next step toward completion plugin API

pkg/analysis_server/lib/src/services/completion/dart/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.computer.dart.manager;
+
+import 'package:analysis_server/plugin/protocol/protocol.dart'
+    show CompletionSuggestion, CompletionSuggestionKind;
+import 'package:analysis_server/src/provisional/completion/completion_dart.dart';
+import 'package:analysis_server/src/services/completion/dart_completion_manager.dart'
+    show DART_RELEVANCE_DEFAULT, DART_RELEVANCE_LOCAL_FUNCTION;
+import 'package:analysis_server/src/services/completion/suggestion_builder.dart';
+import 'package:analyzer/src/generated/element.dart';
+
+// TODO (danrubel) revise a move existing manager to this file
+
+/**
+ * An internal implementation of [DartSuggestionCollector] for building
+ * and collecting suggestions based upon elements.
+ */
+class DartSuggestionCollectorImpl implements DartSuggestionCollector {
+  List<CompletionSuggestion> suggestions = <CompletionSuggestion>[];
+
+  @override
+  void addCompletionSuggestion(CompletionSuggestion suggestion) {
+    if (suggestion != null) {
+      suggestions.add(suggestion);
+    }
+  }
+
+  @override
+  void addElementSuggestion(Element element,
+      {bool includePrivateElements: false,
+      String prefix,
+      int relevance: DART_RELEVANCE_DEFAULT}) {
+    if (element.isPrivate && !includePrivateElements) {
+      return;
+    }
+    if (prefix == null && element.isSynthetic) {
+      if ((element is PropertyAccessorElement) ||
+          element is FieldElement && !_isSpecialEnumField(element)) {
+        return;
+      }
+    }
+    String completion = element.displayName;
+    if (prefix != null && prefix.length > 0) {
+      if (completion == null || completion.length <= 0) {
+        completion = prefix;
+      } else {
+        completion = '$prefix.$completion';
+      }
+    }
+    if (completion == null || completion.length <= 0) {
+      return;
+    }
+    addCompletionSuggestion(createSuggestion(element,
+        completion: completion,
+        kind: CompletionSuggestionKind.IDENTIFIER,
+        relevance: relevance));
+  }
+
+  /**
+   * Determine if the given element is one of the synthetic enum accessors
+   * for which we should generate a suggestion.
+   */
+  bool _isSpecialEnumField(FieldElement element) {
+    Element parent = element.enclosingElement;
+    if (parent is ClassElement && parent.isEnum) {
+      if (element.name == 'values') {
+        return true;
+      }
+    }
+    return false;
+  }
+}