Add JSNative utility class with static methods methods to efficiently manipulate typed JSInterop objects in cases where the member name is not known statically. These methods would be extension methods on JSObject if Dart supported extension methods. Update package js to export these methods. Implement in Dart2JS. Implement JS$ in dart2js.

BUG=
R=alanknight@google.com, sra@google.com

Review URL: https://codereview.chromium.org/2150313003 .

Author: jacob314

pkg/compiler/lib/src/js_backend/native_data.dart

@@ -35,6 +35,10 @@ class NativeData {
   Map<MemberElement, NativeBehavior> nativeFieldStoreBehavior =
       <FieldElement, NativeBehavior>{};
 
+  /// Prefix used to escape JS names that are not valid Dart names
+  /// when using JSInterop.
+  static const String _jsInteropEscapePrefix = r'JS$';
+
   /// Returns `true` if [element] is explicitly marked as part of JsInterop.
   bool _isJsInterop(Element element) {
     return jsInteropNames.containsKey(element.declaration);
@@ -93,7 +97,7 @@ class NativeData {
     if (jsInteropName != null && jsInteropName.isNotEmpty) {
       return jsInteropName;
     }
-    return element.isLibrary ? 'self' : element.name;
+    return element.isLibrary ? 'self' : getUnescapedJSInteropName(element.name);
   }
 
   /// Computes the name for [element] to use in the generated JavaScript. This
@@ -216,4 +220,12 @@ class NativeData {
       FieldElement field, NativeBehavior behavior) {
     nativeFieldStoreBehavior[field] = behavior;
   }
+
+  /// Apply JS$ escaping scheme to convert possible escaped Dart names into
+  /// JS names.
+  String getUnescapedJSInteropName(String name) {
+    return name.startsWith(_jsInteropEscapePrefix)
+        ? name.substring(_jsInteropEscapePrefix.length)
+        : name;
+  }
 }

pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart

@@ -345,6 +345,8 @@ class ProgramBuilder {
       for (Element e in elements) {
         if (e is ClassElement && backend.isJsInterop(e)) {
           e.declaration.forEachMember((_, Element member) {
+            var jsName =
+                backend.nativeData.getUnescapedJSInteropName(member.name);
             if (!member.isInstanceMember) return;
             if (member.isGetter || member.isField || member.isFunction) {
               var selectors =
@@ -354,7 +356,7 @@ class ProgramBuilder {
                   var stubName = namer.invocationName(selector);
                   if (stubNames.add(stubName.key)) {
                     interceptorClass.callStubs.add(_buildStubMethod(stubName,
-                        js.js('function(obj) { return obj.# }', [member.name]),
+                        js.js('function(obj) { return obj.# }', [jsName]),
                         element: member));
                   }
                 }
@@ -367,10 +369,8 @@ class ProgramBuilder {
               if (selectors != null && !selectors.isEmpty) {
                 var stubName = namer.setterForElement(member);
                 if (stubNames.add(stubName.key)) {
-                  interceptorClass.callStubs.add(_buildStubMethod(
-                      stubName,
-                      js.js('function(obj, v) { return obj.# = v }',
-                          [member.name]),
+                  interceptorClass.callStubs.add(_buildStubMethod(stubName,
+                      js.js('function(obj, v) { return obj.# = v }', [jsName]),
                       element: member));
                 }
               }
@@ -447,7 +447,7 @@ class ProgramBuilder {
                   interceptorClass.callStubs.add(_buildStubMethod(
                       stubName,
                       js.js('function(receiver, #) { return receiver.#(#) }',
-                          [parameters, member.name, parameters]),
+                          [parameters, jsName, parameters]),
                       element: member));
                 }
               }

pkg/compiler/lib/src/native/native.dart

@@ -19,6 +19,7 @@ const Iterable<String> _allowedDartSchemePaths = const <String>[
   'html_common',
   'indexed_db',
   'js',
+  'js_util',
   'svg',
   '_native_typed_data',
   'web_audio',

