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,