lib/build/script_compactor.dart - web-components - Git at Google

 // Copyright (c) 2015, 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.
 library web_components.build.script_compactor;

 import 'dart:async';
 import 'package:analyzer/analyzer.dart';
 import 'package:barback/barback.dart';
 import 'package:code_transformers/assets.dart';
 import 'package:code_transformers/messages/build_logger.dart';
 import 'package:html5lib/dom.dart' as dom;
 import 'package:html5lib/parser.dart' as parser;
 import 'package:path/path.dart' as path;
 import 'package:source_maps/refactor.dart' show TextEditTransaction;
 import 'package:source_span/source_span.dart';
 import 'common.dart';
 import 'import_crawler.dart';
 import 'messages.dart';

 /// Transformer which combines all dart scripts found in html imports into one
 /// new bootstrap file, and replaces the old entry point script with that file.
 ///
 /// Note: Does not delete the original script files (it can't because the
 /// imports may live in other packages). The [ImportInlinerTransformer] will not
 /// copy scripts when inlining imports into your entry point to compensate for
 /// this.
 class ScriptCompactorTransformer extends Transformer {
   final List<String> entryPoints;

   ScriptCompactorTransformer([this.entryPoints]);

   bool isPrimary(AssetId id) {
     if (entryPoints != null) return entryPoints.contains(id.path);
     // If no entry point is supplied, then any html file under web/ or test/ is
     // an entry point.
     return (id.path.startsWith('web/') || id.path.startsWith('test/')) &&
         id.path.endsWith('.html');
   }

   apply(Transform transform) {
     var logger = new BuildLogger(transform);
     return new ScriptCompactor(transform, transform.primaryInput.id, logger)
         .run()
         .then((Asset bootstrap) {
       if (bootstrap == null) return null;
       return transform.primaryInput.readAsString().then((html) {
         var doc = parser.parse(html);
         var mainScriptTag = doc.querySelector('script[type="$dartType"]');
         mainScriptTag.attributes['src'] =
             _importPath(bootstrap.id, transform.primaryInput.id);
         mainScriptTag.text = '';

         transform.addOutput(
             new Asset.fromString(transform.primaryInput.id, doc.outerHtml));
       });
     });
   }
 }

 /// Helper class which does all the script compacting for a single entry point.
 class ScriptCompactor {
   /// Can be an AggregateTransform or Transform
   final transform;

   /// The primary input to start from.
   final AssetId primaryInput;

   /// The logger to use.
   final BuildLogger logger;

   /// How many inline scripts were extracted.
   int inlineScriptCounter = 0;

   /// Id representing the dart script which lives in the primaryInput.
   AssetId mainScript;

   /// Ids of all the scripts found in html imports.
   final Set<AssetId> importScripts = new Set<AssetId>();

   ScriptCompactor(this.transform, this.primaryInput, this.logger);

   Future<Asset> run() {
     var crawler = new ImportCrawler(transform, primaryInput, logger);
     return crawler.crawlImports().then((imports) {
       Future extractScripts(id) =>
           _extractInlineScripts(id, imports[id].document);

       return Future.forEach(imports.keys, extractScripts).then((_) {
         if (mainScript == null) {
           logger.error(
               exactlyOneScriptPerEntryPoint.create({'url': primaryInput.path}));
           return null;
         }

         var primaryDocument = imports[primaryInput].document;
         assert(primaryDocument != null);

         // Create the new bootstrap file and return its AssetId.
         return _buildBootstrapFile(mainScript, importScripts);
       });
     });
   }

   /// Builds the bootstrap file and returns the path to it relative to
   /// [primaryInput].
   Asset _buildBootstrapFile(AssetId mainScript, Set<AssetId> importScripts) {
     var bootstrapId = new AssetId(mainScript.package,
         mainScript.path.replaceFirst('.dart', '.bootstrap.dart'));

     var buffer = new StringBuffer();
     buffer.writeln('library ${_libraryNameFor(bootstrapId)};');
     buffer.writeln();
     var i = 0;
     for (var script in importScripts) {
       var path = _importPath(script, primaryInput);
       buffer.writeln("import '$path' as i$i;");
       i++;
     }
     var mainScriptPath = _importPath(mainScript, primaryInput);
     buffer.writeln("import '$mainScriptPath' as i$i;");
     buffer.writeln();
     buffer.writeln('void main() { i$i.main(); }');

     var bootstrap = new Asset.fromString(bootstrapId, '$buffer');
     transform.addOutput(bootstrap);
     return bootstrap;
   }