pkg/compiler/lib/src/ssa/builder.dart

@@ -5619,14 +5619,15 @@ class SsaBuilder extends ast.Visitor
       var filteredArguments = <HInstruction>[];
       var parameterNameMap = new Map<String, js.Expression>();
       params.orderedForEachParameter((ParameterElement parameter) {
-        // TODO(jacobr): throw if parameter names do not match names of property
-        // names in the class.
+        // TODO(jacobr): consider throwing if parameter names do not match
+        // names of properties in the class.
         assert(parameter.isNamed);
         HInstruction argument = arguments[i];
         if (argument != null) {
           filteredArguments.add(argument);
-          parameterNameMap[parameter.name] =
-              new js.InterpolatedExpression(positions++);
+          var jsName =
+              backend.nativeData.getUnescapedJSInteropName(parameter.name);
+          parameterNameMap[jsName] = new js.InterpolatedExpression(positions++);
         }
         i++;
       });

pkg/js/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.6.1
+* Add js_util library of utility methods to efficiently manipulate typed
+  JavaScript interop objects in cases where the member name is not known
+  statically. These methods would be extension methods on JSObject if
+  Dart supported extension methods.
+
 ## 0.6.0
 
  * Version 0.6.0 is a complete rewrite of `package:js`.

pkg/js/lib/js_util.dart

@@ -0,0 +1,8 @@
+// Copyright (c) 2016, 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.
+
+/// Allows interoperability with Javascript APIs.
+library js_util;
+
+export 'dart:js_util';

pkg/js/pubspec.yaml

@@ -1,5 +1,5 @@
 name: js
-version: 0.6.0
+version: 0.6.1
 authors:
 - Dart Team <misc@dartlang.org>
 description: Access JavaScript from Dart.

runtime/bin/bin.gypi

@@ -11,6 +11,7 @@
     'html_cc_file': '<(gen_source_dir)/html_gen.cc',
     'html_common_cc_file': '<(gen_source_dir)/html_common_gen.cc',
     'js_cc_file': '<(gen_source_dir)/js_gen.cc',
+    'js_util_cc_file': '<(gen_source_dir)/js_util_gen.cc',
     'blink_cc_file': '<(gen_source_dir)/blink_gen.cc',
     'indexeddb_cc_file': '<(gen_source_dir)/indexeddb_gen.cc',
     'cached_patches_cc_file': '<(gen_source_dir)/cached_patches_gen.cc',
@@ -233,6 +234,38 @@
       },
       ]
     },
+    {
+      'target_name': 'generate_js_util_cc_file',
+      'type': 'none',
+      'toolsets':['host'],
+      'sources': [
+      '../../sdk/lib/js_util/dartium/js_util_dartium.dart',
+      ],
+      'actions': [
+      {
+        'action_name': 'generate_js_util_cc',
+        'inputs': [
+        '../tools/gen_library_src_paths.py',
+        '<(builtin_in_cc_file)',
+        '<@(_sources)',
+        ],
+        'outputs': [
+        '<(js_util_cc_file)',
+        ],
+        'action': [
+        'python',
+        'tools/gen_library_src_paths.py',
+        '--output', '<(js_util_cc_file)',
+        '--input_cc', '<(builtin_in_cc_file)',
+        '--include', 'bin/builtin.h',
+        '--var_name', 'dart::bin::Builtin::js_util_source_paths_',
+        '--library_name', 'dart:js_util',
+        '<@(_sources)',
+        ],
+        'message': 'Generating ''<(js_util_cc_file)'' file.'
+      },
+      ]
+    },
     {
       'target_name': 'generate_blink_cc_file',
       'type': 'none',
@@ -500,6 +533,7 @@
         'generate_html_cc_file#host',
         'generate_html_common_cc_file#host',
         'generate_js_cc_file#host',
+        'generate_js_util_cc_file#host',
         'generate_blink_cc_file#host',
         'generate_indexeddb_cc_file#host',
         'generate_cached_patches_cc_file#host',
@@ -1262,6 +1296,7 @@
         '<(html_cc_file)',
         '<(html_common_cc_file)',
         '<(js_cc_file)',
+        '<(js_util_cc_file)',
         '<(blink_cc_file)',
         '<(indexeddb_cc_file)',
         '<(cached_patches_cc_file)',

