dev/snippets/lib/snippets.dart - mirrors/flutter - Git at Google

 // Copyright 2018 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:convert';
 import 'dart:io';

 import 'package:path/path.dart' as path;
 import 'package:dart_style/dart_style.dart';

 import 'configuration.dart';

 void errorExit(String message) {
   stderr.writeln(message);
   exit(1);
 }

 // A Tuple containing the name and contents associated with a code block in a
 // snippet.
 class _ComponentTuple {
   _ComponentTuple(this.name, this.contents, {String language}) : language = language ?? '';
   final String name;
   final List<String> contents;
   final String language;
   String get mergedContent => contents.join('\n').trim();
 }

 /// Generates the snippet HTML, as well as saving the output snippet main to
 /// the output directory.
 class SnippetGenerator {
   SnippetGenerator({Configuration configuration})
       : configuration = configuration ??
             // Flutter's root is four directories up from this script.
             Configuration(flutterRoot: Directory(Platform.environment['FLUTTER_ROOT']
                 ?? path.canonicalize(path.join(path.dirname(path.fromUri(Platform.script)), '..', '..', '..')))) {
     this.configuration.createOutputDirectory();
   }

   /// The configuration used to determine where to get/save data for the
   /// snippet.
   final Configuration configuration;

   static const JsonEncoder jsonEncoder = JsonEncoder.withIndent('    ');

   /// A Dart formatted used to format the snippet code and finished application
   /// code.
   static DartFormatter formatter = DartFormatter(pageWidth: 80, fixes: StyleFix.all);

   /// This returns the output file for a given snippet ID. Only used for
   /// [SnippetType.application] snippets.
   File getOutputFile(String id) => File(path.join(configuration.outputDirectory.path, '$id.dart'));

   /// Gets the path to the template file requested.
   File getTemplatePath(String templateName, {Directory templatesDir}) {
     final Directory templateDir = templatesDir ?? configuration.templatesDirectory;
     final File templateFile = File(path.join(templateDir.path, '$templateName.tmpl'));
     return templateFile.existsSync() ? templateFile : null;
   }

   /// Injects the [injections] into the [template], and turning the
   /// "description" injection into a comment. Only used for
   /// [SnippetType.application] snippets.
   String interpolateTemplate(List<_ComponentTuple> injections, String template) {
     final RegExp moustacheRegExp = RegExp('{{([^}]+)}}');
     return template.replaceAllMapped(moustacheRegExp, (Match match) {
       if (match[1] == 'description') {
         // Place the description into a comment.
         final List<String> description = injections
             .firstWhere((_ComponentTuple tuple) => tuple.name == match[1])
             .contents
             .map<String>((String line) => '// $line')
             .toList();
         // Remove any leading/trailing empty comment lines.
         // We don't want to remove ALL empty comment lines, only the ones at the
         // beginning and the end.
         while (description.isNotEmpty && description.last == '// ') {
           description.removeLast();
         }
         while (description.isNotEmpty && description.first == '// ') {
           description.removeAt(0);
         }
         return description.join('\n').trim();
       } else {
         // If the match isn't found in the injections, then just remove the
         // moustache reference, since we want to allow the sections to be
         // "optional" in the input: users shouldn't be forced to add an empty
         // "```dart preamble" section if that section would be empty.
         return injections
             .firstWhere((_ComponentTuple tuple) => tuple.name == match[1], orElse: () => null)
             ?.mergedContent ?? '';
       }
     }).trim();
   }

