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

 // Copyright 2016 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:async';
 import 'dart:convert';

 import 'package:yaml/yaml.dart';

 import 'base/context.dart';
 import 'base/file_system.dart';
 import 'build_info.dart';
 import 'cache.dart';
 import 'dart/package_map.dart';
 import 'devfs.dart';
 import 'flutter_manifest.dart';
 import 'globals.dart';

 const AssetBundleFactory _kManifestFactory = const _ManifestAssetBundleFactory();

 /// Injected factory class for spawning [AssetBundle] instances.
 abstract class AssetBundleFactory {
   /// The singleton instance, pulled from the [AppContext].
   static AssetBundleFactory get instance => context[AssetBundleFactory];

   static AssetBundleFactory get defaultInstance => _kManifestFactory;

   /// Creates a new [AssetBundle].
   AssetBundle createBundle();
 }

 abstract class AssetBundle {
   Map<String, DevFSContent> get entries;

   bool wasBuiltOnce();

   bool needsBuild({String manifestPath: _ManifestAssetBundle.defaultManifestPath});

   /// Returns 0 for success; non-zero for failure.
   Future<int> build({
     String manifestPath: _ManifestAssetBundle.defaultManifestPath,
     String assetDirPath,
     String packagesPath,
     bool includeDefaultFonts: true,
     bool reportLicensedPackages: false
   });
 }

 class _ManifestAssetBundleFactory implements AssetBundleFactory {
   const _ManifestAssetBundleFactory();

   @override
   AssetBundle createBundle() => new _ManifestAssetBundle();
 }

 class _ManifestAssetBundle implements AssetBundle {
   @override
   final Map<String, DevFSContent> entries = <String, DevFSContent>{};

   static const String defaultManifestPath = 'pubspec.yaml';
   static const String _kAssetManifestJson = 'AssetManifest.json';
   static const String _kFontManifestJson = 'FontManifest.json';
   static const String _kFontSetMaterial = 'material';
   static const String _kLICENSE = 'LICENSE';

   DateTime _lastBuildTimestamp;

   /// Constructs an [_ManifestAssetBundle] that gathers the set of assets from the
   /// pubspec.yaml manifest.
   _ManifestAssetBundle();

   @override
   bool wasBuiltOnce() => _lastBuildTimestamp != null;

   @override
   bool needsBuild({String manifestPath: defaultManifestPath}) {
     if (_lastBuildTimestamp == null)
       return true;

     final FileStat stat = fs.file(manifestPath).statSync();
     if (stat.type == FileSystemEntityType.NOT_FOUND) // ignore: deprecated_member_use
       return true;

     return stat.modified.isAfter(_lastBuildTimestamp);
   }

   @override
   Future<int> build({
     String manifestPath: defaultManifestPath,
     String assetDirPath,
     String packagesPath,
     bool includeDefaultFonts: true,
     bool reportLicensedPackages: false
   }) async {
     assetDirPath ??= getAssetBuildDirectory();
     packagesPath ??= fs.path.absolute(PackageMap.globalPackagesPath);
     FlutterManifest flutterManifest;
     try {
       flutterManifest = await FlutterManifest.createFromPath(manifestPath);
     } catch (e) {
       printStatus('Error detected in pubspec.yaml:', emphasis: true);
       printError('$e');
       return 1;
     }
     if (flutterManifest == null)
       return 1;

     if (flutterManifest.isEmpty) {
       entries[_kAssetManifestJson] = new DevFSStringContent('{}');
       return 0;
     }

     final String assetBasePath = fs.path.dirname(fs.path.absolute(manifestPath));

     _lastBuildTimestamp = new DateTime.now();

     final PackageMap packageMap = new PackageMap(packagesPath);

     // The _assetVariants map contains an entry for each asset listed
     // in the pubspec.yaml file's assets and font and sections. The
     // value of each image asset is a list of resolution-specific "variants",
     // see _AssetDirectoryCache.
     final Map<_Asset, List<_Asset>> assetVariants = _parseAssets(
       packageMap,
       flutterManifest,
       assetBasePath,
       excludeDirs: <String>[assetDirPath, getBuildDirectory()]
     );

     if (assetVariants == null)
       return 1;

     final List<Map<String, dynamic>> fonts = _parseFonts(
       flutterManifest,
       includeDefaultFonts,
       packageMap,
     );

