Implement MethodMirror.metadata.

dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart

 // Copyright (c) 2012, 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 js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 1143 matching lines @@
     assert(invariant(member, member.isDeclaration));
     // TODO(floitsch): we don't need to deal with members of
     // uninstantiated classes, that have been overwritten by subclasses.
 
     if (member.isFunction()
         || member.isGenerativeConstructorBody()
         || member.isAccessor()) {
       if (member.isAbstract(compiler)) return;
       jsAst.Expression code = backend.generatedCode[member];
       if (code == null) return;
-      builder.addProperty(namer.getName(member), code);
+      String name = namer.getName(member);
+      builder.addProperty(name, code);
       code = backend.generatedBailoutCode[member];
       if (code != null) {
         builder.addProperty(namer.getBailoutName(member), code);
       }
       FunctionElement function = member;
       FunctionSignature parameters = function.computeSignature(compiler);
       if (!parameters.optionalParameters.isEmpty) {
         addParameterStubs(member, builder.addProperty);
       }
+      var metadata = buildMetadataFunction(member);
+      if (metadata != null) {
+        builder.addProperty('@$name', metadata);
+      }
     } else if (!member.isField()) {
       compiler.internalError('unexpected kind: "${member.kind}"',
                              element: member);
     }
     emitExtraAccessors(member, builder);
   }
 
   /**
    * Documentation wanted -- johnniwinther
    *
@@ skipping 605 matching lines @@
     Iterable<Element> elements =
         backend.generatedCode.keys.where(isStaticFunction);
     Set<Element> pendingElementsWithBailouts =
         backend.generatedBailoutCode.keys
             .where(isStaticFunction)
             .toSet();
 
     for (Element element in Elements.sortedByPosition(elements)) {
       CodeBuffer buffer = bufferForElement(element, eagerBuffer);
       jsAst.Expression code = backend.generatedCode[element];
-      emitStaticFunction(buffer, namer.getName(element), code);
+      String name = namer.getName(element);
+      emitStaticFunction(buffer, name, code);
+      var metadata = buildMetadataFunction(element);
+      if (metadata != null) {
+        buffer.write(',$n$n"@$name":$_');
+        buffer.write(jsAst.prettyPrint(metadata, compiler));
+      }
       jsAst.Expression bailoutCode = backend.generatedBailoutCode[element];
       if (bailoutCode != null) {
         pendingElementsWithBailouts.remove(element);
         emitStaticFunction(buffer, namer.getBailoutName(element), bailoutCode);
       }
     }
 
     if (!pendingElementsWithBailouts.isEmpty) {
       addComment('pendingElementsWithBailouts', eagerBuffer);
     }
@@ skipping 1435 matching lines @@
     var data = reflectionData[i];
     var name = data[0];
     var uri = data[1];
     var metadata = data[2];
     var descriptor = data[3];
     var classes = [];
     var functions = [];
     for (var property in descriptor) {
       if (!hasOwnProperty.call(descriptor, property)) continue;
       var element = descriptor[property];
-      if (typeof element === "function") {
+      if (property.substring(0, 1) == "@") {
+        property = property.substring(1);
+        ${namer.CURRENT_ISOLATE}[property]["${namer.metadataField}"] = element;
+      } else if (typeof element === "function") {
         ${namer.CURRENT_ISOLATE}[property] = element;
         functions.push(property);
       } else {
-        $classesCollector[property] = element;
+        var newDesc = {}
+        for (var prop in element) {
+          if (!hasOwnProperty.call(element, prop)) continue;
+          if (prop.substring(0, 1) == "@" && prop != "@") {
+            newDesc[prop.substring(1)]["${namer.metadataField}"] ='''
+'''element[prop];
+          } else {
+            newDesc[prop] = element[prop];
+          }
+        }
+        $classesCollector[property] = newDesc;
         classes.push(property);
         classes.push(element[""]);
       }
     }
     libraries.push([name, uri, classes, functions, metadata]);
   }
 })''';
   }
 }
 
 const String GENERATED_BY = """
 // Generated by dart2js, the Dart to JavaScript compiler.
 """;
 
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;