packages/flutter_tools/lib/src/flutter_manifest.dart - mirrors/flutter - Git at Google

 // Copyright 2014 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 // @dart = 2.8

 import 'package:meta/meta.dart';
 import 'package:pub_semver/pub_semver.dart';
 import 'package:yaml/yaml.dart';

 import 'base/deferred_component.dart';
 import 'base/file_system.dart';
 import 'base/logger.dart';
 import 'base/user_messages.dart';
 import 'base/utils.dart';
 import 'plugins.dart';

 const Set<String> _kValidPluginPlatforms = <String>{
   'android', 'ios', 'web', 'windows', 'linux', 'macos'
 };

 /// A wrapper around the `flutter` section in the `pubspec.yaml` file.
 class FlutterManifest {
   FlutterManifest._(this._logger);

   /// Returns an empty manifest.
   factory FlutterManifest.empty({ @required Logger logger }) {
     final FlutterManifest manifest = FlutterManifest._(logger);
     manifest._descriptor = const <String, dynamic>{};
     manifest._flutterDescriptor = const <String, dynamic>{};
     return manifest;
   }

   /// Returns null on invalid manifest. Returns empty manifest on missing file.
   static FlutterManifest createFromPath(String path, {
     @required FileSystem fileSystem,
     @required Logger logger,
   }) {
     if (path == null || !fileSystem.isFileSync(path)) {
       return _createFromYaml(null, logger);
     }
     final String manifest = fileSystem.file(path).readAsStringSync();
     return FlutterManifest.createFromString(manifest, logger: logger);
   }

   /// Returns null on missing or invalid manifest.
   @visibleForTesting
   static FlutterManifest createFromString(String manifest, { @required Logger logger }) {
     return _createFromYaml(manifest != null ? loadYaml(manifest) : null, logger);
   }

   static FlutterManifest _createFromYaml(dynamic yamlDocument, Logger logger) {
     if (yamlDocument != null && !_validate(yamlDocument, logger)) {
       return null;
     }

     final FlutterManifest pubspec = FlutterManifest._(logger);
     final Map<dynamic, dynamic> yamlMap = yamlDocument as YamlMap;
     if (yamlMap != null) {
       pubspec._descriptor = yamlMap.cast<String, dynamic>();
     } else {
       pubspec._descriptor = <String, dynamic>{};
     }

     final Map<dynamic, dynamic> flutterMap = pubspec._descriptor['flutter'] as Map<dynamic, dynamic>;
     if (flutterMap != null) {
       pubspec._flutterDescriptor = flutterMap.cast<String, dynamic>();
     } else {
       pubspec._flutterDescriptor = <String, dynamic>{};
     }

     return pubspec;
   }

   final Logger _logger;

   /// A map representation of the entire `pubspec.yaml` file.
   Map<String, dynamic> _descriptor;

   /// A map representation of the `flutter` section in the `pubspec.yaml` file.
   Map<String, dynamic> _flutterDescriptor;

   /// True if the `pubspec.yaml` file does not exist.
   bool get isEmpty => _descriptor.isEmpty;

   /// The string value of the top-level `name` property in the `pubspec.yaml` file.
   String get appName => _descriptor['name'] as String ?? '';

   /// Contains the name of the dependencies.
   /// These are the keys specified in the `dependency` map.
   Set<String> get dependencies {
     final YamlMap dependencies = _descriptor['dependencies'] as YamlMap;
     return dependencies != null ? <String>{...dependencies.keys.cast<String>()} : <String>{};
   }

   // Flag to avoid printing multiple invalid version messages.
   bool _hasShowInvalidVersionMsg = false;

   /// The version String from the `pubspec.yaml` file.
   /// Can be null if it isn't set or has a wrong format.
   String get appVersion {
     final String verStr = _descriptor['version']?.toString();
     if (verStr == null) {
       return null;
     }

     Version version;
     try {
       version = Version.parse(verStr);
     } on Exception {
       if (!_hasShowInvalidVersionMsg) {
         _logger.printStatus(userMessages.invalidVersionSettingHintMessage(verStr), emphasis: true);
         _hasShowInvalidVersionMsg = true;
       }
     }
     return version?.toString();
   }

   /// The build version name from the `pubspec.yaml` file.
   /// Can be null if version isn't set or has a wrong format.
   String get buildName {
     if (appVersion != null && appVersion.contains('+')) {
       return appVersion.split('+')?.elementAt(0);
     }
     return appVersion;
   }

   /// The build version number from the `pubspec.yaml` file.
   /// Can be null if version isn't set or has a wrong format.
   String get buildNumber {
     if (appVersion != null && appVersion.contains('+')) {
       final String value = appVersion.split('+')?.elementAt(1);
       return value;
     } else {
       return null;
     }
   }

   bool get usesMaterialDesign {
     return _flutterDescriptor['uses-material-design'] as bool ?? false;
   }

   /// True if this Flutter module should use AndroidX dependencies.
   ///
   /// If false the deprecated Android Support library will be used.
   bool get usesAndroidX {
     if (_flutterDescriptor.containsKey('module')) {
       return _flutterDescriptor['module']['androidX'] as bool;
     }
     return false;
   }

   /// Any additional license files listed under the `flutter` key.
   ///
   /// This is expected to be a list of file paths that should be treated as
   /// relative to the pubspec in this directory.
   ///
   /// For example:
   ///
   /// ```yaml
   /// flutter:
   ///   licenses:
   ///     - assets/foo_license.txt
   /// ```
   List<String> get additionalLicenses => _flutterDescriptor.containsKey('licenses')
     ? (_flutterDescriptor['licenses'] as YamlList).map((dynamic element) => element.toString()).toList()
     : <String>[];

