pkg/analysis_server/tool/benchmark_tools/language_server_benchmark.dart - sdk - Git at Google

 // Copyright (c) 2025, 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:convert';
 import 'dart:io';
 import 'dart:typed_data';

 import 'io_utils.dart';
 import 'legacy_messages.dart';
 import 'lsp_messages.dart';
 import 'utils.dart';

 abstract class DartLanguageServerBenchmark {
   int verbosity = 0;
   final Uri repoDir = computeRepoDirUri();
   late final Process p;
   late final Timer longRunningRequestsTimer;
   bool _launched = false;
   bool _exited = false;
   Completer<bool> _analyzingCompleter = Completer();
   final _buffer = _Uint8ListHelper();
   int? _headerContentLength;
   bool _printedVmServiceStuff = false;
   final String executableToUse;

   /// There's something weird about getting (several) id 3's that wasn't
   /// requested...
   int largestIdSeen = 3;

   final RegExp _newLineRegExp = RegExp('\r?\n');
   final Map<int, OutstandingRequest> _outstandingRequestsWithId = {};

   bool _addedInitialAnalysisDuration = false;
   List<DurationInfo> durationInfo = [];
   List<MemoryInfo> memoryInfo = [];

   final bool _lsp;

   DartLanguageServerBenchmark(List<String> args, {required bool useLspProtocol})
     : _lsp = useLspProtocol,
       executableToUse = extractDartParamOrDefault(args) {
     _checkCorrectDart();
   }

   List<Uri> get additionalWorkspaceUris => const [];
   Uri? get cacheFolder => null;

   LaunchFrom get launchFrom => LaunchFrom.Source;

   Uri get rootUri;
   Future<void> afterInitialization();

   void exit() {
     _exited = true;
     longRunningRequestsTimer.cancel();
     if (Platform.isLinux) {
       try {
         File f = File('/proc/${p.pid}/status');
         for (var line in f.readAsLinesSync()) {
           if (line.startsWith('VmPeak:')) {
             memoryInfo.addInfoMaybe(
               'peak virtual memory size',
               _extractSizeFromProcStatusMemoryLine(line),
             );
           } else if (line.startsWith('VmSize:')) {
             memoryInfo.addInfoMaybe(
               'total program size (virtual)',
               _extractSizeFromProcStatusMemoryLine(line),
             );
           } else if (line.startsWith('VmHWM:')) {
             memoryInfo.addInfoMaybe(
               'peak resident set size ("high water mark")',
               _extractSizeFromProcStatusMemoryLine(line),
             );
           } else if (line.startsWith('VmRSS:')) {
             memoryInfo.addInfoMaybe(
               'size of memory portions (rss)',
               _extractSizeFromProcStatusMemoryLine(line),
             );
           }
         }
       } catch (e) {
         // ignore
       }
     }
     p.kill();
   }

   Future<void> run() async {
     if (_lsp) {
       await _runLsp();
     } else {
       await _runLegacy();
     }
   }

   Future<OutstandingRequest?> send(Map<String, dynamic> json) async {
     // Mostly copied from
     // pkg/analysis_server/lib/src/lsp/channel/lsp_byte_stream_channel.dart
     var jsonEncodedBody = jsonEncode(json);
     var utf8EncodedBody = utf8.encode(jsonEncodedBody);
     var header =
         'Content-Length: ${utf8EncodedBody.length}\r\n'
         'Content-Type: application/vscode-jsonrpc; charset=utf-8\r\n\r\n';
     var asciiEncodedHeader = ascii.encode(header);

     OutstandingRequest? result;

     dynamic possibleId = json['id'];
     if (!_lsp && possibleId is String && int.tryParse(possibleId) != null) {
       possibleId = int.tryParse(possibleId);
     }
     if (possibleId is int) {
       if (possibleId > largestIdSeen) {
         largestIdSeen = possibleId;
       }
       result = OutstandingRequest();
       _outstandingRequestsWithId[possibleId] = result;
       if (verbosity > 2) {
         print('Sending message with id $possibleId');
       }
     }
     if (verbosity > 3) {
       print('Sending message: $jsonEncodedBody');
     }

     if (_lsp) {
       // Header is always ascii, body is always utf8!
       p.stdin.add(asciiEncodedHeader);
     }
     p.stdin.add(utf8EncodedBody);
     if (!_lsp) {
       p.stdin.add(const [10]);
     }
     await p.stdin.flush();
     if (verbosity > 2) {
       print('\n\nMessage sent\n\n');
     }
     return result;
   }

