convert ImportedReferenceContributor to new API

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

Index: pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
new file mode 100644
index 0000000000000000000000000000000000000000..e25dc188e1983d7495b1d577921ca910521b4a03
--- /dev/null
+++ b/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
@@ -0,0 +1,96 @@
+// 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.contributor.dart.imported_ref;
+
+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';
+import 'package:analysis_server/src/services/completion/optype.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart';
+
+import '../../../protocol_server.dart'
+    show CompletionSuggestion, CompletionSuggestionKind;
+import 'package:analyzer/src/generated/resolver.dart';
+
+/**
+ * A contributor for calculating suggestions for imported top level members.
+ */
+class ImportedReferenceContributor extends DartCompletionContributor {
+  DartCompletionRequest request;
+  OpType optype;
+
+  @override
+  Future<List<CompletionSuggestion>> computeSuggestions(
+      DartCompletionRequest request) async {
+    if (!request.includeIdentifiers) {
+      return EMPTY_LIST;
+    }
+
+    List<Directive> directives = await request.resolveDirectives();
+    if (directives == null) {
+      return EMPTY_LIST;
+    }
+
+    this.request = request;
+    this.optype = (request as DartCompletionRequestImpl).opType;
+
+    // Traverse dart:core
+    List<CompletionSuggestion> suggestions =
+        _buildSuggestions(request.coreLib.exportNamespace);
+
+    // Traverse imports
+    for (Directive directive in directives) {
+      if (directive is ImportDirective) {
+        ImportElement importElem = directive.element;
+        LibraryElement libElem = importElem?.importedLibrary;
+        if (libElem != null) {
+          suggestions.addAll(_buildSuggestions(libElem.exportNamespace,
+              prefix: importElem.prefix?.name,
+              showNames: showNamesIn(importElem),
+              hiddenNames: hiddenNamesIn(importElem)));
+        }
+      }
+    }
+
+    return suggestions;
+  }
+
+  List<CompletionSuggestion> _buildSuggestions(Namespace namespace,
+      {String prefix, List<String> showNames, List<String> hiddenNames}) {
+    LibraryElementSuggestionBuilder visitor =
+        new LibraryElementSuggestionBuilder(request, optype, prefix);
+    for (Element elem in namespace.definedNames.values) {
+      if (showNames != null && !showNames.contains(elem.name)) {
+        continue;
+      }
+      if (hiddenNames != null && hiddenNames.contains(elem.name)) {
+        continue;
+      }
+      elem.accept(visitor);
+    }
+    return visitor.suggestions;
+  }
+}
+
+List<String> showNamesIn(ImportElement importElem) {
+  for (NamespaceCombinator combinator in importElem.combinators) {
+    if (combinator is ShowElementCombinator) {
+      return combinator.shownNames;
+    }
+  }
+  return null;
+}
+
+List<String> hiddenNamesIn(ImportElement importElem) {
+  for (NamespaceCombinator combinator in importElem.combinators) {
+    if (combinator is HideElementCombinator) {
+      return combinator.hiddenNames;
+    }
+  }
+  return null;
+}