   /// True if this manifest declares a Flutter module project.
   ///
   /// A Flutter project is considered a module when it has a `module:`
   /// descriptor. A Flutter module project supports integration into an
   /// existing host app, and has managed platform host code.
   ///
   /// Such a project can be created using `flutter create -t module`.
   bool get isModule => _flutterDescriptor.containsKey('module');

   /// True if this manifest declares a Flutter plugin project.
   ///
   /// A Flutter project is considered a plugin when it has a `plugin:`
   /// descriptor. A Flutter plugin project wraps custom Android and/or
   /// iOS code in a Dart interface for consumption by other Flutter app
   /// projects.
   ///
   /// Such a project can be created using `flutter create -t plugin`.
   bool get isPlugin => _flutterDescriptor.containsKey('plugin');

   /// Returns the Android package declared by this manifest in its
   /// module or plugin descriptor. Returns null, if there is no
   /// such declaration.
   String get androidPackage {
     if (isModule) {
       return _flutterDescriptor['module']['androidPackage'] as String;
     }
     if (supportedPlatforms == null) {
       // Pre-multi-platform plugin format
       if (isPlugin) {
         final YamlMap plugin = _flutterDescriptor['plugin'] as YamlMap;
         return plugin['androidPackage'] as String;
       }
       return null;
     }
     if (supportedPlatforms.containsKey('android')) {
        return supportedPlatforms['android']['package'] as String;
     }
     return null;
   }

   /// Returns the deferred components configuration if declared. Returns
   /// null if no deferred components are declared.
   List<DeferredComponent> get deferredComponents => _deferredComponents ??= computeDeferredComponents();
   List<DeferredComponent> _deferredComponents;
   List<DeferredComponent> computeDeferredComponents() {
     if (!_flutterDescriptor.containsKey('deferred-components')) {
       return null;
     }
     final List<DeferredComponent> components = <DeferredComponent>[];
     if (_flutterDescriptor['deferred-components'] == null) {
       return components;
     }
     for (final dynamic componentData in _flutterDescriptor['deferred-components']) {
       final YamlMap component = componentData as YamlMap;
       List<Uri> assetsUri = <Uri>[];
       final List<dynamic> assets = component['assets'] as List<dynamic>;
       if (assets == null) {
         assetsUri = const <Uri>[];
       } else {
         for (final Object asset in assets) {
           if (asset is! String || asset == null || asset == '') {
             _logger.printError('Deferred component asset manifest contains a null or empty uri.');
             continue;
           }
           final String stringAsset = asset as String;
           try {
             assetsUri.add(Uri.parse(stringAsset));
           } on FormatException {
             _logger.printError('Asset manifest contains invalid uri: $asset.');
           }
         }
       }
       components.add(
         DeferredComponent(
           name: component['name'] as String,
           libraries: component['libraries'] == null ?
               <String>[] : component['libraries'].cast<String>() as List<String>,
           assets: assetsUri,
         )
       );
     }
     return components;
   }

   /// Returns the iOS bundle identifier declared by this manifest in its
   /// module descriptor. Returns null if there is no such declaration.
   String get iosBundleIdentifier {
     if (isModule) {
       return _flutterDescriptor['module']['iosBundleIdentifier'] as String;
     }
     return null;
   }

   /// Gets the supported platforms. This only supports the new `platforms` format.
   ///
   /// If the plugin uses the legacy pubspec format, this method returns null.
   Map<String, dynamic> get supportedPlatforms {
     if (isPlugin) {
       final YamlMap plugin = _flutterDescriptor['plugin'] as YamlMap;
       if (plugin.containsKey('platforms')) {
         final YamlMap platformsMap = plugin['platforms'] as YamlMap;
         return platformsMap.value.cast<String, dynamic>();
       }
     }
     return null;
   }

   /// Like [supportedPlatforms], but only returns the valid platforms that are supported in flutter plugins.
   Map<String, dynamic> get validSupportedPlatforms {
     final Map<String, dynamic> allPlatforms = supportedPlatforms;
     if (allPlatforms == null) {
       return null;
     }
     final Map<String, dynamic> platforms = <String, dynamic>{}..addAll(supportedPlatforms);
     platforms.removeWhere((String key, dynamic _) => !_kValidPluginPlatforms.contains(key));
     if (platforms.isEmpty) {
       return null;
     }
     return platforms;
   }

   List<Map<String, dynamic>> get fontsDescriptor {
     return fonts.map((Font font) => font.descriptor).toList();
   }

   List<Map<String, dynamic>> get _rawFontsDescriptor {
     final List<dynamic> fontList = _flutterDescriptor['fonts'] as List<dynamic>;
     return fontList == null
         ? const <Map<String, dynamic>>[]
         : fontList.map<Map<String, dynamic>>(castStringKeyedMap).toList();
   }

   List<Uri> get assets => _assets ??= _computeAssets();
   List<Uri> _assets;
   List<Uri> _computeAssets() {
     final List<dynamic> assets = _flutterDescriptor['assets'] as List<dynamic>;
     if (assets == null) {
       return const <Uri>[];
     }
     final List<Uri> results = <Uri>[];
     for (final Object asset in assets) {
       if (asset is! String || asset == null || asset == '') {
         _logger.printError('Asset manifest contains a null or empty uri.');
         continue;
       }
       final String stringAsset = asset as String;
       try {
         results.add(Uri(pathSegments: stringAsset.split('/')));
       } on FormatException {
         _logger.printError('Asset manifest contains invalid uri: $asset.');
       }
     }
     return results;
   }

   List<Font> _fonts;