   Future<bool> waitUntilIsAnalyzingChanges() async {
     return await _analyzingCompleter.future;
   }

   Future<void> waitWhileAnalyzing() async {
     // Wait until it's done analyzing.
     bool isAnalyzing = await _analyzingCompleter.future;
     Stopwatch stopwatch = Stopwatch()..start();
     while (isAnalyzing) {
       isAnalyzing = await _analyzingCompleter.future;
     }
     if (verbosity >= 0) {
       print('isAnalyzing is now done after ${stopwatch.elapsed}');
     }
     if (!_addedInitialAnalysisDuration) {
       _addedInitialAnalysisDuration = true;
       durationInfo.add(DurationInfo('Initial analysis', stopwatch.elapsed));
     }
   }

   void _checkCorrectDart() {
     Uri exe = Uri.base.resolveUri(Uri.file(executableToUse));
     Uri librariesDart = exe.resolve(
       '../lib/_internal/sdk_library_metadata/lib/libraries.dart',
     );
     if (!File.fromUri(librariesDart).existsSync()) {
       throw 'Execute with a dart that has '
           "'../lib/_internal/sdk_library_metadata/lib/libraries.dart' "
           'available (e.g. out/ReleaseX64/dart-sdk/bin/dart)';
     }
   }

   void _checkLongRunningRequests(Timer timer) {
     if (verbosity < 0) return;
     bool reportedSomething = false;
     for (MapEntry<int, OutstandingRequest> waitingFor
         in _outstandingRequestsWithId.entries) {
       if (waitingFor.value.stopwatch.elapsed > const Duration(seconds: 1)) {
         if (!reportedSomething) {
           print('----');
           reportedSomething = true;
         }
         print(
           '==> Has been waiting for required #${waitingFor.key} for '
           '${waitingFor.value.stopwatch.elapsed}',
         );
       }
     }
     if (reportedSomething) {
       print('----');
     } else {
       // print(" -- not waiting for anything -- ");
     }
   }

   /// Copied from pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart.
   bool _endsWithCrLfCrLf() {
     var l = _buffer.length;
     return l > 4 &&
         _buffer[l - 1] == 10 &&
         _buffer[l - 2] == 13 &&
         _buffer[l - 3] == 10 &&
         _buffer[l - 4] == 13;
   }

   bool _endsWithLf() {
     var l = _buffer.length;
     return l > 1 && _buffer[l - 1] == 10;
   }

   int? _extractSizeFromProcStatusMemoryLine(String line) {
     int colon = line.indexOf(':');
     if (colon < 0) return null;
     int kb = line.indexOf('kB', colon);
     if (kb < 0) return null;
     String substring = line.substring(colon + 1, kb).trim();
     return int.tryParse(substring);
   }

   Future<void> _initializeLegacy() async {
     await send(LegacyMessages.getVersion(largestIdSeen + 1));
     await send(LegacyMessages.setSubscriptionsStatus(largestIdSeen + 1));
     await send(LegacyMessages.updateOptions(largestIdSeen + 1));
     await send(LegacyMessages.setClientCapabilities(largestIdSeen + 1));
     await send(
       LegacyMessages.setAnalysisRoots(largestIdSeen + 1, [
         rootUri,
         ...additionalWorkspaceUris,
       ]),
     );

     // Wait until it's done analyzing.
     await waitWhileAnalyzing();
   }

   Future<void> _initializeLsp() async {
     OutstandingRequest? request = await send(
       LspMessages.initMessage(pid, rootUri, additionalWorkspaceUris),
     );
     await request?.completer.future;
     await send(LspMessages.initNotification);

     // Wait until it's done analyzing.
     await waitWhileAnalyzing();
   }

   Future<void> _launch({required bool lsp}) async {
     if (_launched) throw 'Already launched';
     _launched = true;

     List<String> cacheFolderArgs = [];
     if (cacheFolder != null) {
       cacheFolderArgs.add('--cache');
       cacheFolderArgs.add(cacheFolder!.toFilePath());
     }

     switch (launchFrom) {
       case LaunchFrom.Source:
         File serverFile = File.fromUri(
           repoDir.resolve('pkg/analysis_server/bin/server.dart'),
         );
         if (!serverFile.existsSync()) {
           throw "Couldn't find 'analysis_server/bin/server.dart' "
               'expected it at $serverFile';
         }