     // Add fonts and assets from packages.
     for (String packageName in packageMap.map.keys) {
       final Uri package = packageMap.map[packageName];
       if (package != null && package.scheme == 'file') {
         final String packageManifestPath = fs.path.fromUri(package.resolve('../pubspec.yaml'));
         final FlutterManifest packageFlutterManifest = await FlutterManifest.createFromPath(packageManifestPath);
         if (packageFlutterManifest == null)
           continue;
         // Skip the app itself
         if (packageFlutterManifest.appName == flutterManifest.appName)
           continue;
         final String packageBasePath = fs.path.dirname(packageManifestPath);

         final Map<_Asset, List<_Asset>> packageAssets = _parseAssets(
           packageMap,
           packageFlutterManifest,
           packageBasePath,
           packageName: packageName,
         );

         if (packageAssets == null)
           return 1;
         assetVariants.addAll(packageAssets);

         fonts.addAll(_parseFonts(
           packageFlutterManifest,
           includeDefaultFonts,
           packageMap,
           packageName: packageName,
         ));
       }
     }

     // Save the contents of each image, image variant, and font
     // asset in entries.
     for (_Asset asset in assetVariants.keys) {
       if (!asset.assetFileExists && assetVariants[asset].isEmpty) {
         printStatus('Error detected in pubspec.yaml:', emphasis: true);
         printError('No file or variants found for $asset.\n');
         return 1;
       }
       // The file name for an asset's "main" entry is whatever appears in
       // the pubspec.yaml file. The main entry's file must always exist for
       // font assets. It need not exist for an image if resolution-specific
       // variant files exist. An image's main entry is treated the same as a
       // "1x" resolution variant and if both exist then the explicit 1x
       // variant is preferred.
       if (asset.assetFileExists) {
         assert(!assetVariants[asset].contains(asset));
         assetVariants[asset].insert(0, asset);
       }
       for (_Asset variant in assetVariants[asset]) {
         assert(variant.assetFileExists);
         entries[variant.entryUri.path] = new DevFSFileContent(variant.assetFile);
       }
     }

     final List<_Asset> materialAssets = <_Asset>[];
     if (flutterManifest.usesMaterialDesign && includeDefaultFonts) {
       materialAssets.addAll(_getMaterialAssets(_kFontSetMaterial));
     }
     for (_Asset asset in materialAssets) {
       assert(asset.assetFileExists);
       entries[asset.entryUri.path] = new DevFSFileContent(asset.assetFile);
     }

     entries[_kAssetManifestJson] = _createAssetManifest(assetVariants);

     entries[_kFontManifestJson] = new DevFSStringContent(json.encode(fonts));

     // TODO(ianh): Only do the following line if we've changed packages or if our LICENSE file changed
     entries[_kLICENSE] = await _obtainLicenses(packageMap, assetBasePath, reportPackages: reportLicensedPackages);

     return 0;
   }
 }

 class _Asset {
   _Asset({ this.baseDir, this.relativeUri, this.entryUri });

   final String baseDir;

   /// A platform-independent Uri where this asset can be found on disk on the
   /// host system relative to [baseDir].
   final Uri relativeUri;

   /// A platform-independent Uri representing the entry for the asset manifest.
   final Uri entryUri;

   File get assetFile {
     return fs.file(fs.path.join(baseDir, fs.path.fromUri(relativeUri)));
   }

   bool get assetFileExists => assetFile.existsSync();

   /// The delta between what the entryUri is and the relativeUri (e.g.,
   /// packages/flutter_gallery).
   Uri get symbolicPrefixUri {
     if (entryUri == relativeUri)
       return null;
     final int index = entryUri.path.indexOf(relativeUri.path);
     return index == -1 ? null : new Uri(path: entryUri.path.substring(0, index));
   }

   @override
   String toString() => 'asset: $entryUri';

   @override
   bool operator ==(dynamic other) {
     if (identical(other, this))
       return true;
     if (other.runtimeType != runtimeType)
       return false;
     final _Asset otherAsset = other;
     return otherAsset.baseDir == baseDir
         && otherAsset.relativeUri == relativeUri
         && otherAsset.entryUri == entryUri;
   }

