pkg/analysis_server/lib/src/domain_completion.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:async';

 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/domain_abstract.dart';
 import 'package:analysis_server/src/domains/completion/available_suggestions.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/provisional/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart';
 import 'package:analysis_server/src/services/completion/token_details/token_detail_builder.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/analysis/session.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/util/performance/operation_performance.dart';
 import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';

 /// Instances of the class [CompletionDomainHandler] implement a
 /// [RequestHandler] that handles requests in the completion domain.
 class CompletionDomainHandler extends AbstractRequestHandler {
   /// The maximum number of performance measurements to keep.
   static const int performanceListMaxLength = 50;

   /// The completion services that the client is currently subscribed.
   final Set<CompletionService> subscriptions = <CompletionService>{};

   /// The next completion response id.
   int _nextCompletionId = 0;

   /// Code completion performance for the last completion operation.
   CompletionPerformance performance;

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

   /// The current request being processed or `null` if none.
   CompletionRequestImpl _currentRequest;

   /// The identifiers of the latest `getSuggestionDetails` request.
   /// We use it to abort previous requests.
   int _latestGetSuggestionDetailsId = 0;

   /// Initialize a new request handler for the given [server].
   CompletionDomainHandler(AnalysisServer server) : super(server);

   /// Compute completion results for the given request and append them to the
   /// stream. Clients should not call this method directly as it is
   /// automatically called when a client listens to the stream returned by
   /// [results]. Subclasses should override this method, append at least one
   /// result to the [controller], and close the controller stream once complete.
   Future<CompletionResult> computeSuggestions(
     OperationPerformanceImpl perf,
     CompletionRequestImpl request,
     CompletionGetSuggestionsParams params,
     Set<ElementKind> includedElementKinds,
     Set<String> includedElementNames,
     List<IncludedSuggestionRelevanceTag> includedSuggestionRelevanceTags,
   ) async {
     //
     // Allow plugins to start computing fixes.
     //
     Map<PluginInfo, Future<plugin.Response>> pluginFutures;
     plugin.CompletionGetSuggestionsParams requestParams;
     var file = params.file;
     var offset = params.offset;
     var driver = server.getAnalysisDriver(file);
     if (driver != null) {
       requestParams = plugin.CompletionGetSuggestionsParams(file, offset);
       pluginFutures = server.pluginManager
           .broadcastRequest(requestParams, contextRoot: driver.contextRoot);
     }
     //
     // Compute completions generated by server.
     //
     var suggestions = <CompletionSuggestion>[];
     if (request.result != null) {
       const COMPUTE_SUGGESTIONS_TAG = 'computeSuggestions';
       await perf.runAsync(COMPUTE_SUGGESTIONS_TAG, (perf) async {
         var manager = DartCompletionManager(
           dartdocDirectiveInfo: server.getDartdocDirectiveInfoFor(
             request.result,
           ),
           includedElementKinds: includedElementKinds,
           includedElementNames: includedElementNames,
           includedSuggestionRelevanceTags: includedSuggestionRelevanceTags,
         );

         var contributorTag = 'computeSuggestions - ${manager.runtimeType}';
         await perf.runAsync(contributorTag, (performance) async {
           try {
             suggestions.addAll(
               await manager.computeSuggestions(performance, request),
             );
           } on AbortCompletion {
             suggestions.clear();
           }
         });
       });
     }
     // TODO (danrubel) if request is obsolete (processAnalysisRequest returns
     // false) then send empty results

     //
     // Add the completions produced by plugins to the server-generated list.
     //
     if (pluginFutures != null) {
       var responses = await waitForResponses(pluginFutures,
           requestParameters: requestParams, timeout: 100);
       for (var response in responses) {
         var result =
             plugin.CompletionGetSuggestionsResult.fromResponse(response);
         if (result.results != null && result.results.isNotEmpty) {
           if (suggestions.isEmpty) {
             request.replacementOffset = result.replacementOffset;
             request.replacementLength = result.replacementLength;
           } else if (request.replacementOffset != result.replacementOffset &&
               request.replacementLength != result.replacementLength) {
             server.instrumentationService
                 .logError('Plugin completion-results dropped due to conflicting'
                     ' replacement offset/length: ${result.toJson()}');
             continue;
           }
           suggestions.addAll(result.results);
         }
       }
     }
     //
     // Return the result.
     //
     return CompletionResult(
         request.replacementOffset, request.replacementLength, suggestions);
   }

