feat(dart/transform): Use the best available Change Detectors

Enable pregenerated (for Dart) and JIT (for Js) change detectors when
possible. Previously we would always use `DynamicChangeDetector`s, but
these cause megamorphic calls and are therefore much slower.

Closes #502

modules/angular2/src/transform/common/directive_metadata_reader.dart

@@ -88,20 +88,20 @@ class _DirectiveMetadataVisitor extends Object
   }
 
   DirectiveMetadata get meta => DirectiveMetadata.create(
-    type: _type,
-    selector: _selector,
-    compileChildren: _compileChildren,
-    properties: _properties,
-    host: _host,
-    readAttributes: _readAttributes,
-    exportAs: _exportAs,
-    callOnDestroy: _callOnDestroy,
-    callOnChange: _callOnChange,
-    callOnCheck: _callOnCheck,
-    callOnInit: _callOnInit,
-    callOnAllChangesDone: _callOnAllChangesDone,
-    changeDetection: _changeDetection,
-    events: _events);
+      type: _type,
+      selector: _selector,
+      compileChildren: _compileChildren,
+      properties: _properties,
+      host: _host,
+      readAttributes: _readAttributes,
+      exportAs: _exportAs,
+      callOnDestroy: _callOnDestroy,
+      callOnChange: _callOnChange,
+      callOnCheck: _callOnCheck,
+      callOnInit: _callOnInit,
+      callOnAllChangesDone: _callOnAllChangesDone,
+      changeDetection: _changeDetection,
+      events: _events);
 
   @override
   Object visitAnnotation(Annotation node) {

modules/angular2/src/transform/common/options.dart

@@ -8,6 +8,9 @@ const DEFAULT_OPTIMIZATION_PHASES = 5;
 
 const CUSTOM_ANNOTATIONS_PARAM = 'custom_annotations';
 const ENTRY_POINT_PARAM = 'entry_points';
+const GENERATE_CHANGE_DETECTORS_PARAM = 'generate_change_detectors';
+const INIT_REFLECTOR_PARAM = 'init_reflector';
+const MIRROR_MODE_PARAM = 'mirror_mode';
 const OPTIMIZATION_PHASES_PARAM = 'optimization_phases';
 const REFLECTION_ENTRY_POINT_PARAM = 'reflection_entry_points';
 
@@ -32,6 +35,9 @@ class TransformerOptions {
   /// The [AnnotationMatcher] which is used to identify angular annotations.
   final AnnotationMatcher annotationMatcher;
 
+  /// Whether to create change detector classes for discovered `@View`s.
+  final bool generateChangeDetectors;
+
   /// The number of phases to spend optimizing output size.
   /// Each additional phase adds time to the transformation but may decrease
   /// final output size. There is a limit beyond which this will no longer
@@ -43,13 +49,15 @@ class TransformerOptions {
 
   TransformerOptions._internal(this.entryPoints, this.reflectionEntryPoints,
       this.modeName, this.mirrorMode, this.initReflector,
-      this.annotationMatcher, this.optimizationPhases);
+      this.annotationMatcher, this.optimizationPhases,
+      this.generateChangeDetectors);
 
   factory TransformerOptions(List<String> entryPoints,
       {List<String> reflectionEntryPoints, String modeName: 'release',
       MirrorMode mirrorMode: MirrorMode.none, bool initReflector: true,
       List<AnnotationDescriptor> customAnnotationDescriptors: const [],
-      int optimizationPhases: DEFAULT_OPTIMIZATION_PHASES}) {
+      int optimizationPhases: DEFAULT_OPTIMIZATION_PHASES,
+      bool generateChangeDetectors: true}) {
     if (reflectionEntryPoints == null || reflectionEntryPoints.isEmpty) {
       reflectionEntryPoints = entryPoints;
     }
@@ -58,6 +66,6 @@ class TransformerOptions {
     optimizationPhases = optimizationPhases.isNegative ? 0 : optimizationPhases;
     return new TransformerOptions._internal(entryPoints, reflectionEntryPoints,
         modeName, mirrorMode, initReflector, annotationMatcher,
-        optimizationPhases);
+        optimizationPhases, generateChangeDetectors);
   }
 }