   /// Split inline scripts into their own files. We need to do this for dart2js
   /// to be able to compile them.
   ///
   /// This also validates that there weren't any duplicate scripts.
   Future _extractInlineScripts(AssetId asset, dom.Document doc) {
     var scripts = doc.querySelectorAll('script[type="$dartType"]');
     return Future.forEach(scripts, (script) {
       var type = script.attributes['type'];
       var src = script.attributes['src'];

       if (src != null) {
         return _addScript(
             asset, uriToAssetId(asset, src, logger, script.sourceSpan),
             span: script.sourceSpan);
       }

       final count = inlineScriptCounter++;
       var code = script.text;
       // TODO(sigmund): ensure this path is unique (dartbug.com/12618).
       var newId = primaryInput.addExtension('.$count.dart');
       if (!_hasLibraryDirective(code)) {
         var libName = _libraryNameFor(primaryInput, count);
         code = "library $libName;\n$code";
       }

       // Normalize dart import paths.
       code = _normalizeDartImports(code, asset, primaryInput);

       // Write out the file and record it.
       transform.addOutput(new Asset.fromString(newId, code));

       return _addScript(asset, newId, validate: false).then((_) {
         // If in the entry point, replace the inline script with one pointing to
         // the new source file.
         if (primaryInput == asset) {
           script.text = '';
           script.attributes['src'] = path.url.relative(newId.path,
               from: path.url.dirname(primaryInput.path));
         }
       });
     });
   }

   // Normalize dart import paths when moving code from one asset to another.
   String _normalizeDartImports(String code, AssetId from, AssetId to) {
     var unit = parseDirectives(code, suppressErrors: true);
     var file = new SourceFile(code, url: spanUrlFor(from, to, logger));
     var output = new TextEditTransaction(code, file);
     var foundLibraryDirective = false;
     for (Directive directive in unit.directives) {
       if (directive is UriBasedDirective) {
         var uri = directive.uri.stringValue;
         var span = getSpan(file, directive.uri);

         var id = uriToAssetId(from, uri, logger, span, errorOnAbsolute: false);
         if (id == null) continue;

         var primaryId = primaryInput;
         var newUri = assetUrlFor(id, primaryId, logger);
         if (newUri != uri) {
           output.edit(span.start.offset, span.end.offset, "'$newUri'");
         }
       } else if (directive is LibraryDirective) {
         foundLibraryDirective = true;
       }
     }

     if (!output.hasEdits) return code;

     // TODO(sigmund): emit source maps when barback supports it (see
     // dartbug.com/12340)
     return (output.commit()..build(file.url.toString())).text;
   }

   Future _addScript(AssetId from, AssetId scriptId,
       {bool validate: true, SourceSpan span}) {
     var validateFuture;
     if (validate && !importScripts.contains(scriptId)) {
       validateFuture = transform.hasInput(scriptId);
     } else {
       validateFuture = new Future.value(true);
     }
     return validateFuture.then((exists) {
       if (!exists) {
         logger.warning(scriptFileNotFound.create({'url': scriptId}),
             span: span);
       }

       if (from == primaryInput) {
         if (mainScript != null) {
           logger
               .error(exactlyOneScriptPerEntryPoint.create({'url': from.path}));
         }
         mainScript = scriptId;
       } else {
         importScripts.add(scriptId);
       }
     });
   }
 }

 /// Generate a library name for an asset.
 String _libraryNameFor(AssetId id, [int suffix]) {
   var name = '${path.withoutExtension(id.path)}_'
       '${path.extension(id.path).substring(1)}';
   if (name.startsWith('lib/')) name = name.substring(4);
   name = name.split('/').map((part) {
     part = part.replaceAll(_invalidLibCharsRegex, '_');
     if (part.startsWith(_numRegex)) part = '_${part}';
     return part;
   }).join(".");
   var suffixString = suffix != null ? '_$suffix' : '';
   return '${id.package}.${name}$suffixString';
 }

 /// Parse [code] and determine whether it has a library directive.
 bool _hasLibraryDirective(String code) =>
     parseDirectives(code, suppressErrors: true).directives
         .any((d) => d is LibraryDirective);

 /// Returns the dart import path to reach [id] relative to [primaryInput].
 String _importPath(AssetId id, AssetId primaryInput) {
   var parts = path.url.split(id.path);
   if (parts[0] == 'lib') {
     parts[0] = id.package;
     return 'package:${path.url.joinAll(parts)}';
   }
   return path.url.relative(id.path, from: path.url.dirname(primaryInput.path));
 }