   List<Font> get fonts {
     _fonts ??= _extractFonts();
     return _fonts;
   }

   List<Font> _extractFonts() {
     if (!_flutterDescriptor.containsKey('fonts')) {
       return <Font>[];
     }

     final List<Font> fonts = <Font>[];
     for (final Map<String, dynamic> fontFamily in _rawFontsDescriptor) {
       final YamlList fontFiles = fontFamily['fonts'] as YamlList;
       final String familyName = fontFamily['family'] as String;
       if (familyName == null) {
         _logger.printError('Warning: Missing family name for font.', emphasis: true);
         continue;
       }
       if (fontFiles == null) {
         _logger.printError('Warning: No fonts specified for font $familyName', emphasis: true);
         continue;
       }

       final List<FontAsset> fontAssets = <FontAsset>[];
       for (final Map<dynamic, dynamic> fontFile in fontFiles.cast<Map<dynamic, dynamic>>()) {
         final String asset = fontFile['asset'] as String;
         if (asset == null) {
           _logger.printError('Warning: Missing asset in fonts for $familyName', emphasis: true);
           continue;
         }

         fontAssets.add(FontAsset(
           Uri.parse(asset),
           weight: fontFile['weight'] as int,
           style: fontFile['style'] as String,
         ));
       }
       if (fontAssets.isNotEmpty) {
         fonts.add(Font(fontFamily['family'] as String, fontAssets));
       }
     }
     return fonts;
   }

   /// Whether a synthetic flutter_gen package should be generated.
   ///
   /// This can be provided to the [Pub] interface to inject a new entry
   /// into the package_config.json file which points to `.dart_tool/flutter_gen`.
   ///
   /// This allows generated source code to be imported using a package
   /// alias.
   bool get generateSyntheticPackage => _generateSyntheticPackage ??= _computeGenerateSyntheticPackage();
   bool _generateSyntheticPackage;
   bool _computeGenerateSyntheticPackage() {
     if (!_flutterDescriptor.containsKey('generate')) {
       return false;
     }
     final Object value = _flutterDescriptor['generate'];
     if (value is! bool) {
       return false;
     }
     return value as bool;
   }
 }

 class Font {
   Font(this.familyName, this.fontAssets)
     : assert(familyName != null),
       assert(fontAssets != null),
       assert(fontAssets.isNotEmpty);

   final String familyName;
   final List<FontAsset> fontAssets;

   Map<String, dynamic> get descriptor {
     return <String, dynamic>{
       'family': familyName,
       'fonts': fontAssets.map<Map<String, dynamic>>((FontAsset a) => a.descriptor).toList(),
     };
   }

   @override
   String toString() => '$runtimeType(family: $familyName, assets: $fontAssets)';
 }

 class FontAsset {
   FontAsset(this.assetUri, {this.weight, this.style})
     : assert(assetUri != null);

   final Uri assetUri;
   final int weight;
   final String style;

   Map<String, dynamic> get descriptor {
     final Map<String, dynamic> descriptor = <String, dynamic>{};
     if (weight != null) {
       descriptor['weight'] = weight;
     }

     if (style != null) {
       descriptor['style'] = style;
     }

     descriptor['asset'] = assetUri.path;
     return descriptor;
   }

   @override
   String toString() => '$runtimeType(asset: ${assetUri.path}, weight; $weight, style: $style)';
 }


 bool _validate(dynamic manifest, Logger logger) {
   final List<String> errors = <String>[];
   if (manifest is! YamlMap) {
     errors.add('Expected YAML map');
   } else {
     for (final MapEntry<dynamic, dynamic> kvp in (manifest as YamlMap).entries) {
       if (kvp.key is! String) {
         errors.add('Expected YAML key to be a string, but got ${kvp.key}.');
         continue;
       }
       switch (kvp.key as String) {
         case 'name':
           if (kvp.value is! String) {
             errors.add('Expected "${kvp.key}" to be a string, but got ${kvp.value}.');
           }
           break;
         case 'flutter':
           if (kvp.value == null) {
             continue;
           }
           if (kvp.value is! YamlMap) {
             errors.add('Expected "${kvp.key}" section to be an object or null, but got ${kvp.value}.');
           } else {
             _validateFlutter(kvp.value as YamlMap, errors);
           }
           break;
         default:
         // additionalProperties are allowed.
           break;
       }
     }
   }

   if (errors.isNotEmpty) {
     logger.printStatus('Error detected in pubspec.yaml:', emphasis: true);
     logger.printError(errors.join('\n'));
     return false;
   }

   return true;
 }

 void _validateFlutter(YamlMap yaml, List<String> errors) {
   if (yaml == null || yaml.entries == null) {
     return;
   }
   for (final MapEntry<dynamic, dynamic> kvp in yaml.entries) {
     if (kvp.key is! String) {
       errors.add('Expected YAML key to be a string, but got ${kvp.key} (${kvp.value.runtimeType}).');
       continue;
     }
     switch (kvp.key as String) {
       case 'uses-material-design':
         if (kvp.value is! bool) {
           errors.add('Expected "${kvp.key}" to be a bool, but got ${kvp.value} (${kvp.value.runtimeType}).');
         }
         break;
       case 'assets':
         if (kvp.value is! YamlList || kvp.value[0] is! String) {
           errors.add('Expected "${kvp.key}" to be a list, but got ${kvp.value} (${kvp.value.runtimeType}).');
         }
         break;
       case 'fonts':
         if (kvp.value is! YamlList || kvp.value[0] is! YamlMap) {
           errors.add('Expected "${kvp.key}" to be a list, but got ${kvp.value} (${kvp.value.runtimeType}).');
         } else {
           _validateFonts(kvp.value as YamlList, errors);
         }
         break;
       case 'licenses':
         final dynamic value = kvp.value;
         if (value is YamlList) {
           _validateListType<String>(value, errors, '"${kvp.key}"', 'files');
         } else {
           errors.add('Expected "${kvp.key}" to be a list of files, but got $value (${value.runtimeType})');
         }
         break;
       case 'module':
         if (kvp.value is! YamlMap) {
           errors.add('Expected "${kvp.key}" to be an object, but got ${kvp.value} (${kvp.value.runtimeType}).');
         }

