feat(dart/transform): Inline templateUrl values

Modify DirectiveProcessor to inline `templateUrl` values to avoid making
additional browser requests.

Closes #1035

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

@@ -0,0 +1,75 @@
+library angular2.transform.common.async_string_writer;
+
+import 'dart:async';
+import 'package:analyzer/src/generated/java_core.dart';
+
+/// [PrintWriter] implementation that allows asynchronous printing via
+/// [asyncPrint] and [asyncToString]. See those methods for details.
+class AsyncStringWriter extends PrintWriter {
+  /// All [Future]s we are currently waiting on.
+  final List<Future<String>> _toAwait = <Future<String>>[];
+  final List<StringBuffer> _bufs;
+  StringBuffer _curr;
+  int _asyncCount = 0;
+
+  AsyncStringWriter._(StringBuffer curr)
+      : _curr = curr,
+        _bufs = <StringBuffer>[curr];
+
+  AsyncStringWriter() : this._(new StringBuffer());
+
+  void print(x) {
+    _curr.write(x);
+  }
+
+  /// Adds the result of `futureText` to the writer at the current position
+  /// in the string being built. If using this method, you must use
+  /// [asyncToString] instead of [toString] to get the value of the writer or
+  /// your string may not appear as expected.
+  Future<String> asyncPrint(Future<String> futureText) {
+    _semaphoreIncrement();
+    var myBuf = new StringBuffer();
+    _bufs.add(myBuf);
+    _curr = new StringBuffer();
+    _bufs.add(_curr);
+
+    var toAwait = futureText.then((val) {
+      myBuf.write(val);
+      return val;
+    });
+    _toAwait.add(toAwait);
+    return toAwait.whenComplete(() {
+      _semaphoreDecrementAndCleanup();
+      _toAwait.remove(toAwait);
+    });
+  }
+
+  /// Waits for any values added via [asyncPrint] and returns the fully
+  /// built string.
+  Future<String> asyncToString() {
+    _semaphoreIncrement();
+    var bufLen = _bufs.length;
+    return Future.wait(_toAwait).then((_) {
+      return _bufs.sublist(0, bufLen).join('');
+    }).whenComplete(_semaphoreDecrementAndCleanup);
+  }
+
+  String toString() => _bufs.map((buf) => '$buf').join('(async gap)');
+
+  void _semaphoreIncrement() {
+    ++_asyncCount;
+  }
+
+  void _semaphoreDecrementAndCleanup() {
+    assert(_asyncCount > 0);
+
+    --_asyncCount;
+    if (_asyncCount == 0) {
+      _curr = _bufs[0];
+      for (var i = 1; i < _bufs.length; ++i) {
+        _curr.write('${_bufs[i]}');
+      }
+      _bufs.removeRange(1, _bufs.length);
+    }
+  }
+}

modules/angular2/src/transform/directive_processor/rewriter.dart

@@ -1,10 +1,15 @@
 library angular2.transform.directive_processor.rewriter;
 
+import 'dart:async';
+
 import 'package:analyzer/analyzer.dart';
-import 'package:analyzer/src/generated/java_core.dart';
+import 'package:angular2/src/services/xhr.dart' show XHR;
 import 'package:angular2/src/transform/common/annotation_matcher.dart';
+import 'package:angular2/src/transform/common/asset_reader.dart';
+import 'package:angular2/src/transform/common/async_string_writer.dart';
 import 'package:angular2/src/transform/common/logging.dart';
 import 'package:angular2/src/transform/common/names.dart';
+import 'package:angular2/src/transform/common/xhr_impl.dart';
 import 'package:barback/barback.dart' show AssetId;
 import 'package:path/path.dart' as path;
 