         // TODO(jensj): Option of passing --profiler
         p = await Process.start(executableToUse, [
           '--enable-vm-service',
           '--profiler',
           serverFile.path,
           lsp ? '--protocol=lsp' : '--protocol=analyzer',
           '--port=9102',
           ...cacheFolderArgs,
         ]);
       case LaunchFrom.Dart:
         // TODO(jensj): Option of wrapping in `perf record -g` call.
         p = await Process.start(executableToUse, [
           'language-server',
           lsp ? '--protocol=lsp' : '--protocol=analyzer',
           '--port=9102',
           ...cacheFolderArgs,
         ]);
       case LaunchFrom.AotWithPerf:
       case LaunchFrom.Aot:
         File serverFile = File.fromUri(
           repoDir.resolve('pkg/analysis_server/bin/server.aot'),
         );
         if (!serverFile.existsSync()) {
           throw "Couldn't find 'analysis_server/bin/server.aot' "
               'expected it at $serverFile';
         }

         // TODO(jensj): Option of passing --profiler
         Uri dart = Uri.base.resolveUri(Uri.file(executableToUse));
         File aotRuntime = File.fromUri(dart.resolve('dartaotruntime'));
         if (!aotRuntime.existsSync()) {
           throw "Couldn't find 'dartaotruntime' expected it at $aotRuntime";
         }

         p = await Process.start(aotRuntime.path, [
           serverFile.path,
           lsp ? '--protocol=lsp' : '--protocol=analyzer',
           '--port=9102',
           ...cacheFolderArgs,
         ]);

         if (launchFrom == LaunchFrom.AotWithPerf) {
           await Process.start('perf', [
             'record',
             '-p',
             '${p.pid}',
             '-g',
           ], mode: ProcessStartMode.inheritStdio);
         }
     }

     // ignore: unawaited_futures
     p.exitCode.then((exitCode) {
       if (verbosity >= 0) {
         print('Process existed with exitCode $exitCode');
       }
       if (!_exited) {
         _analyzingCompleter.completeError('Process exited 1.');
         while (_outstandingRequestsWithId.isNotEmpty) {
           var entry = _outstandingRequestsWithId.entries.first;
           _outstandingRequestsWithId.remove(entry.key);
           entry.value.completer.completeError('Process exited 2.');
         }
       }
     });

     if (verbosity >= 0) {
       print('Launched with pid ${p.pid}');
     }
   }

   void _listenToStdout(List<int> event) {
     // General idea taken from
     // pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart
     for (int element in event) {
       _buffer.add(element);
       if (verbosity > 3 &&
           _buffer.length >= 1000 &&
           _buffer.length % 1000 == 0) {
         print(
           'DEBUG MESSAGE: Stdout buffer with length ${_buffer.length} so far: '
           '${utf8.decode(_buffer.view())}',
         );
       }
       if (_lsp && _headerContentLength == null && _endsWithCrLfCrLf()) {
         String headerRaw = utf8.decode(_buffer.view());
         _buffer.clear();
         // Use a regex that makes the '\r' optional to handle "The Dart VM service
         // is listening on [..." message - at least on linux - being \n terminated
         // which would otherwise mean that we'd be stuck because no message would
         // start with 'Content-Length:'.
         List<String> headers = headerRaw.split(_newLineRegExp);
         for (String header in headers) {
           if (!_printedVmServiceStuff &&
               header.startsWith('The Dart VM service')) {
             if (verbosity >= 0) {
               print('\n\n$header\n\n');
             }
             _printedVmServiceStuff = true;
           }
           if (header.startsWith('Content-Length:')) {
             String contentLength =
                 header.substring('Content-Length:'.length).trim();
             _headerContentLength = int.parse(contentLength);
             break;
           }
         }
       } else if ((_lsp &&
               _headerContentLength != null &&
               _buffer.length == _headerContentLength!) ||
           (!_lsp && _endsWithLf())) {
         String messageString = utf8.decode(_buffer.view());
         _buffer.clear();
         _headerContentLength = null;

         if (messageString.startsWith('The Dart VM service')) {
           if (verbosity >= 0) print('\n\n$messageString\n\n');
           continue;
         }
         if (messageString.startsWith('The Dart DevTools')) {
           if (verbosity >= 0) print('\n\n$messageString\n\n');
           continue;
         }