   /// Interpolates the [injections] into an HTML skeleton file.
   ///
   /// Similar to interpolateTemplate, but we are only looking for `code-`
   /// components, and we care about the order of the injections.
   ///
   /// Takes into account the [type] and doesn't substitute in the id and the app
   /// if not a [SnippetType.application] snippet.
   String interpolateSkeleton(SnippetType type, List<_ComponentTuple> injections, String skeleton, Map<String, Object> metadata) {
     final List<String> result = <String>[];
     const HtmlEscape htmlEscape = HtmlEscape();
     String language;
     for (_ComponentTuple injection in injections) {
       if (!injection.name.startsWith('code')) {
         continue;
       }
       result.addAll(injection.contents);
       if (injection.language.isNotEmpty) {
         language = injection.language;
       }
       result.addAll(<String>['', '// ...', '']);
     }
     if (result.length > 3) {
       result.removeRange(result.length - 3, result.length);
     }
     // Only insert a div for the description if there actually is some text there.
     // This means that the {{description}} marker in the skeleton needs to
     // be inside of an {@inject-html} block.
     String description = injections.firstWhere((_ComponentTuple tuple) => tuple.name == 'description').mergedContent;
     description = description.trim().isNotEmpty
         ? '<div class="snippet-description">{@end-inject-html}$description{@inject-html}</div>'
         : '';
     final Map<String, String> substitutions = <String, String>{
       'description': description,
       'code': htmlEscape.convert(result.join('\n')),
       'language': language ?? 'dart',
     }..addAll(type == SnippetType.application
         ? <String, String>{
             'serial': metadata['serial'].toString() ?? '0',
             'id':
                 injections.firstWhere((_ComponentTuple tuple) => tuple.name == 'id').mergedContent,
             'app':
                 htmlEscape.convert(injections.firstWhere((_ComponentTuple tuple) => tuple.name == 'app').mergedContent),
           }
         : <String, String>{'serial': '', 'id': '', 'app': ''});
     return skeleton.replaceAllMapped(RegExp('{{(${substitutions.keys.join('|')})}}'), (Match match) {
       return substitutions[match[1]];
     });
   }

   /// Parses the input for the various code and description segments, and
   /// returns them in the order found.
   List<_ComponentTuple> parseInput(String input) {
     bool inCodeBlock = false;
     input = input.trim();
     final List<String> description = <String>[];
     final List<_ComponentTuple> components = <_ComponentTuple>[];
     String language;
     final RegExp codeStartEnd = RegExp(r'^\s*```([-\w]+|[-\w]+ ([-\w]+))?\s*$');
     for (String line in input.split('\n')) {
       final Match match = codeStartEnd.firstMatch(line);
       if (match != null) { // If we saw the start or end of a code block
         inCodeBlock = !inCodeBlock;
         if (match[1] != null) {
           language = match[1];
           if (match[2] != null) {
             components.add(_ComponentTuple('code-${match[2]}', <String>[], language: language));
           } else {
             components.add(_ComponentTuple('code', <String>[], language: language));
           }
         } else {
           language = null;
         }
         continue;
       }
       if (!inCodeBlock) {
         description.add(line);
       } else {
         assert(language != null);
         components.last.contents.add(line);
       }
     }
     return <_ComponentTuple>[
       _ComponentTuple('description', description),
     ]..addAll(components);
   }

   String _loadFileAsUtf8(File file) {
     return file.readAsStringSync(encoding: Encoding.getByName('utf-8'));
   }

   String _addLineNumbers(String app) {
     final StringBuffer buffer = StringBuffer();
     int count = 0;
     for (String line in app.split('\n')) {
       count++;
       buffer.writeln('${count.toString().padLeft(5, ' ')}: $line');
     }
     return buffer.toString();
   }

   /// The main routine for generating snippets.
   ///
   /// The [input] is the file containing the dartdoc comments (minus the leading
   /// comment markers).
   ///
   /// The [type] is the type of snippet to create: either a
   /// [SnippetType.application] or a [SnippetType.sample].
   ///
   /// The [template] must not be null if the [type] is
   /// [SnippetType.application], and specifies the name of the template to use
   /// for the application code.
   ///
   /// The [id] is a string ID to use for the output file, and to tell the user
   /// about in the `flutter create` hint. It must not be null if the [type] is
   /// [SnippetType.application].
   String generate(File input, SnippetType type, {String template, String id, File output, Map<String, Object> metadata}) {
     assert(template != null || type != SnippetType.application);
     assert(id != null || type != SnippetType.application);
     assert(input != null);
     final List<_ComponentTuple> snippetData = parseInput(_loadFileAsUtf8(input));
     switch (type) {
       case SnippetType.application:
         final Directory templatesDir = configuration.templatesDirectory;
         if (templatesDir == null) {
           stderr.writeln('Unable to find the templates directory.');
           exit(1);
         }
         final File templateFile = getTemplatePath(template, templatesDir: templatesDir);
         if (templateFile == null) {
           stderr.writeln(
               'The template $template was not found in the templates directory ${templatesDir.path}');
           exit(1);
         }
         snippetData.add(_ComponentTuple('id', <String>[id]));
         final String templateContents = _loadFileAsUtf8(templateFile);
         String app = interpolateTemplate(snippetData, templateContents);