   @override
   int get hashCode {
     return baseDir.hashCode
         ^relativeUri.hashCode
         ^ entryUri.hashCode;
   }
 }

 Map<String, dynamic> _readMaterialFontsManifest() {
   final String fontsPath = fs.path.join(fs.path.absolute(Cache.flutterRoot),
       'packages', 'flutter_tools', 'schema', 'material_fonts.yaml');

   return loadYaml(fs.file(fontsPath).readAsStringSync());
 }

 final Map<String, dynamic> _materialFontsManifest = _readMaterialFontsManifest();

 List<Map<String, dynamic>> _getMaterialFonts(String fontSet) {
   return _materialFontsManifest[fontSet];
 }

 List<_Asset> _getMaterialAssets(String fontSet) {
   final List<_Asset> result = <_Asset>[];

   for (Map<String, dynamic> family in _getMaterialFonts(fontSet)) {
     for (Map<String, dynamic> font in family['fonts']) {
       final Uri entryUri = fs.path.toUri(font['asset']);
       result.add(new _Asset(
         baseDir: fs.path.join(Cache.flutterRoot, 'bin', 'cache', 'artifacts', 'material_fonts'),
         relativeUri: new Uri(path: entryUri.pathSegments.last),
         entryUri: entryUri
       ));
     }
   }

   return result;
 }

 final String _licenseSeparator = '\n' + ('-' * 80) + '\n';

 /// Returns a DevFSContent representing the license file.
 Future<DevFSContent> _obtainLicenses(
   PackageMap packageMap,
   String assetBase,
   { bool reportPackages }
 ) async {
   // Read the LICENSE file from each package in the .packages file, splitting
   // each one into each component license (so that we can de-dupe if possible).
   //
   // Individual licenses inside each LICENSE file should be separated by 80
   // hyphens on their own on a line.
   //
   // If a LICENSE file contains more than one component license, then each
   // component license must start with the names of the packages to which the
   // component license applies, with each package name on its own line, and the
   // list of package names separated from the actual license text by a blank
   // line. (The packages need not match the names of the pub package. For
   // example, a package might itself contain code from multiple third-party
   // sources, and might need to include a license for each one.)
   final Map<String, Set<String>> packageLicenses = <String, Set<String>>{};
   final Set<String> allPackages = new Set<String>();
   for (String packageName in packageMap.map.keys) {
     final Uri package = packageMap.map[packageName];
     if (package != null && package.scheme == 'file') {
       final File file = fs.file(package.resolve('../LICENSE'));
       if (file.existsSync()) {
         final List<String> rawLicenses =
             (await file.readAsString()).split(_licenseSeparator);
         for (String rawLicense in rawLicenses) {
           List<String> packageNames;
           String licenseText;
           if (rawLicenses.length > 1) {
             final int split = rawLicense.indexOf('\n\n');
             if (split >= 0) {
               packageNames = rawLicense.substring(0, split).split('\n');
               licenseText = rawLicense.substring(split + 2);
             }
           }
           if (licenseText == null) {
             packageNames = <String>[packageName];
             licenseText = rawLicense;
           }
           packageLicenses.putIfAbsent(licenseText, () => new Set<String>())
             ..addAll(packageNames);
           allPackages.addAll(packageNames);
         }
       }
     }
   }

   if (reportPackages) {
     final List<String> allPackagesList = allPackages.toList()..sort();
     printStatus('Licenses were found for the following packages:');
     printStatus(allPackagesList.join(', '));
   }

   final List<String> combinedLicensesList = packageLicenses.keys.map(
     (String license) {
       final List<String> packageNames = packageLicenses[license].toList()
        ..sort();
       return packageNames.join('\n') + '\n\n' + license;
     }
   ).toList();
   combinedLicensesList.sort();

   final String combinedLicenses = combinedLicensesList.join(_licenseSeparator);

   return new DevFSStringContent(combinedLicenses);
 }

 DevFSContent _createAssetManifest(Map<_Asset, List<_Asset>> assetVariants) {
   final Map<String, List<String>> jsonObject = <String, List<String>>{};
   for (_Asset main in assetVariants.keys) {
     final List<String> variants = <String>[];
     for (_Asset variant in assetVariants[main])
       variants.add(variant.entryUri.path);
     jsonObject[main.entryUri.path] = variants;
   }
   return new DevFSStringContent(json.encode(jsonObject));
 }