         Map<String, dynamic> message =
             json.decode(messageString) as Map<String, dynamic>;

         // LSP: {"jsonrpc":"2.0","method":"$/analyzerStatus","params":{"isAnalyzing":false}}
         // Analyzer: {"event":"server.status","params":{"analysis":{"isAnalyzing":true}}}
         if ((_lsp && message['method'] == r'$/analyzerStatus') ||
             (!_lsp && message['event'] == 'server.status')) {
           dynamic params = message['params'];
           if (params is Map) {
             dynamic isAnalyzing =
                 _lsp
                     ? params['isAnalyzing']
                     : params['analysis']?['isAnalyzing'];
             if (isAnalyzing is bool) {
               _analyzingCompleter.complete(isAnalyzing);
               _analyzingCompleter = Completer<bool>();
               if (verbosity > 0) {
                 print('Got analyzerStatus isAnalyzing = $isAnalyzing');
               }
             }
           }
         }
         dynamic possibleId = message['id'];
         if (!_lsp && possibleId is String && int.tryParse(possibleId) != null) {
           possibleId = int.tryParse(possibleId);
         }
         if (possibleId is int) {
           if (possibleId > largestIdSeen) {
             largestIdSeen = possibleId;
           }

           if (verbosity > 0) {
             if (messageString.length > 100) {
               print('Got message ${messageString.substring(0, 100)}...');
             } else {
               print('Got message $messageString');
             }
           }

           OutstandingRequest? outstandingRequest = _outstandingRequestsWithId
               .remove(possibleId);
           if (outstandingRequest != null) {
             outstandingRequest.stopwatch.stop();
             outstandingRequest.completer.complete(message);
             if (verbosity > 2) {
               print(
                 ' => Got response for $possibleId in '
                 '${outstandingRequest.stopwatch.elapsed}',
               );
             }
           }
         } else if (verbosity > 1) {
           if (messageString.length > 100) {
             print('Got message ${messageString.substring(0, 100)}...');
           } else {
             print('Got message $messageString');
           }
         }
       }
     }
   }

   Future<void> _runLegacy() async {
     assert(!_lsp);
     await _launch(lsp: false);
     p.stdout.listen(_listenToStdout);
     p.stderr.listen(stderr.add);
     longRunningRequestsTimer = Timer.periodic(
       const Duration(seconds: 1),
       _checkLongRunningRequests,
     );

     await _initializeLegacy();
     if (verbosity >= 0) {
       print('Should now be initialized.');
     }

     await afterInitialization();
   }

   Future<void> _runLsp() async {
     assert(_lsp);
     await _launch(lsp: true);
     p.stdout.listen(_listenToStdout);
     p.stderr.listen(stderr.add);
     longRunningRequestsTimer = Timer.periodic(
       const Duration(seconds: 1),
       _checkLongRunningRequests,
     );

     await _initializeLsp();
     if (verbosity >= 0) {
       print('Should now be initialized.');
     }

     await afterInitialization();
   }
 }

 class DurationInfo {
   final String name;
   final Duration duration;

   DurationInfo(this.name, this.duration);
 }

 enum LaunchFrom { Source, Dart, Aot, AotWithPerf }

 class MemoryInfo {
   final String name;
   final int kb;

   MemoryInfo(this.name, this.kb);
 }

 class OutstandingRequest {
   final Stopwatch stopwatch = Stopwatch();
   final Completer<Map<String, dynamic>> completer = Completer();
   OutstandingRequest() {
     stopwatch.start();
   }
 }

 class _Uint8ListHelper {
   Uint8List data;
   int length = 0;
   _Uint8ListHelper() : data = Uint8List(1024);

   int operator [](int index) {
     if (index < 0 || index >= length) throw 'Out of bounds: $index';
     return data[index];
   }

   void add(int i) {
     if (length == data.length) {
       var newData = Uint8List(length * 2);
       newData.setRange(0, length, data);
       data = newData;
     }
     data[length++] = i;
   }

   void clear() {
     length = 0;
   }

   Uint8List view() {
     return Uint8List.sublistView(data, 0, length);
   }
 }

 extension on List<MemoryInfo> {
   void addInfoMaybe(String description, int? value) {
     if (value == null) return;
     add(MemoryInfo(description, value));
   }
 }
	// Copyright (c) 2025, 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:convert';
	import 'dart:io';
	import 'dart:typed_data';

