pkg/analysis_server/lib/src/analysis_server.dart - sdk.git - Git at Google

 // Copyright (c) 2014, 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 'dart:io';

 import 'package:analysis_server/src/analytics/analytics_manager.dart';
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/context_manager.dart';
 import 'package:analysis_server/src/domains/completion/available_suggestions.dart';
 import 'package:analysis_server/src/legacy_analysis_server.dart';
 import 'package:analysis_server/src/plugin/notification_manager.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/plugin/plugin_watcher.dart';
 import 'package:analysis_server/src/server/crash_reporting_attachments.dart';
 import 'package:analysis_server/src/server/diagnostic_server.dart';
 import 'package:analysis_server/src/server/performance.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
 import 'package:analysis_server/src/services/correction/namespace.dart';
 import 'package:analysis_server/src/services/pub/pub_api.dart';
 import 'package:analysis_server/src/services/pub/pub_command.dart';
 import 'package:analysis_server/src/services/pub/pub_package_service.dart';
 import 'package:analysis_server/src/services/search/element_visitors.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analysis_server/src/services/search/search_engine_internal.dart';
 import 'package:analysis_server/src/utilities/file_string_sink.dart';
 import 'package:analysis_server/src/utilities/null_string_sink.dart';
 import 'package:analysis_server/src/utilities/process.dart';
 import 'package:analysis_server/src/utilities/request_statistics.dart';
 import 'package:analysis_server/src/utilities/tee_string_sink.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/analysis/session.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/overlay_file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart' as analysis;
 import 'package:analyzer/src/dart/analysis/file_byte_store.dart'
     show EvictingFileByteStore;
 import 'package:analyzer/src/dart/analysis/file_content_cache.dart';
 import 'package:analyzer/src/dart/analysis/performance_logger.dart';
 import 'package:analyzer/src/dart/analysis/results.dart';
 import 'package:analyzer/src/dart/ast/element_locator.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dartdoc/dartdoc_directive_info.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/services/available_declarations.dart';
 import 'package:analyzer/src/util/file_paths.dart' as file_paths;
 import 'package:analyzer/src/util/performance/operation_performance.dart';
 import 'package:collection/collection.dart';
 import 'package:http/http.dart' as http;
 import 'package:meta/meta.dart';

 /// Implementations of [AnalysisServer] implement a server that listens
 /// on a [CommunicationChannel] for analysis messages and process them.
 abstract class AnalysisServer {
   /// The options of this server instance.
   AnalysisServerOptions options;

   /// The object through which analytics are to be sent.
   final AnalyticsManager analyticsManager;

   /// The builder for attachments that should be included into crash reports.
   final CrashReportingAttachmentsBuilder crashReportingAttachmentsBuilder;

   /// The [ContextManager] that handles the mapping from analysis roots to
   /// context directories.
   late ContextManager contextManager;

   /// The object used to manage sending a subset of notifications to the client.
   /// The subset of notifications are those to which plugins may contribute.
   /// This field is `null` when the new plugin support is disabled.
   AbstractNotificationManager notificationManager;

   /// The object used to manage the execution of plugins.
   late PluginManager pluginManager;

   /// The object used to manage the SDK's known to this server.
   final DartSdkManager sdkManager;

   /// The [SearchEngine] for this server.
   late final SearchEngine searchEngine;

   late ByteStore byteStore;
   late FileContentCache fileContentCache;

   late analysis.AnalysisDriverScheduler analysisDriverScheduler;

   DeclarationsTracker? declarationsTracker;
   DeclarationsTrackerData? declarationsTrackerData;

   /// The DiagnosticServer for this AnalysisServer. If available, it can be used
   /// to start an http diagnostics server or return the port for an existing
   /// server.
   final DiagnosticServer? diagnosticServer;

   /// A [RecentBuffer] of the most recent exceptions encountered by the analysis
   /// server.
   final RecentBuffer<ServerException> exceptions = RecentBuffer(10);

   /// The instrumentation service that is to be used by this analysis server.
   InstrumentationService instrumentationService;

   /// Performance information after initial analysis is complete
   /// or `null` if the initial analysis is not yet complete
   ServerPerformance? performanceAfterStartup;

   /// A client for making requests to the pub.dev API.
   final PubApi pubApi;

   /// A service for fetching pub.dev package details.
   late PubPackageService pubPackageService;

   /// The class into which performance information is currently being recorded.
   /// During startup, this will be the same as [performanceDuringStartup]
   /// and after startup is complete, this switches to [performanceAfterStartup].
   late ServerPerformance performance;

   /// Performance information before initial analysis is complete.
   final ServerPerformance performanceDuringStartup = ServerPerformance();

   /// Performance about recent requests.
   final ServerRecentPerformance recentPerformance = ServerRecentPerformance();

   RequestStatisticsHelper? requestStatistics;

   PerformanceLog? analysisPerformanceLogger;