   /// Process a `completion.getSuggestionDetails` request.
   void getSuggestionDetails(Request request) async {
     var params = CompletionGetSuggestionDetailsParams.fromRequest(request);

     var file = params.file;
     if (server.sendResponseErrorIfInvalidFilePath(request, file)) {
       return;
     }

     var libraryId = params.id;
     var library = server.declarationsTracker.getLibrary(libraryId);
     if (library == null) {
       server.sendResponse(Response.invalidParameter(
         request,
         'libraryId',
         'No such library: $libraryId',
       ));
       return;
     }

     // The label might be `MyEnum.myValue`, but we import only `MyEnum`.
     var requestedName = params.label;
     if (requestedName.contains('.')) {
       requestedName = requestedName.substring(
         0,
         requestedName.indexOf('.'),
       );
     }

     const timeout = Duration(milliseconds: 1000);
     var timer = Stopwatch()..start();
     var id = ++_latestGetSuggestionDetailsId;
     while (id == _latestGetSuggestionDetailsId && timer.elapsed < timeout) {
       try {
         var analysisDriver = server.getAnalysisDriver(file);
         var session = analysisDriver.currentSession;

         var completion = params.label;
         var builder = ChangeBuilder(session: session);
         await builder.addDartFileEdit(file, (builder) {
           var result = builder.importLibraryElement(library.uri);
           if (result.prefix != null) {
             completion = '${result.prefix}.$completion';
           }
         });

         server.sendResponse(
           CompletionGetSuggestionDetailsResult(
             completion,
             change: builder.sourceChange,
           ).toResponse(request.id),
         );
         return;
       } on InconsistentAnalysisException {
         // Loop around to try again.
       }
     }

     // Timeout or abort, send the empty response.
     server.sendResponse(
       CompletionGetSuggestionDetailsResult('').toResponse(request.id),
     );
   }

   @override
   Response handleRequest(Request request) {
     if (!server.options.featureSet.completion) {
       return Response.invalidParameter(
         request,
         'request',
         'The completion feature is not enabled',
       );
     }

     return runZonedGuarded(() {
       var requestName = request.method;

       if (requestName == COMPLETION_REQUEST_GET_SUGGESTION_DETAILS) {
         getSuggestionDetails(request);
         return Response.DELAYED_RESPONSE;
       } else if (requestName == COMPLETION_REQUEST_GET_SUGGESTIONS) {
         processRequest(request);
         return Response.DELAYED_RESPONSE;
       } else if (requestName == COMPLETION_REQUEST_LIST_TOKEN_DETAILS) {
         listTokenDetails(request);
         return Response.DELAYED_RESPONSE;
       } else if (requestName == COMPLETION_REQUEST_SET_SUBSCRIPTIONS) {
         return setSubscriptions(request);
       }
       return null;
     }, (exception, stackTrace) {
       AnalysisEngine.instance.instrumentationService.logException(
           CaughtException.withMessage(
               'Failed to handle completion domain request: ${request.method}',
               exception,
               stackTrace));
     });
   }

   void ifMatchesRequestClear(CompletionRequest completionRequest) {
     if (_currentRequest == completionRequest) {
       _currentRequest = null;
     }
   }

   /// Process a `completion.listTokenDetails` request.
   Future<void> listTokenDetails(Request request) async {
     var params = CompletionListTokenDetailsParams.fromRequest(request);

     var file = params.file;
     if (server.sendResponseErrorIfInvalidFilePath(request, file)) {
       return;
     }

     var analysisDriver = server.getAnalysisDriver(file);
     if (analysisDriver == null) {
       server.sendResponse(Response.invalidParameter(
         request,
         'file',
         'File is not being analyzed: $file',
       ));
     }
     var session = analysisDriver.currentSession;
     var result = await session.getResolvedUnit(file);
     if (result.state != ResultState.VALID) {
       server.sendResponse(Response.invalidParameter(
         request,
         'file',
         'File does not exist or cannot be read: $file',
       ));
     }

     var builder = TokenDetailBuilder();
     builder.visitNode(result.unit);
     server.sendResponse(
       CompletionListTokenDetailsResult(builder.details).toResponse(request.id),
     );
   }