runtime/bin/builtin.cc

@@ -24,6 +24,7 @@ Builtin::builtin_lib_props Builtin::builtin_libraries_[] = {
   { "dart:html", html_source_paths_, NULL, NULL, true },
   { "dart:html_common", html_common_source_paths_, NULL, NULL, true},
   { "dart:js", js_source_paths_, NULL, NULL, true},
+  { "dart:js_util", js_util_source_paths_, NULL, NULL, true},
   { "dart:_blink", blink_source_paths_, NULL, NULL, true },
   { "dart:indexed_db", indexeddb_source_paths_, NULL, NULL, true },
   { "cached_patches.dart", cached_patches_source_paths_, NULL, NULL, true },

runtime/bin/builtin.h

@@ -74,6 +74,7 @@ class Builtin {
   static const char* html_source_paths_[];
   static const char* html_common_source_paths_[];
   static const char* js_source_paths_[];
+  static const char* js_util_source_paths_[];
   static const char* blink_source_paths_[];
   static const char* indexeddb_source_paths_[];
   static const char* cached_patches_source_paths_[];

sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart

@@ -116,6 +116,12 @@ const Map<String, LibraryInfo> libraries = const {
       maturity: Maturity.STABLE,
       dart2jsPath: "js/dart2js/js_dart2js.dart"),
 
+  "js_util": const LibraryInfo(
+      "js_util/dartium/js_util_dartium.dart",
+      categories: "Client",
+      maturity: Maturity.STABLE,
+      dart2jsPath: "js_util/dart2js/js_util_dart2js.dart"),
+
   "math": const LibraryInfo(
       "math/math.dart",
       categories: "Client,Server,Embedded",

sdk/lib/dart2dart.platform

@@ -25,6 +25,7 @@ indexed_db: indexed_db/dart2js/indexed_db_dart2js.dart
 io: io/io.dart
 isolate: isolate/isolate.dart
 js: js/dart2js/js_dart2js.dart
+js_util: js_util/dart2js/js_util_dart2js.dart
 math: math/math.dart
 mirrors: mirrors/mirrors.dart
 nativewrappers: html/dart2js/nativewrappers.dart

sdk/lib/dart_client.platform

@@ -26,6 +26,7 @@ indexed_db: indexed_db/dart2js/indexed_db_dart2js.dart
 io: unsupported:
 isolate: isolate/isolate.dart
 js: js/dart2js/js_dart2js.dart
+js_util: js_util/dart2js/js_util_dart2js.dart
 math: math/math.dart
 mirrors: mirrors/mirrors.dart
 nativewrappers: html/dart2js/nativewrappers.dart

sdk/lib/dart_shared.platform

@@ -24,6 +24,7 @@ indexed_db: indexed_db/dart2js/indexed_db_dart2js.dart
 io: io/io.dart
 isolate: isolate/isolate.dart
 js: js/dart2js/js_dart2js.dart
+js_util: js_util/dart2js/js_util_dart2js.dart
 math: math/math.dart
 mirrors: mirrors/mirrors.dart
 nativewrappers: html/dart2js/nativewrappers.dart

sdk/lib/js/dart2js/js_dart2js.dart

@@ -707,7 +707,7 @@ _callDartFunctionFastCaptureThis(callback, self, List arguments) {
   return Function.apply(callback, [self]..addAll(arguments));
 }
 
-Function /*=F*/ allowInterop/*<F extends Function>*/(Function /*=F*/ f) {
+Function/*=F*/ allowInterop/*<F extends Function>*/(Function/*=F*/ f) {
   if (JS('bool', 'typeof(#) == "function"', f)) {
     // Already supports interop, just use the existing function.
     return f;