	import 'io_utils.dart';
	import 'legacy_messages.dart';
	import 'lsp_messages.dart';
	import 'utils.dart';

	abstract class DartLanguageServerBenchmark {
	int verbosity = 0;
	final Uri repoDir = computeRepoDirUri();
	late final Process p;
	late final Timer longRunningRequestsTimer;
	bool _launched = false;
	bool _exited = false;
	Completer<bool> _analyzingCompleter = Completer();
	final _buffer = _Uint8ListHelper();
	int? _headerContentLength;
	bool _printedVmServiceStuff = false;
	final String executableToUse;

	/// There's something weird about getting (several) id 3's that wasn't
	/// requested...
	int largestIdSeen = 3;

	final RegExp _newLineRegExp = RegExp('\r?\n');
	final Map<int, OutstandingRequest> _outstandingRequestsWithId = {};

	bool _addedInitialAnalysisDuration = false;
	List<DurationInfo> durationInfo = [];
	List<MemoryInfo> memoryInfo = [];

	final bool _lsp;

	DartLanguageServerBenchmark(List<String> args, {required bool useLspProtocol})
	: _lsp = useLspProtocol,
	executableToUse = extractDartParamOrDefault(args) {
	_checkCorrectDart();
	}

	List<Uri> get additionalWorkspaceUris => const [];
	Uri? get cacheFolder => null;

	LaunchFrom get launchFrom => LaunchFrom.Source;

	Uri get rootUri;
	Future<void> afterInitialization();

	void exit() {
	_exited = true;
	longRunningRequestsTimer.cancel();
	if (Platform.isLinux) {
	try {
	File f = File('/proc/${p.pid}/status');
	for (var line in f.readAsLinesSync()) {
	if (line.startsWith('VmPeak:')) {
	memoryInfo.addInfoMaybe(
	'peak virtual memory size',
	_extractSizeFromProcStatusMemoryLine(line),
	);
	} else if (line.startsWith('VmSize:')) {
	memoryInfo.addInfoMaybe(
	'total program size (virtual)',
	_extractSizeFromProcStatusMemoryLine(line),
	);
	} else if (line.startsWith('VmHWM:')) {
	memoryInfo.addInfoMaybe(
	'peak resident set size ("high water mark")',
	_extractSizeFromProcStatusMemoryLine(line),
	);
	} else if (line.startsWith('VmRSS:')) {
	memoryInfo.addInfoMaybe(
	'size of memory portions (rss)',
	_extractSizeFromProcStatusMemoryLine(line),
	);
	}
	}
	} catch (e) {
	// ignore
	}
	}
	p.kill();
	}

	Future<void> run() async {
	if (_lsp) {
	await _runLsp();
	} else {
	await _runLegacy();
	}
	}

	Future<OutstandingRequest?> send(Map<String, dynamic> json) async {
	// Mostly copied from
	// pkg/analysis_server/lib/src/lsp/channel/lsp_byte_stream_channel.dart
	var jsonEncodedBody = jsonEncode(json);
	var utf8EncodedBody = utf8.encode(jsonEncodedBody);
	var header =
	'Content-Length: ${utf8EncodedBody.length}\r\n'
	'Content-Type: application/vscode-jsonrpc; charset=utf-8\r\n\r\n';
	var asciiEncodedHeader = ascii.encode(header);

	OutstandingRequest? result;

	dynamic possibleId = json['id'];
	if (!_lsp && possibleId is String && int.tryParse(possibleId) != null) {
	possibleId = int.tryParse(possibleId);
	}
	if (possibleId is int) {
	if (possibleId > largestIdSeen) {
	largestIdSeen = possibleId;
	}
	result = OutstandingRequest();
	_outstandingRequestsWithId[possibleId] = result;
	if (verbosity > 2) {
	print('Sending message with id $possibleId');
	}
	}
	if (verbosity > 3) {
	print('Sending message: $jsonEncodedBody');
	}

	if (_lsp) {
	// Header is always ascii, body is always utf8!
	p.stdin.add(asciiEncodedHeader);
	}
	p.stdin.add(utf8EncodedBody);
	if (!_lsp) {
	p.stdin.add(const [10]);
	}
	await p.stdin.flush();
	if (verbosity > 2) {
	print('\n\nMessage sent\n\n');
	}
	return result;
	}