 // Constant and final variables
 final _invalidLibCharsRegex = new RegExp('[^a-z0-9_]');
 final _numRegex = new RegExp('[0-9]');
	// Copyright (c) 2015, 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.
	library web_components.build.script_compactor;

	import 'dart:async';
	import 'package:analyzer/analyzer.dart';
	import 'package:barback/barback.dart';
	import 'package:code_transformers/assets.dart';
	import 'package:code_transformers/messages/build_logger.dart';
	import 'package:html5lib/dom.dart' as dom;
	import 'package:html5lib/parser.dart' as parser;
	import 'package:path/path.dart' as path;
	import 'package:source_maps/refactor.dart' show TextEditTransaction;
	import 'package:source_span/source_span.dart';
	import 'common.dart';
	import 'import_crawler.dart';
	import 'messages.dart';

	/// Transformer which combines all dart scripts found in html imports into one
	/// new bootstrap file, and replaces the old entry point script with that file.
	///
	/// Note: Does not delete the original script files (it can't because the
	/// imports may live in other packages). The [ImportInlinerTransformer] will not
	/// copy scripts when inlining imports into your entry point to compensate for
	/// this.
	class ScriptCompactorTransformer extends Transformer {
	final List<String> entryPoints;

	ScriptCompactorTransformer([this.entryPoints]);

	bool isPrimary(AssetId id) {
	if (entryPoints != null) return entryPoints.contains(id.path);
	// If no entry point is supplied, then any html file under web/ or test/ is
	// an entry point.
	return (id.path.startsWith('web/') \|\| id.path.startsWith('test/')) &&
	id.path.endsWith('.html');
	}

	apply(Transform transform) {
	var logger = new BuildLogger(transform);
	return new ScriptCompactor(transform, transform.primaryInput.id, logger)
	.run()
	.then((Asset bootstrap) {
	if (bootstrap == null) return null;
	return transform.primaryInput.readAsString().then((html) {
	var doc = parser.parse(html);
	var mainScriptTag = doc.querySelector('script[type="$dartType"]');
	mainScriptTag.attributes['src'] =
	_importPath(bootstrap.id, transform.primaryInput.id);
	mainScriptTag.text = '';

	transform.addOutput(
	new Asset.fromString(transform.primaryInput.id, doc.outerHtml));
	});
	});
	}
	}

	/// Helper class which does all the script compacting for a single entry point.
	class ScriptCompactor {
	/// Can be an AggregateTransform or Transform
	final transform;

	/// The primary input to start from.
	final AssetId primaryInput;

	/// The logger to use.
	final BuildLogger logger;

	/// How many inline scripts were extracted.
	int inlineScriptCounter = 0;

	/// Id representing the dart script which lives in the primaryInput.
	AssetId mainScript;

	/// Ids of all the scripts found in html imports.
	final Set<AssetId> importScripts = new Set<AssetId>();

	ScriptCompactor(this.transform, this.primaryInput, this.logger);

	Future<Asset> run() {
	var crawler = new ImportCrawler(transform, primaryInput, logger);
	return crawler.crawlImports().then((imports) {
	Future extractScripts(id) =>
	_extractInlineScripts(id, imports[id].document);

	return Future.forEach(imports.keys, extractScripts).then((_) {
	if (mainScript == null) {
	logger.error(
	exactlyOneScriptPerEntryPoint.create({'url': primaryInput.path}));
	return null;
	}

	var primaryDocument = imports[primaryInput].document;
	assert(primaryDocument != null);

	// Create the new bootstrap file and return its AssetId.
	return _buildBootstrapFile(mainScript, importScripts);
	});
	});
	}

	/// Builds the bootstrap file and returns the path to it relative to
	/// [primaryInput].
	Asset _buildBootstrapFile(AssetId mainScript, Set<AssetId> importScripts) {
	var bootstrapId = new AssetId(mainScript.package,
	mainScript.path.replaceFirst('.dart', '.bootstrap.dart'));

	var buffer = new StringBuffer();
	buffer.writeln('library ${_libraryNameFor(bootstrapId)};');
	buffer.writeln();
	var i = 0;
	for (var script in importScripts) {
	var path = _importPath(script, primaryInput);
	buffer.writeln("import '$path' as i$i;");
	i++;
	}
	var mainScriptPath = _importPath(mainScript, primaryInput);
	buffer.writeln("import '$mainScriptPath' as i$i;");
	buffer.writeln();
	buffer.writeln('void main() { i$i.main(); }');

	var bootstrap = new Asset.fromString(bootstrapId, '$buffer');
	transform.addOutput(bootstrap);
	return bootstrap;
	}