   /// The set of the files that are currently priority.
   final Set<String> priorityFiles = <String>{};

   /// The [ResourceProvider] using which paths are converted into [Resource]s.
   final OverlayResourceProvider resourceProvider;

   /// The next modification stamp for a changed file in the [resourceProvider].
   ///
   /// This value is increased each time it is used and used instead of real
   /// modification stamps. It's seeded with `millisecondsSinceEpoch` to reduce
   /// the chance of colliding with values used in previous analysis sessions if
   /// used as a cache key.
   int overlayModificationStamp = DateTime.now().millisecondsSinceEpoch;

   AnalysisServer(
     this.options,
     this.sdkManager,
     this.diagnosticServer,
     this.analyticsManager,
     this.crashReportingAttachmentsBuilder,
     ResourceProvider baseResourceProvider,
     this.instrumentationService,
     http.Client? httpClient,
     ProcessRunner? processRunner,
     this.notificationManager, {
     this.requestStatistics,
     bool enableBlazeWatcher = false,
   })  : resourceProvider = OverlayResourceProvider(baseResourceProvider),
         pubApi = PubApi(instrumentationService, httpClient,
             Platform.environment['PUB_HOSTED_URL']) {
     // We can only spawn processes (eg. to run pub commands) when backed by
     // a real file system, otherwise we may try to run commands in folders that
     // don't really exist. If processRunner was supplied, it's likely a mock
     // from a test in which case the pub command should still be created.
     if (baseResourceProvider is PhysicalResourceProvider) {
       processRunner ??= ProcessRunner();
     }
     final pubCommand = processRunner != null &&
             Platform.environment[PubCommand.disablePubCommandEnvironmentKey] ==
                 null
         ? PubCommand(instrumentationService, processRunner)
         : null;

     pubPackageService = PubPackageService(
         instrumentationService, baseResourceProvider, pubApi, pubCommand);
     performance = performanceDuringStartup;

     pluginManager = PluginManager(
         resourceProvider,
         _getByteStorePath(),
         sdkManager.defaultSdkDirectory,
         notificationManager,
         instrumentationService);
     var pluginWatcher = PluginWatcher(resourceProvider, pluginManager);

     var name = options.newAnalysisDriverLog;
     StringSink sink = NullStringSink();
     if (name != null) {
       if (name == 'stdout') {
         sink = io.stdout;
       } else if (name.startsWith('file:')) {
         var path = name.substring('file:'.length);
         sink = FileStringSink(path);
       }
     }
     final requestStatistics = this.requestStatistics;
     if (requestStatistics != null) {
       sink = TeeStringSink(sink, requestStatistics.perfLoggerStringSink);
     }
     final analysisPerformanceLogger =
         this.analysisPerformanceLogger = PerformanceLog(sink);

     byteStore = createByteStore(resourceProvider);
     fileContentCache = FileContentCache(resourceProvider);

     analysisDriverScheduler = analysis.AnalysisDriverScheduler(
         analysisPerformanceLogger,
         driverWatcher: pluginWatcher);

     if (options.featureSet.completion) {
       var tracker = declarationsTracker =
           DeclarationsTracker(byteStore, resourceProvider);
       declarationsTrackerData = DeclarationsTrackerData(tracker);
       analysisDriverScheduler.outOfBandWorker =
           CompletionLibrariesWorker(tracker);
     }

     contextManager = ContextManagerImpl(
       resourceProvider,
       sdkManager,
       options.packagesFile,
       options.enabledExperiments,
       byteStore,
       fileContentCache,
       analysisPerformanceLogger,
       analysisDriverScheduler,
       instrumentationService,
       enableBlazeWatcher: enableBlazeWatcher,
     );
     searchEngine = SearchEngineImpl(driverMap.values);
   }

   /// The list of current analysis sessions in all contexts.
   Future<List<AnalysisSession>> get currentSessions async {
     var sessions = <AnalysisSession>[];
     for (var driver in driverMap.values) {
       await driver.applyPendingFileChanges();
       sessions.add(driver.currentSession);
     }
     return sessions;
   }

   /// A table mapping [Folder]s to the [AnalysisDriver]s associated with them.
   Map<Folder, analysis.AnalysisDriver> get driverMap =>
       contextManager.driverMap;

   /// Return the total time the server's been alive.
   Duration get uptime {
     var start =
         DateTime.fromMillisecondsSinceEpoch(performanceDuringStartup.startTime);
     return DateTime.now().difference(start);
   }

   void addContextsToDeclarationsTracker() {
     declarationsTracker?.discardContexts();
     for (var driver in driverMap.values) {
       declarationsTracker?.addContext(driver.analysisContext!);
     }
   }