   /// Process a `completion.getSuggestions` request.
   Future<void> processRequest(Request request) async {
     performance = CompletionPerformance();

     await performance.runRequestOperation((perf) async {
       // extract and validate params
       var params = CompletionGetSuggestionsParams.fromRequest(request);
       var file = params.file;
       var offset = params.offset;

       if (server.sendResponseErrorIfInvalidFilePath(request, file)) {
         return;
       }

       var resolvedUnit = await server.getResolvedUnit(file);
       server.requestStatistics?.addItemTimeNow(request, 'resolvedUnit');
       if (resolvedUnit?.state == ResultState.VALID) {
         if (offset < 0 || offset > resolvedUnit.content.length) {
           server.sendResponse(Response.invalidParameter(
               request,
               'params.offset',
               'Expected offset between 0 and source length inclusive,'
                   ' but found $offset'));
           return;
         }

         recordRequest(performance, file, resolvedUnit.content, offset);
       }
       var completionRequest = CompletionRequestImpl(
           resolvedUnit, offset, server.options.useNewRelevance, performance);

       var completionId = (_nextCompletionId++).toString();

       setNewRequest(completionRequest);

       // initial response without results
       server.sendResponse(
           CompletionGetSuggestionsResult(completionId).toResponse(request.id));

       // If the client opted into using available suggestion sets,
       // create the kinds set, so signal the completion manager about opt-in.
       Set<ElementKind> includedElementKinds;
       Set<String> includedElementNames;
       List<IncludedSuggestionRelevanceTag> includedSuggestionRelevanceTags;
       if (subscriptions.contains(CompletionService.AVAILABLE_SUGGESTION_SETS)) {
         includedElementKinds = <ElementKind>{};
         includedElementNames = <String>{};
         includedSuggestionRelevanceTags = <IncludedSuggestionRelevanceTag>[];
       }

       // Compute suggestions in the background
       try {
         var result = await computeSuggestions(
           perf,
           completionRequest,
           params,
           includedElementKinds,
           includedElementNames,
           includedSuggestionRelevanceTags,
         );
         String libraryFile;
         var includedSuggestionSets = <IncludedSuggestionSet>[];
         if (includedElementKinds != null && resolvedUnit != null) {
           libraryFile = resolvedUnit.libraryElement.source.fullName;
           server.sendNotification(
             createExistingImportsNotification(resolvedUnit),
           );
           computeIncludedSetList(
             server.declarationsTracker,
             resolvedUnit,
             includedSuggestionSets,
             includedElementNames,
           );
         }

         const SEND_NOTIFICATION_TAG = 'send notification';
         perf.run(SEND_NOTIFICATION_TAG, (_) {
           sendCompletionNotification(
             completionId,
             result.replacementOffset,
             result.replacementLength,
             result.suggestions,
             libraryFile,
             includedSuggestionSets,
             includedElementKinds?.toList(),
             includedSuggestionRelevanceTags,
           );
         });

         performance.suggestionCount = result.suggestions.length;
       } finally {
         ifMatchesRequestClear(completionRequest);
       }
     });
   }

   /// If tracking code completion performance over time, then
   /// record addition information about the request in the performance record.
   void recordRequest(CompletionPerformance performance, String path,
       String content, int offset) {
     performance.path = path;
     if (performanceListMaxLength == 0) {
       return;
     }
     performance.setContentsAndOffset(content, offset);
     performanceList.add(performance);
   }

   /// Send completion notification results.
   void sendCompletionNotification(
     String completionId,
     int replacementOffset,
     int replacementLength,
     Iterable<CompletionSuggestion> results,
     String libraryFile,
     List<IncludedSuggestionSet> includedSuggestionSets,
     List<ElementKind> includedElementKinds,
     List<IncludedSuggestionRelevanceTag> includedSuggestionRelevanceTags,
   ) {
     server.sendNotification(
       CompletionResultsParams(
         completionId,
         replacementOffset,
         replacementLength,
         results,
         true,
         libraryFile: libraryFile,
         includedSuggestionSets: includedSuggestionSets,
         includedElementKinds: includedElementKinds,
         includedSuggestionRelevanceTags: includedSuggestionRelevanceTags,
       ).toNotification(),
     );
   }

   void setNewRequest(CompletionRequest completionRequest) {
     _abortCurrentRequest();
     _currentRequest = completionRequest;
   }