modules/angular2/src/transform/common/options_reader.dart

@@ -10,10 +10,12 @@ TransformerOptions parseBarbackSettings(BarbackSettings settings) {
   var entryPoints = _readFileList(config, ENTRY_POINT_PARAM);
   var reflectionEntryPoints =
       _readFileList(config, REFLECTION_ENTRY_POINT_PARAM);
-  var initReflector = !config.containsKey('init_reflector') ||
-      config['init_reflector'] != false;
+  var initReflector =
+      _readBool(config, INIT_REFLECTOR_PARAM, defaultValue: true);
+  var generateChangeDetectors =
+      _readBool(config, GENERATE_CHANGE_DETECTORS_PARAM, defaultValue: true);
   String mirrorModeVal =
-      config.containsKey('mirror_mode') ? config['mirror_mode'] : '';
+      config.containsKey(MIRROR_MODE_PARAM) ? config[MIRROR_MODE_PARAM] : '';
   var mirrorMode = MirrorMode.none;
   switch (mirrorModeVal) {
     case 'debug':
@@ -34,7 +36,14 @@ TransformerOptions parseBarbackSettings(BarbackSettings settings) {
       mirrorMode: mirrorMode,
       initReflector: initReflector,
       customAnnotationDescriptors: _readCustomAnnotations(config),
-      optimizationPhases: optimizationPhases);
+      optimizationPhases: optimizationPhases,
+      generateChangeDetectors: generateChangeDetectors);
+}
+
+bool _readBool(Map config, String paramName, {bool defaultValue}) {
+  return config.containsKey(paramName)
+      ? config[paramName] != false
+      : defaultValue;
 }
 
 /// Cribbed from the polymer project.

modules/angular2/src/transform/template_compiler/change_detector_codegen.dart

@@ -14,15 +14,31 @@ import 'package:angular2/src/facade/lang.dart' show BaseException;
 /// This code should be kept in sync with the `ChangeDetectorJITGenerator`
 /// class. If you make updates here, please make equivalent changes there.
 class Codegen {
+  /// Stores the generated class definitions.
   final StringBuffer _buf = new StringBuffer();
+  /// Stores all generated initialization code.
+  final StringBuffer _initBuf = new StringBuffer();
+  /// The names of already generated classes.
+  final Set<String> _names = new Set<String>();
 
-  /// Generates a change detector class with name `changeDetectorTypeName`
-  /// which is used to detect changes in Objects of type `typeName`.
+  /// Generates a change detector class with name `changeDetectorTypeName`,
+  /// which must not conflict with other generated classes in the same
+  /// `.ng_deps.dart` file.  The change detector is used to detect changes in
+  /// Objects of type `typeName`.
   void generate(String typeName, String changeDetectorTypeName,
       ChangeDetectorDefinition def) {
-    new _CodegenState(typeName, changeDetectorTypeName, def)._writeToBuf(_buf);
+    if (_names.contains(changeDetectorTypeName)) {
+      throw new BaseException(
+          'Change detector named "${changeDetectorTypeName}" for ${typeName} '
+          'conflicts with an earlier generated change detector class.');
+    }
+    _names.add(changeDetectorTypeName);
+    new _CodegenState(typeName, changeDetectorTypeName, def)
+      .._writeToBuf(_buf)
+      .._writeInitToBuf(_initBuf);
   }
 
+  /// Gets all imports necessary for the generated code.
   String get imports {
     return _buf.isEmpty
         ? ''
@@ -31,13 +47,27 @@ class Codegen {
 
   bool get isEmpty => _buf.isEmpty;
 
+  /// Gets the initilization code that registers the generated classes with
+  /// the Angular 2 change detection system.
+  String get initialize => '$_initBuf';
+
   @override
   String toString() => '$_buf';
 }
 
 /// The state needed to generate a change detector for a single `Component`.
 class _CodegenState {
+  /// The `id` of the `ChangeDetectorDefinition` we are generating this class
+  /// for.
+  final String _changeDetectorDefId;
+
+  /// The name of the `Type` this change detector is generated for. For example,
+  /// this is `MyComponent` if the generated class will detect changes in
+  /// `MyComponent` objects.
   final String _contextTypeName;
+
+  /// The name of the generated change detector class. This is an implementation
+  /// detail and should not be visible to users.
   final String _changeDetectorTypeName;
   final String _changeDetectionMode;
   final List<ProtoRecord> _records;
@@ -47,9 +77,9 @@ class _CodegenState {
   final List<String> _fieldNames;
   final List<String> _pipeNames;
 
