Add an initial version of a 'dart language-server' command.

Change-Id: Iffb8dedf7419a421e5282e09b4584e768c47e53f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/176485
Commit-Queue: Devon Carew <devoncarew@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/README.md

@@ -13,8 +13,8 @@ not have a human-friendly user interface.
 Clients (typically tools, such as an editor) are expected to run the analysis
 server in a separate process and communicate with it using a JSON protocol. The
 original protocol is specified in the file [`analysis_server/doc/api.html`][api]
-and (less complete) [Language Server Protocol][lsp_spec] support is documented
-in [`tool/lsp_spec/README.md`](tool/lsp_spec/README.md).
+and [Language Server Protocol][lsp_spec] support is documented in
+[`tool/lsp_spec/README.md`](tool/lsp_spec/README.md).
 
 ## Features and bugs
 

pkg/analysis_server/lib/src/server/driver.dart

@@ -98,6 +98,11 @@ class Driver implements ServerStarter {
   /// The path to the data cache.
   static const String CACHE_FOLDER = 'cache';
 
+  /// The name of the flag specifying the server protocol to use.
+  static const String SERVER_PROTOCOL = 'protocol';
+  static const String PROTOCOL_ANALYZER = 'analyzer';
+  static const String PROTOCOL_LSP = 'lsp';
+
   /// The name of the flag to use the Language Server Protocol (LSP).
   static const String USE_LSP = 'lsp';
 
@@ -124,17 +129,26 @@ class Driver implements ServerStarter {
   /// If [sendPort] is not null, assumes this is launched in an isolate and will
   /// connect to the original isolate via an [IsolateChannel].
   @override
-  void start(List<String> arguments, [SendPort sendPort]) {
-    var parser = _createArgParser();
+  void start(
+    List<String> arguments, {
+    SendPort sendPort,
+    bool defaultToLsp = false,
+  }) {
+    var parser = createArgParser(defaultToLsp: defaultToLsp);
     var results = parser.parse(arguments);
 
     var analysisServerOptions = AnalysisServerOptions();
     analysisServerOptions.newAnalysisDriverLog =
         results[ANALYSIS_DRIVER_LOG] ?? results[ANALYSIS_DRIVER_LOG_ALIAS];
     analysisServerOptions.clientId = results[CLIENT_ID];
-    analysisServerOptions.useLanguageServerProtocol = results[USE_LSP];
-    // For clients that don't supply their own identifier, use a default based on
-    // whether the server will run in LSP mode or not.
+    if (results.wasParsed(USE_LSP)) {
+      analysisServerOptions.useLanguageServerProtocol = results[USE_LSP];
+    } else {
+      analysisServerOptions.useLanguageServerProtocol =
+          results[SERVER_PROTOCOL] == PROTOCOL_LSP;
+    }
+    // For clients that don't supply their own identifier, use a default based
+    // on whether the server will run in LSP mode or not.
     analysisServerOptions.clientId ??=
         analysisServerOptions.useLanguageServerProtocol
             ? 'unknown.client.lsp'
@@ -478,11 +492,95 @@ class Driver implements ServerStarter {
     return runZoned(callback, zoneSpecification: zoneSpecification);
   }
 