   /// Implement the 'completion.setSubscriptions' request.
   Response setSubscriptions(Request request) {
     var params = CompletionSetSubscriptionsParams.fromRequest(request);

     subscriptions.clear();
     subscriptions.addAll(params.subscriptions);

     if (subscriptions.contains(CompletionService.AVAILABLE_SUGGESTION_SETS)) {
       var data = server.declarationsTrackerData;
       var soFarLibraries = data.startListening((change) {
         server.sendNotification(
           createCompletionAvailableSuggestionsNotification(
             change.changed,
             change.removed,
           ),
         );
       });
       server.sendNotification(
         createCompletionAvailableSuggestionsNotification(
           soFarLibraries,
           [],
         ),
       );
     } else {
       server.declarationsTrackerData.stopListening();
     }

     return CompletionSetSubscriptionsResult().toResponse(request.id);
   }

   /// Abort the current completion request, if any.
   void _abortCurrentRequest() {
     if (_currentRequest != null) {
       _currentRequest.abort();
       _currentRequest = null;
     }
   }
 }

 /// The result of computing suggestions for code completion.
 class CompletionResult {
   /// The length of the text to be replaced if the remainder of the identifier
   /// containing the cursor is to be replaced when the suggestion is applied
   /// (that is, the number of characters in the existing identifier).
   final int replacementLength;

   /// The offset of the start of the text to be replaced. This will be different
   /// than the offset used to request the completion suggestions if there was a
   /// portion of an identifier before the original offset. In particular, the
   /// replacementOffset will be the offset of the beginning of said identifier.
   final int replacementOffset;

   /// The suggested completions.
   final List<CompletionSuggestion> suggestions;

   CompletionResult(
       this.replacementOffset, this.replacementLength, this.suggestions);
 }
	// 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:async';

	import 'package:analysis_server/protocol/protocol.dart';
	import 'package:analysis_server/protocol/protocol_constants.dart';
	import 'package:analysis_server/protocol/protocol_generated.dart';
	import 'package:analysis_server/src/analysis_server.dart';
	import 'package:analysis_server/src/collections.dart';
	import 'package:analysis_server/src/domain_abstract.dart';
	import 'package:analysis_server/src/domains/completion/available_suggestions.dart';
	import 'package:analysis_server/src/plugin/plugin_manager.dart';
	import 'package:analysis_server/src/provisional/completion/completion_core.dart';
	import 'package:analysis_server/src/services/completion/completion_core.dart';
	import 'package:analysis_server/src/services/completion/completion_performance.dart';
	import 'package:analysis_server/src/services/completion/dart/completion_manager.dart';
	import 'package:analysis_server/src/services/completion/token_details/token_detail_builder.dart';
	import 'package:analyzer/dart/analysis/results.dart';
	import 'package:analyzer/dart/analysis/session.dart';
	import 'package:analyzer/exception/exception.dart';
	import 'package:analyzer/src/generated/engine.dart';
	import 'package:analyzer/src/util/performance/operation_performance.dart';
	import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
	import 'package:analyzer_plugin/protocol/protocol_common.dart';
	import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
	import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';

	/// Instances of the class [CompletionDomainHandler] implement a
	/// [RequestHandler] that handles requests in the completion domain.
	class CompletionDomainHandler extends AbstractRequestHandler {
	/// The maximum number of performance measurements to keep.
	static const int performanceListMaxLength = 50;

	/// The completion services that the client is currently subscribed.
	final Set<CompletionService> subscriptions = <CompletionService>{};

	/// The next completion response id.
	int _nextCompletionId = 0;

	/// Code completion performance for the last completion operation.
	CompletionPerformance performance;

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

	/// The current request being processed or `null` if none.
	CompletionRequestImpl _currentRequest;

	/// The identifiers of the latest `getSuggestionDetails` request.
	/// We use it to abort previous requests.
	int _latestGetSuggestionDetailsId = 0;

	/// Initialize a new request handler for the given [server].
	CompletionDomainHandler(AnalysisServer server) : super(server);