         try {
           app = formatter.format(app);
         } on FormatterException catch (exception) {
           stderr.write('Code to format:\n${_addLineNumbers(app)}\n');
           errorExit('Unable to format snippet app template: $exception');
         }

         snippetData.add(_ComponentTuple('app', app.split('\n')));
         final File outputFile = output ?? getOutputFile(id);
         stderr.writeln('Writing to ${outputFile.absolute.path}');
         outputFile.writeAsStringSync(app);

         final File metadataFile = File(path.join(path.dirname(outputFile.path),
             '${path.basenameWithoutExtension(outputFile.path)}.json'));
         stderr.writeln('Writing metadata to ${metadataFile.absolute.path}');
         final _ComponentTuple description = snippetData.firstWhere(
           (_ComponentTuple data) => data.name == 'description',
           orElse: () => null,
         );
         metadata ??= <String, Object>{};
         metadata.addAll(<String, Object>{
           'id': id,
           'file': path.basename(outputFile.path),
           'description': description != null
               ? description.mergedContent
               : null,
         });
         metadataFile.writeAsStringSync(jsonEncoder.convert(metadata));
         break;
       case SnippetType.sample:
         break;
     }
     final String skeleton = _loadFileAsUtf8(configuration.getHtmlSkeletonFile(type));
     return interpolateSkeleton(type, snippetData, skeleton, metadata);
   }
 }
	// Copyright 2018 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:convert';
	import 'dart:io';

	import 'package:path/path.dart' as path;
	import 'package:dart_style/dart_style.dart';

	import 'configuration.dart';

	void errorExit(String message) {
	stderr.writeln(message);
	exit(1);
	}

	// A Tuple containing the name and contents associated with a code block in a
	// snippet.
	class _ComponentTuple {
	_ComponentTuple(this.name, this.contents, {String language}) : language = language ?? '';
	final String name;
	final List<String> contents;
	final String language;
	String get mergedContent => contents.join('\n').trim();
	}

	/// Generates the snippet HTML, as well as saving the output snippet main to
	/// the output directory.
	class SnippetGenerator {
	SnippetGenerator({Configuration configuration})
	: configuration = configuration ??
	// Flutter's root is four directories up from this script.
	Configuration(flutterRoot: Directory(Platform.environment['FLUTTER_ROOT']
	?? path.canonicalize(path.join(path.dirname(path.fromUri(Platform.script)), '..', '..', '..')))) {
	this.configuration.createOutputDirectory();
	}

	/// The configuration used to determine where to get/save data for the
	/// snippet.
	final Configuration configuration;

	static const JsonEncoder jsonEncoder = JsonEncoder.withIndent(' ');

	/// A Dart formatted used to format the snippet code and finished application
	/// code.
	static DartFormatter formatter = DartFormatter(pageWidth: 80, fixes: StyleFix.all);

	/// This returns the output file for a given snippet ID. Only used for
	/// [SnippetType.application] snippets.
	File getOutputFile(String id) => File(path.join(configuration.outputDirectory.path, '$id.dart'));

	/// Gets the path to the template file requested.
	File getTemplatePath(String templateName, {Directory templatesDir}) {
	final Directory templateDir = templatesDir ?? configuration.templatesDirectory;
	final File templateFile = File(path.join(templateDir.path, '$templateName.tmpl'));
	return templateFile.existsSync() ? templateFile : null;
	}

