pkg/polymer/lib/src/build/script_compactor.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 combines multiple dart script tags into a single one.
 library polymer.src.build.script_compactor;

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

 import 'package:html5lib/dom.dart' show Document, Element;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:barback/barback.dart';
 import 'package:code_transformers/assets.dart';
 import 'package:path/path.dart' as path;
 import 'package:source_maps/span.dart' show SourceFile;

 import 'import_inliner.dart' show ImportInliner; // just for docs.
 import 'common.dart';

 /// Combines Dart script tags into a single script tag, and creates a new Dart
 /// file that calls the main function of each of the original script tags.
 ///
 /// This transformer assumes that all script tags point to external files. To
 /// support script tags with inlined code, use this transformer after running
 /// [ImportInliner] on an earlier phase.
 ///
 /// Internally, this transformer will convert each script tag into an import
 /// statement to a library, and then uses `initPolymer` (see polymer.dart)  to
 /// process `@initMethod` and `@CustomTag` annotations in those libraries.
 class ScriptCompactor extends Transformer {
   final TransformOptions options;

   ScriptCompactor(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 _ScriptCompactor(transform, options).apply();
 }

 /// Helper class mainly use to flatten the async code.
 class _ScriptCompactor extends PolymerTransformer {
   final TransformOptions options;
   final Transform transform;
   final TransformLogger logger;
   final AssetId docId;
   final AssetId bootstrapId;

   Document document;
   List<AssetId> entryLibraries;
   AssetId mainLibraryId;
   Element mainScriptTag;
   final Map<AssetId, List<_Initializer>> initializers = {};

   _ScriptCompactor(Transform transform, this.options)
       : transform = transform,
         logger = transform.logger,
         docId = transform.primaryInput.id,
         bootstrapId = transform.primaryInput.id.addExtension('_bootstrap.dart');

   Future apply() =>
       _loadDocument()
       .then(_loadEntryLibraries)
       .then(_processHtml)
       .then(_emitNewEntrypoint);

   /// Loads the primary input as an html document.
   Future _loadDocument() =>
       readPrimaryAsHtml(transform).then((doc) { document = doc; });

   /// Populates [entryLibraries] as a list containing the asset ids of each
   /// library loaded on a script tag. The actual work of computing this is done
   /// in an earlier phase and emited in the `entrypoint.scriptUrls` asset.
   Future _loadEntryLibraries(_) =>
       transform.readInputAsString(docId.addExtension('.scriptUrls'))
           .then((libraryIds) {
         entryLibraries = (JSON.decode(libraryIds) as Iterable)
             .map((data) => new AssetId.deserialize(data)).toList();
       });

   /// Removes unnecessary script tags, and identifies the main entry point Dart
   /// script tag (if any).
   void _processHtml(_) {
     for (var tag in document.querySelectorAll('script')) {
       var src = tag.attributes['src'];
       if (src == 'packages/polymer/boot.js') {
         tag.remove();
         continue;
       }
       if (tag.attributes['type'] != 'application/dart') continue;
       if (src == null) {
         logger.warning('unexpected script without a src url. The '
           'ScriptCompactor transformer should run after running the '
           'InlineCodeExtractor', span: tag.sourceSpan);
         continue;
       }
       if (mainLibraryId != null) {
         logger.warning('unexpected script. Only one Dart script tag '
           'per document is allowed.', span: tag.sourceSpan);
         tag.remove();
         continue;
       }
       mainLibraryId = uriToAssetId(docId, src, logger, tag.sourceSpan);
       mainScriptTag = tag;
     }
   }

   /// Emits the main HTML and Dart bootstrap code for the application. If there
   /// were not Dart entry point files, then this simply emits the original HTML.
   Future _emitNewEntrypoint(_) {
     if (mainScriptTag == null) {
       // We didn't find any main library, nothing to do.
       transform.addOutput(transform.primaryInput);
       return null;
     }

     // Emit the bootstrap .dart file
     mainScriptTag.attributes['src'] = path.url.basename(bootstrapId.path);
     entryLibraries.add(mainLibraryId);
     return _computeInitializers().then(_createBootstrapCode).then((code) {
       transform.addOutput(new Asset.fromString(bootstrapId, code));
       transform.addOutput(new Asset.fromString(docId, document.outerHtml));
     });
   }

