extract LibraryPrefixContributor from imported reference contributor

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

 // Copyright (c) 2015, 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.manager;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/provisional/completion/completion_core.dart'
     show CompletionContributor, CompletionRequest;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_plugin.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_target.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/context/context.dart'
     show AnalysisFutureHelper, AnalysisContextImpl;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart' hide AnalysisContextImpl;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/dart.dart';
 import 'package:analyzer/task/dart.dart';
+import 'package:analysis_server/src/services/completion/optype.dart';
 
 /**
  * [DartCompletionManager] determines if a completion request is Dart specific
  * and forwards those requests to all [DartCompletionContributor]s.
  */
 class DartCompletionManager implements CompletionContributor {
   @override
   Future<List<CompletionSuggestion>> computeSuggestions(
       CompletionRequest request) async {
     if (!AnalysisEngine.isDartFileName(request.source.shortName)) {
@@ skipping 68 matching lines @@
    * The [DartType] for Object in dart:core
    */
   InterfaceType _objectType;
 
   @override
   Expression dotTarget;
 
   @override
   Source librarySource;
 
+  OpType _opType;
+
   @override
   CompletionTarget target;
 
   @override
+  bool get includeIdentifiers {
+    if (_opType == null) {
+      _opType = new OpType.forCompletion(target, offset);
+    }
+    return !_opType.isPrefixed &&
+        (_opType.includeReturnValueSuggestions ||
+            _opType.includeTypeNameSuggestions ||
+            _opType.includeVoidReturnSuggestions ||
+            _opType.includeConstructorSuggestions);
+  }
+
+  @override
   LibraryElement get libraryElement {
     //TODO(danrubel) build the library element rather than all the declarations
     CompilationUnit unit = target.unit;
     if (unit != null) {
       CompilationUnitElement elem = unit.element;
       if (elem != null) {
         return elem.library;
       }
     }
     return null;
@@ skipping 55 matching lines @@
     }
 
     // Recompute the target for the newly resolved unit
     _updateTargets(resolvedUnit);
   }
 
   /**
    * Update the completion [target] and [dotTarget] based on the given [unit].
    */
   void _updateTargets(CompilationUnit unit) {
+    _opType = null;
     dotTarget = null;
     target = new CompletionTarget.forOffset(unit, offset);
     AstNode node = target.containingNode;
     if (node is MethodInvocation) {
       if (identical(node.methodName, target.entity)) {
         dotTarget = node.realTarget;
       } else if (node.isCascaded && node.operator.offset + 1 == target.offset) {
         dotTarget = node.realTarget;
       }
     }
     if (node is PropertyAccess) {
       if (identical(node.propertyName, target.entity)) {
         dotTarget = node.realTarget;
       } else if (node.isCascaded && node.operator.offset + 1 == target.offset) {
         dotTarget = node.realTarget;
       }
     }
     if (node is PrefixedIdentifier) {
       if (identical(node.identifier, target.entity)) {
         dotTarget = node.prefix;
       }
     }
   }
 }