Add @JSName annotation for native fields and methods - second try.

sdk/lib/_internal/compiler/implementation/native_handler.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.
 
 library native;
 
 import 'dart:uri';
 import 'dart2jslib.dart' hide SourceString;
 import 'elements/elements.dart';
 import 'js_backend/js_backend.dart';
@@ skipping 17 matching lines @@
 }
 
 
 /**
  * This could be an abstract class but we use it as a stub for the dart_backend.
  */
 class NativeEnqueuer {
   /// Initial entry point to native enqueuer.
   void processNativeClasses(Collection<LibraryElement> libraries) {}
 
+  /// Notification of a main Enqueuer worklist element.  For methods, adds
+  /// information from metadata attributes, and computes types instantiated due
+  /// to calling the method.
   void registerElement(Element element) {}
 
-  /// Method is a member of a native class.
-  void registerMethod(Element method) {}
+  /// Notification of native field.  Adds information from metadata attributes.
+  void registerField(Element field) {}
 
-  /// Compute types instantiated due to getting a native field.
+  /// Computes types instantiated due to getting a native field.
   void registerFieldLoad(Element field) {}
 
-  /// Compute types instantiated due to setting a native field.
+  /// Computes types instantiated due to setting a native field.
   void registerFieldStore(Element field) {}
 
   /**
    * Handles JS-calls, which can be an instantiation point for types.
    *
    * For example, the following code instantiates and returns native classes
    * that are `_DOMWindowImpl` or a subtype.
    *
    *     JS('_DOMWindowImpl', 'window')
    *
@@ skipping 29 matching lines @@
   final queue = new Queue();
   bool flushing = false;
 
 
   final Enqueuer world;
   final Compiler compiler;
   final bool enableLiveTypeAnalysis;
 
   ClassElement _annotationCreatesClass;
   ClassElement _annotationReturnsClass;
+  ClassElement _annotationJsNameClass;
 
   /// Subclasses of [NativeEnqueuerBase] are constructed by the backend.
   NativeEnqueuerBase(this.world, this.compiler, this.enableLiveTypeAnalysis);
 
   void processNativeClasses(Collection<LibraryElement> libraries) {
     libraries.forEach(processNativeClassesInLibrary);
     if (!enableLiveTypeAnalysis) {
       nativeClasses.forEach((c) => enqueueClass(c, 'forced'));
       flushQueue();
     }
   }
 
   void processNativeClassesInLibrary(LibraryElement library) {
     // Use implementation to ensure the inclusion of injected members.
     library.implementation.forEachLocalMember((Element element) {
       if (element.kind == ElementKind.CLASS) {
         ClassElement classElement = element;
         if (classElement.isNative()) {
           nativeClasses.add(classElement);
           unusedClasses.add(classElement);
 
           // Resolve class to ensure the class has valid inheritance info.
           classElement.ensureResolved(compiler);
         }
       }
     });
   }
 
   ClassElement get annotationCreatesClass {
-    if (_annotationCreatesClass == null) findAnnotationClasses();
+    findAnnotationClasses();
     return _annotationCreatesClass;
   }
 
   ClassElement get annotationReturnsClass {
-    if (_annotationReturnsClass == null) findAnnotationClasses();
+    findAnnotationClasses();
     return _annotationReturnsClass;
   }
 
+  ClassElement get annotationJsNameClass {
+    findAnnotationClasses();
+    return _annotationJsNameClass;
+  }
+
   void findAnnotationClasses() {
+    if (_annotationCreatesClass != null) return;
     ClassElement find(name) {
       Element e = compiler.findHelper(name);
       if (e == null || e is! ClassElement) {
         compiler.cancel("Could not find implementation class '${name}'");
       }
       return e;
     }
     _annotationCreatesClass = find(const SourceString('Creates'));
     _annotationReturnsClass = find(const SourceString('Returns'));
+    _annotationJsNameClass = find(const SourceString('JSName'));
   }
 
