combine script extractor and import inliner

pkg/polymer/lib/src/build/code_extractor.dart

-// Copyright (c) 2013, 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.
-
-/// Transfomer that extracts inlined script code into separate assets.
-library polymer.src.build.code_extractor;
-
-import 'dart:async';
-
-import 'package:analyzer/src/generated/ast.dart';
-import 'package:analyzer/src/generated/error.dart';
-import 'package:analyzer/src/generated/parser.dart';
-import 'package:analyzer/src/generated/scanner.dart';
-import 'package:barback/barback.dart';
-import 'package:path/path.dart' as path;
-
-import 'common.dart';
-
-/// Transformer that extracts Dart code inlined in HTML script tags and outputs
-/// a separate file for each.
-class InlineCodeExtractor extends Transformer with PolymerTransformer {
-  final TransformOptions options;
-
-  InlineCodeExtractor(this.options);
-
-  /// Only run this transformer on .html files.
-  final String allowedExtensions = ".html";
-
-  Future apply(Transform transform) {
-    var input = transform.primaryInput;
-    var id = transform.primaryInput.id;
-    return readPrimaryAsHtml(transform).then((document) {
-      int count = 0;
-      bool htmlChanged = false;
-      for (var tag in document.querySelectorAll('script')) {
-        // Only process tags that have inline Dart code
-        if (tag.attributes['type'] != 'application/dart' ||
-          tag.attributes.containsKey('src')) {
-          continue;
-        }
-        htmlChanged = true;
-
-        // Remove empty tags
-        if (tag.nodes.length == 0) {
-          tag.remove();
-          continue;
-        }
-
-        var filename = path.url.basename(id.path);
-        // TODO(sigmund): ensure this filename is unique (dartbug.com/12618).
-        tag.attributes['src'] = '$filename.$count.dart';
-        var textContent = tag.nodes.first;
-        var code = textContent.text;
-        var newId = id.addExtension('.$count.dart');
-        if (!_hasLibraryDirective(code)) {
-          var libname = path.withoutExtension(newId.path)
-              .replaceAll(new RegExp('[-./]'), '_');
-          code = "library $libname;\n$code";
-        }
-        transform.addOutput(new Asset.fromString(newId, code));
-        textContent.remove();
-        count++;
-      }
-      transform.addOutput(
-          htmlChanged ? new Asset.fromString(id, document.outerHtml) : input);
-    });
-  }
-}
-
-/// Parse [code] and determine whether it has a library directive.
-bool _hasLibraryDirective(String code) {
-  var errorListener = new _ErrorCollector();
-  var reader = new CharSequenceReader(code);
-  var scanner = new Scanner(null, reader, errorListener);
-  var token = scanner.tokenize();
-  var unit = new Parser(null, errorListener).parseCompilationUnit(token);
-  return unit.directives.any((d) => d is LibraryDirective);
-}
-
-class _ErrorCollector extends AnalysisErrorListener {
-  final errors = <AnalysisError>[];
-  onError(error) => errors.add(error);
-}