	Future<bool> waitUntilIsAnalyzingChanges() async {
	return await _analyzingCompleter.future;
	}

	Future<void> waitWhileAnalyzing() async {
	// Wait until it's done analyzing.
	bool isAnalyzing = await _analyzingCompleter.future;
	Stopwatch stopwatch = Stopwatch()..start();
	while (isAnalyzing) {
	isAnalyzing = await _analyzingCompleter.future;
	}
	if (verbosity >= 0) {
	print('isAnalyzing is now done after ${stopwatch.elapsed}');
	}
	if (!_addedInitialAnalysisDuration) {
	_addedInitialAnalysisDuration = true;
	durationInfo.add(DurationInfo('Initial analysis', stopwatch.elapsed));
	}
	}

	void _checkCorrectDart() {
	Uri exe = Uri.base.resolveUri(Uri.file(executableToUse));
	Uri librariesDart = exe.resolve(
	'../lib/_internal/sdk_library_metadata/lib/libraries.dart',
	);
	if (!File.fromUri(librariesDart).existsSync()) {
	throw 'Execute with a dart that has '
	"'../lib/_internal/sdk_library_metadata/lib/libraries.dart' "
	'available (e.g. out/ReleaseX64/dart-sdk/bin/dart)';
	}
	}

	void _checkLongRunningRequests(Timer timer) {
	if (verbosity < 0) return;
	bool reportedSomething = false;
	for (MapEntry<int, OutstandingRequest> waitingFor
	in _outstandingRequestsWithId.entries) {
	if (waitingFor.value.stopwatch.elapsed > const Duration(seconds: 1)) {
	if (!reportedSomething) {
	print('----');
	reportedSomething = true;
	}
	print(
	'==> Has been waiting for required #${waitingFor.key} for '
	'${waitingFor.value.stopwatch.elapsed}',
	);
	}
	}
	if (reportedSomething) {
	print('----');
	} else {
	// print(" -- not waiting for anything -- ");
	}
	}

	/// Copied from pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart.
	bool _endsWithCrLfCrLf() {
	var l = _buffer.length;
	return l > 4 &&
	_buffer[l - 1] == 10 &&
	_buffer[l - 2] == 13 &&
	_buffer[l - 3] == 10 &&
	_buffer[l - 4] == 13;
	}

	bool _endsWithLf() {
	var l = _buffer.length;
	return l > 1 && _buffer[l - 1] == 10;
	}

	int? _extractSizeFromProcStatusMemoryLine(String line) {
	int colon = line.indexOf(':');
	if (colon < 0) return null;
	int kb = line.indexOf('kB', colon);
	if (kb < 0) return null;
	String substring = line.substring(colon + 1, kb).trim();
	return int.tryParse(substring);
	}

	Future<void> _initializeLegacy() async {
	await send(LegacyMessages.getVersion(largestIdSeen + 1));
	await send(LegacyMessages.setSubscriptionsStatus(largestIdSeen + 1));
	await send(LegacyMessages.updateOptions(largestIdSeen + 1));
	await send(LegacyMessages.setClientCapabilities(largestIdSeen + 1));
	await send(
	LegacyMessages.setAnalysisRoots(largestIdSeen + 1, [
	rootUri,
	...additionalWorkspaceUris,
	]),
	);

	// Wait until it's done analyzing.
	await waitWhileAnalyzing();
	}

	Future<void> _initializeLsp() async {
	OutstandingRequest? request = await send(
	LspMessages.initMessage(pid, rootUri, additionalWorkspaceUris),
	);
	await request?.completer.future;
	await send(LspMessages.initNotification);

	// Wait until it's done analyzing.
	await waitWhileAnalyzing();
	}

	Future<void> _launch({required bool lsp}) async {
	if (_launched) throw 'Already launched';
	_launched = true;

	List<String> cacheFolderArgs = [];
	if (cacheFolder != null) {
	cacheFolderArgs.add('--cache');
	cacheFolderArgs.add(cacheFolder!.toFilePath());
	}

	switch (launchFrom) {
	case LaunchFrom.Source:
	File serverFile = File.fromUri(
	repoDir.resolve('pkg/analysis_server/bin/server.dart'),
	);
	if (!serverFile.existsSync()) {
	throw "Couldn't find 'analysis_server/bin/server.dart' "
	'expected it at $serverFile';
	}