   /// If the state location can be accessed, return the file byte store,
   /// otherwise return the memory byte store.
   ByteStore createByteStore(ResourceProvider resourceProvider) {
     const M = 1024 * 1024 /*1 MiB*/;
     const G = 1024 * 1024 * 1024 /*1 GiB*/;

     const memoryCacheSize = 128 * M;

     if (resourceProvider is OverlayResourceProvider) {
       resourceProvider = resourceProvider.baseProvider;
     }
     if (resourceProvider is PhysicalResourceProvider) {
       var stateLocation = resourceProvider.getStateLocation('.analysis-driver');
       if (stateLocation != null) {
         return MemoryCachingByteStore(
             EvictingFileByteStore(stateLocation.path, G), memoryCacheSize);
       }
     }

     return MemoryCachingByteStore(NullByteStore(), memoryCacheSize);
   }

   /// Return an analysis driver to which the file with the given [path] is
   /// added if one exists, otherwise a driver in which the file was analyzed if
   /// one exists, otherwise the first driver, otherwise `null`.
   analysis.AnalysisDriver? getAnalysisDriver(String path) {
     var drivers = driverMap.values.toList();
     if (drivers.isNotEmpty) {
       // Sort the drivers so that more deeply nested contexts will be checked
       // before enclosing contexts.
       drivers.sort((first, second) {
         var firstRoot = first.analysisContext!.contextRoot.root.path;
         var secondRoot = second.analysisContext!.contextRoot.root.path;
         return secondRoot.length - firstRoot.length;
       });
       var driver = drivers.firstWhereOrNull(
           (driver) => driver.analysisContext!.contextRoot.isAnalyzed(path));
       driver ??= drivers
           .firstWhereOrNull((driver) => driver.knownFiles.contains(path));
       driver ??= drivers.first;
       return driver;
     }
     return null;
   }

   /// Return an [AnalysisSession] in which the file with the given [path]
   /// should be analyzed, preferring the one in which it is analyzed, then
   /// the one where it is referenced, then the first, otherwise `null`.
   Future<AnalysisSession?> getAnalysisSession(String path) async {
     var analysisDriver = getAnalysisDriver(path);
     if (analysisDriver != null) {
       await analysisDriver.applyPendingFileChanges();
       return analysisDriver.currentSession;
     }
     return null;
   }

   DartdocDirectiveInfo getDartdocDirectiveInfoFor(ResolvedUnitResult result) {
     return getDartdocDirectiveInfoForSession(result.session);
   }

   DartdocDirectiveInfo getDartdocDirectiveInfoForSession(
     AnalysisSession session,
   ) {
     return declarationsTracker
             ?.getContext(session.analysisContext)
             ?.dartdocDirectiveInfo ??
         DartdocDirectiveInfo();
   }

   /// Return a [Future] that completes with the [Element] at the given
   /// [offset] of the given [file], or with `null` if there is no node at the
   /// [offset] or the node does not have an element.
   Future<Element?> getElementAtOffset(String file, int offset) async {
     if (!priorityFiles.contains(file)) {
       var driver = getAnalysisDriver(file);
       if (driver == null) {
         return null;
       }

       var unitElementResult = await driver.getUnitElement(file);
       if (unitElementResult is! UnitElementResult) {
         return null;
       }

       var element = findElementByNameOffset(unitElementResult.element, offset);
       if (element != null) {
         return element;
       }
     }

     var node = await getNodeAtOffset(file, offset);
     return getElementOfNode(node);
   }

   /// Return the [Element] of the given [node], or `null` if [node] is `null` or
   /// does not have an element.
   Element? getElementOfNode(AstNode? node) {
     if (node == null) {
       return null;
     }
     if (node is SimpleIdentifier && node.parent is LibraryIdentifier) {
       node = node.parent;
     }
     if (node is LibraryIdentifier) {
       node = node.parent;
     }
     if (node is StringLiteral && node.parent is UriBasedDirective) {
       return null;
     }
     var element = ElementLocator.locate(node);
     if (node is SimpleIdentifier && element is PrefixElement) {
       element = getImportElement(node);
     }
     return element;
   }

   /// Return a [Future] that completes with the resolved [AstNode] at the
   /// given [offset] of the given [file], or with `null` if there is no node as
   /// the [offset].
   Future<AstNode?> getNodeAtOffset(String file, int offset) async {
     var result = await getResolvedUnit(file);
     var unit = result?.unit;
     if (unit != null) {
       return NodeLocator(offset).searchWithin(unit);
     }
     return null;
   }

   /// Return the unresolved unit for the file with the given [path].
   ///
   /// Callers should handle [InconsistentAnalysisException] exceptions that may
   /// occur if a file is modified during this operation.
   Future<ParsedUnitResult?> getParsedUnit(String path) async {
     if (!file_paths.isDart(resourceProvider.pathContext, path)) {
       return null;
     }

     var session = await getAnalysisSession(path);
     if (session == null) {
       return null;
     }

     var result = session.getParsedUnit(path);
     return result is ParsedUnitResult ? result : null;
   }