@@ -17,20 +22,22 @@ import 'visitors.dart';
 /// If no Angular 2 `Directive`s are found in `code`, returns the empty
 /// string unless `forceGenerate` is true, in which case an empty ngDeps
 /// file is created.
-String createNgDeps(
-    String code, AssetId assetId, AnnotationMatcher annotationMatcher) {
+Future<String> createNgDeps(AssetReader reader, AssetId assetId,
+    AnnotationMatcher annotationMatcher) async {
   // TODO(kegluneq): Shortcut if we can determine that there are no
   // [Directive]s present, taking into account `export`s.
-  var writer = new PrintStringWriter();
-  var visitor = new CreateNgDepsVisitor(writer, assetId, annotationMatcher);
-  parseCompilationUnit(code, name: assetId.toString()).accept(visitor);
-  return '$writer';
+  var writer = new AsyncStringWriter();
+  var visitor = new CreateNgDepsVisitor(
+      writer, assetId, new XhrImpl(reader, assetId), annotationMatcher);
+  var code = await reader.readAsString(assetId);
+  parseCompilationUnit(code, name: assetId.path).accept(visitor);
+  return await writer.asyncToString();
 }
 
 /// Visitor responsible for processing [CompilationUnit] and creating an
 /// associated .ng_deps.dart file.
 class CreateNgDepsVisitor extends Object with SimpleAstVisitor<Object> {
-  final PrintWriter writer;
+  final AsyncStringWriter writer;
   bool _foundNgDirectives = false;
   bool _wroteImport = false;
   final ToSourceVisitor _copyVisitor;
@@ -42,12 +49,13 @@ class CreateNgDepsVisitor extends Object with SimpleAstVisitor<Object> {
   /// The assetId for the file which we are parsing.
   final AssetId assetId;
 
-  CreateNgDepsVisitor(PrintWriter writer, this.assetId, this._annotationMatcher)
+  CreateNgDepsVisitor(
+      AsyncStringWriter writer, this.assetId, XHR xhr, this._annotationMatcher)
       : writer = writer,
         _copyVisitor = new ToSourceVisitor(writer),
         _factoryVisitor = new FactoryTransformVisitor(writer),
         _paramsVisitor = new ParameterTransformVisitor(writer),
-        _metaVisitor = new AnnotationsTransformVisitor(writer);
+        _metaVisitor = new AnnotationsTransformVisitor(writer, xhr);
 
   void _visitNodeListWithSeparator(NodeList<AstNode> list, String separator) {
     if (list == null) return;

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

@@ -2,6 +2,7 @@ library angular2.transform.directive_processor.transformer;
 
 import 'dart:async';
 
+import 'package:angular2/src/transform/common/asset_reader.dart';
 import 'package:angular2/src/transform/common/logging.dart' as log;
 import 'package:angular2/src/transform/common/names.dart';
 import 'package:angular2/src/transform/common/options.dart';
@@ -32,9 +33,9 @@ class DirectiveProcessor extends Transformer {
 
     try {
       var asset = transform.primaryInput;
-      var assetCode = await asset.readAsString();
+      var reader = new AssetReader.fromTransform(transform);
       var ngDepsSrc =
-          createNgDeps(assetCode, asset.id, options.annotationMatcher);
+          await createNgDeps(reader, asset.id, options.annotationMatcher);
       if (ngDepsSrc != null && ngDepsSrc.isNotEmpty) {
         var ngDepsAssetId =
             transform.primaryInput.id.changeExtension(DEPS_EXTENSION);

modules/angular2/src/transform/directive_processor/visitors.dart

@@ -2,6 +2,8 @@ library angular2.transform.directive_processor.visitors;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/java_core.dart';
+import 'package:angular2/src/services/xhr.dart' show XHR;
+import 'package:angular2/src/transform/common/async_string_writer.dart';
 import 'package:angular2/src/transform/common/logging.dart';
 
 /// `ToSourceVisitor` designed to accept {@link ConstructorDeclaration} nodes.
@@ -200,11 +202,17 @@ class FactoryTransformVisitor extends _CtorTransformVisitor {
   }
 }
 