	// TODO(jensj): Option of passing --profiler
	p = await Process.start(executableToUse, [
	'--enable-vm-service',
	'--profiler',
	serverFile.path,
	lsp ? '--protocol=lsp' : '--protocol=analyzer',
	'--port=9102',
	...cacheFolderArgs,
	]);
	case LaunchFrom.Dart:
	// TODO(jensj): Option of wrapping in `perf record -g` call.
	p = await Process.start(executableToUse, [
	'language-server',
	lsp ? '--protocol=lsp' : '--protocol=analyzer',
	'--port=9102',
	...cacheFolderArgs,
	]);
	case LaunchFrom.AotWithPerf:
	case LaunchFrom.Aot:
	File serverFile = File.fromUri(
	repoDir.resolve('pkg/analysis_server/bin/server.aot'),
	);
	if (!serverFile.existsSync()) {
	throw "Couldn't find 'analysis_server/bin/server.aot' "
	'expected it at $serverFile';
	}

	// TODO(jensj): Option of passing --profiler
	Uri dart = Uri.base.resolveUri(Uri.file(executableToUse));
	File aotRuntime = File.fromUri(dart.resolve('dartaotruntime'));
	if (!aotRuntime.existsSync()) {
	throw "Couldn't find 'dartaotruntime' expected it at $aotRuntime";
	}

	p = await Process.start(aotRuntime.path, [
	serverFile.path,
	lsp ? '--protocol=lsp' : '--protocol=analyzer',
	'--port=9102',
	...cacheFolderArgs,
	]);

	if (launchFrom == LaunchFrom.AotWithPerf) {
	await Process.start('perf', [
	'record',
	'-p',
	'${p.pid}',
	'-g',
	], mode: ProcessStartMode.inheritStdio);
	}
	}

	// ignore: unawaited_futures
	p.exitCode.then((exitCode) {
	if (verbosity >= 0) {
	print('Process existed with exitCode $exitCode');
	}
	if (!_exited) {
	_analyzingCompleter.completeError('Process exited 1.');
	while (_outstandingRequestsWithId.isNotEmpty) {
	var entry = _outstandingRequestsWithId.entries.first;
	_outstandingRequestsWithId.remove(entry.key);
	entry.value.completer.completeError('Process exited 2.');
	}
	}
	});

	if (verbosity >= 0) {
	print('Launched with pid ${p.pid}');
	}
	}

	void _listenToStdout(List<int> event) {
	// General idea taken from
	// pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart
	for (int element in event) {
	_buffer.add(element);
	if (verbosity > 3 &&
	_buffer.length >= 1000 &&
	_buffer.length % 1000 == 0) {
	print(
	'DEBUG MESSAGE: Stdout buffer with length ${_buffer.length} so far: '
	'${utf8.decode(_buffer.view())}',
	);
	}
	if (_lsp && _headerContentLength == null && _endsWithCrLfCrLf()) {
	String headerRaw = utf8.decode(_buffer.view());
	_buffer.clear();
	// Use a regex that makes the '\r' optional to handle "The Dart VM service
	// is listening on [..." message - at least on linux - being \n terminated
	// which would otherwise mean that we'd be stuck because no message would
	// start with 'Content-Length:'.
	List<String> headers = headerRaw.split(_newLineRegExp);
	for (String header in headers) {
	if (!_printedVmServiceStuff &&
	header.startsWith('The Dart VM service')) {
	if (verbosity >= 0) {
	print('\n\n$header\n\n');
	}
	_printedVmServiceStuff = true;
	}
	if (header.startsWith('Content-Length:')) {
	String contentLength =
	header.substring('Content-Length:'.length).trim();
	_headerContentLength = int.parse(contentLength);
	break;
	}
	}
	} else if ((_lsp &&
	_headerContentLength != null &&
	_buffer.length == _headerContentLength!) \|\|
	(!_lsp && _endsWithLf())) {
	String messageString = utf8.decode(_buffer.view());
	_buffer.clear();
	_headerContentLength = null;

	if (messageString.startsWith('The Dart VM service')) {
	if (verbosity >= 0) print('\n\n$messageString\n\n');
	continue;
	}
	if (messageString.startsWith('The Dart DevTools')) {
	if (verbosity >= 0) print('\n\n$messageString\n\n');
	continue;
	}

