Element.fromEngine() constructor.

pkg/analysis_server/lib/src/computer/element.dart

 // 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 computer.element;
 
 import 'package:analysis_server/src/constants.dart';
+import 'package:analyzer/src/generated/element.dart' as engine;
+import 'package:analyzer/src/generated/utilities_dart.dart' as engine;
 
 
 /**
  * Information about an element.
  */
 class Element {
   static const List<Element> EMPTY_ARRAY = const <Element>[];
 
-  static const int _FLAG_ABSTRACT = 0x01;
-  static const int _FLAG_CONST = 0x02;
-  static const int _FLAG_DEPRECATED = 0x20;
-  static const int _FLAG_FINAL = 0x04;
-  static const int _FLAG_PRIVATE = 0x10;
-  static const int _FLAG_STATIC = 0x08;
+  static const int FLAG_ABSTRACT = 0x01;
+  static const int FLAG_CONST = 0x02;
+  static const int FLAG_DEPRECATED = 0x20;
+  static const int FLAG_FINAL = 0x04;
+  static const int FLAG_PRIVATE = 0x10;
+  static const int FLAG_STATIC = 0x08;
 
   final bool isAbstract;
   final bool isConst;
   final bool isDeprecated;
   final bool isFinal;
   final bool isPrivate;
   final bool isStatic;
 
   /**
    * The kind of the element.
@@ skipping 26 matching lines @@
    * The return type of the element.
    * If the element is not a method or function then `null`.
    * If the element does not have a declared return type, then an empty string.
    */
   final String returnType;
 
   Element(this.kind, this.name, this.offset, this.length, this.isPrivate,
       this.isDeprecated, {this.parameters, this.returnType, this.isAbstract: false,
       this.isConst: false, this.isFinal: false, this.isStatic: false});
 
+  factory Element.fromEngine(engine.Element element) {
+    String name = element.displayName;
+    int nameLength = name != null ? name.length : 0;
+    String elementParameters = _getParametersString(element);
+    String elementReturnType = _getReturnTypeString(element);
+    return new Element(ElementKind.valueOfEngine(element.kind), name,
+        element.nameOffset, nameLength, element.isPrivate, element.isDeprecated,
+        parameters: elementParameters, returnType: elementReturnType, isAbstract:
+        _isAbstract(element), isConst: _isConst(element), isFinal: _isFinal(element),
+        isStatic: _isStatic(element));
+  }
+
   factory Element.fromJson(Map<String, Object> map) {
     ElementKind kind = ElementKind.valueOf(map[KIND]);
     int flags = map[FLAGS];
     return new Element(kind, map[NAME], map[OFFSET], map[LENGTH], _hasFlag(
-        flags, _FLAG_PRIVATE), _hasFlag(flags, _FLAG_DEPRECATED), parameters:
+        flags, FLAG_PRIVATE), _hasFlag(flags, FLAG_DEPRECATED), parameters:
         map[PARAMETERS], returnType: map[RETURN_TYPE], isAbstract: _hasFlag(flags,
-        _FLAG_ABSTRACT), isConst: _hasFlag(flags, _FLAG_CONST), isFinal: _hasFlag(flags,
-        _FLAG_FINAL), isStatic: _hasFlag(flags, _FLAG_STATIC));
+        FLAG_ABSTRACT), isConst: _hasFlag(flags, FLAG_CONST), isFinal: _hasFlag(flags,
+        FLAG_FINAL), isStatic: _hasFlag(flags, FLAG_STATIC));
   }
 
   int get flags {
     int flags = 0;
-    if (isAbstract) flags |= _FLAG_ABSTRACT;
-    if (isConst) flags |= _FLAG_CONST;
-    if (isFinal) flags |= _FLAG_FINAL;
-    if (isStatic) flags |= _FLAG_STATIC;
-    if (isPrivate) flags |= _FLAG_PRIVATE;
-    if (isDeprecated) flags |= _FLAG_DEPRECATED;
+    if (isAbstract) flags |= FLAG_ABSTRACT;
+    if (isConst) flags |= FLAG_CONST;
+    if (isFinal) flags |= FLAG_FINAL;
+    if (isStatic) flags |= FLAG_STATIC;
+    if (isPrivate) flags |= FLAG_PRIVATE;
+    if (isDeprecated) flags |= FLAG_DEPRECATED;
     return flags;
   }
 