+  DartSdk _createDefaultSdk(String defaultSdkPath) {
+    var resourceProvider = PhysicalResourceProvider.INSTANCE;
+    return FolderBasedDartSdk(
+      resourceProvider,
+      resourceProvider.getFolder(defaultSdkPath),
+    );
+  }
+
+  /// Constructs a uuid combining the current date and a random integer.
+  String _generateUuidString() {
+    var millisecondsSinceEpoch = DateTime.now().millisecondsSinceEpoch;
+    var random = Random().nextInt(0x3fffffff);
+    return '$millisecondsSinceEpoch$random';
+  }
+
+  String _getSdkPath(ArgResults args) {
+    if (args[DART_SDK] != null) {
+      return args[DART_SDK];
+    } else if (args[DART_SDK_ALIAS] != null) {
+      return args[DART_SDK_ALIAS];
+    } else {
+      return getSdkPath();
+    }
+  }
+
+  /// Print information about how to use the server.
+  void _printUsage(
+    ArgParser parser,
+    telemetry.Analytics analytics, {
+    bool fromHelp = false,
+  }) {
+    print('Usage: $BINARY_NAME [flags]');
+    print('');
+    print('Supported flags are:');
+    print(parser.usage);
+
+    if (telemetry.SHOW_ANALYTICS_UI) {
+      // Print analytics status and information.
+      if (fromHelp) {
+        print('');
+        print(telemetry.analyticsNotice);
+      }
+      print('');
+      print(telemetry.createAnalyticsStatusMessage(analytics.enabled,
+          command: ANALYTICS_FLAG));
+    }
+  }
+
+  /// Read the UUID from disk, generating and storing a new one if necessary.
+  String _readUuid(InstrumentationService service) {
+    final instrumentationLocation =
+        PhysicalResourceProvider.INSTANCE.getStateLocation('.instrumentation');
+    if (instrumentationLocation == null) {
+      return _generateUuidString();
+    }
+    var uuidFile = File(instrumentationLocation.getChild('uuid.txt').path);
+    try {
+      if (uuidFile.existsSync()) {
+        var uuid = uuidFile.readAsStringSync();
+        if (uuid != null && uuid.length > 5) {
+          return uuid;
+        }
+      }
+    } catch (exception, stackTrace) {
+      service.logException(exception, stackTrace);
+    }
+    var uuid = _generateUuidString();
+    try {
+      uuidFile.parent.createSync(recursive: true);
+      uuidFile.writeAsStringSync(uuid);
+    } catch (exception, stackTrace) {
+      service.logException(exception, stackTrace);
+      // Slightly alter the uuid to indicate it was not persisted
+      uuid = 'temp-$uuid';
+    }
+    return uuid;
+  }
+
   /// Create and return the parser used to parse the command-line arguments.
-  ArgParser _createArgParser() {
-    var parser = ArgParser();
-    parser.addFlag(HELP_OPTION,
-        abbr: 'h', negatable: false, help: 'Print this usage information.');
+  static ArgParser createArgParser({
+    int usageLineLength,
+    bool includeHelpFlag = true,
+    bool defaultToLsp = false,
+  }) {
+    var parser = ArgParser(usageLineLength: usageLineLength);
+    if (includeHelpFlag) {
+      parser.addFlag(HELP_OPTION,
+          abbr: 'h', negatable: false, help: 'Print this usage information.');
+    }
     parser.addOption(CLIENT_ID,
         valueHelp: 'name',
         help: 'An identifier for the analysis server client.');
@@ -495,10 +593,28 @@ class Driver implements ServerStarter {
     parser.addOption(CACHE_FOLDER,
         valueHelp: 'path',
         help: 'Override the location of the analysis server\'s cache.');
+
+    parser.addOption(
+      SERVER_PROTOCOL,
+      defaultsTo: defaultToLsp ? PROTOCOL_LSP : PROTOCOL_ANALYZER,
+      valueHelp: 'protocol',
+      allowed: [PROTOCOL_LSP, PROTOCOL_ANALYZER],
+      allowedHelp: {
+        PROTOCOL_LSP: 'The Language Server Protocol '
+            '(https://microsoft.github.io/language-server-protocol)',
+        PROTOCOL_ANALYZER: 'Dart\'s analysis server protocol '
+            '(https://dart.dev/go/analysis-server-protocol)',
+      },
+      help:
+          'Specify the protocol to use to communicate with the analysis server.',
+    );
+    // This option is hidden but still accepted; it's effectively translated to
+    // the 'protocol' option above.
     parser.addFlag(USE_LSP,
         defaultsTo: false,
         negatable: false,
-        help: 'Whether to use the Language Server Protocol (LSP).');
+        help: 'Whether to use the Language Server Protocol (LSP).',
+        hide: true);
 
     parser.addSeparator('Server diagnostics:');
 
@@ -584,84 +700,6 @@ class Driver implements ServerStarter {
     return parser;
   }
 
