Use time budget in NotImportedContributor.

Change-Id: Ief0ef8185accd68c7b99132393fa0a4db6be31c4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/218380
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analysis_server/lib/src/cider/completion.dart

@@ -85,6 +85,9 @@ class CiderCompletionComputer {
                 <IncludedSuggestionRelevanceTag>[];
 
             var manager = DartCompletionManager(
+              budget: CompletionBudget(
+                const Duration(milliseconds: 100),
+              ),
               includedElementKinds: includedElementKinds,
               includedElementNames: includedElementNames,
               includedSuggestionRelevanceTags: includedSuggestionRelevanceTags,

pkg/analysis_server/lib/src/domain_completion.dart

@@ -34,7 +34,7 @@ import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dar
 /// [RequestHandler] that handles requests in the completion domain.
 class CompletionDomainHandler extends AbstractRequestHandler {
   /// The time budget for a completion request.
-  static const Duration _budgetDuration = Duration(milliseconds: 100);
+  static Duration budgetDuration = Duration(milliseconds: 100);
 
   /// The maximum number of performance measurements to keep.
   static const int performanceListMaxLength = 50;
@@ -90,6 +90,7 @@ class CompletionDomainHandler extends AbstractRequestHandler {
     var suggestions = <CompletionSuggestion>[];
     await performance.runAsync('computeSuggestions', (performance) async {
       var manager = DartCompletionManager(
+        budget: budget,
         includedElementKinds: includedElementKinds,
         includedElementNames: includedElementNames,
         includedSuggestionRelevanceTags: includedSuggestionRelevanceTags,
@@ -213,7 +214,7 @@ class CompletionDomainHandler extends AbstractRequestHandler {
 
   /// Implement the 'completion.getSuggestions2' request.
   void getSuggestions2(Request request) async {
-    var budget = CompletionBudget(_budgetDuration);
+    var budget = CompletionBudget(budgetDuration);
 
     var params = CompletionGetSuggestions2Params.fromRequest(request);
     var file = params.file;
@@ -337,7 +338,7 @@ class CompletionDomainHandler extends AbstractRequestHandler {
 
   /// Process a `completion.getSuggestions` request.
   Future<void> processRequest(Request request) async {
-    var budget = CompletionBudget(_budgetDuration);
+    var budget = CompletionBudget(budgetDuration);
 
     final performance = this.performance = CompletionPerformance();
 

pkg/analysis_server/lib/src/domains/execution/completion.dart

@@ -74,7 +74,11 @@ class RuntimeCompletionComputer {
       offset: targetOffset,
     );
 
-    var suggestions = await DartCompletionManager().computeSuggestions(
+    var suggestions = await DartCompletionManager(
+      budget: CompletionBudget(
+        const Duration(milliseconds: 100),
+      ),
+    ).computeSuggestions(
       dartRequest,
       OperationPerformanceImpl('<root>'),
     );

pkg/analysis_server/lib/src/lsp/handlers/handler_completion.dart

@@ -233,6 +233,9 @@ class CompletionHandler
 
       try {
         var contributor = DartCompletionManager(
+          budget: CompletionBudget(
+            const Duration(milliseconds: 100),
+          ),
           includedElementKinds: includedElementKinds,
           includedElementNames: includedElementNames,
           includedSuggestionRelevanceTags: includedSuggestionRelevanceTags,

pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart

@@ -52,6 +52,10 @@ class CompletionBudget {
 
   CompletionBudget(this._budget);
 
+  bool get isEmpty {
+    return _timer.elapsed > _budget;
+  }
+
   Duration get left {
     var result = _budget - _timer.elapsed;
     return result.isNegative ? Duration.zero : result;
@@ -61,6 +65,9 @@ class CompletionBudget {
 /// [DartCompletionManager] determines if a completion request is Dart specific
 /// and forwards those requests to all [DartCompletionContributor]s.
 class DartCompletionManager {
+  /// Time budget to computing suggestions.
+  final CompletionBudget budget;
+
   /// If not `null`, then instead of using [ImportedReferenceContributor],
   /// fill this set with kinds of elements that are applicable at the
   /// completion location, so should be suggested from available suggestion
@@ -91,6 +98,7 @@ class DartCompletionManager {
   /// [includedSuggestionRelevanceTags] must either all be `null` or must all be
   /// non-`null`.
   DartCompletionManager({
+    required this.budget,
     this.includedElementKinds,
     this.includedElementNames,
     this.includedSuggestionRelevanceTags,
@@ -156,7 +164,7 @@ class DartCompletionManager {
     final librariesToImport = this.librariesToImport;
     if (librariesToImport != null) {
       contributors.add(
-        NotImportedContributor(request, builder, librariesToImport),
+        NotImportedContributor(request, builder, budget, librariesToImport),
       );
     }
 

pkg/analysis_server/lib/src/services/completion/dart/not_imported_contributor.dart