   /// Return the resolved unit for the file with the given [path]. The file is
   /// analyzed in one of the analysis drivers to which the file was added,
   /// otherwise in the first driver, otherwise `null` is returned.
   Future<ResolvedUnitResult?>? getResolvedUnit(String path,
       {bool sendCachedToStream = false}) {
     if (!file_paths.isDart(resourceProvider.pathContext, path)) {
       return null;
     }

     var driver = getAnalysisDriver(path);
     if (driver == null) {
       return Future.value();
     }

     return driver
         .getResult(path, sendCachedToStream: sendCachedToStream)
         .then((value) => value is ResolvedUnitResult ? value : null)
         .catchError((Object e, StackTrace st) {
       instrumentationService.logException(e, st);
       return null;
     });
   }

   /// Return `true` if the file or directory with the given [path] will be
   /// analyzed in one of the analysis contexts.
   bool isAnalyzed(String path) {
     return contextManager.isAnalyzed(path);
   }

   void logExceptionResult(analysis.ExceptionResult result) {
     var message = 'Analysis failed: ${result.filePath}';
     if (result.contextKey != null) {
       message += ' context: ${result.contextKey}';
     }

     var attachments =
         crashReportingAttachmentsBuilder.forExceptionResult(result);

     // TODO(39284): should this exception be silent?
     instrumentationService.logException(
       SilentException.wrapInMessage(message, result.exception),
       null,
       attachments,
     );
   }

   /// Notify the declarations tracker that the file with the given [path] was
   /// changed - added, updated, or removed.  Schedule processing of the file.
   void notifyDeclarationsTracker(String path) {
     declarationsTracker?.changeFile(path);
     analysisDriverScheduler.notify(null);
   }

   /// Notify the flutter widget properties support that the file with the
   /// given [path] was changed - added, updated, or removed.
   void notifyFlutterWidgetDescriptions(String path) {}

   /// Read all files, resolve all URIs, and perform required analysis in
   /// all current analysis drivers.
   Future<void> reanalyze() async {
     await contextManager.refresh();
   }

   Future<ResolvedForCompletionResultImpl?> resolveForCompletion({
     required String path,
     required int offset,
     required OperationPerformanceImpl performance,
   }) async {
     if (!file_paths.isDart(resourceProvider.pathContext, path)) {
       return null;
     }

     var driver = getAnalysisDriver(path);
     if (driver == null) {
       return null;
     }

     try {
       await driver.applyPendingFileChanges();
       return await driver.resolveForCompletion(
         path: path,
         offset: offset,
         performance: performance,
       );
     } catch (e, st) {
       instrumentationService.logException(e, st);
     }
     return null;
   }

   /// Sends an error notification to the user.
   void sendServerErrorNotification(
     String message,
     Object exception,
     StackTrace? stackTrace, {
     bool fatal = false,
   });

   @mustCallSuper
   void shutdown() {
     // For now we record plugins only on shutdown. We might want to record them
     // every time the set of plugins changes, in which case we'll need to listen
     // to the `PluginManager.pluginsChanged` stream.
     analyticsManager.changedPlugins(pluginManager);
     // For now we record context-dependent information only on shutdown. We
     // might want to record it on start-up as well.
     analyticsManager.createdAnalysisContexts(contextManager.analysisContexts);

     pubPackageService.shutdown();
     analyticsManager.shutdown();
   }

   /// Return the path to the location of the byte store on disk, or `null` if
   /// there is no on-disk byte store.
   String? _getByteStorePath() {
     ResourceProvider provider = resourceProvider;
     if (provider is OverlayResourceProvider) {
       provider = provider.baseProvider;
     }
     if (provider is PhysicalResourceProvider) {
       var stateLocation = provider.getStateLocation('.analysis-driver');
       if (stateLocation != null) {
         return stateLocation.path;
       }
     }
     return null;
   }
 }

 class ServerRecentPerformance {
   /// The maximum number of performance measurements to keep.
   static const int performanceListMaxLength = 50;

   /// A list of code completion performance measurements for the latest
   /// completion operation up to [performanceListMaxLength] measurements.
   final RecentBuffer<CompletionPerformance> completion =
       RecentBuffer<CompletionPerformance>(performanceListMaxLength);

   /// A [RecentBuffer] for performance information about the most recent
   /// requests.
   final RecentBuffer<RequestPerformance> requests =
       RecentBuffer(performanceListMaxLength);
 }
	// Copyright (c) 2014, 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 'dart:io';