   Map<String, Object> toJson() {
     Map<String, Object> json = {
       KIND: kind.name,
       NAME: name,
       OFFSET: offset,
       LENGTH: length,
       FLAGS: flags
     };
     if (parameters != null) {
       json[PARAMETERS] = parameters;
     }
     if (returnType != null) {
       json[RETURN_TYPE] = returnType;
     }
     return json;
   }
 
+  static String _getParametersString(engine.Element element) {
+    if (element is engine.ExecutableElement) {
+      var sb = new StringBuffer();

[Brian Wilkerson, 2014/06/25 13:50:08]

This duplicates code in engine.ExecutableElement. We should extract the code in
engine.ExecutableElement so that we have a single implementation of it.

[scheglov, 2014/06/25 17:20:46]

I've added TODO.

+      String closeOptionalString = '';
+      for (var parameter in element.parameters) {
+        if (sb.isNotEmpty) {
+          sb.write(', ');
+        }
+        if (closeOptionalString.isEmpty) {
+          if (parameter.kind == engine.ParameterKind.NAMED) {
+            sb.write('{');
+            closeOptionalString = '}';
+          }
+          if (parameter.kind == engine.ParameterKind.POSITIONAL) {
+            sb.write('[');
+            closeOptionalString = ']';
+          }
+        }
+        sb.write(parameter.toString());
+      }
+      sb.write(closeOptionalString);
+      return '(' + sb.toString() + ')';
+    } else {
+      return null;
+    }
+  }
+
+  static String _getReturnTypeString(engine.Element element) {
+    if ((element is engine.ExecutableElement)) {
+      return element.returnType.toString();
+    } else {
+      return null;
+    }
+  }
+
   static bool _hasFlag(int flags, int flag) => (flags & flag) != 0;
+
+  static bool _isAbstract(engine.Element element) {
+    if (element is engine.ClassElement) {

[Brian Wilkerson, 2014/06/25 13:50:08]

Code with lots of 'is' expressions is always suspect, even though it's sometimes
the better option. But in this case I think it makes sense to define
engine.Element.isAbstract() to return 'false' so that we can use polymorphism
rather than 'is' tests. Similarly for isConst, isFinal, and isStatic.

[scheglov, 2014/06/25 17:20:46]

I've added TODO.

+      return element.isAbstract;
+    }
+    if (element is engine.MethodElement) {
+      return element.isAbstract;
+    }
+    if (element is engine.PropertyAccessorElement) {
+      return element.isAbstract;
+    }
+    return false;
+  }
+
+  static bool _isConst(engine.Element element) {
+    if (element is engine.ConstructorElement) {
+      return element.isConst;
+    }
+    if (element is engine.VariableElement) {
+      return element.isConst;
+    }
+    return false;
+  }
+
+  static bool _isFinal(engine.Element element) {
+    if (element is engine.VariableElement) {
+      return element.isFinal;
+    }
+    return false;
+  }
+
+  static bool _isStatic(engine.Element element) {
+    if (element is engine.ExecutableElement) {
+      return element.isStatic;
+    }
+    if (element is engine.PropertyInducingElement) {
+      return element.isStatic;
+    }
+    return false;
+  }
 }
 