-  DartSdk _createDefaultSdk(String defaultSdkPath) {
-    var resourceProvider = PhysicalResourceProvider.INSTANCE;
-    return FolderBasedDartSdk(
-      resourceProvider,
-      resourceProvider.getFolder(defaultSdkPath),
-    );
-  }
-
-  /// Constructs a uuid combining the current date and a random integer.
-  String _generateUuidString() {
-    var millisecondsSinceEpoch = DateTime.now().millisecondsSinceEpoch;
-    var random = Random().nextInt(0x3fffffff);
-    return '$millisecondsSinceEpoch$random';
-  }
-
-  String _getSdkPath(ArgResults args) {
-    if (args[DART_SDK] != null) {
-      return args[DART_SDK];
-    } else if (args[DART_SDK_ALIAS] != null) {
-      return args[DART_SDK_ALIAS];
-    } else {
-      return getSdkPath();
-    }
-  }
-
-  /// Print information about how to use the server.
-  void _printUsage(
-    ArgParser parser,
-    telemetry.Analytics analytics, {
-    bool fromHelp = false,
-  }) {
-    print('Usage: $BINARY_NAME [flags]');
-    print('');
-    print('Supported flags are:');
-    print(parser.usage);
-
-    if (telemetry.SHOW_ANALYTICS_UI) {
-      // Print analytics status and information.
-      if (fromHelp) {
-        print('');
-        print(telemetry.analyticsNotice);
-      }
-      print('');
-      print(telemetry.createAnalyticsStatusMessage(analytics.enabled,
-          command: ANALYTICS_FLAG));
-    }
-  }
-
-  /// Read the UUID from disk, generating and storing a new one if necessary.
-  String _readUuid(InstrumentationService service) {
-    final instrumentationLocation =
-        PhysicalResourceProvider.INSTANCE.getStateLocation('.instrumentation');
-    if (instrumentationLocation == null) {
-      return _generateUuidString();
-    }
-    var uuidFile = File(instrumentationLocation.getChild('uuid.txt').path);
-    try {
-      if (uuidFile.existsSync()) {
-        var uuid = uuidFile.readAsStringSync();
-        if (uuid != null && uuid.length > 5) {
-          return uuid;
-        }
-      }
-    } catch (exception, stackTrace) {
-      service.logException(exception, stackTrace);
-    }
-    var uuid = _generateUuidString();
-    try {
-      uuidFile.parent.createSync(recursive: true);
-      uuidFile.writeAsStringSync(uuid);
-    } catch (exception, stackTrace) {
-      service.logException(exception, stackTrace);
-      // Slightly alter the uuid to indicate it was not persisted
-      uuid = 'temp-$uuid';
-    }
-    return uuid;
-  }
-
   /// Perform log files rolling.
   ///
   /// Rename existing files with names `[path].(x)` to `[path].(x+1)`.

pkg/analysis_server/lib/starter.dart

@@ -31,5 +31,6 @@ abstract class ServerStarter {
   set instrumentationService(InstrumentationService service);
 
   /// Use the given command-line [arguments] to start this server.
-  void start(List<String> arguments, [SendPort sendPort]);
+  void start(List<String> arguments,
+      {SendPort sendPort, bool defaultToLsp = false});
 }

pkg/dartdev/lib/dartdev.dart

@@ -20,6 +20,7 @@ import 'src/commands/analyze.dart';
 import 'src/commands/compile.dart';
 import 'src/commands/create.dart';
 import 'src/commands/fix.dart';
+import 'src/commands/language_server.dart';
 import 'src/commands/run.dart';
 import 'src/commands/test.dart';
 import 'src/core.dart';
@@ -96,6 +97,7 @@ class DartdevRunner extends CommandRunner<int> {
     addCommand(CompileCommand(verbose: verbose));
     addCommand(FixCommand(verbose: verbose));
     addCommand(FormatCommand(verbose: verbose));
+    addCommand(LanguageServerCommand(verbose: verbose));
     addCommand(MigrateCommand(verbose: verbose));
     addCommand(pubCommand());
     addCommand(RunCommand(verbose: verbose));

pkg/dartdev/lib/src/commands/language_server.dart

@@ -0,0 +1,53 @@
+// Copyright (c) 2021, 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:io' as io;
+
+import 'package:analysis_server/src/server/driver.dart' as server_driver;
+import 'package:args/args.dart';
+
+import '../core.dart';
+import '../utils.dart';
+
+class LanguageServerCommand extends DartdevCommand {
+  static const String commandName = 'language-server';
+
+  static const String commandDescription = '''
+Start Dart's analysis server.
+
+This is a long-running process used to provide language services to IDEs and other tooling clients.
+
+It communicates over stdin and stdout and provides services like code completion, errors and warnings, and refactorings. This command is generally not user-facing but consumed by higher level tools.
+
+For more information about the server's capabilities and configuration, see:
+
+  https://github.com/dart-lang/sdk/tree/master/pkg/analysis_server''';
+
+  LanguageServerCommand({bool verbose = false})
+      : super(commandName, commandDescription, hidden: !verbose);
+
+  @override
+  ArgParser createArgParser() {
+    return server_driver.Driver.createArgParser(
+      usageLineLength: dartdevUsageLineLength,
+      includeHelpFlag: false,
+      defaultToLsp: true,
+    );
+  }
+
+  @override
+  Future<int> run() async {
+    final driver = server_driver.Driver();
+    driver.start(
+      argResults.arguments,
+      defaultToLsp: true,
+    );
+
+    // The server will continue to run past the return from this method.
+    //
+    // On an error on startup, the server will set the dart:io exitCode value
+    // (or, call exit() directly).
+    return io.exitCode;
+  }
+}

