| // 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. |
| |
| /** Common methods used by transfomers. */ |
| library polymer.src.transform.common; |
| |
| import 'dart:async'; |
| |
| import 'package:barback/barback.dart'; |
| import 'package:html5lib/dom.dart' show Document; |
| import 'package:html5lib/parser.dart' show HtmlParser; |
| import 'package:path/path.dart' as path; |
| import 'package:source_maps/span.dart' show Span; |
| |
| /** |
| * Parses an HTML file [contents] and returns a DOM-like tree. Adds emitted |
| * error/warning to [logger]. |
| */ |
| Document _parseHtml(String contents, String sourcePath, TransformLogger logger, |
| {bool checkDocType: true}) { |
| // TODO(jmesserly): make HTTP encoding configurable |
| var parser = new HtmlParser(contents, encoding: 'utf8', generateSpans: true, |
| sourceUrl: sourcePath); |
| var document = parser.parse(); |
| |
| // Note: errors aren't fatal in HTML (unless strict mode is on). |
| // So just print them as warnings. |
| for (var e in parser.errors) { |
| if (checkDocType || e.errorCode != 'expected-doctype-but-got-start-tag') { |
| logger.warning(e.message, e.span); |
| } |
| } |
| return document; |
| } |
| |
| Future<Document> readPrimaryAsHtml(Transform transform) { |
| var asset = transform.primaryInput; |
| var id = asset.id; |
| return asset.readAsString().then((content) { |
| return _parseHtml(content, id.path, transform.logger, |
| checkDocType: isPrimaryHtml(id)); |
| }); |
| } |
| |
| Future<Document> readAsHtml(AssetId id, Transform transform) { |
| var primaryId = transform.primaryInput.id; |
| var url = (id.package == primaryId.package) ? id.path |
| : assetUrlFor(id, primaryId, transform.logger, allowAssetUrl: true); |
| return transform.readInputAsString(id).then((content) { |
| return _parseHtml(content, url, transform.logger, |
| checkDocType: isPrimaryHtml(id)); |
| }); |
| } |
| |
| /** Create an [AssetId] for a [url] seen in the [source] asset. */ |
| // TODO(sigmund): delete once this is part of barback (dartbug.com/12610) |
| AssetId resolve(AssetId source, String url, TransformLogger logger, Span span) { |
| if (url == null || url == '') return null; |
| var uri = Uri.parse(url); |
| var urlBuilder = path.url; |
| if (uri.host != '' || uri.scheme != '' || urlBuilder.isAbsolute(url)) { |
| logger.error('absolute paths not allowed: "$url"', span); |
| return null; |
| } |
| |
| var package; |
| var targetPath; |
| var segments = urlBuilder.split(url); |
| if (segments[0] == 'packages') { |
| if (segments.length < 3) { |
| logger.error("incomplete packages/ path. It should have at least 3 " |
| "segments packages/name/path-from-name's-lib-dir", span); |
| return null; |
| } |
| package = segments[1]; |
| targetPath = urlBuilder.join('lib', |
| urlBuilder.joinAll(segments.sublist(2))); |
| } else if (segments[0] == 'assets') { |
| if (segments.length < 3) { |
| logger.error("incomplete assets/ path. It should have at least 3 " |
| "segments assets/name/path-from-name's-asset-dir", span); |
| } |
| package = segments[1]; |
| targetPath = urlBuilder.join('asset', |
| urlBuilder.joinAll(segments.sublist(2))); |
| } else { |
| package = source.package; |
| targetPath = urlBuilder.normalize( |
| urlBuilder.join(urlBuilder.dirname(source.path), url)); |
| } |
| return new AssetId(package, targetPath); |
| } |
| |
| /** Whether an asset with [id] is considered a primary entry point HTML file. */ |
| bool isPrimaryHtml(AssetId id) => id.extension == '.html' && |
| // Note: [id.path] is a relative path from the root of a package. |
| (id.path.startsWith('web/') || id.path.startsWith('test/')); |
| |
| /** |
| * Generate the import url for a file described by [id], referenced by a file |
| * with [sourceId]. |
| */ |
| // TODO(sigmund): this should also be in barback (dartbug.com/12610) |
| String assetUrlFor(AssetId id, AssetId sourceId, TransformLogger logger, |
| {bool allowAssetUrl: false}) { |
| // use package: and asset: urls if possible |
| if (id.path.startsWith('lib/')) { |
| return 'package:${id.package}/${id.path.substring(4)}'; |
| } |
| |
| if (id.path.startsWith('asset/')) { |
| if (!allowAssetUrl) { |
| logger.error("asset urls not allowed. " |
| "Don't know how to refer to $id from $sourceId"); |
| return null; |
| } |
| return 'asset:${id.package}/${id.path.substring(6)}'; |
| } |
| |
| // Use relative urls only if it's possible. |
| if (id.package != sourceId.package) { |
| logger.error("don't know how to refer to $id from $sourceId"); |
| return null; |
| } |
| |
| var builder = path.url; |
| return builder.relative(builder.join('/', id.path), |
| from: builder.join('/', builder.dirname(sourceId.path))); |
| } |