         if (kvp.value['androidX'] != null && kvp.value['androidX'] is! bool) {
           errors.add('The "androidX" value must be a bool if set.');
         }
         if (kvp.value['androidPackage'] != null && kvp.value['androidPackage'] is! String) {
           errors.add('The "androidPackage" value must be a string if set.');
         }
         if (kvp.value['iosBundleIdentifier'] != null && kvp.value['iosBundleIdentifier'] is! String) {
           errors.add('The "iosBundleIdentifier" section must be a string if set.');
         }
         break;
       case 'plugin':
         if (kvp.value is! YamlMap || kvp.value == null) {
           errors.add('Expected "${kvp.key}" to be an object, but got ${kvp.value} (${kvp.value.runtimeType}).');
           break;
         }
         final List<String> pluginErrors = Plugin.validatePluginYaml(kvp.value as YamlMap);
         errors.addAll(pluginErrors);
         break;
       case 'generate':
         break;
       case 'deferred-components':
         _validateDeferredComponents(kvp, errors);
         break;
       default:
         errors.add('Unexpected child "${kvp.key}" found under "flutter".');
         break;
     }
   }
 }

 void _validateListType<T>(YamlList yamlList, List<String> errors, String context, String typeAlias) {
   for (int i = 0; i < yamlList.length; i++) {
     if (yamlList[i] is! T) {
       errors.add('Expected $context to be a list of $typeAlias, but element $i was a ${yamlList[i].runtimeType}');
     }
   }
 }

 void _validateDeferredComponents(MapEntry<dynamic, dynamic> kvp, List<String> errors) {
   if (kvp.value != null && (kvp.value is! YamlList || kvp.value[0] is! YamlMap)) {
     errors.add('Expected "${kvp.key}" to be a list, but got ${kvp.value} (${kvp.value.runtimeType}).');
   } else if (kvp.value != null) {
     for (int i = 0; i < (kvp.value as YamlList).length; i++) {
       if (kvp.value[i] is! YamlMap) {
         errors.add('Expected the $i element in "${kvp.key}" to be a map, but got ${kvp.value[i]} (${kvp.value[i].runtimeType}).');
         continue;
       }
       if (!(kvp.value[i] as YamlMap).containsKey('name') || kvp.value[i]['name'] is! String) {
         errors.add('Expected the $i element in "${kvp.key}" to have required key "name" of type String');
       }
       if ((kvp.value[i] as YamlMap).containsKey('libraries')) {
         if (kvp.value[i]['libraries'] is! YamlList) {
           errors.add('Expected "libraries" key in the $i element of "${kvp.key}" to be a list, but got ${kvp.value[i]['libraries']} (${kvp.value[i]['libraries'].runtimeType}).');
         } else {
           _validateListType<String>(kvp.value[i]['libraries'] as YamlList, errors, '"libraries" key in the $i element of "${kvp.key}"', 'dart library Strings');
         }
       }
       if ((kvp.value[i] as YamlMap).containsKey('assets')) {
         if (kvp.value[i]['assets'] is! YamlList) {
           errors.add('Expected "assets" key in the $i element of "${kvp.key}" to be a list, but got ${kvp.value[i]['assets']} (${kvp.value[i]['assets'].runtimeType}).');
         } else {
           _validateListType<String>(kvp.value[i]['assets'] as YamlList, errors, '"assets" key in the $i element of "${kvp.key}"', 'file paths');
         }
       }
     }
   }
 }

 void _validateFonts(YamlList fonts, List<String> errors) {
   if (fonts == null) {
     return;
   }
   const Set<int> fontWeights = <int>{
     100, 200, 300, 400, 500, 600, 700, 800, 900,
   };
   for (final dynamic fontListEntry in fonts) {
     if (fontListEntry is! YamlMap) {
       errors.add('Unexpected child "$fontListEntry" found under "fonts". Expected a map.');
       continue;
     }
     final YamlMap fontMap = fontListEntry as YamlMap;
     for (final dynamic key in fontMap.keys.where((dynamic key) => key != 'family' && key != 'fonts')) {
       errors.add('Unexpected child "$key" found under "fonts".');
     }
     if (fontMap['family'] != null && fontMap['family'] is! String) {
       errors.add('Font family must either be null or a String.');
     }
     if (fontMap['fonts'] == null) {
       continue;
     } else if (fontMap['fonts'] is! YamlList) {
       errors.add('Expected "fonts" to either be null or a list.');
       continue;
     }
     for (final dynamic fontListItem in fontMap['fonts']) {
       if (fontListItem is! YamlMap) {
         errors.add('Expected "fonts" to be a list of maps.');
         continue;
       }
       final YamlMap fontMapList = fontListItem as YamlMap;
       for (final MapEntry<dynamic, dynamic> kvp in fontMapList.entries) {
         if (kvp.key is! String) {
           errors.add('Expected "${kvp.key}" under "fonts" to be a string.');
         }
         switch(kvp.key as String) {
           case 'asset':
             if (kvp.value is! String) {
               errors.add('Expected font asset ${kvp.value} ((${kvp.value.runtimeType})) to be a string.');
             }
             break;
           case 'weight':
             if (!fontWeights.contains(kvp.value)) {
               errors.add('Invalid value ${kvp.value} ((${kvp.value.runtimeType})) for font -> weight.');
             }
             break;
           case 'style':
             if (kvp.value != 'normal' && kvp.value != 'italic') {
               errors.add('Invalid value ${kvp.value} ((${kvp.value.runtimeType})) for font -> style.');
             }
             break;
           default:
             errors.add('Unexpected key ${kvp.key} ((${kvp.value.runtimeType})) under font.');
             break;
         }
       }
     }
   }
 }
	// Copyright 2014 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	// @dart = 2.8

	import 'package:meta/meta.dart';
	import 'package:pub_semver/pub_semver.dart';
	import 'package:yaml/yaml.dart';

	import 'base/deferred_component.dart';
	import 'base/file_system.dart';
	import 'base/logger.dart';
	import 'base/user_messages.dart';
	import 'base/utils.dart';
	import 'plugins.dart';

	const Set<String> _kValidPluginPlatforms = <String>{
	'android', 'ios', 'web', 'windows', 'linux', 'macos'
	};