+// TODO(kegluenq): Use pull #1772 to detect when available.
+bool _isViewAnnotation(Annotation node) => '${node.name}' == 'View';
+
 /// ToSourceVisitor designed to print a `ClassDeclaration` node as a
 /// 'annotations' value for Angular2's `registerType` calls.
 class AnnotationsTransformVisitor extends ToSourceVisitor {
-  final PrintWriter writer;
-  AnnotationsTransformVisitor(PrintWriter writer)
+  final AsyncStringWriter writer;
+  final XHR _xhr;
+  bool _processingView = false;
+
+  AnnotationsTransformVisitor(AsyncStringWriter writer, this._xhr)
       : this.writer = writer,
         super(writer);
 
@@ -226,6 +234,7 @@ class AnnotationsTransformVisitor extends ToSourceVisitor {
   Object visitAnnotation(Annotation node) {
     writer.print('const ');
     if (node.name != null) {
+      _processingView = _isViewAnnotation(node);
       node.name.accept(this);
     }
     if (node.constructorName != null) {
@@ -237,4 +246,25 @@ class AnnotationsTransformVisitor extends ToSourceVisitor {
     }
     return null;
   }
+
+  /// These correspond to the annotation parameters.
+  @override
+  Object visitNamedExpression(NamedExpression node) {
+    // TODO(kegluneq): Remove this limitation.
+    if (!_processingView ||
+        node.name is! Label ||
+        node.name.label is! SimpleIdentifier) {
+      return super.visitNamedExpression(node);
+    }
+    var keyString = '${node.name.label}';
+    if (keyString == 'templateUrl' && node.expression is SimpleStringLiteral) {
+      var url = stringLiteralToString(node.expression);
+      writer.print("template: r'''");
+      writer.asyncPrint(_xhr.get(url));
+      writer.print("'''");
+      return null;
+    } else {
+      return super.visitNamedExpression(node);
+    }
+  }
 }

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

@@ -7,18 +7,18 @@ import 'package:angular2/src/change_detection/parser/parser.dart' as ng;
 import 'package:angular2/src/render/api.dart';
 import 'package:angular2/src/render/dom/compiler/compiler.dart';
 import 'package:angular2/src/render/dom/compiler/template_loader.dart';
-import "package:angular2/src/services/xhr.dart" show XHR;
+import 'package:angular2/src/services/xhr.dart' show XHR;
 import 'package:angular2/src/reflection/reflection.dart';
 import 'package:angular2/src/services/url_resolver.dart';
 import 'package:angular2/src/transform/common/asset_reader.dart';
 import 'package:angular2/src/transform/common/names.dart';
 import 'package:angular2/src/transform/common/property_utils.dart' as prop;
+import 'package:angular2/src/transform/common/xhr_impl.dart';
 import 'package:barback/barback.dart';
 
 import 'compile_step_factory.dart';
 import 'recording_reflection_capabilities.dart';
 import 'view_definition_creator.dart';
-import 'xhr_impl.dart';
 
 /// Reads the `.ng_deps.dart` file represented by `entryPoint` and parses any
 /// Angular 2 `View` annotations it declares to generate `getter`s,