	import 'package:analysis_server/src/analytics/analytics_manager.dart';
	import 'package:analysis_server/src/collections.dart';
	import 'package:analysis_server/src/context_manager.dart';
	import 'package:analysis_server/src/domains/completion/available_suggestions.dart';
	import 'package:analysis_server/src/legacy_analysis_server.dart';
	import 'package:analysis_server/src/plugin/notification_manager.dart';
	import 'package:analysis_server/src/plugin/plugin_manager.dart';
	import 'package:analysis_server/src/plugin/plugin_watcher.dart';
	import 'package:analysis_server/src/server/crash_reporting_attachments.dart';
	import 'package:analysis_server/src/server/diagnostic_server.dart';
	import 'package:analysis_server/src/server/performance.dart';
	import 'package:analysis_server/src/services/completion/completion_performance.dart';
	import 'package:analysis_server/src/services/correction/namespace.dart';
	import 'package:analysis_server/src/services/pub/pub_api.dart';
	import 'package:analysis_server/src/services/pub/pub_command.dart';
	import 'package:analysis_server/src/services/pub/pub_package_service.dart';
	import 'package:analysis_server/src/services/search/element_visitors.dart';
	import 'package:analysis_server/src/services/search/search_engine.dart';
	import 'package:analysis_server/src/services/search/search_engine_internal.dart';
	import 'package:analysis_server/src/utilities/file_string_sink.dart';
	import 'package:analysis_server/src/utilities/null_string_sink.dart';
	import 'package:analysis_server/src/utilities/process.dart';
	import 'package:analysis_server/src/utilities/request_statistics.dart';
	import 'package:analysis_server/src/utilities/tee_string_sink.dart';
	import 'package:analyzer/dart/analysis/results.dart';
	import 'package:analyzer/dart/analysis/session.dart';
	import 'package:analyzer/dart/ast/ast.dart';
	import 'package:analyzer/dart/element/element.dart';
	import 'package:analyzer/exception/exception.dart';
	import 'package:analyzer/file_system/file_system.dart';
	import 'package:analyzer/file_system/overlay_file_system.dart';
	import 'package:analyzer/file_system/physical_file_system.dart';
	import 'package:analyzer/instrumentation/instrumentation.dart';
	import 'package:analyzer/src/dart/analysis/byte_store.dart';
	import 'package:analyzer/src/dart/analysis/driver.dart' as analysis;
	import 'package:analyzer/src/dart/analysis/file_byte_store.dart'
	show EvictingFileByteStore;
	import 'package:analyzer/src/dart/analysis/file_content_cache.dart';
	import 'package:analyzer/src/dart/analysis/performance_logger.dart';
	import 'package:analyzer/src/dart/analysis/results.dart';
	import 'package:analyzer/src/dart/ast/element_locator.dart';
	import 'package:analyzer/src/dart/ast/utilities.dart';
	import 'package:analyzer/src/dartdoc/dartdoc_directive_info.dart';
	import 'package:analyzer/src/generated/sdk.dart';
	import 'package:analyzer/src/services/available_declarations.dart';
	import 'package:analyzer/src/util/file_paths.dart' as file_paths;
	import 'package:analyzer/src/util/performance/operation_performance.dart';
	import 'package:collection/collection.dart';
	import 'package:http/http.dart' as http;
	import 'package:meta/meta.dart';

	/// Implementations of [AnalysisServer] implement a server that listens
	/// on a [CommunicationChannel] for analysis messages and process them.
	abstract class AnalysisServer {
	/// The options of this server instance.
	AnalysisServerOptions options;

	/// The object through which analytics are to be sent.
	final AnalyticsManager analyticsManager;

	/// The builder for attachments that should be included into crash reports.
	final CrashReportingAttachmentsBuilder crashReportingAttachmentsBuilder;

	/// The [ContextManager] that handles the mapping from analysis roots to
	/// context directories.
	late ContextManager contextManager;

	/// The object used to manage sending a subset of notifications to the client.
	/// The subset of notifications are those to which plugins may contribute.
	/// This field is `null` when the new plugin support is disabled.
	AbstractNotificationManager notificationManager;

	/// The object used to manage the execution of plugins.
	late PluginManager pluginManager;

	/// The object used to manage the SDK's known to this server.
	final DartSdkManager sdkManager;

	/// The [SearchEngine] for this server.
	late final SearchEngine searchEngine;

	late ByteStore byteStore;
	late FileContentCache fileContentCache;

	late analysis.AnalysisDriverScheduler analysisDriverScheduler;

	DeclarationsTracker? declarationsTracker;
	DeclarationsTrackerData? declarationsTrackerData;

	/// The DiagnosticServer for this AnalysisServer. If available, it can be used
	/// to start an http diagnostics server or return the port for an existing
	/// server.
	final DiagnosticServer? diagnosticServer;

	/// A [RecentBuffer] of the most recent exceptions encountered by the analysis
	/// server.
	final RecentBuffer<ServerException> exceptions = RecentBuffer(10);

	/// The instrumentation service that is to be used by this analysis server.
	InstrumentationService instrumentationService;

	/// Performance information after initial analysis is complete
	/// or `null` if the initial analysis is not yet complete
	ServerPerformance? performanceAfterStartup;

	/// A client for making requests to the pub.dev API.
	final PubApi pubApi;

	/// A service for fetching pub.dev package details.
	late PubPackageService pubPackageService;