	/// A wrapper around the `flutter` section in the `pubspec.yaml` file.
	class FlutterManifest {
	FlutterManifest._(this._logger);

	/// Returns an empty manifest.
	factory FlutterManifest.empty({ @required Logger logger }) {
	final FlutterManifest manifest = FlutterManifest._(logger);
	manifest._descriptor = const <String, dynamic>{};
	manifest._flutterDescriptor = const <String, dynamic>{};
	return manifest;
	}

	/// Returns null on invalid manifest. Returns empty manifest on missing file.
	static FlutterManifest createFromPath(String path, {
	@required FileSystem fileSystem,
	@required Logger logger,
	}) {
	if (path == null \|\| !fileSystem.isFileSync(path)) {
	return _createFromYaml(null, logger);
	}
	final String manifest = fileSystem.file(path).readAsStringSync();
	return FlutterManifest.createFromString(manifest, logger: logger);
	}

	/// Returns null on missing or invalid manifest.
	@visibleForTesting
	static FlutterManifest createFromString(String manifest, { @required Logger logger }) {
	return _createFromYaml(manifest != null ? loadYaml(manifest) : null, logger);
	}

	static FlutterManifest _createFromYaml(dynamic yamlDocument, Logger logger) {
	if (yamlDocument != null && !_validate(yamlDocument, logger)) {
	return null;
	}

	final FlutterManifest pubspec = FlutterManifest._(logger);
	final Map<dynamic, dynamic> yamlMap = yamlDocument as YamlMap;
	if (yamlMap != null) {
	pubspec._descriptor = yamlMap.cast<String, dynamic>();
	} else {
	pubspec._descriptor = <String, dynamic>{};
	}

	final Map<dynamic, dynamic> flutterMap = pubspec._descriptor['flutter'] as Map<dynamic, dynamic>;
	if (flutterMap != null) {
	pubspec._flutterDescriptor = flutterMap.cast<String, dynamic>();
	} else {
	pubspec._flutterDescriptor = <String, dynamic>{};
	}

	return pubspec;
	}

	final Logger _logger;

	/// A map representation of the entire `pubspec.yaml` file.
	Map<String, dynamic> _descriptor;

	/// A map representation of the `flutter` section in the `pubspec.yaml` file.
	Map<String, dynamic> _flutterDescriptor;

	/// True if the `pubspec.yaml` file does not exist.
	bool get isEmpty => _descriptor.isEmpty;

	/// The string value of the top-level `name` property in the `pubspec.yaml` file.
	String get appName => _descriptor['name'] as String ?? '';

	/// Contains the name of the dependencies.
	/// These are the keys specified in the `dependency` map.
	Set<String> get dependencies {
	final YamlMap dependencies = _descriptor['dependencies'] as YamlMap;
	return dependencies != null ? <String>{...dependencies.keys.cast<String>()} : <String>{};
	}

	// Flag to avoid printing multiple invalid version messages.
	bool _hasShowInvalidVersionMsg = false;

	/// The version String from the `pubspec.yaml` file.
	/// Can be null if it isn't set or has a wrong format.
	String get appVersion {
	final String verStr = _descriptor['version']?.toString();
	if (verStr == null) {
	return null;
	}

	Version version;
	try {
	version = Version.parse(verStr);
	} on Exception {
	if (!_hasShowInvalidVersionMsg) {
	_logger.printStatus(userMessages.invalidVersionSettingHintMessage(verStr), emphasis: true);
	_hasShowInvalidVersionMsg = true;
	}
	}
	return version?.toString();
	}

	/// The build version name from the `pubspec.yaml` file.
	/// Can be null if version isn't set or has a wrong format.
	String get buildName {
	if (appVersion != null && appVersion.contains('+')) {
	return appVersion.split('+')?.elementAt(0);
	}
	return appVersion;
	}

	/// The build version number from the `pubspec.yaml` file.
	/// Can be null if version isn't set or has a wrong format.
	String get buildNumber {
	if (appVersion != null && appVersion.contains('+')) {
	final String value = appVersion.split('+')?.elementAt(1);
	return value;
	} else {
	return null;
	}
	}

	bool get usesMaterialDesign {
	return _flutterDescriptor['uses-material-design'] as bool ?? false;
	}

	/// True if this Flutter module should use AndroidX dependencies.
	///
	/// If false the deprecated Android Support library will be used.
	bool get usesAndroidX {
	if (_flutterDescriptor.containsKey('module')) {
	return _flutterDescriptor['module']['androidX'] as bool;
	}
	return false;
	}

	/// Any additional license files listed under the `flutter` key.
	///
	/// This is expected to be a list of file paths that should be treated as
	/// relative to the pubspec in this directory.
	///
	/// For example:
	///
	/// ```yaml
	/// flutter:
	/// licenses:
	/// - assets/foo_license.txt
	/// ```
	List<String> get additionalLicenses => _flutterDescriptor.containsKey('licenses')
	? (_flutterDescriptor['licenses'] as YamlList).map((dynamic element) => element.toString()).toList()
	: <String>[];

	/// True if this manifest declares a Flutter module project.
	///
	/// A Flutter project is considered a module when it has a `module:`
	/// descriptor. A Flutter module project supports integration into an
	/// existing host app, and has managed platform host code.
	///
	/// Such a project can be created using `flutter create -t module`.
	bool get isModule => _flutterDescriptor.containsKey('module');

