Better mirrors support for mixins and private fields

pkg/dev_compiler/tool/input_sdk/lib/internal/symbol.dart

 // Copyright (c) 2013, 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.
 
 part of dart._internal;
 
 /**
  * Implementation of [core.Symbol].  This class uses the same name as
  * a core class so a user can't tell the difference.
  *
  * The purpose of this class is to hide [_name] from user code, but
  * make it accessible to Dart platform code via the static method
  * [getName].
  */
 class Symbol implements core.Symbol {
   final String _name;
 
+  // Used internally by DDC to map ES6 symbols to Dart.
+  final dynamic _nativeSymbol;
+
   /**
    * Source of RegExp matching Dart reserved words.
    *
    * Reserved words are not allowed as identifiers.
    */
   static const String reservedWordRE =
       r'(?:assert|break|c(?:a(?:se|tch)|lass|on(?:st|tinue))|d(?:efault|o)|'
       r'e(?:lse|num|xtends)|f(?:alse|inal(?:ly)?|or)|i[fns]|n(?:ew|ull)|'
       r'ret(?:hrow|urn)|s(?:uper|witch)|t(?:h(?:is|row)|r(?:ue|y))|'
       r'v(?:ar|oid)|w(?:hile|ith))';
@@ skipping 60 matching lines @@
   // which matches any identifier.
 
   /**
    * RegExp that validates a non-empty symbol.
    *
    * Private symbols are accepted.
    *
    * The empty symbol is handled before this regexp is used, and is not
    * accepted.
    */
-  static final RegExp symbolPattern = new RegExp(
-      '^(?:$operatorRE\$|$identifierRE(?:=?\$|[.](?!\$)))+?\$');
+  static final RegExp symbolPattern =
+      new RegExp('^(?:$operatorRE\$|$identifierRE(?:=?\$|[.](?!\$)))+?\$');
 
   external const Symbol(String name);
 
+  external const Symbol.es6(String name, nativeSymbol);
+
   /**
    * Platform-private method used by the mirror system to create
    * otherwise invalid names.
    */
-  const Symbol.unvalidated(this._name);
+  const Symbol.unvalidated(this._name) : this._nativeSymbol = null;
 
   // This is called by dart2js.
   Symbol.validated(String name)
-      : this._name = validatePublicSymbol(name);
+      : this._name = validatePublicSymbol(name),
+        this._nativeSymbol = null;
 
-  bool operator ==(Object other) => other is Symbol && _name == other._name;
+  bool operator ==(Object other) =>
+      other is Symbol &&
+      _name == other._name &&
+      _nativeSymbol == other._nativeSymbol;
 
   external int get hashCode;
 
   toString() => 'Symbol("$_name")';
 
   /// Platform-private accessor which cannot be called from user libraries.
   static String getName(Symbol symbol) => symbol._name;
 
+  static dynamic getNativeSymbol(Symbol symbol) => symbol._nativeSymbol;
+
   static String validatePublicSymbol(String name) {
     if (name.isEmpty || publicSymbolPattern.hasMatch(name)) return name;
     if (name.startsWith('_')) {
       // There may be other private parts in a qualified name than the first
       // one, but this is a common case that deserves a specific error
       // message.
       throw new ArgumentError('"$name" is a private identifier');
     }
-    throw new ArgumentError(
-        '"$name" is not a valid (qualified) symbol name');
+    throw new ArgumentError('"$name" is not a valid (qualified) symbol name');
   }
 
   /**
    * Checks whether name is a valid symbol name.
    *
    * This test allows both private and non-private symbols.
    */
   static bool isValidSymbol(String name) {
     return (name.isEmpty || symbolPattern.hasMatch(name));
   }
 }