+  /// Returns the JSName annotation string or `null` if no JSName annotation is
+  /// present.
+  String findJsNameFromAnnotation(Element element) {
+    String name = null;
+    ClassElement annotationClass = annotationJsNameClass;
+    for (Link<MetadataAnnotation> link = element.metadata;
+         !link.isEmpty;
+         link = link.tail) {
+      MetadataAnnotation annotation = link.head.ensureResolved(compiler);
+      var value = annotation.value;
+      if (value is! ConstructedConstant) continue;
+      if (value.type is! InterfaceType) continue;
+      if (!identical(value.type.element, annotationClass)) continue;
+
+      var fields = value.fields;
+      // TODO(sra): Better validation of the constant.
+      if (fields.length != 1 || fields[0] is! StringConstant) {
+        PartialMetadataAnnotation partial = annotation;
+        compiler.cancel(
+            'Annotations needs one string: ${partial.parseNode(compiler)}');
+      }
+      String specString = fields[0].toDartString().slowToString();
+      if (name == null) {
+        name = specString;
+      } else {
+        PartialMetadataAnnotation partial = annotation;
+        compiler.cancel(
+            'Too many JSName annotations: ${partial.parseNode(compiler)}');
+      }
+    }
+    return name;
+  }
 
   enqueueClass(ClassElement classElement, cause) {
     assert(unusedClasses.contains(classElement));
     unusedClasses.remove(classElement);
     pendingClasses.add(classElement);
     queue.add(() { processClass(classElement, cause); });
   }
 
   void flushQueue() {
     if (flushing) return;
@@ skipping 16 matching lines @@
     // Also parse the node to know all its methods because otherwise it will
     // only be parsed if there is a call to one of its constructors.
     classElement.parseNode(compiler);
 
     if (firstTime) {
       queue.add(onFirstNativeClass);
     }
   }
 
   registerElement(Element element) {
-    if (element.isFunction()) return registerMethod(element);
+    if (element.isFunction() || element.isGetter() || element.isSetter()) {
+      return registerMethod(element);
+    }
+  }
+
+  registerField(Element element) {
+    if (element.enclosingElement.isNative()) {
+      setNativeName(element);
+    }
   }
 
   registerMethod(Element method) {
     if (isNativeMethod(method)) {
+      setNativeName(method);
       processNativeBehavior(
           NativeBehavior.ofMethod(method, compiler),
           method);
       flushQueue();
     }
   }
 
+  /// Sets the native name of [element], either from an annotation, or
+  /// defaulting to the Dart name.
+  void setNativeName(Element element) {
+    String name = findJsNameFromAnnotation(element);
+    if (name == null) name = element.name.slowToString();
+    element.setNative(name);
+  }
+
   bool isNativeMethod(Element element) {
     if (!element.getLibrary().canUseNative) return false;
     // Native method?
     return compiler.withCurrentElement(element, () {
       Node node = element.parseNode(compiler);
       if (node is! FunctionExpression) return false;
       node = node.body;
       Token token = node.getBeginToken();
       if (identical(token.stringValue, 'native')) return true;
       return false;
@@ skipping 456 matching lines @@
     listener.endLiteralString(0);
     token = token.next;
   }
   listener.endReturnStatement(hasExpression, begin, token);
   // TODO(ngeoffray): expect a ';'.
   // Currently there are method with both native marker and Dart body.
   return token.next;
 }
 
 SourceString checkForNativeClass(ElementListener listener) {
-  SourceString nativeName;
+  SourceString nativeTagInfo;
   Node node = listener.nodes.head;
   if (node != null
       && node.asIdentifier() != null
       && node.asIdentifier().source.stringValue == 'native') {
-    nativeName = node.asIdentifier().token.next.value;
+    nativeTagInfo = node.asIdentifier().token.next.value;
     listener.popNode();
   }
-  return nativeName;
+  return nativeTagInfo;
 }
 
