,
workingDirectory: args.cwd,
environment: env,
);
_process = process;
pidsToTerminate.add(process.pid);
process.stdout.transform(ByteToLineTransformer()).listen(_handleStdout);
process.stderr.listen(_handleStderr);
unawaited(process.exitCode.then(_handleExitCode));
}
/// restart is called by the client when the user invokes a restart (for example with the button on the debug toolbar).
///
/// For Flutter, we handle this ourselves be sending a Hot Restart request
/// to the running app.
@override
Future<void> restartRequest(
Request request,
RestartArguments? args,
void Function() sendResponse,
) async {
await _performRestart(true);
sendResponse();
}
/// Sends a request to the Flutter daemon that is running/attaching to the app and waits for a response.
///
/// If [failSilently] is `true` (the default) and there is no process, the
/// message will be silently ignored (this is common during the application
/// being stopped, where async messages may be processed). Setting it to
/// `false` will cause a [DebugAdapterException] to be thrown in that case.
Future<Object?> sendFlutterRequest(
String method,
Map<String, Object?>? params, {
bool failSilently = true,
}) async {
final Process? process = _process;
if (process == null) {
if (failSilently) {
return null;
} else {
throw DebugAdapterException(
'Unable to Restart because Flutter process is not available',
);
}
}
final Completer<Object?> completer = Completer<Object?>();
final int id = _flutterRequestId++;
_flutterRequestCompleters[id] = completer;
// Flutter requests are always wrapped in brackets as an array.
final String messageString = jsonEncode(
<String, Object?>{'id': id, 'method': method, 'params': params},
);
final String payload = '[$messageString]\n';
process.stdin.writeln(payload);
return completer.future;
}
/// Called by [terminateRequest] to request that we gracefully shut down the app being run (or in the case of an attach, disconnect).
@override
Future<void> terminateImpl() async {
if (isAttach) {
await preventBreakingAndResume();
}
// Send a request to stop/detach to give Flutter chance to do some cleanup.
// It's possible the Flutter process will terminate before we process the
// response, so accept either a response or the process exiting.
if (appId != null) {
final String method = isAttach ? 'app.detach' : 'app.stop';
await Future.any<void>(<Future<void>>[
sendFlutterRequest(method, <String, Object?>{'appId': appId}),
_process?.exitCode ?? Future<void>.value(),
]);
}
terminatePids(ProcessSignal.sigterm);
await _process?.exitCode;
}
/// Connects to the VM Service if the app.started event has fired, and a VM Service URI is available.
Future<void> _connectDebugger(Uri vmServiceUri) async {
if (enableDebugger) {
await connectDebugger(vmServiceUri);
} else {
// Usually, `connectDebugger` (in the base Dart adapter) will send this
// event when it connects a debugger. Since we're not connecting a
// debugger we send this ourselves, to allow clients to connect to the
// VM Service for things like starting DevTools, even if debugging is
// not available.
// TODO(dantup): Switch this to call `sendDebuggerUris()` on the base
// adapter once rolled into Flutter.
sendEvent(
RawEventBody(<String, Object?>{
'vmServiceUri': vmServiceUri.toString(),
}),
eventType: 'dart.debuggerUris',
);
}
}
/// Handles the app.start event from Flutter.
void _handleAppStart(Map<String, Object?> params) {
appId = params['appId'] as String?;
if(appId == null) {
throw DebugAdapterException('Unexpected null `appId` in app.start event');
}
}
/// Handles the app.started event from Flutter.
Future<void> _handleAppStarted() async {
appStartedCompleter.complete();
// Send a custom event so the editor knows the app has started.
//
// This may be useful when there's no VM Service (for example Profile mode)
// but the editor still wants to know that startup has finished.
await debuggerInitialized; // Ensure we're fully initialized before sending.
sendEvent(
RawEventBody(<String, Object?>{}),
eventType: 'flutter.appStarted',
);
}
/// Handles the daemon.connected event, recording the pid of the flutter_tools process.
void _handleDaemonConnected(Map<String, Object?> params) {
// On Windows, the pid from the process we spawn is the shell running
// flutter.bat and terminating it may not be reliable, so we also take the
// pid provided from the VM running flutter_tools.
final int? pid = params['pid'] as int?;
if (pid != null) {
pidsToTerminate.add(pid);
}
}
/// Handles the app.debugPort event from Flutter, connecting to the VM Service if everything else is ready.