	/// Split inline scripts into their own files. We need to do this for dart2js
	/// to be able to compile them.
	///
	/// This also validates that there weren't any duplicate scripts.
	Future _extractInlineScripts(AssetId asset, dom.Document doc) {
	var scripts = doc.querySelectorAll('script[type="$dartType"]');
	return Future.forEach(scripts, (script) {
	var type = script.attributes['type'];
	var src = script.attributes['src'];

	if (src != null) {
	return _addScript(
	asset, uriToAssetId(asset, src, logger, script.sourceSpan),
	span: script.sourceSpan);
	}

	final count = inlineScriptCounter++;
	var code = script.text;
	// TODO(sigmund): ensure this path is unique (dartbug.com/12618).
	var newId = primaryInput.addExtension('.$count.dart');
	if (!_hasLibraryDirective(code)) {
	var libName = _libraryNameFor(primaryInput, count);
	code = "library $libName;\n$code";
	}

	// Normalize dart import paths.
	code = _normalizeDartImports(code, asset, primaryInput);

	// Write out the file and record it.
	transform.addOutput(new Asset.fromString(newId, code));

	return _addScript(asset, newId, validate: false).then((_) {
	// If in the entry point, replace the inline script with one pointing to
	// the new source file.
	if (primaryInput == asset) {
	script.text = '';
	script.attributes['src'] = path.url.relative(newId.path,
	from: path.url.dirname(primaryInput.path));
	}
	});
	});
	}

	// Normalize dart import paths when moving code from one asset to another.
	String _normalizeDartImports(String code, AssetId from, AssetId to) {
	var unit = parseDirectives(code, suppressErrors: true);
	var file = new SourceFile(code, url: spanUrlFor(from, to, logger));
	var output = new TextEditTransaction(code, file);
	var foundLibraryDirective = false;
	for (Directive directive in unit.directives) {
	if (directive is UriBasedDirective) {
	var uri = directive.uri.stringValue;
	var span = getSpan(file, directive.uri);

	var id = uriToAssetId(from, uri, logger, span, errorOnAbsolute: false);
	if (id == null) continue;

	var primaryId = primaryInput;
	var newUri = assetUrlFor(id, primaryId, logger);
	if (newUri != uri) {
	output.edit(span.start.offset, span.end.offset, "'$newUri'");
	}
	} else if (directive is LibraryDirective) {
	foundLibraryDirective = true;
	}
	}

	if (!output.hasEdits) return code;

	// TODO(sigmund): emit source maps when barback supports it (see
	// dartbug.com/12340)
	return (output.commit()..build(file.url.toString())).text;
	}

	Future _addScript(AssetId from, AssetId scriptId,
	{bool validate: true, SourceSpan span}) {
	var validateFuture;
	if (validate && !importScripts.contains(scriptId)) {
	validateFuture = transform.hasInput(scriptId);
	} else {
	validateFuture = new Future.value(true);
	}
	return validateFuture.then((exists) {
	if (!exists) {
	logger.warning(scriptFileNotFound.create({'url': scriptId}),
	span: span);
	}

	if (from == primaryInput) {
	if (mainScript != null) {
	logger
	.error(exactlyOneScriptPerEntryPoint.create({'url': from.path}));
	}
	mainScript = scriptId;
	} else {
	importScripts.add(scriptId);
	}
	});
	}
	}

	/// Generate a library name for an asset.
	String _libraryNameFor(AssetId id, [int suffix]) {
	var name = '${path.withoutExtension(id.path)}_'
	'${path.extension(id.path).substring(1)}';
	if (name.startsWith('lib/')) name = name.substring(4);
	name = name.split('/').map((part) {
	part = part.replaceAll(_invalidLibCharsRegex, '_');
	if (part.startsWith(_numRegex)) part = '_${part}';
	return part;
	}).join(".");
	var suffixString = suffix != null ? '_$suffix' : '';
	return '${id.package}.${name}$suffixString';
	}

	/// Parse [code] and determine whether it has a library directive.
	bool _hasLibraryDirective(String code) =>
	parseDirectives(code, suppressErrors: true).directives
	.any((d) => d is LibraryDirective);

	/// Returns the dart import path to reach [id] relative to [primaryInput].
	String _importPath(AssetId id, AssetId primaryInput) {
	var parts = path.url.split(id.path);
	if (parts[0] == 'lib') {
	parts[0] = id.package;
	return 'package:${path.url.joinAll(parts)}';
	}
	return path.url.relative(id.path, from: path.url.dirname(primaryInput.path));
	}

	// Constant and final variables
	final _invalidLibCharsRegex = new RegExp('[^a-z0-9_]');
	final _numRegex = new RegExp('[0-9]');