	/// Compute completion results for the given request and append them to the
	/// stream. Clients should not call this method directly as it is
	/// automatically called when a client listens to the stream returned by
	/// [results]. Subclasses should override this method, append at least one
	/// result to the [controller], and close the controller stream once complete.
	Future<CompletionResult> computeSuggestions(
	OperationPerformanceImpl perf,
	CompletionRequestImpl request,
	CompletionGetSuggestionsParams params,
	Set<ElementKind> includedElementKinds,
	Set<String> includedElementNames,
	List<IncludedSuggestionRelevanceTag> includedSuggestionRelevanceTags,
	) async {
	//
	// Allow plugins to start computing fixes.
	//
	Map<PluginInfo, Future<plugin.Response>> pluginFutures;
	plugin.CompletionGetSuggestionsParams requestParams;
	var file = params.file;
	var offset = params.offset;
	var driver = server.getAnalysisDriver(file);
	if (driver != null) {
	requestParams = plugin.CompletionGetSuggestionsParams(file, offset);
	pluginFutures = server.pluginManager
	.broadcastRequest(requestParams, contextRoot: driver.contextRoot);
	}
	//
	// Compute completions generated by server.
	//
	var suggestions = <CompletionSuggestion>[];
	if (request.result != null) {
	const COMPUTE_SUGGESTIONS_TAG = 'computeSuggestions';
	await perf.runAsync(COMPUTE_SUGGESTIONS_TAG, (perf) async {
	var manager = DartCompletionManager(
	dartdocDirectiveInfo: server.getDartdocDirectiveInfoFor(
	request.result,
	),
	includedElementKinds: includedElementKinds,
	includedElementNames: includedElementNames,
	includedSuggestionRelevanceTags: includedSuggestionRelevanceTags,
	);

	var contributorTag = 'computeSuggestions - ${manager.runtimeType}';
	await perf.runAsync(contributorTag, (performance) async {
	try {
	suggestions.addAll(
	await manager.computeSuggestions(performance, request),
	);
	} on AbortCompletion {
	suggestions.clear();
	}
	});
	});
	}
	// TODO (danrubel) if request is obsolete (processAnalysisRequest returns
	// false) then send empty results

	//
	// Add the completions produced by plugins to the server-generated list.
	//
	if (pluginFutures != null) {
	var responses = await waitForResponses(pluginFutures,
	requestParameters: requestParams, timeout: 100);
	for (var response in responses) {
	var result =
	plugin.CompletionGetSuggestionsResult.fromResponse(response);
	if (result.results != null && result.results.isNotEmpty) {
	if (suggestions.isEmpty) {
	request.replacementOffset = result.replacementOffset;
	request.replacementLength = result.replacementLength;
	} else if (request.replacementOffset != result.replacementOffset &&
	request.replacementLength != result.replacementLength) {
	server.instrumentationService
	.logError('Plugin completion-results dropped due to conflicting'
	' replacement offset/length: ${result.toJson()}');
	continue;
	}
	suggestions.addAll(result.results);
	}
	}
	}
	//
	// Return the result.
	//
	return CompletionResult(
	request.replacementOffset, request.replacementLength, suggestions);
	}

	/// Process a `completion.getSuggestionDetails` request.
	void getSuggestionDetails(Request request) async {
	var params = CompletionGetSuggestionDetailsParams.fromRequest(request);

	var file = params.file;
	if (server.sendResponseErrorIfInvalidFilePath(request, file)) {
	return;
	}

	var libraryId = params.id;
	var library = server.declarationsTracker.getLibrary(libraryId);
	if (library == null) {
	server.sendResponse(Response.invalidParameter(
	request,
	'libraryId',
	'No such library: $libraryId',
	));
	return;
	}

	// The label might be `MyEnum.myValue`, but we import only `MyEnum`.
	var requestedName = params.label;
	if (requestedName.contains('.')) {
	requestedName = requestedName.substring(
	0,
	requestedName.indexOf('.'),
	);
	}

	const timeout = Duration(milliseconds: 1000);
	var timer = Stopwatch()..start();
	var id = ++_latestGetSuggestionDetailsId;
	while (id == _latestGetSuggestionDetailsId && timer.elapsed < timeout) {
	try {
	var analysisDriver = server.getAnalysisDriver(file);
	var session = analysisDriver.currentSession;

	var completion = params.label;
	var builder = ChangeBuilder(session: session);
	await builder.addDartFileEdit(file, (builder) {
	var result = builder.importLibraryElement(library.uri);
	if (result.prefix != null) {
	completion = '${result.prefix}.$completion';
	}
	});

	server.sendResponse(
	CompletionGetSuggestionDetailsResult(
	completion,
	change: builder.sourceChange,
	).toResponse(request.id),
	);
	return;
	} on InconsistentAnalysisException {
	// Loop around to try again.
	}
	}