   /// Emits the actual bootstrap code.
   String _createBootstrapCode(_) {
     StringBuffer code = new StringBuffer()..writeln(MAIN_HEADER);
     for (int i = 0; i < entryLibraries.length; i++) {
       var url = assetUrlFor(entryLibraries[i], bootstrapId, logger);
       if (url != null) code.writeln("import '$url' as i$i;");
     }

     code..write('\n')
         ..writeln('void main() {')
         ..writeln('  configureForDeployment([');

     // Inject @CustomTag and @initMethod initializations for each library
     // that is sourced in a script tag.
     for (int i = 0; i < entryLibraries.length; i++) {
       for (var init in initializers[entryLibraries[i]]) {
         var initCode = init.asCode('i$i');
         code.write("      $initCode,\n");
       }
     }
     code..writeln('    ]);')
         ..writeln('  i${entryLibraries.length - 1}.main();')
         ..writeln('}');
     return code.toString();
   }

   /// Computes initializers needed for each library in [entryLibraries]. Results
   /// are available afterwards in [initializers].
   Future _computeInitializers() => Future.forEach(entryLibraries, (lib) {
       return _initializersOf(lib).then((res) {
         initializers[lib] = res;
       });
     });

   /// Computes the initializers of [dartLibrary]. That is, a closure that calls
   /// Polymer.register for each @CustomTag, and any public top-level methods
   /// labeled with @initMethod.
   Future<List<_Initializer>> _initializersOf(AssetId dartLibrary) {
     var result = [];
     return transform.readInputAsString(dartLibrary).then((code) {
       var file = new SourceFile.text(_simpleUriForSource(dartLibrary), code);
       var unit = parseCompilationUnit(code);

       return Future.forEach(unit.directives, (directive) {
         // Include anything from parts.
         if (directive is PartDirective) {
           var targetId = uriToAssetId(dartLibrary, directive.uri.stringValue,
               logger, _getSpan(file, directive));
           return _initializersOf(targetId).then(result.addAll);
         }

         // Similarly, include anything from exports except what's filtered by
         // the show/hide combinators.
         if (directive is ExportDirective) {
           var targetId = uriToAssetId(dartLibrary, directive.uri.stringValue,
               logger, _getSpan(file, directive));
           return _initializersOf(targetId).then(
             (r) => _processExportDirective(directive, r, result));
         }
       }).then((_) {
         // Scan the code for classes and top-level functions.
         for (var node in unit.declarations) {
           if (node is ClassDeclaration) {
             _processClassDeclaration(node, result, file, logger);
           } else if (node is FunctionDeclaration &&
               node.metadata.any(_isInitMethodAnnotation)) {
             _processFunctionDeclaration(node, result, file, logger);
           }
         }
         return result;
       });
     });
   }

   static String _simpleUriForSource(AssetId source) =>
       source.path.startsWith('lib/')
       ? 'package:${source.package}/${source.path.substring(4)}' : source.path;

   /// Filter [exportedInitializers] according to [directive]'s show/hide
   /// combinators and add the result to [result].
   // TODO(sigmund): call the analyzer's resolver instead?
   static _processExportDirective(ExportDirective directive,
       List<_Initializer> exportedInitializers,
       List<_Initializer> result) {
     for (var combinator in directive.combinators) {
       if (combinator is ShowCombinator) {
         var show = combinator.shownNames.map((n) => n.name).toSet();
         exportedInitializers.retainWhere((e) => show.contains(e.symbolName));
       } else if (combinator is HideCombinator) {
         var hide = combinator.hiddenNames.map((n) => n.name).toSet();
         exportedInitializers.removeWhere((e) => hide.contains(e.symbolName));
       }
     }
     result.addAll(exportedInitializers);
   }