 bool isOverriddenMethod(FunctionElement element,
                         ClassElement cls,
                         NativeEmitter nativeEmitter) {
   List<ClassElement> subtypes = nativeEmitter.subtypes[cls];
   if (subtypes == null) return false;
   for (ClassElement subtype in subtypes) {
     if (subtype.lookupLocalMember(element.name) != null) return true;
   }
   return false;
 }
 
 final RegExp nativeRedirectionRegExp = new RegExp(r'^[a-zA-Z][a-zA-Z_$0-9]*$');
 
 void handleSsaNative(SsaBuilder builder, Expression nativeBody) {
   Compiler compiler = builder.compiler;
   FunctionElement element = builder.work.element;
-  element.setNative();
   NativeEmitter nativeEmitter = builder.emitter.nativeEmitter;
   // If what we're compiling is a getter named 'typeName' and the native
   // class is named 'DOMType', we generate a call to the typeNameOf
   // function attached on the isolate.
   // The DOM classes assume that their 'typeName' property, which is
   // not a JS property on the DOM types, returns the type name.
   if (element.name == const SourceString('typeName')
       && element.isGetter()
       && nativeEmitter.toNativeName(element.getEnclosingClass()) == 'DOMType') {
     Element helper =
         compiler.findHelper(const SourceString('getTypeNameOf'));
     builder.pushInvokeHelper1(helper, builder.localsHandler.readThis());
     builder.close(new HReturn(builder.pop())).addSuccessor(builder.graph.exit);
   }
 
   HInstruction convertDartClosure(Element parameter, FunctionType type) {
     HInstruction local = builder.localsHandler.readLocal(parameter);
     Constant arityConstant =
         builder.constantSystem.createInt(type.computeArity());
     HInstruction arity = builder.graph.addConstant(arityConstant);
     // TODO(ngeoffray): For static methods, we could pass a method with a
     // defined arity.
     Element helper = builder.interceptors.getClosureConverter();
     builder.pushInvokeHelper2(helper, local, arity);
     HInstruction closure = builder.pop();
     return closure;
   }
 
   // Check which pattern this native method follows:
-  // 1) foo() native; hasBody = false, isRedirecting = false
-  // 2) foo() native "bar"; hasBody = false, isRedirecting = true
-  // 3) foo() native "return 42"; hasBody = true, isRedirecting = false
+  // 1) foo() native;
+  //      hasBody = false, isRedirecting = false
+  // 2) foo() native "bar";
+  //      hasBody = false, isRedirecting = true, no longer supported.
+  // 3) foo() native "return 42";
+  //      hasBody = true, isRedirecting = false
   bool hasBody = false;
-  bool isRedirecting = false;
-  String nativeMethodName = element.name.slowToString();
+  assert(element.isNative());
+  String nativeMethodName = element.nativeName();
   if (nativeBody != null) {
     LiteralString jsCode = nativeBody.asLiteralString();
     String str = jsCode.dartString.slowToString();
     if (nativeRedirectionRegExp.hasMatch(str)) {
-      nativeMethodName = str;
-      isRedirecting = true;
-      nativeEmitter.addRedirectingMethod(element, nativeMethodName);
-    } else {
-      hasBody = true;
+      compiler.cancel("Deprecated syntax, use @JSName('name') instead.",
+                      node: nativeBody);
     }
+    hasBody = true;
   }
 
   if (!hasBody) {
     nativeEmitter.nativeMethods.add(element);
   }
 
   FunctionSignature parameters = element.computeSignature(builder.compiler);
   if (!hasBody) {
     List<String> arguments = <String>[];
     List<HInstruction> inputs = <HInstruction>[];
@@ skipping 49 matching lines @@
         builder.add(new HForeign(
             new DartString.literal('${parameter.name.slowToString()} = #'),
             const LiteralDartString('void'),
             <HInstruction>[jsClosure]));
       }
     });
     LiteralString jsCode = nativeBody.asLiteralString();
     builder.push(new HForeign.statement(jsCode.dartString, <HInstruction>[]));
   }
 }