	/// True if this manifest declares a Flutter plugin project.
	///
	/// A Flutter project is considered a plugin when it has a `plugin:`
	/// descriptor. A Flutter plugin project wraps custom Android and/or
	/// iOS code in a Dart interface for consumption by other Flutter app
	/// projects.
	///
	/// Such a project can be created using `flutter create -t plugin`.
	bool get isPlugin => _flutterDescriptor.containsKey('plugin');

	/// Returns the Android package declared by this manifest in its
	/// module or plugin descriptor. Returns null, if there is no
	/// such declaration.
	String get androidPackage {
	if (isModule) {
	return _flutterDescriptor['module']['androidPackage'] as String;
	}
	if (supportedPlatforms == null) {
	// Pre-multi-platform plugin format
	if (isPlugin) {
	final YamlMap plugin = _flutterDescriptor['plugin'] as YamlMap;
	return plugin['androidPackage'] as String;
	}
	return null;
	}
	if (supportedPlatforms.containsKey('android')) {
	return supportedPlatforms['android']['package'] as String;
	}
	return null;
	}

	/// Returns the deferred components configuration if declared. Returns
	/// null if no deferred components are declared.
	List<DeferredComponent> get deferredComponents => _deferredComponents ??= computeDeferredComponents();
	List<DeferredComponent> _deferredComponents;
	List<DeferredComponent> computeDeferredComponents() {
	if (!_flutterDescriptor.containsKey('deferred-components')) {
	return null;
	}
	final List<DeferredComponent> components = <DeferredComponent>[];
	if (_flutterDescriptor['deferred-components'] == null) {
	return components;
	}
	for (final dynamic componentData in _flutterDescriptor['deferred-components']) {
	final YamlMap component = componentData as YamlMap;
	List<Uri> assetsUri = <Uri>[];
	final List<dynamic> assets = component['assets'] as List<dynamic>;
	if (assets == null) {
	assetsUri = const <Uri>[];
	} else {
	for (final Object asset in assets) {
	if (asset is! String \|\| asset == null \|\| asset == '') {
	_logger.printError('Deferred component asset manifest contains a null or empty uri.');
	continue;
	}
	final String stringAsset = asset as String;
	try {
	assetsUri.add(Uri.parse(stringAsset));
	} on FormatException {
	_logger.printError('Asset manifest contains invalid uri: $asset.');
	}
	}
	}
	components.add(
	DeferredComponent(
	name: component['name'] as String,
	libraries: component['libraries'] == null ?
	<String>[] : component['libraries'].cast<String>() as List<String>,
	assets: assetsUri,
	)
	);
	}
	return components;
	}

	/// Returns the iOS bundle identifier declared by this manifest in its
	/// module descriptor. Returns null if there is no such declaration.
	String get iosBundleIdentifier {
	if (isModule) {
	return _flutterDescriptor['module']['iosBundleIdentifier'] as String;
	}
	return null;
	}

	/// Gets the supported platforms. This only supports the new `platforms` format.
	///
	/// If the plugin uses the legacy pubspec format, this method returns null.
	Map<String, dynamic> get supportedPlatforms {
	if (isPlugin) {
	final YamlMap plugin = _flutterDescriptor['plugin'] as YamlMap;
	if (plugin.containsKey('platforms')) {
	final YamlMap platformsMap = plugin['platforms'] as YamlMap;
	return platformsMap.value.cast<String, dynamic>();
	}
	}
	return null;
	}

	/// Like [supportedPlatforms], but only returns the valid platforms that are supported in flutter plugins.
	Map<String, dynamic> get validSupportedPlatforms {
	final Map<String, dynamic> allPlatforms = supportedPlatforms;
	if (allPlatforms == null) {
	return null;
	}
	final Map<String, dynamic> platforms = <String, dynamic>{}..addAll(supportedPlatforms);
	platforms.removeWhere((String key, dynamic _) => !_kValidPluginPlatforms.contains(key));
	if (platforms.isEmpty) {
	return null;
	}
	return platforms;
	}

	List<Map<String, dynamic>> get fontsDescriptor {
	return fonts.map((Font font) => font.descriptor).toList();
	}

	List<Map<String, dynamic>> get _rawFontsDescriptor {
	final List<dynamic> fontList = _flutterDescriptor['fonts'] as List<dynamic>;
	return fontList == null
	? const <Map<String, dynamic>>[]
	: fontList.map<Map<String, dynamic>>(castStringKeyedMap).toList();
	}

	List<Uri> get assets => _assets ??= _computeAssets();
	List<Uri> _assets;
	List<Uri> _computeAssets() {
	final List<dynamic> assets = _flutterDescriptor['assets'] as List<dynamic>;
	if (assets == null) {
	return const <Uri>[];
	}
	final List<Uri> results = <Uri>[];
	for (final Object asset in assets) {
	if (asset is! String \|\| asset == null \|\| asset == '') {
	_logger.printError('Asset manifest contains a null or empty uri.');
	continue;
	}
	final String stringAsset = asset as String;
	try {
	results.add(Uri(pathSegments: stringAsset.split('/')));
	} on FormatException {
	_logger.printError('Asset manifest contains invalid uri: $asset.');
	}
	}
	return results;
	}

	List<Font> _fonts;

