Add defaultCompletionSorter allowing sorting to be overridden - fixes #24339

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

 // 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.
 
 library services.completion.dart;
 
 import 'dart:async';
 
 import 'package:analysis_server/completion/completion_core.dart'
     show CompletionRequest;
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/arglist_contributor.dart';
 import 'package:analysis_server/src/services/completion/combinator_contributor.dart';
 import 'package:analysis_server/src/services/completion/common_usage_computer.dart';
 import 'package:analysis_server/src/services/completion/completion_manager.dart';
 import 'package:analysis_server/src/services/completion/completion_target.dart';
+import 'package:analysis_server/src/services/completion/contribution_sorter.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_cache.dart';
-import 'package:analysis_server/src/services/completion/uri_contributor.dart';
 import 'package:analysis_server/src/services/completion/imported_reference_contributor.dart';
 import 'package:analysis_server/src/services/completion/keyword_contributor.dart';
 import 'package:analysis_server/src/services/completion/local_reference_contributor.dart';
 import 'package:analysis_server/src/services/completion/optype.dart';
 import 'package:analysis_server/src/services/completion/prefixed_element_contributor.dart';
+import 'package:analysis_server/src/services/completion/uri_contributor.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 const int DART_RELEVANCE_COMMON_USAGE = 1200;
 const int DART_RELEVANCE_DEFAULT = 1000;
 const int DART_RELEVANCE_HIGH = 2000;
 const int DART_RELEVANCE_INHERITED_ACCESSOR = 1057;
@@ skipping 30 matching lines @@
    * in the given completion context are resolved.
    * Returns `true` if the receiver modified the list of suggestions.
    */
   Future<bool> computeFull(DartCompletionRequest request);
 }
 
 /**
  * Manages code completion for a given Dart file completion request.
  */
 class DartCompletionManager extends CompletionManager {
+
+  /**
+   * The [defaultContributionSorter] is a long-lived object that isn't allowed
+   * to maintain state between calls to [ContributionSorter#sort(...)].
+   */
+  static ContributionSorter defaultContributionSorter = new CommonUsageComputer();
+
   final SearchEngine searchEngine;
   final DartCompletionCache cache;
   List<DartCompletionContributor> contributors;
-  CommonUsageComputer commonUsageComputer;
+  ContributionSorter contributionSorter;
 
   DartCompletionManager(
       AnalysisContext context, this.searchEngine, Source source, this.cache,
-      [this.contributors, this.commonUsageComputer])
+      [this.contributors, this.contributionSorter])
       : super(context, source) {
     if (contributors == null) {
       contributors = [
         // LocalReferenceContributor before ImportedReferenceContributor
         // because local suggestions take precedence
         // and can hide other suggestions with the same name
         new LocalReferenceContributor(),
         new ImportedReferenceContributor(),
         new KeywordContributor(),
         new ArgListContributor(),
         new CombinatorContributor(),
         new PrefixedElementContributor(),
         new UriContributor(),
       ];
     }
-    if (commonUsageComputer == null) {
-      commonUsageComputer = new CommonUsageComputer();
+    if (contributionSorter == null) {
+      contributionSorter = defaultContributionSorter;
     }
   }
 
   /**
    * Create a new initialized Dart source completion manager
    */
   factory DartCompletionManager.create(
       AnalysisContext context, SearchEngine searchEngine, Source source) {
     return new DartCompletionManager(context, searchEngine, source,
         new DartCompletionCache(context, source));
@@ skipping 50 matching lines @@
           }
         }
       }
 
       List<DartCompletionContributor> todo = new List.from(contributors);
       todo.removeWhere((DartCompletionContributor c) {
         return performance.logElapseTime('computeFast ${c.runtimeType}', () {
           return c.computeFast(request);
         });
       });
-      commonUsageComputer.computeFast(request);
+      contributionSorter.sort(request);
       sendResults(request, todo.isEmpty);
       return todo;
     });
   }
 
   /**
    * If there is remaining work to be done, then wait for the unit to be
    * resolved and request that each remaining contributor finish their work.
    * Return a [Future] that completes when the last notification has been sent.
    */
@@ skipping 17 matching lines @@
         int count = todo.length;
         todo.forEach((DartCompletionContributor c) {
           String name = c.runtimeType.toString();
           String completeTag = 'computeFull $name complete';
           performance.logStartTime(completeTag);
           performance.logElapseTime('computeFull $name', () {
             c.computeFull(request).then((bool changed) {
               performance.logElapseTime(completeTag);
               bool last = --count == 0;
               if (changed || last) {
-                commonUsageComputer.computeFull(request);
+                contributionSorter.sort(request);
                 sendResults(request, last);
               }
             });
           });
         });
       });
     });
   }
 
   @override
@@ skipping 173 matching lines @@
             parameterNames: suggestion.parameterNames,
             parameterTypes: suggestion.parameterTypes,
             requiredParameterCount: suggestion.requiredParameterCount,
             hasNamedParameters: suggestion.hasNamedParameters,
             returnType: suggestion.returnType,
             element: suggestion.element);
       }
     }
   }
 }