move combinator contributor to new task model

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

Index: pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart
new file mode 100644
index 0000000000000000000000000000000000000000..cba3bd4c44181273c0bcfd17b120dae68e542435
--- /dev/null
+++ b/pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart
@@ -0,0 +1,57 @@
+// 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.combinator;
+
+import 'dart:async';
+
+import 'package:analysis_server/src/protocol_server.dart'
+    hide Element, ElementKind;
+import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
+import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart';
+
+/**
+ * A contributor for calculating `completion.getSuggestions` request results
+ * for the import combinators show and hide.
+ */
+class CombinatorContributor extends DartCompletionContributor {
+  @override
+  Future<List<CompletionSuggestion>> computeSuggestions(
+      DartCompletionRequest request) async {
+    AstNode node = request.target.containingNode;
+    if (node is! Combinator) {
+      return EMPTY_LIST;
+    }
+
+    // Partially resolve the compilation unit
+    CompilationUnit unit = await request.resolveDeclarationsInScope();

[scheglov, 2015/12/04 17:43:26]

It seems too wide.
It would be enough to get LIBRARY_ELEMENT4 for the directive's source.

[danrubel, 2015/12/04 20:46:22]

Thanks for the info. I'll address this in the next CL.

+    // Gracefully degrade if the compilation unit could not be resolved
+    // e.g. detached part file or source change
+    if (unit == null) {
+      return EMPTY_LIST;
+    }
+
+    // Check the target since resolution may have changed it
+    node = request.target.containingNode;
+    if (node is! Combinator) {
+      return EMPTY_LIST;
+    }
+
+    // Build list of suggestions
+    var directive = node.getAncestor((parent) => parent is NamespaceDirective);
+    if (directive is NamespaceDirective) {
+      LibraryElement library = directive.uriElement;
+      if (library != null) {
+        LibraryElementSuggestionBuilder builder =
+            new LibraryElementSuggestionBuilder(
+                request, CompletionSuggestionKind.IDENTIFIER, false, false);
+        library.visitChildren(builder);
+        return builder.suggestions;
+      }
+    }
+    return EMPTY_LIST;
+  }
+}