   /// Add an initializer to register [node] as a polymer element if it contains
   /// an appropriate [CustomTag] annotation.
   static _processClassDeclaration(ClassDeclaration node,
       List<_Initializer> result, SourceFile file,
       TransformLogger logger) {
     for (var meta in node.metadata) {
       if (!_isCustomTagAnnotation(meta)) continue;
       var args = meta.arguments.arguments;
       if (args == null || args.length == 0) {
         logger.error('Missing argument in @CustomTag annotation',
             span: _getSpan(file, meta));
         continue;
       }

       var tagName = args[0].stringValue;
       var typeName = node.name.name;
       if (typeName.startsWith('_')) {
         logger.error('@CustomTag is no longer supported on private '
           'classes: $tagName', span: _getSpan(file, node.name));
         continue;
       }
       result.add(new _CustomTagInitializer(tagName, typeName));
     }
   }

   /// Add a method initializer for [function].
   static _processFunctionDeclaration(FunctionDeclaration function,
       List<_Initializer> result, SourceFile file,
       TransformLogger logger) {
     var name = function.name.name;
     if (name.startsWith('_')) {
       logger.error('@initMethod is no longer supported on private '
         'functions: $name', span: _getSpan(file, function.name));
       return;
     }
     result.add(new _InitMethodInitializer(name));
   }
 }

 // TODO(sigmund): consider support for importing annotations with prefixes.
 bool _isInitMethodAnnotation(Annotation node) =>
     node.name.name == 'initMethod' && node.constructorName == null &&
     node.arguments == null;
 bool _isCustomTagAnnotation(Annotation node) => node.name.name == 'CustomTag';

 abstract class _Initializer {
   String get symbolName;
   String asCode(String prefix);
 }

 class _InitMethodInitializer implements _Initializer {
   String methodName;
   String get symbolName => methodName;
   _InitMethodInitializer(this.methodName);

   String asCode(String prefix) => "$prefix.$methodName";
 }

 class _CustomTagInitializer implements _Initializer {
   String tagName;
   String typeName;
   String get symbolName => typeName;
   _CustomTagInitializer(this.tagName, this.typeName);

   String asCode(String prefix) =>
       "() => Polymer.register('$tagName', $prefix.$typeName)";
 }

 _getSpan(SourceFile file, AstNode node) => file.span(node.offset, node.end);

 const MAIN_HEADER = """
 library app_bootstrap;

 import 'package:polymer/polymer.dart';
 import 'package:smoke/static.dart' as smoke;
 """;
	// 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 combines multiple dart script tags into a single one.
	library polymer.src.build.script_compactor;

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

	import 'package:html5lib/dom.dart' show Document, Element;
	import 'package:analyzer/src/generated/ast.dart';
	import 'package:barback/barback.dart';
	import 'package:code_transformers/assets.dart';
	import 'package:path/path.dart' as path;
	import 'package:source_maps/span.dart' show SourceFile;

	import 'import_inliner.dart' show ImportInliner; // just for docs.
	import 'common.dart';

	/// Combines Dart script tags into a single script tag, and creates a new Dart
	/// file that calls the main function of each of the original script tags.
	///
	/// This transformer assumes that all script tags point to external files. To
	/// support script tags with inlined code, use this transformer after running
	/// [ImportInliner] on an earlier phase.
	///
	/// Internally, this transformer will convert each script tag into an import
	/// statement to a library, and then uses `initPolymer` (see polymer.dart) to
	/// process `@initMethod` and `@CustomTag` annotations in those libraries.
	class ScriptCompactor extends Transformer {
	final TransformOptions options;

	ScriptCompactor(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 _ScriptCompactor(transform, options).apply();
	}

	/// Helper class mainly use to flatten the async code.
	class _ScriptCompactor extends PolymerTransformer {
	final TransformOptions options;
	final Transform transform;
	final TransformLogger logger;
	final AssetId docId;
	final AssetId bootstrapId;

	Document document;
	List<AssetId> entryLibraries;
	AssetId mainLibraryId;
	Element mainScriptTag;
	final Map<AssetId, List<_Initializer>> initializers = {};

	_ScriptCompactor(Transform transform, this.options)
	: transform = transform,
	logger = transform.logger,
	docId = transform.primaryInput.id,
	bootstrapId = transform.primaryInput.id.addExtension('_bootstrap.dart');

	Future apply() =>
	_loadDocument()
	.then(_loadEntryLibraries)
	.then(_processHtml)
	.then(_emitNewEntrypoint);

	/// Loads the primary input as an html document.
	Future _loadDocument() =>
	readPrimaryAsHtml(transform).then((doc) { document = doc; });