 List<Map<String, dynamic>> _parseFonts(
   FlutterManifest manifest,
   bool includeDefaultFonts,
   PackageMap packageMap, {
   String packageName
 }) {
   final List<Map<String, dynamic>> fonts = <Map<String, dynamic>>[];
   if (manifest.usesMaterialDesign && includeDefaultFonts) {
     fonts.addAll(_getMaterialFonts(_ManifestAssetBundle._kFontSetMaterial));
   }
   if (packageName == null) {
     fonts.addAll(manifest.fontsDescriptor);
   } else {
     fonts.addAll(_createFontsDescriptor(_parsePackageFonts(
       manifest,
       packageName,
       packageMap,
     )));
   }
   return fonts;
 }

 /// Prefixes family names and asset paths of fonts included from packages with
 /// 'packages/<package_name>'
 List<Font> _parsePackageFonts(
   FlutterManifest manifest,
   String packageName,
   PackageMap packageMap,
 ) {
   final List<Font> packageFonts = <Font>[];
   for (Font font in manifest.fonts) {
     final List<FontAsset> packageFontAssets = <FontAsset>[];
     for (FontAsset fontAsset in font.fontAssets) {
       final Uri assetUri = fontAsset.assetUri;
       if (assetUri.pathSegments.first == 'packages' &&
           !fs.isFileSync(fs.path.fromUri(packageMap.map[packageName].resolve('../${assetUri.path}')))) {
         packageFontAssets.add(new FontAsset(
           fontAsset.assetUri,
           weight: fontAsset.weight,
           style: fontAsset.style,
         ));
       } else {
         packageFontAssets.add(new FontAsset(
           new Uri(pathSegments: <String>['packages', packageName]..addAll(assetUri.pathSegments)),
           weight: fontAsset.weight,
           style: fontAsset.style,
         ));
       }
     }
     packageFonts.add(new Font('packages/$packageName/${font.familyName}', packageFontAssets));
   }
   return packageFonts;
 }

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

 // Given an assets directory like this:
 //
 // assets/foo
 // assets/var1/foo
 // assets/var2/foo
 // assets/bar
 //
 // variantsFor('assets/foo') => ['/assets/var1/foo', '/assets/var2/foo']
 // variantsFor('assets/bar') => []
 class _AssetDirectoryCache {
   _AssetDirectoryCache(Iterable<String> excluded) {
     _excluded = excluded.map<String>((String path) => fs.path.absolute(path) + fs.path.separator);
   }

   Iterable<String> _excluded;
   final Map<String, Map<String, List<String>>> _cache = <String, Map<String, List<String>>>{};

   List<String> variantsFor(String assetPath) {
     final String assetName = fs.path.basename(assetPath);
     final String directory = fs.path.dirname(assetPath);

     if (!fs.directory(directory).existsSync())
       return const <String>[];

     if (_cache[directory] == null) {
       final List<String> paths = <String>[];
       for (FileSystemEntity entity in fs.directory(directory).listSync(recursive: true)) {
         final String path = entity.path;
         if (fs.isFileSync(path) && !_excluded.any((String exclude) => path.startsWith(exclude)))
           paths.add(path);
       }

       final Map<String, List<String>> variants = <String, List<String>>{};
       for (String path in paths) {
         final String variantName = fs.path.basename(path);
         if (directory == fs.path.dirname(path))
           continue;
         variants[variantName] ??= <String>[];
         variants[variantName].add(path);
       }
       _cache[directory] = variants;
     }

     return _cache[directory][assetName] ?? const <String>[];
   }
 }

 /// Given an assetBase location and a pubspec.yaml Flutter manifest, return a
 /// map of assets to asset variants.
 ///
 /// Returns null on missing assets.
 Map<_Asset, List<_Asset>> _parseAssets(
   PackageMap packageMap,
   FlutterManifest flutterManifest,
   String assetBase, {
   List<String> excludeDirs: const <String>[],
   String packageName
 }) {
   final Map<_Asset, List<_Asset>> result = <_Asset, List<_Asset>>{};

