pkg/polymer/lib/src/build/import_inliner.dart - sdk.git - Git at Google

 // 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 inlines polymer-element definitions from html imports. */
 library polymer.src.build.import_inliner;

 import 'dart:async';
 import 'dart:convert';

 import 'package:barback/barback.dart';
 import 'package:path/path.dart' as path;
 import 'package:html5lib/dom.dart' show
     Document, DocumentFragment, Element, Node;
 import 'package:html5lib/dom_parsing.dart' show TreeVisitor;
 import 'package:source_maps/span.dart' show Span;

 import 'code_extractor.dart'; // import just for documentation.
 import 'common.dart';

 class _HtmlInliner extends PolymerTransformer {
   final TransformOptions options;
   final Transform transform;
   final TransformLogger logger;
   final AssetId docId;
   final seen = new Set<AssetId>();
   final imported = new DocumentFragment();
   final scriptIds = <AssetId>[];

   _HtmlInliner(this.options, Transform transform)
       : transform = transform,
         logger = transform.logger,
         docId = transform.primaryInput.id;

   Future apply() {
     seen.add(docId);

     Document document;

     return readPrimaryAsHtml(transform).then((document) =>
         _visitImports(document, docId).then((importsFound) {

       if (importsFound) {
         document.body.insertBefore(imported, document.body.firstChild);
         transform.addOutput(new Asset.fromString(docId, document.outerHtml));
       } else {
         transform.addOutput(transform.primaryInput);
       }

       // We produce a secondary asset with extra information for later phases.
       transform.addOutput(new Asset.fromString(
           docId.addExtension('.scriptUrls'),
           JSON.encode(scriptIds, toEncodable: (id) => id.serialize())));
     }));
   }

   /**
    * Visits imports in [document] and add the imported documents to [documents].
    * Documents are added in the order they appear, transitive imports are added
    * first.
    */
   Future<bool> _visitImports(Document document, AssetId sourceId) {
     bool hasImports = false;

     // Note: we need to preserve the import order in the generated output.
     return Future.forEach(document.querySelectorAll('link'), (Element tag) {
       if (tag.attributes['rel'] != 'import') return null;
       var href = tag.attributes['href'];
       var id = resolve(sourceId, href, transform.logger, tag.sourceSpan);
       hasImports = true;

       tag.remove();
       if (id == null || !seen.add(id) ||
          (id.package == 'polymer' && id.path == 'lib/init.html')) return null;

       return _inlineImport(id);
     }).then((_) => hasImports);
   }

   // Loads an asset identified by [id], visits its imports and collects its
   // html imports. Then inlines it into the main document.
   Future _inlineImport(AssetId id) =>
       readAsHtml(id, transform).then((doc) => _visitImports(doc, id).then((_) {

     new _UrlNormalizer(transform, id).visit(doc);
     _extractScripts(doc);

     // TODO(jmesserly): figure out how this is working in vulcanizer.
     // Do they produce a <body> tag with a <head> and <body> inside?
     imported.nodes
         ..addAll(doc.head.nodes)
         ..addAll(doc.body.nodes);
   }));

   /**
    * Split Dart script tags from all the other elements. Now that Dartium
    * only allows a single script tag per page, we can't inline script
    * tags. Instead, we collect the urls of each script tag so we import
    * them directly from the Dart bootstrap code.
    */
   void _extractScripts(Document document) {
     bool first = true;
     for (var script in document.querySelectorAll('script')) {
       if (script.attributes['type'] == 'application/dart') {
         script.remove();

         // only one Dart script per document is supported in Dartium.
         if (first) {
           first = false;

           var src = script.attributes['src'];
           if (src == null) {
             logger.warning('unexpected script without a src url. The '
               'ImportInliner transformer should run after running the '
               'InlineCodeExtractor', span: script.sourceSpan);
             continue;
           }
           scriptIds.add(resolve(docId, src, logger, script.sourceSpan));

         } else {
           // TODO(jmesserly): remove this when we are running linter.
           logger.warning('more than one Dart script per HTML '
               'document is not supported. Script will be ignored.',
               span: script.sourceSpan);
         }
       }
     }
   }
 }

 /**
  * Recursively inlines the contents of HTML imports. Produces as output a single
  * HTML file that inlines the polymer-element definitions, and a text file that
  * contains, in order, the URIs to each library that sourced in a script tag.
  *
  * This transformer assumes that all script tags point to external files. To
  * support script tags with inlined code, use this transformer after running
  * [InlineCodeExtractor] on an earlier phase.
  */
 class ImportInliner extends Transformer {
   final TransformOptions options;

   ImportInliner(this.options);

   /** Only run on entry point .html files. */
   Future<bool> isPrimary(Asset input) =>
       new Future.value(options.isHtmlEntryPoint(input.id));