	List<Font> get fonts {
	_fonts ??= _extractFonts();
	return _fonts;
	}

	List<Font> _extractFonts() {
	if (!_flutterDescriptor.containsKey('fonts')) {
	return <Font>[];
	}

	final List<Font> fonts = <Font>[];
	for (final Map<String, dynamic> fontFamily in _rawFontsDescriptor) {
	final YamlList fontFiles = fontFamily['fonts'] as YamlList;
	final String familyName = fontFamily['family'] as String;
	if (familyName == null) {
	_logger.printError('Warning: Missing family name for font.', emphasis: true);
	continue;
	}
	if (fontFiles == null) {
	_logger.printError('Warning: No fonts specified for font $familyName', emphasis: true);
	continue;
	}

	final List<FontAsset> fontAssets = <FontAsset>[];
	for (final Map<dynamic, dynamic> fontFile in fontFiles.cast<Map<dynamic, dynamic>>()) {
	final String asset = fontFile['asset'] as String;
	if (asset == null) {
	_logger.printError('Warning: Missing asset in fonts for $familyName', emphasis: true);
	continue;
	}

	fontAssets.add(FontAsset(
	Uri.parse(asset),
	weight: fontFile['weight'] as int,
	style: fontFile['style'] as String,
	));
	}
	if (fontAssets.isNotEmpty) {
	fonts.add(Font(fontFamily['family'] as String, fontAssets));
	}
	}
	return fonts;
	}

	/// Whether a synthetic flutter_gen package should be generated.
	///
	/// This can be provided to the [Pub] interface to inject a new entry
	/// into the package_config.json file which points to `.dart_tool/flutter_gen`.
	///
	/// This allows generated source code to be imported using a package
	/// alias.
	bool get generateSyntheticPackage => _generateSyntheticPackage ??= _computeGenerateSyntheticPackage();
	bool _generateSyntheticPackage;
	bool _computeGenerateSyntheticPackage() {
	if (!_flutterDescriptor.containsKey('generate')) {
	return false;
	}
	final Object value = _flutterDescriptor['generate'];
	if (value is! bool) {
	return false;
	}
	return value as bool;
	}
	}

	class Font {
	Font(this.familyName, this.fontAssets)
	: assert(familyName != null),
	assert(fontAssets != null),
	assert(fontAssets.isNotEmpty);

	final String familyName;
	final List<FontAsset> fontAssets;

	Map<String, dynamic> get descriptor {
	return <String, dynamic>{
	'family': familyName,
	'fonts': fontAssets.map<Map<String, dynamic>>((FontAsset a) => a.descriptor).toList(),
	};
	}

	@override
	String toString() => '$runtimeType(family: $familyName, assets: $fontAssets)';
	}

	class FontAsset {
	FontAsset(this.assetUri, {this.weight, this.style})
	: assert(assetUri != null);

	final Uri assetUri;
	final int weight;
	final String style;

	Map<String, dynamic> get descriptor {
	final Map<String, dynamic> descriptor = <String, dynamic>{};
	if (weight != null) {
	descriptor['weight'] = weight;
	}

	if (style != null) {
	descriptor['style'] = style;
	}

	descriptor['asset'] = assetUri.path;
	return descriptor;
	}

	@override
	String toString() => '$runtimeType(asset: ${assetUri.path}, weight; $weight, style: $style)';
	}


	bool _validate(dynamic manifest, Logger logger) {
	final List<String> errors = <String>[];
	if (manifest is! YamlMap) {
	errors.add('Expected YAML map');
	} else {
	for (final MapEntry<dynamic, dynamic> kvp in (manifest as YamlMap).entries) {
	if (kvp.key is! String) {
	errors.add('Expected YAML key to be a string, but got ${kvp.key}.');
	continue;
	}
	switch (kvp.key as String) {
	case 'name':
	if (kvp.value is! String) {
	errors.add('Expected "${kvp.key}" to be a string, but got ${kvp.value}.');
	}
	break;
	case 'flutter':
	if (kvp.value == null) {
	continue;
	}
	if (kvp.value is! YamlMap) {
	errors.add('Expected "${kvp.key}" section to be an object or null, but got ${kvp.value}.');
	} else {
	_validateFlutter(kvp.value as YamlMap, errors);
	}
	break;
	default:
	// additionalProperties are allowed.
	break;
	}
	}
	}

	if (errors.isNotEmpty) {
	logger.printStatus('Error detected in pubspec.yaml:', emphasis: true);
	logger.printError(errors.join('\n'));
	return false;
	}

	return true;
	}

	void _validateFlutter(YamlMap yaml, List<String> errors) {
	if (yaml == null \|\| yaml.entries == null) {
	return;
	}
	for (final MapEntry<dynamic, dynamic> kvp in yaml.entries) {
	if (kvp.key is! String) {
	errors.add('Expected YAML key to be a string, but got ${kvp.key} (${kvp.value.runtimeType}).');
	continue;
	}
	switch (kvp.key as String) {
	case 'uses-material-design':
	if (kvp.value is! bool) {
	errors.add('Expected "${kvp.key}" to be a bool, but got ${kvp.value} (${kvp.value.runtimeType}).');
	}
	break;
	case 'assets':
	if (kvp.value is! YamlList \|\| kvp.value[0] is! String) {
	errors.add('Expected "${kvp.key}" to be a list, but got ${kvp.value} (${kvp.value.runtimeType}).');
	}
	break;
	case 'fonts':
	if (kvp.value is! YamlList \|\| kvp.value[0] is! YamlMap) {
	errors.add('Expected "${kvp.key}" to be a list, but got ${kvp.value} (${kvp.value.runtimeType}).');
	} else {
	_validateFonts(kvp.value as YamlList, errors);
	}
	break;
	case 'licenses':
	final dynamic value = kvp.value;
	if (value is YamlList) {
	_validateListType<String>(value, errors, '"${kvp.key}"', 'files');
	} else {
	errors.add('Expected "${kvp.key}" to be a list of files, but got $value (${value.runtimeType})');
	}
	break;
	case 'module':
	if (kvp.value is! YamlMap) {
	errors.add('Expected "${kvp.key}" to be an object, but got ${kvp.value} (${kvp.value.runtimeType}).');
	}