	/// Populates [entryLibraries] as a list containing the asset ids of each
	/// library loaded on a script tag. The actual work of computing this is done
	/// in an earlier phase and emited in the `entrypoint.scriptUrls` asset.
	Future _loadEntryLibraries(_) =>
	transform.readInputAsString(docId.addExtension('.scriptUrls'))
	.then((libraryIds) {
	entryLibraries = (JSON.decode(libraryIds) as Iterable)
	.map((data) => new AssetId.deserialize(data)).toList();
	});

	/// Removes unnecessary script tags, and identifies the main entry point Dart
	/// script tag (if any).
	void _processHtml(_) {
	for (var tag in document.querySelectorAll('script')) {
	var src = tag.attributes['src'];
	if (src == 'packages/polymer/boot.js') {
	tag.remove();
	continue;
	}
	if (tag.attributes['type'] != 'application/dart') continue;
	if (src == null) {
	logger.warning('unexpected script without a src url. The '
	'ScriptCompactor transformer should run after running the '
	'InlineCodeExtractor', span: tag.sourceSpan);
	continue;
	}
	if (mainLibraryId != null) {
	logger.warning('unexpected script. Only one Dart script tag '
	'per document is allowed.', span: tag.sourceSpan);
	tag.remove();
	continue;
	}
	mainLibraryId = uriToAssetId(docId, src, logger, tag.sourceSpan);
	mainScriptTag = tag;
	}
	}

	/// Emits the main HTML and Dart bootstrap code for the application. If there
	/// were not Dart entry point files, then this simply emits the original HTML.
	Future _emitNewEntrypoint(_) {
	if (mainScriptTag == null) {
	// We didn't find any main library, nothing to do.
	transform.addOutput(transform.primaryInput);
	return null;
	}

	// Emit the bootstrap .dart file
	mainScriptTag.attributes['src'] = path.url.basename(bootstrapId.path);
	entryLibraries.add(mainLibraryId);
	return _computeInitializers().then(_createBootstrapCode).then((code) {
	transform.addOutput(new Asset.fromString(bootstrapId, code));
	transform.addOutput(new Asset.fromString(docId, document.outerHtml));
	});
	}

	/// Emits the actual bootstrap code.
	String _createBootstrapCode(_) {
	StringBuffer code = new StringBuffer()..writeln(MAIN_HEADER);
	for (int i = 0; i < entryLibraries.length; i++) {
	var url = assetUrlFor(entryLibraries[i], bootstrapId, logger);
	if (url != null) code.writeln("import '$url' as i$i;");
	}

	code..write('\n')
	..writeln('void main() {')
	..writeln(' configureForDeployment([');

	// Inject @CustomTag and @initMethod initializations for each library
	// that is sourced in a script tag.
	for (int i = 0; i < entryLibraries.length; i++) {
	for (var init in initializers[entryLibraries[i]]) {
	var initCode = init.asCode('i$i');
	code.write(" $initCode,\n");
	}
	}
	code..writeln(' ]);')
	..writeln(' i${entryLibraries.length - 1}.main();')
	..writeln('}');
	return code.toString();
	}

	/// Computes initializers needed for each library in [entryLibraries]. Results
	/// are available afterwards in [initializers].
	Future _computeInitializers() => Future.forEach(entryLibraries, (lib) {
	return _initializersOf(lib).then((res) {
	initializers[lib] = res;
	});
	});

	/// Computes the initializers of [dartLibrary]. That is, a closure that calls
	/// Polymer.register for each @CustomTag, and any public top-level methods
	/// labeled with @initMethod.
	Future<List<_Initializer>> _initializersOf(AssetId dartLibrary) {
	var result = [];
	return transform.readInputAsString(dartLibrary).then((code) {
	var file = new SourceFile.text(_simpleUriForSource(dartLibrary), code);
	var unit = parseCompilationUnit(code);

	return Future.forEach(unit.directives, (directive) {
	// Include anything from parts.
	if (directive is PartDirective) {
	var targetId = uriToAssetId(dartLibrary, directive.uri.stringValue,
	logger, _getSpan(file, directive));
	return _initializersOf(targetId).then(result.addAll);
	}