modules/angular2/test/transform/common/async_string_writer_tests.dart

@@ -0,0 +1,106 @@
+library angular2.test.transform.common.async_string_writer;
+
+import 'dart:async';
+import 'package:angular2/src/transform/common/async_string_writer.dart';
+import 'package:guinness/guinness.dart';
+
+void allTests() {
+  it('should function as a basic Writer without async calls.', () {
+    var writer = new AsyncStringWriter();
+    writer.print('hello');
+    expect('$writer').toEqual('hello');
+    writer.println(', world');
+    expect('$writer').toEqual('hello, world\n');
+  });
+
+  it('should concatenate futures added with `asyncPrint`.', () async {
+    var writer = new AsyncStringWriter();
+    writer.print('hello');
+    expect('$writer').toEqual('hello');
+    writer.asyncPrint(new Future.value(', world.'));
+    writer.print(' It is a beautiful day.');
+    expect(await writer.asyncToString())
+        .toEqual('hello, world. It is a beautiful day.');
+  });
+
+  it('should concatenate multiple futures regardless of order.', () async {
+    var completer1 = new Completer<String>();
+    var completer2 = new Completer<String>();
+
+    var writer = new AsyncStringWriter();
+    writer.print('hello');
+    expect('$writer').toEqual('hello');
+    writer.asyncPrint(completer1.future);
+    writer.asyncPrint(completer2.future);
+
+    completer2.complete(' It is a beautiful day.');
+    completer1.complete(', world.');
+
+    expect(await writer.asyncToString())
+        .toEqual('hello, world. It is a beautiful day.');
+  });
+
+  it('should allow multiple "rounds" of `asyncPrint`.', () async {
+    var writer = new AsyncStringWriter();
+    writer.print('hello');
+    expect('$writer').toEqual('hello');
+    writer.asyncPrint(new Future.value(', world.'));
+    expect(await writer.asyncToString()).toEqual('hello, world.');
+
+    writer.asyncPrint(new Future.value(' It is '));
+    writer.asyncPrint(new Future.value('a beautiful '));
+    writer.asyncPrint(new Future.value('day.'));
+
+    expect(await writer.asyncToString())
+        .toEqual('hello, world. It is a beautiful day.');
+  });
+
+  it('should handle calls to async methods while waiting.', () {
+    var completer1 = new Completer<String>();
+    var completer2 = new Completer<String>();
+
+    var writer = new AsyncStringWriter();
+    writer.print('hello');
+    expect('$writer').toEqual('hello');
+
+    writer.asyncPrint(completer1.future);
+    var f1 = writer.asyncToString().then((result) {
+      expect(result).toEqual('hello, world.');
+    });
+
+    writer.asyncPrint(completer2.future);
+    var f2 = writer.asyncToString().then((result) {
+      expect(result).toEqual('hello, world. It is a beautiful day.');
+    });
+
+    completer1.complete(', world.');
+    completer2.complete(' It is a beautiful day.');
+
+    return Future.wait([f1, f2]);
+  });
+
+  it('should handle calls to async methods that complete in reverse '
+      'order while waiting.', () {
+    var completer1 = new Completer<String>();
+    var completer2 = new Completer<String>();
+
+    var writer = new AsyncStringWriter();
+    writer.print('hello');
+    expect('$writer').toEqual('hello');
+
+    writer.asyncPrint(completer1.future);
+    var f1 = writer.asyncToString().then((result) {
+      expect(result).toEqual('hello, world.');
+    });
+
+    writer.asyncPrint(completer2.future);
+    var f2 = writer.asyncToString().then((result) {
+      expect(result).toEqual('hello, world. It is a beautiful day.');
+    });
+
+    completer2.complete(' It is a beautiful day.');
+    completer1.complete(', world.');
+
+    return Future.wait([f1, f2]);
+  });
+}

modules/angular2/test/transform/common/read_file.dart

@@ -19,15 +19,29 @@ String readFile(String path) {
 }
 
 class TestAssetReader implements AssetReader {
-  Future<String> readAsString(AssetId id, {Encoding encoding}) =>
-      new Future.value(readFile(id.path));
+  /// This allows "faking"
+  final Map<AssetId, String> _overrideAssets = <AssetId, String>{};
+
+  Future<String> readAsString(AssetId id, {Encoding encoding}) {
+    if (_overrideAssets.containsKey(id)) {
+      return new Future.value(_overrideAssets[id]);
+    } else {
+      return new Future.value(readFile(id.path));
+    }
+  }
 
   Future<bool> hasInput(AssetId id) {
-    var exists = false;
+    var exists = _overrideAssets.containsKey(id);
+    if (exists) return new Future.value(true);
+
     for (var myPath in [id.path, 'test/transform/${id.path}']) {
       var file = new File(myPath);
       exists = exists || file.existsSync();
     }
     return new Future.value(exists);
   }
+
+  void addAsset(AssetId id, String contents) {
+    _overrideAssets[id] = contents;
+  }
 }

modules/angular2/test/transform/directive_processor/all_tests.dart

@@ -3,10 +3,10 @@ library angular2.test.transform.directive_processor.all_tests;
 import 'package:barback/barback.dart';
 import 'package:angular2/src/transform/directive_processor/rewriter.dart';
 import 'package:angular2/src/transform/common/annotation_matcher.dart';
-import '../common/read_file.dart';
 import 'package:dart_style/dart_style.dart';
 import 'package:guinness/guinness.dart';
 import 'package:path/path.dart' as path;
+import '../common/read_file.dart';
 
 var formatter = new DartFormatter();
 