-  _CodegenState._(this._contextTypeName, this._changeDetectorTypeName,
-      String changeDetectionStrategy, this._records, this._directiveRecords,
-      List<String> localNames)
+  _CodegenState._(this._changeDetectorDefId, this._contextTypeName,
+      this._changeDetectorTypeName, String changeDetectionStrategy,
+      this._records, this._directiveRecords, List<String> localNames)
       : this._localNames = localNames,
         _changeNames = _getChangeNames(localNames),
         _fieldNames = _getFieldNames(localNames),
@@ -63,8 +93,8 @@ class _CodegenState {
     def.bindingRecords
         .forEach((rec) => protoRecords.add(rec, def.variableNames));
     var records = coalesce(protoRecords.records);
-    return new _CodegenState._(typeName, changeDetectorTypeName, def.strategy,
-        records, def.directiveRecords, _getLocalNames(records));
+    return new _CodegenState._(def.id, typeName, changeDetectorTypeName,
+        def.strategy, records, def.directiveRecords, _getLocalNames(records));
   }
 
   /// Generates sanitized names for use as local variables.
@@ -167,6 +197,13 @@ class _CodegenState {
     ''');
   }
 
+  void _writeInitToBuf(StringBuffer buf) {
+    buf.write('''
+      $_GEN_PREFIX.preGeneratedProtoDetectors['$_changeDetectorDefId'] =
+          $_changeDetectorTypeName.newProtoChangeDetector;
+    ''');
+  }
+
   List<String> _genGetDirectiveFieldNames() {
     return _directiveRecords
         .map((d) => _genGetDirective(d.directiveIndex))

modules/angular2/src/transform/template_compiler/generator.dart

@@ -64,11 +64,14 @@ Future<String> processTemplates(AssetReader reader, AssetId entryPoint,
       viewDefResults.ngDeps.lib != null ? viewDefResults.ngDeps.lib.end : 0;
   var codeInjectIdx =
       viewDefResults.ngDeps.registeredTypes.last.registerMethod.end;
+  var initInjectIdx = viewDefResults.ngDeps.setupMethod.end - 1;
   return '${code.substring(0, importInjectIdx)}'
       '${changeDetectorClasses.imports}'
       '${code.substring(importInjectIdx, codeInjectIdx)}'
       '${registrations}'
-      '${code.substring(codeInjectIdx)}'
+      '${code.substring(codeInjectIdx, initInjectIdx)}'
+      '${changeDetectorClasses.initialize}'
+      '${code.substring(initInjectIdx)}'
       '$changeDetectorClasses';
 }
 
@@ -100,8 +103,8 @@ class _TemplateExtractor {
     var pipeline =
         new CompilePipeline(_factory.createSteps(viewDef, subtaskPromises));
 
-    var compileElements = pipeline.process(
-        templateEl, ViewType.COMPONENT, viewDef.componentId);
+    var compileElements =
+        pipeline.process(templateEl, ViewType.COMPONENT, viewDef.componentId);
     var protoViewDto = compileElements[0].inheritedProtoView
         .build(new PropertySetterFactory());
 

modules/angular2/src/transform/template_compiler/transformer.dart

@@ -34,8 +34,8 @@ class TemplateCompiler extends Transformer {
       Html5LibDomAdapter.makeCurrent();
       var id = transform.primaryInput.id;
       var reader = new AssetReader.fromTransform(transform);
-      var transformedCode =
-          formatter.format(await processTemplates(reader, id));
+      var transformedCode = formatter.format(await processTemplates(reader, id,
+          generateChangeDetectors: options.generateChangeDetectors));
       transform.addOutput(new Asset.fromString(id, transformedCode));
     } catch (ex, stackTrace) {
       log.logger.error('Parsing ng templates failed.\n'

modules/angular2/src/transform/template_compiler/view_definition_creator.dart

@@ -33,8 +33,7 @@ class ViewDefinitionEntry {
   ViewDefinitionEntry._(this.hostMetadata, this.viewDef);
 }
 
-String _getComponentId(AssetId assetId, String className) =>
-    '$assetId:$className';
+String _getComponentId(AssetId assetId, String className) => '$className';
 
 // TODO(kegluenq): Improve this test.
 bool _isViewAnnotation(InstanceCreationExpression node) =>