	// Timeout or abort, send the empty response.
	server.sendResponse(
	CompletionGetSuggestionDetailsResult('').toResponse(request.id),
	);
	}

	@override
	Response handleRequest(Request request) {
	if (!server.options.featureSet.completion) {
	return Response.invalidParameter(
	request,
	'request',
	'The completion feature is not enabled',
	);
	}

	return runZonedGuarded(() {
	var requestName = request.method;

	if (requestName == COMPLETION_REQUEST_GET_SUGGESTION_DETAILS) {
	getSuggestionDetails(request);
	return Response.DELAYED_RESPONSE;
	} else if (requestName == COMPLETION_REQUEST_GET_SUGGESTIONS) {
	processRequest(request);
	return Response.DELAYED_RESPONSE;
	} else if (requestName == COMPLETION_REQUEST_LIST_TOKEN_DETAILS) {
	listTokenDetails(request);
	return Response.DELAYED_RESPONSE;
	} else if (requestName == COMPLETION_REQUEST_SET_SUBSCRIPTIONS) {
	return setSubscriptions(request);
	}
	return null;
	}, (exception, stackTrace) {
	AnalysisEngine.instance.instrumentationService.logException(
	CaughtException.withMessage(
	'Failed to handle completion domain request: ${request.method}',
	exception,
	stackTrace));
	});
	}

	void ifMatchesRequestClear(CompletionRequest completionRequest) {
	if (_currentRequest == completionRequest) {
	_currentRequest = null;
	}
	}

	/// Process a `completion.listTokenDetails` request.
	Future<void> listTokenDetails(Request request) async {
	var params = CompletionListTokenDetailsParams.fromRequest(request);

	var file = params.file;
	if (server.sendResponseErrorIfInvalidFilePath(request, file)) {
	return;
	}

	var analysisDriver = server.getAnalysisDriver(file);
	if (analysisDriver == null) {
	server.sendResponse(Response.invalidParameter(
	request,
	'file',
	'File is not being analyzed: $file',
	));
	}
	var session = analysisDriver.currentSession;
	var result = await session.getResolvedUnit(file);
	if (result.state != ResultState.VALID) {
	server.sendResponse(Response.invalidParameter(
	request,
	'file',
	'File does not exist or cannot be read: $file',
	));
	}

	var builder = TokenDetailBuilder();
	builder.visitNode(result.unit);
	server.sendResponse(
	CompletionListTokenDetailsResult(builder.details).toResponse(request.id),
	);
	}

	/// Process a `completion.getSuggestions` request.
	Future<void> processRequest(Request request) async {
	performance = CompletionPerformance();

	await performance.runRequestOperation((perf) async {
	// extract and validate params
	var params = CompletionGetSuggestionsParams.fromRequest(request);
	var file = params.file;
	var offset = params.offset;

	if (server.sendResponseErrorIfInvalidFilePath(request, file)) {
	return;
	}

	var resolvedUnit = await server.getResolvedUnit(file);
	server.requestStatistics?.addItemTimeNow(request, 'resolvedUnit');
	if (resolvedUnit?.state == ResultState.VALID) {
	if (offset < 0 \|\| offset > resolvedUnit.content.length) {
	server.sendResponse(Response.invalidParameter(
	request,
	'params.offset',
	'Expected offset between 0 and source length inclusive,'
	' but found $offset'));
	return;
	}

	recordRequest(performance, file, resolvedUnit.content, offset);
	}
	var completionRequest = CompletionRequestImpl(
	resolvedUnit, offset, server.options.useNewRelevance, performance);

	var completionId = (_nextCompletionId++).toString();

	setNewRequest(completionRequest);

	// initial response without results
	server.sendResponse(
	CompletionGetSuggestionsResult(completionId).toResponse(request.id));

	// If the client opted into using available suggestion sets,
	// create the kinds set, so signal the completion manager about opt-in.
	Set<ElementKind> includedElementKinds;
	Set<String> includedElementNames;
	List<IncludedSuggestionRelevanceTag> includedSuggestionRelevanceTags;
	if (subscriptions.contains(CompletionService.AVAILABLE_SUGGESTION_SETS)) {
	includedElementKinds = <ElementKind>{};
	includedElementNames = <String>{};
	includedSuggestionRelevanceTags = <IncludedSuggestionRelevanceTag>[];
	}