@@ -2,6 +2,8 @@
 // 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/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart';
 import 'package:analysis_server/src/services/completion/dart/local_library_contributor.dart';
@@ -17,11 +19,13 @@ import 'package:collection/collection.dart';
 
 /// A contributor of suggestions from not yet imported libraries.
 class NotImportedContributor extends DartCompletionContributor {
+  final CompletionBudget budget;
   final List<Uri> librariesToImport;
 
   NotImportedContributor(
     DartCompletionRequest request,
     SuggestionBuilder builder,
+    this.budget,
     this.librariesToImport,
   ) : super(request, builder);
 
@@ -37,10 +41,18 @@ class NotImportedContributor extends DartCompletionContributor {
     var fsState = analysisDriver.fsState;
     var filter = _buildFilter(fsState);
 
-    await analysisDriver.discoverAvailableFiles();
+    try {
+      await analysisDriver.discoverAvailableFiles().timeout(budget.left);
+    } on TimeoutException {
+      return;
+    }
 
     var knownFiles = fsState.knownFiles.toList();
     for (var file in knownFiles) {
+      if (budget.isEmpty) {
+        return;
+      }
+
       if (!filter.shouldInclude(file)) {
         continue;
       }

pkg/analysis_server/test/domain_completion_test.dart

@@ -73,6 +73,7 @@ class CompletionDomainHandlerGetSuggestions2Test with ResourceProviderMixin {
   }
 
   void setUp() {
+    CompletionDomainHandler.budgetDuration = const Duration(seconds: 30);
     serverChannel = MockServerChannel();
 
     var sdkRoot = newFolder('/sdk');
@@ -93,6 +94,29 @@ class CompletionDomainHandlerGetSuggestions2Test with ResourceProviderMixin {
     );
   }
 
+  Future<void> test_notImported_emptyBudget() async {
+    await _configureWithWorkspaceRoot();
+
+    // Empty budget, so no not yet imported libraries.
+    CompletionDomainHandler.budgetDuration = const Duration(milliseconds: 0);
+
+    var responseValidator = await _getTestCodeSuggestions('''
+void f() {
+  Rand^
+}
+''');
+
+    responseValidator
+      ..assertComplete()
+      ..assertReplacementBack(4)
+      ..assertLibrariesToImport(includes: [], excludes: [
+        'dart:core',
+        'dart:math',
+      ]);
+
+    responseValidator.suggestions.withElementClass().assertEmpty();
+  }
+
   Future<void> test_notImported_pub_dependencies_inLib() async {
     // TODO(scheglov) Switch to PubspecYamlFileConfig
     newPubspecYamlFile(testPackageRootPath, r'''

pkg/analysis_server/test/stress/completion/completion_runner.dart

@@ -57,7 +57,9 @@ class CompletionRunner {
     var collection = AnalysisContextCollection(
         includedPaths: <String>[analysisRoot],
         resourceProvider: resourceProvider);
-    var contributor = DartCompletionManager();
+    var contributor = DartCompletionManager(
+      budget: CompletionBudget(const Duration(seconds: 30)),
+    );
     var statistics = CompletionPerformance();
     var stamp = 1;
 

pkg/analysis_server/tool/code_completion/completion_metrics.dart

@@ -1205,9 +1205,11 @@ class CompletionMetricsComputer {
           availableSuggestionsParams]) async {
     List<protocol.CompletionSuggestion> suggestions;
 
+    const budgetDuration = Duration(seconds: 30);
     if (declarationsTracker == null) {
       // available suggestions == false
       suggestions = await DartCompletionManager(
+        budget: CompletionBudget(budgetDuration),
         listener: listener,
       ).computeSuggestions(dartRequest, performance);
     } else {
@@ -1218,6 +1220,7 @@ class CompletionMetricsComputer {
           <protocol.IncludedSuggestionRelevanceTag>[];
       var includedSuggestionSetList = <protocol.IncludedSuggestionSet>[];
       suggestions = await DartCompletionManager(
+        budget: CompletionBudget(budgetDuration),
         includedElementKinds: includedElementKinds,
         includedElementNames: includedElementNames,
         includedSuggestionRelevanceTags: includedSuggestionRelevanceTagList,