	Map<String, dynamic> message =
	json.decode(messageString) as Map<String, dynamic>;

	// LSP: {"jsonrpc":"2.0","method":"$/analyzerStatus","params":{"isAnalyzing":false}}
	// Analyzer: {"event":"server.status","params":{"analysis":{"isAnalyzing":true}}}
	if ((_lsp && message['method'] == r'$/analyzerStatus') \|\|
	(!_lsp && message['event'] == 'server.status')) {
	dynamic params = message['params'];
	if (params is Map) {
	dynamic isAnalyzing =
	_lsp
	? params['isAnalyzing']
	: params['analysis']?['isAnalyzing'];
	if (isAnalyzing is bool) {
	_analyzingCompleter.complete(isAnalyzing);
	_analyzingCompleter = Completer<bool>();
	if (verbosity > 0) {
	print('Got analyzerStatus isAnalyzing = $isAnalyzing');
	}
	}
	}
	}
	dynamic possibleId = message['id'];
	if (!_lsp && possibleId is String && int.tryParse(possibleId) != null) {
	possibleId = int.tryParse(possibleId);
	}
	if (possibleId is int) {
	if (possibleId > largestIdSeen) {
	largestIdSeen = possibleId;
	}

	if (verbosity > 0) {
	if (messageString.length > 100) {
	print('Got message ${messageString.substring(0, 100)}...');
	} else {
	print('Got message $messageString');
	}
	}

	OutstandingRequest? outstandingRequest = _outstandingRequestsWithId
	.remove(possibleId);
	if (outstandingRequest != null) {
	outstandingRequest.stopwatch.stop();
	outstandingRequest.completer.complete(message);
	if (verbosity > 2) {
	print(
	' => Got response for $possibleId in '
	'${outstandingRequest.stopwatch.elapsed}',
	);
	}
	}
	} else if (verbosity > 1) {
	if (messageString.length > 100) {
	print('Got message ${messageString.substring(0, 100)}...');
	} else {
	print('Got message $messageString');
	}
	}
	}
	}
	}

	Future<void> _runLegacy() async {
	assert(!_lsp);
	await _launch(lsp: false);
	p.stdout.listen(_listenToStdout);
	p.stderr.listen(stderr.add);
	longRunningRequestsTimer = Timer.periodic(
	const Duration(seconds: 1),
	_checkLongRunningRequests,
	);

	await _initializeLegacy();
	if (verbosity >= 0) {
	print('Should now be initialized.');
	}

	await afterInitialization();
	}

	Future<void> _runLsp() async {
	assert(_lsp);
	await _launch(lsp: true);
	p.stdout.listen(_listenToStdout);
	p.stderr.listen(stderr.add);
	longRunningRequestsTimer = Timer.periodic(
	const Duration(seconds: 1),
	_checkLongRunningRequests,
	);

	await _initializeLsp();
	if (verbosity >= 0) {
	print('Should now be initialized.');
	}

	await afterInitialization();
	}
	}

	class DurationInfo {
	final String name;
	final Duration duration;

	DurationInfo(this.name, this.duration);
	}

	enum LaunchFrom { Source, Dart, Aot, AotWithPerf }

	class MemoryInfo {
	final String name;
	final int kb;

	MemoryInfo(this.name, this.kb);
	}

	class OutstandingRequest {
	final Stopwatch stopwatch = Stopwatch();
	final Completer<Map<String, dynamic>> completer = Completer();
	OutstandingRequest() {
	stopwatch.start();
	}
	}

	class _Uint8ListHelper {
	Uint8List data;
	int length = 0;
	_Uint8ListHelper() : data = Uint8List(1024);

	int operator [](int index) {
	if (index < 0 \|\| index >= length) throw 'Out of bounds: $index';
	return data[index];
	}

	void add(int i) {
	if (length == data.length) {
	var newData = Uint8List(length * 2);
	newData.setRange(0, length, data);
	data = newData;
	}
	data[length++] = i;
	}

	void clear() {
	length = 0;
	}

	Uint8List view() {
	return Uint8List.sublistView(data, 0, length);
	}
	}

	extension on List<MemoryInfo> {
	void addInfoMaybe(String description, int? value) {
	if (value == null) return;
	add(MemoryInfo(description, value));
	}
	}