Remove code duplication

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

+// Copyright (c) 2017, 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.
+
+/**
+ * A collection of utility methods used by completion contributors.
+ */
+import 'package:analysis_server/plugin/protocol/protocol.dart' as protocol
+    show Element, ElementKind;
+import 'package:analysis_server/src/protocol_server.dart'
+    show CompletionSuggestion, CompletionSuggestionKind, Location;
+import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/standard_ast_factory.dart';
+import 'package:analyzer/dart/ast/token.dart';
+import 'package:analyzer/src/dart/ast/token.dart';
+import 'package:analyzer/src/generated/source.dart';
+
+/**
+ * The name of the type `dynamic`;
+ */
+const DYNAMIC = 'dynamic';
+
+/**
+ * A marker used in place of `null` when a function has no return type.
+ */
+final TypeName NO_RETURN_TYPE = astFactory.typeName(
+    astFactory.simpleIdentifier(new StringToken(TokenType.IDENTIFIER, '', 0)),
+    null);
+
+/**
+ * Create a new protocol Element for inclusion in a completion suggestion.
+ */
+protocol.Element createLocalElement(
+    Source source, protocol.ElementKind kind, SimpleIdentifier id,
+    {String parameters,
+    TypeName returnType,
+    bool isAbstract: false,
+    bool isDeprecated: false}) {
+  String name;
+  Location location;
+  if (id != null) {
+    name = id.name;
+    // TODO(danrubel) use lineInfo to determine startLine and startColumn
+    location = new Location(source.fullName, id.offset, id.length, 0, 0);
+  } else {
+    name = '';
+    location = new Location(source.fullName, -1, 0, 1, 0);
+  }
+  int flags = protocol.Element.makeFlags(
+      isAbstract: isAbstract,
+      isDeprecated: isDeprecated,
+      isPrivate: Identifier.isPrivateName(name));
+  return new protocol.Element(kind, name, flags,
+      location: location,
+      parameters: parameters,
+      returnType: nameForType(returnType));
+}
+
+/**
+ * Create a new suggestion for the given [fieldDecl]. Return the new suggestion
+ * or `null` if it could not be created.
+ */
+CompletionSuggestion createLocalFieldSuggestion(
+    Source source, FieldDeclaration fieldDecl, VariableDeclaration varDecl) {
+  bool deprecated = isDeprecated(fieldDecl) || isDeprecated(varDecl);
+  TypeName type = fieldDecl.fields.type;
+  return createLocalSuggestion(
+      varDecl.name, deprecated, DART_RELEVANCE_LOCAL_FIELD, type,
+      classDecl: fieldDecl.parent,
+      element: createLocalElement(
+          source, protocol.ElementKind.FIELD, varDecl.name,
+          returnType: type, isDeprecated: deprecated));
+}
+
+/**
+ * Create a new suggestion based upon the given information. Return the new
+ * suggestion or `null` if it could not be created.
+ */
+CompletionSuggestion createLocalSuggestion(SimpleIdentifier id,
+    bool isDeprecated, int defaultRelevance, TypeName returnType,
+    {ClassDeclaration classDecl,
+    CompletionSuggestionKind kind = CompletionSuggestionKind.INVOCATION,
+    protocol.Element element}) {
+  if (id == null) {
+    return null;
+  }
+  String completion = id.name;
+  if (completion == null || completion.length <= 0 || completion == '_') {
+    return null;
+  }
+  CompletionSuggestion suggestion = new CompletionSuggestion(
+      kind,
+      isDeprecated ? DART_RELEVANCE_LOW : defaultRelevance,
+      completion,
+      completion.length,
+      0,
+      isDeprecated,
+      false,
+      returnType: nameForType(returnType),
+      element: element);
+  if (classDecl != null) {
+    SimpleIdentifier classId = classDecl.name;
+    if (classId != null) {
+      String className = classId.name;
+      if (className != null && className.length > 0) {
+        suggestion.declaringType = className;
+      }
+    }
+  }
+  return suggestion;
+}
+
+/**
+ * Return `true` if the @deprecated annotation is present on the given [node].
+ */
+bool isDeprecated(AnnotatedNode node) {
+  if (node != null) {
+    NodeList<Annotation> metadata = node.metadata;
+    if (metadata != null) {
+      return metadata.any((Annotation a) {
+        return a.name is SimpleIdentifier && a.name.name == 'deprecated';
+      });
+    }
+  }
+  return false;
+}
+
+/**
+ * Return the name for the given [type].
+ */
+String nameForType(TypeName type) {
+  if (type == NO_RETURN_TYPE) {
+    return null;
+  }
+  if (type == null) {
+    return DYNAMIC;
+  }
+  Identifier id = type.name;
+  if (id == null) {
+    return DYNAMIC;
+  }
+  String name = id.name;
+  if (name == null || name.length <= 0) {
+    return DYNAMIC;
+  }
+  TypeArgumentList typeArgs = type.typeArguments;
+  if (typeArgs != null) {
+    //TODO (danrubel) include type arguments
+  }
+  return name;
+}