	/// Injects the [injections] into the [template], and turning the
	/// "description" injection into a comment. Only used for
	/// [SnippetType.application] snippets.
	String interpolateTemplate(List<_ComponentTuple> injections, String template) {
	final RegExp moustacheRegExp = RegExp('{{([^}]+)}}');
	return template.replaceAllMapped(moustacheRegExp, (Match match) {
	if (match[1] == 'description') {
	// Place the description into a comment.
	final List<String> description = injections
	.firstWhere((_ComponentTuple tuple) => tuple.name == match[1])
	.contents
	.map<String>((String line) => '// $line')
	.toList();
	// Remove any leading/trailing empty comment lines.
	// We don't want to remove ALL empty comment lines, only the ones at the
	// beginning and the end.
	while (description.isNotEmpty && description.last == '// ') {
	description.removeLast();
	}
	while (description.isNotEmpty && description.first == '// ') {
	description.removeAt(0);
	}
	return description.join('\n').trim();
	} else {
	// If the match isn't found in the injections, then just remove the
	// moustache reference, since we want to allow the sections to be
	// "optional" in the input: users shouldn't be forced to add an empty
	// "```dart preamble" section if that section would be empty.
	return injections
	.firstWhere((_ComponentTuple tuple) => tuple.name == match[1], orElse: () => null)
	?.mergedContent ?? '';
	}
	}).trim();
	}

	/// Interpolates the [injections] into an HTML skeleton file.
	///
	/// Similar to interpolateTemplate, but we are only looking for `code-`
	/// components, and we care about the order of the injections.
	///
	/// Takes into account the [type] and doesn't substitute in the id and the app
	/// if not a [SnippetType.application] snippet.
	String interpolateSkeleton(SnippetType type, List<_ComponentTuple> injections, String skeleton, Map<String, Object> metadata) {
	final List<String> result = <String>[];
	const HtmlEscape htmlEscape = HtmlEscape();
	String language;
	for (_ComponentTuple injection in injections) {
	if (!injection.name.startsWith('code')) {
	continue;
	}
	result.addAll(injection.contents);
	if (injection.language.isNotEmpty) {
	language = injection.language;
	}
	result.addAll(<String>['', '// ...', '']);
	}
	if (result.length > 3) {
	result.removeRange(result.length - 3, result.length);
	}
	// Only insert a div for the description if there actually is some text there.
	// This means that the {{description}} marker in the skeleton needs to
	// be inside of an {@inject-html} block.
	String description = injections.firstWhere((_ComponentTuple tuple) => tuple.name == 'description').mergedContent;
	description = description.trim().isNotEmpty
	? '<div class="snippet-description">{@end-inject-html}$description{@inject-html}</div>'
	: '';
	final Map<String, String> substitutions = <String, String>{
	'description': description,
	'code': htmlEscape.convert(result.join('\n')),
	'language': language ?? 'dart',
	}..addAll(type == SnippetType.application
	? <String, String>{
	'serial': metadata['serial'].toString() ?? '0',
	'id':
	injections.firstWhere((_ComponentTuple tuple) => tuple.name == 'id').mergedContent,
	'app':
	htmlEscape.convert(injections.firstWhere((_ComponentTuple tuple) => tuple.name == 'app').mergedContent),
	}
	: <String, String>{'serial': '', 'id': '', 'app': ''});
	return skeleton.replaceAllMapped(RegExp('{{(${substitutions.keys.join('\|')})}}'), (Match match) {
	return substitutions[match[1]];
	});
	}