   Future apply(Transform transform) =>
       new _HtmlInliner(options, transform).apply();
 }


 /** Internally adjusts urls in the html that we are about to inline. */
 class _UrlNormalizer extends TreeVisitor {
   final Transform transform;

   /** Asset where the original content (and original url) was found. */
   final AssetId sourceId;

   _UrlNormalizer(this.transform, this.sourceId);

   visitElement(Element node) {
     for (var key in node.attributes.keys) {
       if (_urlAttributes.contains(key)) {
         var url = node.attributes[key];
         if (url != null && url != '' && !url.startsWith('{{')) {
           node.attributes[key] = _newUrl(url, node.sourceSpan);
         }
       }
     }
     super.visitElement(node);
   }

   _newUrl(String href, Span span) {
     var uri = Uri.parse(href);
     if (uri.isAbsolute) return href;
     if (!uri.scheme.isEmpty) return href;
     if (!uri.host.isEmpty) return href;
     if (uri.path.isEmpty) return href;  // Implies standalone ? or # in URI.
     if (path.isAbsolute(href)) return href;

     var id = resolve(sourceId, href, transform.logger, span);
     if (id == null) return href;
     var primaryId = transform.primaryInput.id;

     if (id.path.startsWith('lib/')) {
       return 'packages/${id.package}/${id.path.substring(4)}';
     }

     if (id.path.startsWith('asset/')) {
       return 'assets/${id.package}/${id.path.substring(6)}';
     }

     if (primaryId.package != id.package) {
       // Techincally we shouldn't get there
       transform.logger.error("don't know how to include $id from $primaryId",
           span: span);
       return href;
     }

     var builder = path.url;
     return builder.relative(builder.join('/', id.path),
         from: builder.join('/', builder.dirname(primaryId.path)));
   }
 }

 /**
  * HTML attributes that expect a URL value.
  * <http://dev.w3.org/html5/spec/section-index.html#attributes-1>
  *
  * Every one of these attributes is a URL in every context where it is used in
  * the DOM. The comments show every DOM element where an attribute can be used.
  */
 const _urlAttributes = const [
   'action',     // in form
   'background', // in body
   'cite',       // in blockquote, del, ins, q
   'data',       // in object
   'formaction', // in button, input
   'href',       // in a, area, link, base, command
   'icon',       // in command
   'manifest',   // in html
   'poster',     // in video
   'src',        // in audio, embed, iframe, img, input, script, source, track,
                 //    video
 ];
	// 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 inlines polymer-element definitions from html imports. */
	library polymer.src.build.import_inliner;

	import 'dart:async';
	import 'dart:convert';

	import 'package:barback/barback.dart';
	import 'package:path/path.dart' as path;
	import 'package:html5lib/dom.dart' show
	Document, DocumentFragment, Element, Node;
	import 'package:html5lib/dom_parsing.dart' show TreeVisitor;
	import 'package:source_maps/span.dart' show Span;

	import 'code_extractor.dart'; // import just for documentation.
	import 'common.dart';

	class _HtmlInliner extends PolymerTransformer {
	final TransformOptions options;
	final Transform transform;
	final TransformLogger logger;
	final AssetId docId;
	final seen = new Set<AssetId>();
	final imported = new DocumentFragment();
	final scriptIds = <AssetId>[];

	_HtmlInliner(this.options, Transform transform)
	: transform = transform,
	logger = transform.logger,
	docId = transform.primaryInput.id;

	Future apply() {
	seen.add(docId);

	Document document;

	return readPrimaryAsHtml(transform).then((document) =>
	_visitImports(document, docId).then((importsFound) {

	if (importsFound) {
	document.body.insertBefore(imported, document.body.firstChild);
	transform.addOutput(new Asset.fromString(docId, document.outerHtml));
	} else {
	transform.addOutput(transform.primaryInput);
	}

	// We produce a secondary asset with extra information for later phases.
	transform.addOutput(new Asset.fromString(
	docId.addExtension('.scriptUrls'),
	JSON.encode(scriptIds, toEncodable: (id) => id.serialize())));
	}));
	}

	/**
	* Visits imports in [document] and add the imported documents to [documents].
	* Documents are added in the order they appear, transitive imports are added
	* first.
	*/
	Future<bool> _visitImports(Document document, AssetId sourceId) {
	bool hasImports = false;

	// Note: we need to preserve the import order in the generated output.
	return Future.forEach(document.querySelectorAll('link'), (Element tag) {
	if (tag.attributes['rel'] != 'import') return null;
	var href = tag.attributes['href'];
	var id = resolve(sourceId, href, transform.logger, tag.sourceSpan);
	hasImports = true;

	tag.remove();
	if (id == null \|\| !seen.add(id) \|\|
	(id.package == 'polymer' && id.path == 'lib/init.html')) return null;

	return _inlineImport(id);
	}).then((_) => hasImports);
	}

	// Loads an asset identified by [id], visits its imports and collects its
	// html imports. Then inlines it into the main document.
	Future _inlineImport(AssetId id) =>
	readAsHtml(id, transform).then((doc) => _visitImports(doc, id).then((_) {

	new _UrlNormalizer(transform, id).visit(doc);
	_extractScripts(doc);