   final _AssetDirectoryCache cache = new _AssetDirectoryCache(excludeDirs);
   for (Uri assetUri in flutterManifest.assets) {
     final _Asset asset = _resolveAsset(
       packageMap,
       assetBase,
       assetUri,
       packageName,
     );
     final List<_Asset> variants = <_Asset>[];
     for (String path in cache.variantsFor(asset.assetFile.path)) {
       final String relativePath = fs.path.relative(path, from: asset.baseDir);
       final Uri relativeUri = fs.path.toUri(relativePath);
       final Uri entryUri = asset.symbolicPrefixUri == null
           ? relativeUri
           : asset.symbolicPrefixUri.resolveUri(relativeUri);
       variants.add(new _Asset(
         baseDir: asset.baseDir,
         entryUri: entryUri,
         relativeUri: relativeUri,
       ));
     }

     result[asset] = variants;
   }

   // Add assets referenced in the fonts section of the manifest.
   for (Font font in flutterManifest.fonts) {
     for (FontAsset fontAsset in font.fontAssets) {
       final _Asset baseAsset = _resolveAsset(
         packageMap,
         assetBase,
         fontAsset.assetUri,
         packageName,
       );
       if (!baseAsset.assetFileExists) {
         printError('Error: unable to locate asset entry in pubspec.yaml: "${fontAsset.assetUri}".');
         return null;
       }

       result[baseAsset] = <_Asset>[];
     }
   }

   return result;
 }

 _Asset _resolveAsset(
   PackageMap packageMap,
   String assetsBaseDir,
   Uri assetUri,
   String packageName,
 ) {
   final String assetPath = fs.path.fromUri(assetUri);
   if (assetUri.pathSegments.first == 'packages' && !fs.isFileSync(fs.path.join(assetsBaseDir, assetPath))) {
     // The asset is referenced in the pubspec.yaml as
     // 'packages/PACKAGE_NAME/PATH/TO/ASSET .
     final _Asset packageAsset = _resolvePackageAsset(assetUri, packageMap);
     if (packageAsset != null)
       return packageAsset;
   }

   return new _Asset(
     baseDir: assetsBaseDir,
     entryUri: packageName == null
         ? assetUri // Asset from the current application.
         : new Uri(pathSegments: <String>['packages', packageName]..addAll(assetUri.pathSegments)), // Asset from, and declared in $packageName.
     relativeUri: assetUri,
   );
 }

 _Asset _resolvePackageAsset(Uri assetUri, PackageMap packageMap) {
   assert(assetUri.pathSegments.first == 'packages');
   if (assetUri.pathSegments.length > 1) {
     final String packageName = assetUri.pathSegments[1];
     final Uri packageUri = packageMap.map[packageName];
     if (packageUri != null && packageUri.scheme == 'file') {
       return new _Asset(
         baseDir: fs.path.fromUri(packageUri),
         entryUri: assetUri,
         relativeUri: new Uri(pathSegments: assetUri.pathSegments.sublist(2)),
       );
     }
   }
   printStatus('Error detected in pubspec.yaml:', emphasis: true);
   printError('Could not resolve package for asset $assetUri.\n');
   return null;
 }
	// Copyright 2016 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:async';
	import 'dart:convert';

	import 'package:yaml/yaml.dart';

	import 'base/context.dart';
	import 'base/file_system.dart';
	import 'build_info.dart';
	import 'cache.dart';
	import 'dart/package_map.dart';
	import 'devfs.dart';
	import 'flutter_manifest.dart';
	import 'globals.dart';

	const AssetBundleFactory _kManifestFactory = const _ManifestAssetBundleFactory();

	/// Injected factory class for spawning [AssetBundle] instances.
	abstract class AssetBundleFactory {
	/// The singleton instance, pulled from the [AppContext].
	static AssetBundleFactory get instance => context[AssetBundleFactory];

	static AssetBundleFactory get defaultInstance => _kManifestFactory;