	if (kvp.value['androidX'] != null && kvp.value['androidX'] is! bool) {
	errors.add('The "androidX" value must be a bool if set.');
	}
	if (kvp.value['androidPackage'] != null && kvp.value['androidPackage'] is! String) {
	errors.add('The "androidPackage" value must be a string if set.');
	}
	if (kvp.value['iosBundleIdentifier'] != null && kvp.value['iosBundleIdentifier'] is! String) {
	errors.add('The "iosBundleIdentifier" section must be a string if set.');
	}
	break;
	case 'plugin':
	if (kvp.value is! YamlMap \|\| kvp.value == null) {
	errors.add('Expected "${kvp.key}" to be an object, but got ${kvp.value} (${kvp.value.runtimeType}).');
	break;
	}
	final List<String> pluginErrors = Plugin.validatePluginYaml(kvp.value as YamlMap);
	errors.addAll(pluginErrors);
	break;
	case 'generate':
	break;
	case 'deferred-components':
	_validateDeferredComponents(kvp, errors);
	break;
	default:
	errors.add('Unexpected child "${kvp.key}" found under "flutter".');
	break;
	}
	}
	}

	void _validateListType<T>(YamlList yamlList, List<String> errors, String context, String typeAlias) {
	for (int i = 0; i < yamlList.length; i++) {
	if (yamlList[i] is! T) {
	errors.add('Expected $context to be a list of $typeAlias, but element $i was a ${yamlList[i].runtimeType}');
	}
	}
	}

	void _validateDeferredComponents(MapEntry<dynamic, dynamic> kvp, List<String> errors) {
	if (kvp.value != null && (kvp.value is! YamlList \|\| kvp.value[0] is! YamlMap)) {
	errors.add('Expected "${kvp.key}" to be a list, but got ${kvp.value} (${kvp.value.runtimeType}).');
	} else if (kvp.value != null) {
	for (int i = 0; i < (kvp.value as YamlList).length; i++) {
	if (kvp.value[i] is! YamlMap) {
	errors.add('Expected the $i element in "${kvp.key}" to be a map, but got ${kvp.value[i]} (${kvp.value[i].runtimeType}).');
	continue;
	}
	if (!(kvp.value[i] as YamlMap).containsKey('name') \|\| kvp.value[i]['name'] is! String) {
	errors.add('Expected the $i element in "${kvp.key}" to have required key "name" of type String');
	}
	if ((kvp.value[i] as YamlMap).containsKey('libraries')) {
	if (kvp.value[i]['libraries'] is! YamlList) {
	errors.add('Expected "libraries" key in the $i element of "${kvp.key}" to be a list, but got ${kvp.value[i]['libraries']} (${kvp.value[i]['libraries'].runtimeType}).');
	} else {
	_validateListType<String>(kvp.value[i]['libraries'] as YamlList, errors, '"libraries" key in the $i element of "${kvp.key}"', 'dart library Strings');
	}
	}
	if ((kvp.value[i] as YamlMap).containsKey('assets')) {
	if (kvp.value[i]['assets'] is! YamlList) {
	errors.add('Expected "assets" key in the $i element of "${kvp.key}" to be a list, but got ${kvp.value[i]['assets']} (${kvp.value[i]['assets'].runtimeType}).');
	} else {
	_validateListType<String>(kvp.value[i]['assets'] as YamlList, errors, '"assets" key in the $i element of "${kvp.key}"', 'file paths');
	}
	}
	}
	}
	}

	void _validateFonts(YamlList fonts, List<String> errors) {
	if (fonts == null) {
	return;
	}
	const Set<int> fontWeights = <int>{
	100, 200, 300, 400, 500, 600, 700, 800, 900,
	};
	for (final dynamic fontListEntry in fonts) {
	if (fontListEntry is! YamlMap) {
	errors.add('Unexpected child "$fontListEntry" found under "fonts". Expected a map.');
	continue;
	}
	final YamlMap fontMap = fontListEntry as YamlMap;
	for (final dynamic key in fontMap.keys.where((dynamic key) => key != 'family' && key != 'fonts')) {
	errors.add('Unexpected child "$key" found under "fonts".');
	}
	if (fontMap['family'] != null && fontMap['family'] is! String) {
	errors.add('Font family must either be null or a String.');
	}
	if (fontMap['fonts'] == null) {
	continue;
	} else if (fontMap['fonts'] is! YamlList) {
	errors.add('Expected "fonts" to either be null or a list.');
	continue;
	}
	for (final dynamic fontListItem in fontMap['fonts']) {
	if (fontListItem is! YamlMap) {
	errors.add('Expected "fonts" to be a list of maps.');
	continue;
	}
	final YamlMap fontMapList = fontListItem as YamlMap;
	for (final MapEntry<dynamic, dynamic> kvp in fontMapList.entries) {
	if (kvp.key is! String) {
	errors.add('Expected "${kvp.key}" under "fonts" to be a string.');
	}
	switch(kvp.key as String) {
	case 'asset':
	if (kvp.value is! String) {
	errors.add('Expected font asset ${kvp.value} ((${kvp.value.runtimeType})) to be a string.');
	}
	break;
	case 'weight':
	if (!fontWeights.contains(kvp.value)) {
	errors.add('Invalid value ${kvp.value} ((${kvp.value.runtimeType})) for font -> weight.');
	}
	break;
	case 'style':
	if (kvp.value != 'normal' && kvp.value != 'italic') {
	errors.add('Invalid value ${kvp.value} ((${kvp.value.runtimeType})) for font -> style.');
	}
	break;
	default:
	errors.add('Unexpected key ${kvp.key} ((${kvp.value.runtimeType})) under font.');
	break;
	}
	}
	}
	}
	}