	// TODO(jmesserly): figure out how this is working in vulcanizer.
	// Do they produce a <body> tag with a <head> and <body> inside?
	imported.nodes
	..addAll(doc.head.nodes)
	..addAll(doc.body.nodes);
	}));

	/**
	* Split Dart script tags from all the other elements. Now that Dartium
	* only allows a single script tag per page, we can't inline script
	* tags. Instead, we collect the urls of each script tag so we import
	* them directly from the Dart bootstrap code.
	*/
	void _extractScripts(Document document) {
	bool first = true;
	for (var script in document.querySelectorAll('script')) {
	if (script.attributes['type'] == 'application/dart') {
	script.remove();

	// only one Dart script per document is supported in Dartium.
	if (first) {
	first = false;

	var src = script.attributes['src'];
	if (src == null) {
	logger.warning('unexpected script without a src url. The '
	'ImportInliner transformer should run after running the '
	'InlineCodeExtractor', span: script.sourceSpan);
	continue;
	}
	scriptIds.add(resolve(docId, src, logger, script.sourceSpan));

	} else {
	// TODO(jmesserly): remove this when we are running linter.
	logger.warning('more than one Dart script per HTML '
	'document is not supported. Script will be ignored.',
	span: script.sourceSpan);
	}
	}
	}
	}
	}

	/**
	* Recursively inlines the contents of HTML imports. Produces as output a single
	* HTML file that inlines the polymer-element definitions, and a text file that
	* contains, in order, the URIs to each library that sourced in a script tag.
	*
	* This transformer assumes that all script tags point to external files. To
	* support script tags with inlined code, use this transformer after running
	* [InlineCodeExtractor] on an earlier phase.
	*/
	class ImportInliner extends Transformer {
	final TransformOptions options;

	ImportInliner(this.options);

	/** Only run on entry point .html files. */
	Future<bool> isPrimary(Asset input) =>
	new Future.value(options.isHtmlEntryPoint(input.id));

	Future apply(Transform transform) =>
	new _HtmlInliner(options, transform).apply();
	}


	/** Internally adjusts urls in the html that we are about to inline. */
	class _UrlNormalizer extends TreeVisitor {
	final Transform transform;

	/** Asset where the original content (and original url) was found. */
	final AssetId sourceId;

	_UrlNormalizer(this.transform, this.sourceId);

	visitElement(Element node) {
	for (var key in node.attributes.keys) {
	if (_urlAttributes.contains(key)) {
	var url = node.attributes[key];
	if (url != null && url != '' && !url.startsWith('{{')) {
	node.attributes[key] = _newUrl(url, node.sourceSpan);
	}
	}
	}
	super.visitElement(node);
	}

	_newUrl(String href, Span span) {
	var uri = Uri.parse(href);
	if (uri.isAbsolute) return href;
	if (!uri.scheme.isEmpty) return href;
	if (!uri.host.isEmpty) return href;
	if (uri.path.isEmpty) return href; // Implies standalone ? or # in URI.
	if (path.isAbsolute(href)) return href;

	var id = resolve(sourceId, href, transform.logger, span);
	if (id == null) return href;
	var primaryId = transform.primaryInput.id;

	if (id.path.startsWith('lib/')) {
	return 'packages/${id.package}/${id.path.substring(4)}';
	}

	if (id.path.startsWith('asset/')) {
	return 'assets/${id.package}/${id.path.substring(6)}';
	}

	if (primaryId.package != id.package) {
	// Techincally we shouldn't get there
	transform.logger.error("don't know how to include $id from $primaryId",
	span: span);
	return href;
	}

	var builder = path.url;
	return builder.relative(builder.join('/', id.path),
	from: builder.join('/', builder.dirname(primaryId.path)));
	}
	}

	/**
	* HTML attributes that expect a URL value.
	* <http://dev.w3.org/html5/spec/section-index.html#attributes-1>
	*
	* Every one of these attributes is a URL in every context where it is used in
	* the DOM. The comments show every DOM element where an attribute can be used.
	*/
	const _urlAttributes = const [
	'action', // in form
	'background', // in body
	'cite', // in blockquote, del, ins, q
	'data', // in object
	'formaction', // in button, input
	'href', // in a, area, link, base, command
	'icon', // in command
	'manifest', // in html
	'poster', // in video
	'src', // in audio, embed, iframe, img, input, script, source, track,
	// video
	];