fixes #173, ability to use native JS indexers

lib/src/utils.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.
 
 /// Holds a couple utility functions used at various places in the system.
 library dev_compiler.src.utils;
 
 import 'dart:io';
 
 import 'package:path/path.dart' as path;
@@ skipping 331 matching lines @@
 /// For example if we had the ClassDeclaration node for `FontElement`:
 ///
 ///    @JsName('HTMLFontElement')
 ///    @deprecated
 ///    class FontElement { ... }
 ///
 /// We could match `@deprecated` with a test function like:
 ///
 ///    (v) => v.type.name == 'Deprecated' && v.type.element.library.isDartCore
 ///
-DartObjectImpl getAnnotationValue(
+DartObjectImpl findNodeAnnotation(
     AnnotatedNode node, bool test(DartObjectImpl value)) {

[vsm, 2015/05/20 19:15:29]

Could this just call findElementAnnotation(node.element)?

[Jennifer Messerly, 2015/05/20 19:25:32]

you'd think so, but AnnotatedNode doesn't have .element.
Of its three subtypes, Declaration and Directive both have a .element. However
VariableDeclarationList does not. I guess because of cases like:

    @deprecated
    var foo, bar, baz;

yet more reasons VariableDeclarationList is the most annoying thing ever :)
anyway, it does look like we could convert existing usage over to
findElementAnnotation, and just `.element` on the outside. does that work for
you?

[vsm, 2015/05/20 19:39:50]

sgtm

   for (var metadata in node.metadata) {
     ElementAnnotationImpl element = metadata.elementAnnotation;
     if (element == null) continue;
 
     var evalResult = element.evaluationResult;
     if (evalResult == null) continue;
 
     var value = evalResult.value;
     if (value != null && test(value)) return value;
   }
   return null;
 }
 
+/// Similar to [findNodeAnnotation] but starts from any element.
+DartObjectImpl findElementAnnotation(
+    Element element, bool test(DartObjectImpl value)) {
+  for (var metadata in element.metadata) {
+    var evalResult = metadata.evaluationResult;
+    if (evalResult == null) continue;
+
+    var value = evalResult.value;
+    if (value != null && test(value)) return value;
+  }
+  return null;
+}
+
 /// Given a constant [value], a [fieldName], and an [expectedType], returns the
 /// value of that field.
 ///
 /// If the field is missing or is not [expectedType], returns null.
 Object getConstantField(
     DartObjectImpl value, String fieldName, DartType expectedType) {
   if (value == null) return null;
   var f = value.fields[fieldName];
   return (f == null || f.type != expectedType) ? null : f.value;
 }
@@ skipping 76 matching lines @@
   int lineEnd = endLoc.offset;
   int unitEnd = unit.endToken.end;
   int lineNum = lineInfo.getLocation(lineEnd).lineNumber;
   while (lineEnd < unitEnd &&
       lineInfo.getLocation(++lineEnd).lineNumber == lineNum);
 
   var text = content.substring(start, end);
   var lineText = content.substring(lineStart, lineEnd);
   return new SourceSpanWithContext(startLoc, endLoc, text, lineText);
 }