Future<void> _handleDebugPort(Map<String, Object?> params) async {
// Capture the VM Service URL which we'll connect to when we get app.started.
final String? wsUri = params['wsUri'] as String?;
if (wsUri != null) {
final Uri vmServiceUri = Uri.parse(wsUri);
// Also wait for app.started before we connect, to ensure Flutter's
// initialization is all complete.
await appStartedCompleter.future;
await _connectDebugger(vmServiceUri);
}
}
/// Handles the Flutter process exiting, terminating the debug session if it has not already begun terminating.
void _handleExitCode(int code) {
final String codeSuffix = code == 0 ? '' : ' ($code)';
logger?.call('Process exited ($code)');
handleSessionTerminate(codeSuffix);
}
/// Handles incoming JSON events from `flutter run --machine`.
void _handleJsonEvent(String event, Map<String, Object?>? params) {
params ??= <String, Object?>{};
switch (event) {
case 'daemon.connected':
_handleDaemonConnected(params);
break;
case 'app.debugPort':
_handleDebugPort(params);
break;
case 'app.start':
_handleAppStart(params);
break;
case 'app.started':
_handleAppStarted();
break;
}
}
/// Handles incoming JSON messages from `flutter run --machine` that are responses to requests that we sent.
void _handleJsonResponse(int id, Map<String, Object?> response) {
final Completer<Object?>? handler = _flutterRequestCompleters.remove(id);
if (handler == null) {
logger?.call(
'Received response from Flutter run daemon with ID $id '
'but had not matching handler',
);
return;
}
final Object? error = response['error'];
final Object? result = response['result'];
if (error != null) {
handler.completeError(DebugAdapterException('$error'));
} else {
handler.complete(result);
}
}
void _handleStderr(List<int> data) {
logger?.call('stderr: $data');
sendOutput('stderr', utf8.decode(data));
}
/// Handles stdout from the `flutter run --machine` process, decoding the JSON and calling the appropriate handlers.
void _handleStdout(String data) {
// Output intended for us to parse is JSON wrapped in brackets:
// [{"event":"app.foo","params":{"bar":"baz"}}]
// However, it's also possible a user printed things that look a little like
// this so try to detect only things we're interested in:
// - parses as JSON
// - is a List of only a single item that is a Map<String, Object?>
// - the item has an "event" field that is a String
// - the item has a "params" field that is a Map<String, Object?>?
logger?.call('stdout: $data');
// Output is sent as console (eg. output from tooling) until the app has
// started, then stdout (users output). This is so info like
// "Launching lib/main.dart on Device foo" is formatted differently to
// general output printed by the user.
final String outputCategory = _receivedAppStarted ? 'stdout' : 'console';
// Output in stdout can include both user output (eg. print) and Flutter
// daemon output. Since it's not uncommon for users to print JSON while
// debugging, we must try to detect which messages are likely Flutter
// messages as reliably as possible, as trying to process users output
// as a Flutter message may result in an unhandled error that will
// terminate the debug adater in a way that does not provide feedback
// because the standard crash violates the DAP protocol.
Object? jsonData;
try {
jsonData = jsonDecode(data);
} on FormatException {
// If the output wasn't valid JSON, it was standard stdout that should
// be passed through to the user.
sendOutput(outputCategory, data);
return;
}
final Map<String, Object?>? payload = jsonData is List &&
jsonData.length == 1 &&
jsonData.first is Map<String, Object?>
? jsonData.first as Map<String, Object?>
: null;
if (payload == null) {
// JSON didn't match expected format for Flutter responses, so treat as
// standard user output.
sendOutput(outputCategory, data);
return;
}
final Object? event = payload['event'];
final Object? params = payload['params'];
final Object? id = payload['id'];
if (event is String && params is Map<String, Object?>?) {
_handleJsonEvent(event, params);
} else if (id is int && _flutterRequestCompleters.containsKey(id)) {
_handleJsonResponse(id, payload);
} else {
// If it wasn't processed above,
sendOutput(outputCategory, data);
}
}
/// Performs a restart/reload by sending the `app.restart` message to the `flutter run --machine` process.
Future<void> _performRestart(
bool fullRestart, [
String? reason,
]) async {
final String progressId = fullRestart ? 'hotRestart' : 'hotReload';
final String progressMessage = fullRestart ? 'Hot restarting…' : 'Hot reloading…';
final DapProgressReporter progress = startProgressNotification(
progressId,
'Flutter',
message: progressMessage,
);
try {
await sendFlutterRequest('app.restart', <String, Object?>{
'appId': appId,
'fullRestart': fullRestart,
'pause': enableDebugger,
'reason': reason,
'debounce': true,
});
} on DebugAdapterException catch (error) {
final String action = fullRestart ? 'Hot Restart' : 'Hot Reload';
sendOutput('console', 'Failed to $action: $error');
}
finally {
progress.end();
}
}
void _sendServiceExtensionStateChanged(vm.ExtensionData? extensionData) {
final Map<String, dynamic>? data = extensionData?.data;
if (data != null) {
sendEvent(
RawEventBody(data),
eventType: 'flutter.serviceExtensionStateChanged',
);
}
}
}