	// Similarly, include anything from exports except what's filtered by
	// the show/hide combinators.
	if (directive is ExportDirective) {
	var targetId = uriToAssetId(dartLibrary, directive.uri.stringValue,
	logger, _getSpan(file, directive));
	return _initializersOf(targetId).then(
	(r) => _processExportDirective(directive, r, result));
	}
	}).then((_) {
	// Scan the code for classes and top-level functions.
	for (var node in unit.declarations) {
	if (node is ClassDeclaration) {
	_processClassDeclaration(node, result, file, logger);
	} else if (node is FunctionDeclaration &&
	node.metadata.any(_isInitMethodAnnotation)) {
	_processFunctionDeclaration(node, result, file, logger);
	}
	}
	return result;
	});
	});
	}

	static String _simpleUriForSource(AssetId source) =>
	source.path.startsWith('lib/')
	? 'package:${source.package}/${source.path.substring(4)}' : source.path;

	/// Filter [exportedInitializers] according to [directive]'s show/hide
	/// combinators and add the result to [result].
	// TODO(sigmund): call the analyzer's resolver instead?
	static _processExportDirective(ExportDirective directive,
	List<_Initializer> exportedInitializers,
	List<_Initializer> result) {
	for (var combinator in directive.combinators) {
	if (combinator is ShowCombinator) {
	var show = combinator.shownNames.map((n) => n.name).toSet();
	exportedInitializers.retainWhere((e) => show.contains(e.symbolName));
	} else if (combinator is HideCombinator) {
	var hide = combinator.hiddenNames.map((n) => n.name).toSet();
	exportedInitializers.removeWhere((e) => hide.contains(e.symbolName));
	}
	}
	result.addAll(exportedInitializers);
	}

	/// Add an initializer to register [node] as a polymer element if it contains
	/// an appropriate [CustomTag] annotation.
	static _processClassDeclaration(ClassDeclaration node,
	List<_Initializer> result, SourceFile file,
	TransformLogger logger) {
	for (var meta in node.metadata) {
	if (!_isCustomTagAnnotation(meta)) continue;
	var args = meta.arguments.arguments;
	if (args == null \|\| args.length == 0) {
	logger.error('Missing argument in @CustomTag annotation',
	span: _getSpan(file, meta));
	continue;
	}

	var tagName = args[0].stringValue;
	var typeName = node.name.name;
	if (typeName.startsWith('_')) {
	logger.error('@CustomTag is no longer supported on private '
	'classes: $tagName', span: _getSpan(file, node.name));
	continue;
	}
	result.add(new _CustomTagInitializer(tagName, typeName));
	}
	}

	/// Add a method initializer for [function].
	static _processFunctionDeclaration(FunctionDeclaration function,
	List<_Initializer> result, SourceFile file,
	TransformLogger logger) {
	var name = function.name.name;
	if (name.startsWith('_')) {
	logger.error('@initMethod is no longer supported on private '
	'functions: $name', span: _getSpan(file, function.name));
	return;
	}
	result.add(new _InitMethodInitializer(name));
	}
	}

	// TODO(sigmund): consider support for importing annotations with prefixes.
	bool _isInitMethodAnnotation(Annotation node) =>
	node.name.name == 'initMethod' && node.constructorName == null &&
	node.arguments == null;
	bool _isCustomTagAnnotation(Annotation node) => node.name.name == 'CustomTag';

	abstract class _Initializer {
	String get symbolName;
	String asCode(String prefix);
	}

	class _InitMethodInitializer implements _Initializer {
	String methodName;
	String get symbolName => methodName;
	_InitMethodInitializer(this.methodName);

	String asCode(String prefix) => "$prefix.$methodName";
	}

	class _CustomTagInitializer implements _Initializer {
	String tagName;
	String typeName;
	String get symbolName => typeName;
	_CustomTagInitializer(this.tagName, this.typeName);

	String asCode(String prefix) =>
	"() => Polymer.register('$tagName', $prefix.$typeName)";
	}

	_getSpan(SourceFile file, AstNode node) => file.span(node.offset, node.end);

	const MAIN_HEADER = """
	library app_bootstrap;

	import 'package:polymer/polymer.dart';
	import 'package:smoke/static.dart' as smoke;
	""";