	// Compute suggestions in the background
	try {
	var result = await computeSuggestions(
	perf,
	completionRequest,
	params,
	includedElementKinds,
	includedElementNames,
	includedSuggestionRelevanceTags,
	);
	String libraryFile;
	var includedSuggestionSets = <IncludedSuggestionSet>[];
	if (includedElementKinds != null && resolvedUnit != null) {
	libraryFile = resolvedUnit.libraryElement.source.fullName;
	server.sendNotification(
	createExistingImportsNotification(resolvedUnit),
	);
	computeIncludedSetList(
	server.declarationsTracker,
	resolvedUnit,
	includedSuggestionSets,
	includedElementNames,
	);
	}

	const SEND_NOTIFICATION_TAG = 'send notification';
	perf.run(SEND_NOTIFICATION_TAG, (_) {
	sendCompletionNotification(
	completionId,
	result.replacementOffset,
	result.replacementLength,
	result.suggestions,
	libraryFile,
	includedSuggestionSets,
	includedElementKinds?.toList(),
	includedSuggestionRelevanceTags,
	);
	});

	performance.suggestionCount = result.suggestions.length;
	} finally {
	ifMatchesRequestClear(completionRequest);
	}
	});
	}

	/// If tracking code completion performance over time, then
	/// record addition information about the request in the performance record.
	void recordRequest(CompletionPerformance performance, String path,
	String content, int offset) {
	performance.path = path;
	if (performanceListMaxLength == 0) {
	return;
	}
	performance.setContentsAndOffset(content, offset);
	performanceList.add(performance);
	}

	/// Send completion notification results.
	void sendCompletionNotification(
	String completionId,
	int replacementOffset,
	int replacementLength,
	Iterable<CompletionSuggestion> results,
	String libraryFile,
	List<IncludedSuggestionSet> includedSuggestionSets,
	List<ElementKind> includedElementKinds,
	List<IncludedSuggestionRelevanceTag> includedSuggestionRelevanceTags,
	) {
	server.sendNotification(
	CompletionResultsParams(
	completionId,
	replacementOffset,
	replacementLength,
	results,
	true,
	libraryFile: libraryFile,
	includedSuggestionSets: includedSuggestionSets,
	includedElementKinds: includedElementKinds,
	includedSuggestionRelevanceTags: includedSuggestionRelevanceTags,
	).toNotification(),
	);
	}

	void setNewRequest(CompletionRequest completionRequest) {
	_abortCurrentRequest();
	_currentRequest = completionRequest;
	}

	/// Implement the 'completion.setSubscriptions' request.
	Response setSubscriptions(Request request) {
	var params = CompletionSetSubscriptionsParams.fromRequest(request);

	subscriptions.clear();
	subscriptions.addAll(params.subscriptions);

	if (subscriptions.contains(CompletionService.AVAILABLE_SUGGESTION_SETS)) {
	var data = server.declarationsTrackerData;
	var soFarLibraries = data.startListening((change) {
	server.sendNotification(
	createCompletionAvailableSuggestionsNotification(
	change.changed,
	change.removed,
	),
	);
	});
	server.sendNotification(
	createCompletionAvailableSuggestionsNotification(
	soFarLibraries,
	[],
	),
	);
	} else {
	server.declarationsTrackerData.stopListening();
	}

	return CompletionSetSubscriptionsResult().toResponse(request.id);
	}

	/// Abort the current completion request, if any.
	void _abortCurrentRequest() {
	if (_currentRequest != null) {
	_currentRequest.abort();
	_currentRequest = null;
	}
	}
	}

	/// The result of computing suggestions for code completion.
	class CompletionResult {
	/// The length of the text to be replaced if the remainder of the identifier
	/// containing the cursor is to be replaced when the suggestion is applied
	/// (that is, the number of characters in the existing identifier).
	final int replacementLength;

	/// The offset of the start of the text to be replaced. This will be different
	/// than the offset used to request the completion suggestions if there was a
	/// portion of an identifier before the original offset. In particular, the
	/// replacementOffset will be the offset of the beginning of said identifier.
	final int replacementOffset;

	/// The suggested completions.
	final List<CompletionSuggestion> suggestions;

	CompletionResult(
	this.replacementOffset, this.replacementLength, this.suggestions);
	}