	/// The class into which performance information is currently being recorded.
	/// During startup, this will be the same as [performanceDuringStartup]
	/// and after startup is complete, this switches to [performanceAfterStartup].
	late ServerPerformance performance;

	/// Performance information before initial analysis is complete.
	final ServerPerformance performanceDuringStartup = ServerPerformance();

	/// Performance about recent requests.
	final ServerRecentPerformance recentPerformance = ServerRecentPerformance();

	RequestStatisticsHelper? requestStatistics;

	PerformanceLog? analysisPerformanceLogger;

	/// The set of the files that are currently priority.
	final Set<String> priorityFiles = <String>{};

	/// The [ResourceProvider] using which paths are converted into [Resource]s.
	final OverlayResourceProvider resourceProvider;

	/// The next modification stamp for a changed file in the [resourceProvider].
	///
	/// This value is increased each time it is used and used instead of real
	/// modification stamps. It's seeded with `millisecondsSinceEpoch` to reduce
	/// the chance of colliding with values used in previous analysis sessions if
	/// used as a cache key.
	int overlayModificationStamp = DateTime.now().millisecondsSinceEpoch;

	AnalysisServer(
	this.options,
	this.sdkManager,
	this.diagnosticServer,
	this.analyticsManager,
	this.crashReportingAttachmentsBuilder,
	ResourceProvider baseResourceProvider,
	this.instrumentationService,
	http.Client? httpClient,
	ProcessRunner? processRunner,
	this.notificationManager, {
	this.requestStatistics,
	bool enableBlazeWatcher = false,
	}) : resourceProvider = OverlayResourceProvider(baseResourceProvider),
	pubApi = PubApi(instrumentationService, httpClient,
	Platform.environment['PUB_HOSTED_URL']) {
	// We can only spawn processes (eg. to run pub commands) when backed by
	// a real file system, otherwise we may try to run commands in folders that
	// don't really exist. If processRunner was supplied, it's likely a mock
	// from a test in which case the pub command should still be created.
	if (baseResourceProvider is PhysicalResourceProvider) {
	processRunner ??= ProcessRunner();
	}
	final pubCommand = processRunner != null &&
	Platform.environment[PubCommand.disablePubCommandEnvironmentKey] ==
	null
	? PubCommand(instrumentationService, processRunner)
	: null;

	pubPackageService = PubPackageService(
	instrumentationService, baseResourceProvider, pubApi, pubCommand);
	performance = performanceDuringStartup;

	pluginManager = PluginManager(
	resourceProvider,
	_getByteStorePath(),
	sdkManager.defaultSdkDirectory,
	notificationManager,
	instrumentationService);
	var pluginWatcher = PluginWatcher(resourceProvider, pluginManager);

	var name = options.newAnalysisDriverLog;
	StringSink sink = NullStringSink();
	if (name != null) {
	if (name == 'stdout') {
	sink = io.stdout;
	} else if (name.startsWith('file:')) {
	var path = name.substring('file:'.length);
	sink = FileStringSink(path);
	}
	}
	final requestStatistics = this.requestStatistics;
	if (requestStatistics != null) {
	sink = TeeStringSink(sink, requestStatistics.perfLoggerStringSink);
	}
	final analysisPerformanceLogger =
	this.analysisPerformanceLogger = PerformanceLog(sink);

	byteStore = createByteStore(resourceProvider);
	fileContentCache = FileContentCache(resourceProvider);

	analysisDriverScheduler = analysis.AnalysisDriverScheduler(
	analysisPerformanceLogger,
	driverWatcher: pluginWatcher);

	if (options.featureSet.completion) {
	var tracker = declarationsTracker =
	DeclarationsTracker(byteStore, resourceProvider);
	declarationsTrackerData = DeclarationsTrackerData(tracker);
	analysisDriverScheduler.outOfBandWorker =
	CompletionLibrariesWorker(tracker);
	}

	contextManager = ContextManagerImpl(
	resourceProvider,
	sdkManager,
	options.packagesFile,
	options.enabledExperiments,
	byteStore,
	fileContentCache,
	analysisPerformanceLogger,
	analysisDriverScheduler,
	instrumentationService,
	enableBlazeWatcher: enableBlazeWatcher,
	);
	searchEngine = SearchEngineImpl(driverMap.values);
	}

	/// The list of current analysis sessions in all contexts.
	Future<List<AnalysisSession>> get currentSessions async {
	var sessions = <AnalysisSession>[];
	for (var driver in driverMap.values) {
	await driver.applyPendingFileChanges();
	sessions.add(driver.currentSession);
	}
	return sessions;
	}

	/// A table mapping [Folder]s to the [AnalysisDriver]s associated with them.
	Map<Folder, analysis.AnalysisDriver> get driverMap =>
	contextManager.driverMap;