	/// Parses the input for the various code and description segments, and
	/// returns them in the order found.
	List<_ComponentTuple> parseInput(String input) {
	bool inCodeBlock = false;
	input = input.trim();
	final List<String> description = <String>[];
	final List<_ComponentTuple> components = <_ComponentTuple>[];
	String language;
	final RegExp codeStartEnd = RegExp(r'^\s```([-\w]+\|[-\w]+ ([-\w]+))?\s$');
	for (String line in input.split('\n')) {
	final Match match = codeStartEnd.firstMatch(line);
	if (match != null) { // If we saw the start or end of a code block
	inCodeBlock = !inCodeBlock;
	if (match[1] != null) {
	language = match[1];
	if (match[2] != null) {
	components.add(_ComponentTuple('code-${match[2]}', <String>[], language: language));
	} else {
	components.add(_ComponentTuple('code', <String>[], language: language));
	}
	} else {
	language = null;
	}
	continue;
	}
	if (!inCodeBlock) {
	description.add(line);
	} else {
	assert(language != null);
	components.last.contents.add(line);
	}
	}
	return <_ComponentTuple>[
	_ComponentTuple('description', description),
	]..addAll(components);
	}

	String _loadFileAsUtf8(File file) {
	return file.readAsStringSync(encoding: Encoding.getByName('utf-8'));
	}

	String _addLineNumbers(String app) {
	final StringBuffer buffer = StringBuffer();
	int count = 0;
	for (String line in app.split('\n')) {
	count++;
	buffer.writeln('${count.toString().padLeft(5, ' ')}: $line');
	}
	return buffer.toString();
	}

	/// The main routine for generating snippets.
	///
	/// The [input] is the file containing the dartdoc comments (minus the leading
	/// comment markers).
	///
	/// The [type] is the type of snippet to create: either a
	/// [SnippetType.application] or a [SnippetType.sample].
	///
	/// The [template] must not be null if the [type] is
	/// [SnippetType.application], and specifies the name of the template to use
	/// for the application code.
	///
	/// The [id] is a string ID to use for the output file, and to tell the user
	/// about in the `flutter create` hint. It must not be null if the [type] is
	/// [SnippetType.application].
	String generate(File input, SnippetType type, {String template, String id, File output, Map<String, Object> metadata}) {
	assert(template != null \|\| type != SnippetType.application);
	assert(id != null \|\| type != SnippetType.application);
	assert(input != null);
	final List<_ComponentTuple> snippetData = parseInput(_loadFileAsUtf8(input));
	switch (type) {
	case SnippetType.application:
	final Directory templatesDir = configuration.templatesDirectory;
	if (templatesDir == null) {
	stderr.writeln('Unable to find the templates directory.');
	exit(1);
	}
	final File templateFile = getTemplatePath(template, templatesDir: templatesDir);
	if (templateFile == null) {
	stderr.writeln(
	'The template $template was not found in the templates directory ${templatesDir.path}');
	exit(1);
	}
	snippetData.add(_ComponentTuple('id', <String>[id]));
	final String templateContents = _loadFileAsUtf8(templateFile);
	String app = interpolateTemplate(snippetData, templateContents);

	try {
	app = formatter.format(app);
	} on FormatterException catch (exception) {
	stderr.write('Code to format:\n${_addLineNumbers(app)}\n');
	errorExit('Unable to format snippet app template: $exception');
	}

	snippetData.add(_ComponentTuple('app', app.split('\n')));
	final File outputFile = output ?? getOutputFile(id);
	stderr.writeln('Writing to ${outputFile.absolute.path}');
	outputFile.writeAsStringSync(app);

	final File metadataFile = File(path.join(path.dirname(outputFile.path),
	'${path.basenameWithoutExtension(outputFile.path)}.json'));
	stderr.writeln('Writing metadata to ${metadataFile.absolute.path}');
	final _ComponentTuple description = snippetData.firstWhere(
	(_ComponentTuple data) => data.name == 'description',
	orElse: () => null,
	);
	metadata ??= <String, Object>{};
	metadata.addAll(<String, Object>{
	'id': id,
	'file': path.basename(outputFile.path),
	'description': description != null
	? description.mergedContent
	: null,
	});
	metadataFile.writeAsStringSync(jsonEncoder.convert(metadata));
	break;
	case SnippetType.sample:
	break;
	}
	final String skeleton = _loadFileAsUtf8(configuration.getHtmlSkeletonFile(type));
	return interpolateSkeleton(type, snippetData, skeleton, metadata);
	}
	}