@@ -36,6 +36,9 @@ void allTests() {
       customDescriptors: [
     const AnnotationDescriptor('Soup', 'package:soup/soup.dart', 'Component'),
   ]);
+
+  _testNgDeps(
+      'should inline `templateUrl` values.', 'url_expression_files/hello.dart');
 }
 
 void _testNgDeps(String name, String inputPath,
@@ -43,11 +46,13 @@ void _testNgDeps(String name, String inputPath,
   it(name, () async {
     var inputId = _assetIdForPath(inputPath);
     var reader = new TestAssetReader();
-    var input = await reader.readAsString(inputId);
+    if (assetId != null) {
+      reader.addAsset(assetId, await reader.readAsString(inputId));
+      inputId = assetId;
+    }
     var annotationMatcher = new AnnotationMatcher()..addAll(customDescriptors);
-    var proxyInputId = assetId != null ? assetId : inputId;
-    var output =
-        formatter.format(createNgDeps(input, proxyInputId, annotationMatcher));
+    var output = formatter
+        .format(await createNgDeps(reader, inputId, annotationMatcher));
     var expectedPath = path.join(path.dirname(inputPath), 'expected',
         path.basename(inputPath).replaceFirst('.dart', '.ng_deps.dart'));
     var expectedId = _assetIdForPath(expectedPath);

modules/angular2/test/transform/directive_processor/url_expression_files/expected/hello.ng_deps.dart

@@ -0,0 +1,20 @@
+library examples.src.hello_world.index_common_dart.ng_deps.dart;
+
+import 'hello.dart';
+import 'package:angular2/angular2.dart'
+    show bootstrap, Component, Directive, View, NgElement;
+
+var _visited = false;
+void initReflector(reflector) {
+  if (_visited) return;
+  _visited = true;
+  reflector
+    ..registerType(HelloCmp, {
+      'factory': () => new HelloCmp(),
+      'parameters': const [],
+      'annotations': const [
+        const Component(selector: 'hello-app'),
+        const View(template: r'''{{greeting}}''')
+      ]
+    });
+}

modules/angular2/test/transform/directive_processor/url_expression_files/hello.dart

@@ -0,0 +1,8 @@
+library examples.src.hello_world.index_common_dart;
+
+import 'package:angular2/angular2.dart'
+    show bootstrap, Component, Directive, View, NgElement;
+
+@Component(selector: 'hello-app')
+@View(templateUrl: 'template.html')
+class HelloCmp {}

modules/angular2/test/transform/directive_processor/url_expression_files/template.html

@@ -0,0 +1 @@
+{{greeting}}

modules/angular2/test/transform/transform.server.spec.dart

@@ -4,6 +4,7 @@ import 'package:guinness/guinness.dart';
 import 'package:unittest/unittest.dart' hide expect;
 import 'package:unittest/vm_config.dart';
 
+import 'common/async_string_writer_tests.dart' as asyncStringWriter;
 import 'bind_generator/all_tests.dart' as bindGenerator;
 import 'directive_linker/all_tests.dart' as directiveLinker;
 import 'directive_metadata_extractor/all_tests.dart' as directiveMeta;
@@ -14,6 +15,7 @@ import 'template_compiler/all_tests.dart' as templateCompiler;
 
 main() {
   useVMConfiguration();
+  describe('AsyncStringWriter', asyncStringWriter.allTests);
   describe('Bind Generator', bindGenerator.allTests);
   describe('Directive Linker', directiveLinker.allTests);
   describe('Directive Metadata Extractor', directiveMeta.allTests);