	/// Return the total time the server's been alive.
	Duration get uptime {
	var start =
	DateTime.fromMillisecondsSinceEpoch(performanceDuringStartup.startTime);
	return DateTime.now().difference(start);
	}

	void addContextsToDeclarationsTracker() {
	declarationsTracker?.discardContexts();
	for (var driver in driverMap.values) {
	declarationsTracker?.addContext(driver.analysisContext!);
	}
	}

	/// If the state location can be accessed, return the file byte store,
	/// otherwise return the memory byte store.
	ByteStore createByteStore(ResourceProvider resourceProvider) {
	const M = 1024 * 1024 /1 MiB/;
	const G = 1024 * 1024 * 1024 /1 GiB/;

	const memoryCacheSize = 128 * M;

	if (resourceProvider is OverlayResourceProvider) {
	resourceProvider = resourceProvider.baseProvider;
	}
	if (resourceProvider is PhysicalResourceProvider) {
	var stateLocation = resourceProvider.getStateLocation('.analysis-driver');
	if (stateLocation != null) {
	return MemoryCachingByteStore(
	EvictingFileByteStore(stateLocation.path, G), memoryCacheSize);
	}
	}

	return MemoryCachingByteStore(NullByteStore(), memoryCacheSize);
	}

	/// Return an analysis driver to which the file with the given [path] is
	/// added if one exists, otherwise a driver in which the file was analyzed if
	/// one exists, otherwise the first driver, otherwise `null`.
	analysis.AnalysisDriver? getAnalysisDriver(String path) {
	var drivers = driverMap.values.toList();
	if (drivers.isNotEmpty) {
	// Sort the drivers so that more deeply nested contexts will be checked
	// before enclosing contexts.
	drivers.sort((first, second) {
	var firstRoot = first.analysisContext!.contextRoot.root.path;
	var secondRoot = second.analysisContext!.contextRoot.root.path;
	return secondRoot.length - firstRoot.length;
	});
	var driver = drivers.firstWhereOrNull(
	(driver) => driver.analysisContext!.contextRoot.isAnalyzed(path));
	driver ??= drivers
	.firstWhereOrNull((driver) => driver.knownFiles.contains(path));
	driver ??= drivers.first;
	return driver;
	}
	return null;
	}

	/// Return an [AnalysisSession] in which the file with the given [path]
	/// should be analyzed, preferring the one in which it is analyzed, then
	/// the one where it is referenced, then the first, otherwise `null`.
	Future<AnalysisSession?> getAnalysisSession(String path) async {
	var analysisDriver = getAnalysisDriver(path);
	if (analysisDriver != null) {
	await analysisDriver.applyPendingFileChanges();
	return analysisDriver.currentSession;
	}
	return null;
	}

	DartdocDirectiveInfo getDartdocDirectiveInfoFor(ResolvedUnitResult result) {
	return getDartdocDirectiveInfoForSession(result.session);
	}

	DartdocDirectiveInfo getDartdocDirectiveInfoForSession(
	AnalysisSession session,
	) {
	return declarationsTracker
	?.getContext(session.analysisContext)
	?.dartdocDirectiveInfo ??
	DartdocDirectiveInfo();
	}

	/// Return a [Future] that completes with the [Element] at the given
	/// [offset] of the given [file], or with `null` if there is no node at the
	/// [offset] or the node does not have an element.
	Future<Element?> getElementAtOffset(String file, int offset) async {
	if (!priorityFiles.contains(file)) {
	var driver = getAnalysisDriver(file);
	if (driver == null) {
	return null;
	}

	var unitElementResult = await driver.getUnitElement(file);
	if (unitElementResult is! UnitElementResult) {
	return null;
	}

	var element = findElementByNameOffset(unitElementResult.element, offset);
	if (element != null) {
	return element;
	}
	}

	var node = await getNodeAtOffset(file, offset);
	return getElementOfNode(node);
	}

	/// Return the [Element] of the given [node], or `null` if [node] is `null` or
	/// does not have an element.
	Element? getElementOfNode(AstNode? node) {
	if (node == null) {
	return null;
	}
	if (node is SimpleIdentifier && node.parent is LibraryIdentifier) {
	node = node.parent;
	}
	if (node is LibraryIdentifier) {
	node = node.parent;
	}
	if (node is StringLiteral && node.parent is UriBasedDirective) {
	return null;
	}
	var element = ElementLocator.locate(node);
	if (node is SimpleIdentifier && element is PrefixElement) {
	element = getImportElement(node);
	}
	return element;
	}

	/// Return a [Future] that completes with the resolved [AstNode] at the
	/// given [offset] of the given [file], or with `null` if there is no node as
	/// the [offset].
	Future<AstNode?> getNodeAtOffset(String file, int offset) async {
	var result = await getResolvedUnit(file);
	var unit = result?.unit;
	if (unit != null) {
	return NodeLocator(offset).searchWithin(unit);
	}
	return null;
	}