 
 /**
  * An enumeration of the kinds of elements.
  */
 class ElementKind {
   static const CLASS = const ElementKind('CLASS');
   static const CLASS_TYPE_ALIAS = const ElementKind('CLASS_TYPE_ALIAS');
   static const COMPILATION_UNIT = const ElementKind('COMPILATION_UNIT');
   static const CONSTRUCTOR = const ElementKind('CONSTRUCTOR');
   static const FIELD = const ElementKind('FIELD');
   static const FUNCTION = const ElementKind('FUNCTION');
   static const FUNCTION_TYPE_ALIAS = const ElementKind('FUNCTION_TYPE_ALIAS');
   static const GETTER = const ElementKind('GETTER');
   static const LIBRARY = const ElementKind('LIBRARY');
   static const METHOD = const ElementKind('METHOD');
   static const SETTER = const ElementKind('SETTER');
   static const TOP_LEVEL_VARIABLE = const ElementKind('TOP_LEVEL_VARIABLE');
   static const UNIT_TEST_CASE = const ElementKind('UNIT_TEST_CASE');
   static const UNIT_TEST_GROUP = const ElementKind('UNIT_TEST_GROUP');
   static const UNKNOWN = const ElementKind('UNKNOWN');
 
   final String name;
 
   const ElementKind(this.name);
 
+  @override
+  String toString() => name;
+
   static ElementKind valueOf(String name) {
     if (CLASS.name == name) return CLASS;
     if (CLASS_TYPE_ALIAS.name == name) return CLASS_TYPE_ALIAS;
     if (COMPILATION_UNIT.name == name) return COMPILATION_UNIT;
     if (CONSTRUCTOR.name == name) return CONSTRUCTOR;
     if (FIELD.name == name) return FIELD;
     if (FUNCTION.name == name) return FUNCTION;
     if (FUNCTION_TYPE_ALIAS.name == name) return FUNCTION_TYPE_ALIAS;
     if (GETTER.name == name) return GETTER;
     if (LIBRARY.name == name) return LIBRARY;
     if (METHOD.name == name) return METHOD;
     if (SETTER.name == name) return SETTER;
     if (TOP_LEVEL_VARIABLE.name == name) return TOP_LEVEL_VARIABLE;
     if (UNIT_TEST_CASE.name == name) return UNIT_TEST_CASE;
     if (UNIT_TEST_GROUP.name == name) return UNIT_TEST_GROUP;
     if (UNKNOWN.name == name) return UNKNOWN;
     throw new ArgumentError('Unknown ElementKind: $name');
   }
+
+  static ElementKind valueOfEngine(engine.ElementKind kind) {

[Brian Wilkerson, 2014/06/25 13:50:08]

What's the value of having two implementations of ElementKind?

[scheglov, 2014/06/25 17:20:46]

Well, there isn't.
But ElementKind here is the one the server API defines.
Plus UNIT_TEST_CASE is not a part of Engine's ElementKind.

+    if (kind == engine.ElementKind.CLASS) {
+      return CLASS;
+    }
+    if (kind == engine.ElementKind.COMPILATION_UNIT) {
+      return COMPILATION_UNIT;
+    }
+    if (kind == engine.ElementKind.CONSTRUCTOR) {
+      return CONSTRUCTOR;
+    }
+    if (kind == engine.ElementKind.FIELD) {
+      return FIELD;
+    }
+    if (kind == engine.ElementKind.FUNCTION) {
+      return FUNCTION;
+    }
+    if (kind == engine.ElementKind.FUNCTION_TYPE_ALIAS) {
+      return FUNCTION_TYPE_ALIAS;
+    }
+    if (kind == engine.ElementKind.GETTER) {
+      return GETTER;
+    }
+    if (kind == engine.ElementKind.LIBRARY) {
+      return LIBRARY;
+    }
+    if (kind == engine.ElementKind.METHOD) {
+      return METHOD;
+    }
+    if (kind == engine.ElementKind.SETTER) {
+      return SETTER;
+    }
+    if (kind == engine.ElementKind.TOP_LEVEL_VARIABLE) {
+      return TOP_LEVEL_VARIABLE;
+    }
+    return UNKNOWN;
+  }
 }