Initial commit of Dart transformer to generate constructor stubs, see https://github.com/angular/an…

modules/angular2/src/transform/html_transform.dart

+library angular2.transformer;
+
+import 'dart:async';
+import 'package:barback/barback.dart';
+import 'package:html5lib/dom.dart' as dom;
+import 'package:html5lib/parser.dart' show parse;
+import 'package:path/path.dart' as path;
+
+import 'options.dart';
+
+Future transformHtmlEntryPoint(
+    TransformerOptions options, Transform transform) {
+  // For now at least, [options.htmlEntryPoint], [options.entryPoint], and
+  // [options.newEntryPoint] need to be in the same folder.
+  // TODO(jakemac): support package urls with [options.entryPoint] or

[jakemac, 2015/02/18 16:18:50]

The initialize package now handles this, up to you if you want to copy the logic
over. Basically it just accepts an `entry_point` now and based on the file
extension (.dart or .html) it does the right thing.

[tjblasi, 2015/02/18 21:18:25]

Acknowledged.

+  // [options.newEntryPoint] in `lib`, and [options.htmlEntryPoint] in another
+  // directory.
+  var _expectedDir = path.split(options.htmlEntryPoint)[0];
+  if (!options.inSameTopLevelDir()) {
+    transform.logger.error(
+        '${options.htmlEntryPointParam}, ${options.entryPointParam}, and '
+        '${options.newEntryPointParam} (if supplied) all must be in the '
+        'same top level directory.');
+  }
+
+  // The relative path from [options.htmlEntryPoint] to [dartEntry]. You must
+  // ensure that neither of these is null before calling this function.
+  String _relativeDartEntryPath(String dartEntry) =>
+      path.relative(dartEntry, from: path.dirname(options.htmlEntryPoint));
+
+  // Checks if the src of this script tag is pointing at `options.entryPoint`.
+  bool _isEntryPointScript(dom.Element script) =>
+      path.normalize(script.attributes['src']) ==
+          _relativeDartEntryPath(options.entryPoint);
+
+  return transform.primaryInput.readAsString().then((String html) {
+    var found = false;
+    var doc = parse(html);
+    var scripts = doc.querySelectorAll('script[type="application/dart"]');
+    for (dom.Element script in scripts) {
+      if (!_isEntryPointScript(script)) continue;
+      script.attributes['src'] = _relativeDartEntryPath(options.newEntryPoint);
+      found = true;
+    }
+    if (!found) {
+      transform.logger.error('Unable to find script for ${options.entryPoint} '
+          'in ${options.htmlEntryPoint}.');
+    }
+    return transform.addOutput(
+        new Asset.fromString(transform.primaryInput.id, doc.outerHtml));
+  });
+}