	/// Return the unresolved unit for the file with the given [path].
	///
	/// Callers should handle [InconsistentAnalysisException] exceptions that may
	/// occur if a file is modified during this operation.
	Future<ParsedUnitResult?> getParsedUnit(String path) async {
	if (!file_paths.isDart(resourceProvider.pathContext, path)) {
	return null;
	}

	var session = await getAnalysisSession(path);
	if (session == null) {
	return null;
	}

	var result = session.getParsedUnit(path);
	return result is ParsedUnitResult ? result : null;
	}

	/// Return the resolved unit for the file with the given [path]. The file is
	/// analyzed in one of the analysis drivers to which the file was added,
	/// otherwise in the first driver, otherwise `null` is returned.
	Future<ResolvedUnitResult?>? getResolvedUnit(String path,
	{bool sendCachedToStream = false}) {
	if (!file_paths.isDart(resourceProvider.pathContext, path)) {
	return null;
	}

	var driver = getAnalysisDriver(path);
	if (driver == null) {
	return Future.value();
	}

	return driver
	.getResult(path, sendCachedToStream: sendCachedToStream)
	.then((value) => value is ResolvedUnitResult ? value : null)
	.catchError((Object e, StackTrace st) {
	instrumentationService.logException(e, st);
	return null;
	});
	}

	/// Return `true` if the file or directory with the given [path] will be
	/// analyzed in one of the analysis contexts.
	bool isAnalyzed(String path) {
	return contextManager.isAnalyzed(path);
	}

	void logExceptionResult(analysis.ExceptionResult result) {
	var message = 'Analysis failed: ${result.filePath}';
	if (result.contextKey != null) {
	message += ' context: ${result.contextKey}';
	}

	var attachments =
	crashReportingAttachmentsBuilder.forExceptionResult(result);

	// TODO(39284): should this exception be silent?
	instrumentationService.logException(
	SilentException.wrapInMessage(message, result.exception),
	null,
	attachments,
	);
	}

	/// Notify the declarations tracker that the file with the given [path] was
	/// changed - added, updated, or removed. Schedule processing of the file.
	void notifyDeclarationsTracker(String path) {
	declarationsTracker?.changeFile(path);
	analysisDriverScheduler.notify(null);
	}

	/// Notify the flutter widget properties support that the file with the
	/// given [path] was changed - added, updated, or removed.
	void notifyFlutterWidgetDescriptions(String path) {}

	/// Read all files, resolve all URIs, and perform required analysis in
	/// all current analysis drivers.
	Future<void> reanalyze() async {
	await contextManager.refresh();
	}

	Future<ResolvedForCompletionResultImpl?> resolveForCompletion({
	required String path,
	required int offset,
	required OperationPerformanceImpl performance,
	}) async {
	if (!file_paths.isDart(resourceProvider.pathContext, path)) {
	return null;
	}

	var driver = getAnalysisDriver(path);
	if (driver == null) {
	return null;
	}

	try {
	await driver.applyPendingFileChanges();
	return await driver.resolveForCompletion(
	path: path,
	offset: offset,
	performance: performance,
	);
	} catch (e, st) {
	instrumentationService.logException(e, st);
	}
	return null;
	}

	/// Sends an error notification to the user.
	void sendServerErrorNotification(
	String message,
	Object exception,
	StackTrace? stackTrace, {
	bool fatal = false,
	});

	@mustCallSuper
	void shutdown() {
	// For now we record plugins only on shutdown. We might want to record them
	// every time the set of plugins changes, in which case we'll need to listen
	// to the `PluginManager.pluginsChanged` stream.
	analyticsManager.changedPlugins(pluginManager);
	// For now we record context-dependent information only on shutdown. We
	// might want to record it on start-up as well.
	analyticsManager.createdAnalysisContexts(contextManager.analysisContexts);

	pubPackageService.shutdown();
	analyticsManager.shutdown();
	}

	/// Return the path to the location of the byte store on disk, or `null` if
	/// there is no on-disk byte store.
	String? _getByteStorePath() {
	ResourceProvider provider = resourceProvider;
	if (provider is OverlayResourceProvider) {
	provider = provider.baseProvider;
	}
	if (provider is PhysicalResourceProvider) {
	var stateLocation = provider.getStateLocation('.analysis-driver');
	if (stateLocation != null) {
	return stateLocation.path;
	}
	}
	return null;
	}
	}

	class ServerRecentPerformance {
	/// The maximum number of performance measurements to keep.
	static const int performanceListMaxLength = 50;

	/// A list of code completion performance measurements for the latest
	/// completion operation up to [performanceListMaxLength] measurements.
	final RecentBuffer<CompletionPerformance> completion =
	RecentBuffer<CompletionPerformance>(performanceListMaxLength);

	/// A [RecentBuffer] for performance information about the most recent
	/// requests.
	final RecentBuffer<RequestPerformance> requests =
	RecentBuffer(performanceListMaxLength);
	}