pkg/dartdev/pubspec.yaml

@@ -6,6 +6,8 @@ publish_to: none
 environment:
   sdk: '>=2.6.0 <3.0.0'
 dependencies:
+  analysis_server:
+    path: ../analysis_server
   analysis_server_client:
     path: ../analysis_server_client
   analyzer:
@@ -22,8 +24,7 @@ dependencies:
     path: ../nnbd_migration
   path: ^1.0.0
   pedantic: ^1.9.0
-  pub:
-    path: ../../third_party/pkg/pub
+  pub: any
   stagehand: any
   telemetry:
     path: ../telemetry

pkg/dartdev/test/commands/language_server_test.dart

@@ -0,0 +1,101 @@
+// Copyright (c) 2021, 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:test/test.dart';
+
+import '../utils.dart' as utils;
+
+void main() {
+  group(
+    'language-server',
+    defineLanguageServerTests,
+    timeout: utils.longTimeout,
+  );
+}
+
+void defineLanguageServerTests() {
+  utils.TestProject project;
+  Process process;
+
+  tearDown(() {
+    project?.dispose();
+    process?.kill();
+  });
+
+  Future runWithLsp(List<String> args) async {
+    project = utils.project();
+
+    process = await project.start(args);
+
+    final Stream<String> inStream =
+        process.stdout.transform<String>(utf8.decoder);
+
+    // Send an LSP init.
+    final String message = jsonEncode({
+      'jsonrpc': '2.0',
+      'id': 1,
+      'method': 'initialize',
+      'params': {
+        'processId': pid,
+        'clientInfo': {'name': 'dart-cli-tester'},
+        'capabilities': {},
+        'rootUri': project.dir.uri.toString(),
+      },
+    });
+
+    process.stdin.write('Content-Length: ${message.length}\r\n');
+    process.stdin.write('\r\n');
+    process.stdin.write(message);
+
+    List<String> responses = await inStream.take(2).toList();
+    expect(responses, hasLength(2));
+
+    expect(responses[0], startsWith('Content-Length: '));
+
+    final json = jsonDecode(responses[1]);
+    expect(json['id'], 1);
+    expect(json['result'], isNotNull);
+    final result = json['result'];
+    expect(result['capabilities'], isNotNull);
+    expect(result['serverInfo'], isNotNull);
+    final serverInfo = result['serverInfo'];
+    expect(serverInfo['name'], isNotEmpty);
+
+    process.kill();
+    process = null;
+  }
+
+  test('protocol default', () async {
+    return runWithLsp(['language-server']);
+  });
+
+  test('protocol lsp', () async {
+    return runWithLsp(['language-server', '--protocol=lsp']);
+  });
+
+  test('protocol analyzer', () async {
+    project = utils.project();
+
+    process = await project.start(['language-server', '--protocol=analyzer']);
+
+    final Stream<String> inStream = process.stdout
+        .transform<String>(utf8.decoder)
+        .transform<String>(const LineSplitter());
+
+    final line = await inStream.first;
+    final json = jsonDecode(line);
+
+    expect(json['event'], 'server.connected');
+    expect(json['params'], isNotNull);
+    final params = json['params'];
+    expect(params['version'], isNotEmpty);
+    expect(params['pid'], isNot(0));
+
+    process.kill();
+    process = null;
+  });
+}

pkg/dartdev/test/test_all.dart

@@ -12,6 +12,7 @@ import 'commands/fix_test.dart' as fix;
 import 'commands/flag_test.dart' as flag;
 import 'commands/format_test.dart' as format;
 import 'commands/help_test.dart' as help;
+import 'commands/language_server_test.dart' as language_server;
 import 'commands/migrate_test.dart' as migrate;
 import 'commands/pub_test.dart' as pub;
 import 'commands/run_test.dart' as run;
@@ -39,6 +40,7 @@ void main() {
     help.main();
     implicit_smoke.main();
     invalid_smoke.main();
+    language_server.main();
     migrate.main();
     no_such_file.main();
     pub.main();

pkg/dartdev/test/utils.dart

@@ -94,6 +94,20 @@ dev_dependencies:
         environment: {if (logAnalytics) '_DARTDEV_LOG_ANALYTICS': 'true'});
   }
 
+  Future<Process> start(
+    List<String> arguments, {
+    String workingDir,
+  }) {
+    return Process.start(
+        Platform.resolvedExecutable,
+        [
+          '--no-analytics',
+          ...arguments,
+        ],
+        workingDirectory: workingDir ?? dir.path,
+        environment: {if (logAnalytics) '_DARTDEV_LOG_ANALYTICS': 'true'});
+  }
+
   String _sdkRootPath;
 
   /// Return the root of the SDK.