	/// Creates a new [AssetBundle].
	AssetBundle createBundle();
	}

	abstract class AssetBundle {
	Map<String, DevFSContent> get entries;

	bool wasBuiltOnce();

	bool needsBuild({String manifestPath: _ManifestAssetBundle.defaultManifestPath});

	/// Returns 0 for success; non-zero for failure.
	Future<int> build({
	String manifestPath: _ManifestAssetBundle.defaultManifestPath,
	String assetDirPath,
	String packagesPath,
	bool includeDefaultFonts: true,
	bool reportLicensedPackages: false
	});
	}

	class _ManifestAssetBundleFactory implements AssetBundleFactory {
	const _ManifestAssetBundleFactory();

	@override
	AssetBundle createBundle() => new _ManifestAssetBundle();
	}

	class _ManifestAssetBundle implements AssetBundle {
	@override
	final Map<String, DevFSContent> entries = <String, DevFSContent>{};

	static const String defaultManifestPath = 'pubspec.yaml';
	static const String _kAssetManifestJson = 'AssetManifest.json';
	static const String _kFontManifestJson = 'FontManifest.json';
	static const String _kFontSetMaterial = 'material';
	static const String _kLICENSE = 'LICENSE';

	DateTime _lastBuildTimestamp;

	/// Constructs an [_ManifestAssetBundle] that gathers the set of assets from the
	/// pubspec.yaml manifest.
	_ManifestAssetBundle();

	@override
	bool wasBuiltOnce() => _lastBuildTimestamp != null;

	@override
	bool needsBuild({String manifestPath: defaultManifestPath}) {
	if (_lastBuildTimestamp == null)
	return true;

	final FileStat stat = fs.file(manifestPath).statSync();
	if (stat.type == FileSystemEntityType.NOT_FOUND) // ignore: deprecated_member_use
	return true;

	return stat.modified.isAfter(_lastBuildTimestamp);
	}

	@override
	Future<int> build({
	String manifestPath: defaultManifestPath,
	String assetDirPath,
	String packagesPath,
	bool includeDefaultFonts: true,
	bool reportLicensedPackages: false
	}) async {
	assetDirPath ??= getAssetBuildDirectory();
	packagesPath ??= fs.path.absolute(PackageMap.globalPackagesPath);
	FlutterManifest flutterManifest;
	try {
	flutterManifest = await FlutterManifest.createFromPath(manifestPath);
	} catch (e) {
	printStatus('Error detected in pubspec.yaml:', emphasis: true);
	printError('$e');
	return 1;
	}
	if (flutterManifest == null)
	return 1;

	if (flutterManifest.isEmpty) {
	entries[_kAssetManifestJson] = new DevFSStringContent('{}');
	return 0;
	}

	final String assetBasePath = fs.path.dirname(fs.path.absolute(manifestPath));

	_lastBuildTimestamp = new DateTime.now();

	final PackageMap packageMap = new PackageMap(packagesPath);

	// The _assetVariants map contains an entry for each asset listed
	// in the pubspec.yaml file's assets and font and sections. The
	// value of each image asset is a list of resolution-specific "variants",
	// see _AssetDirectoryCache.
	final Map<_Asset, List<_Asset>> assetVariants = _parseAssets(
	packageMap,
	flutterManifest,
	assetBasePath,
	excludeDirs: <String>[assetDirPath, getBuildDirectory()]
	);

	if (assetVariants == null)
	return 1;

	final List<Map<String, dynamic>> fonts = _parseFonts(
	flutterManifest,
	includeDefaultFonts,
	packageMap,
	);

	// Add fonts and assets from packages.
	for (String packageName in packageMap.map.keys) {
	final Uri package = packageMap.map[packageName];
	if (package != null && package.scheme == 'file') {
	final String packageManifestPath = fs.path.fromUri(package.resolve('../pubspec.yaml'));
	final FlutterManifest packageFlutterManifest = await FlutterManifest.createFromPath(packageManifestPath);
	if (packageFlutterManifest == null)
	continue;
	// Skip the app itself
	if (packageFlutterManifest.appName == flutterManifest.appName)
	continue;
	final String packageBasePath = fs.path.dirname(packageManifestPath);

	final Map<_Asset, List<_Asset>> packageAssets = _parseAssets(
	packageMap,
	packageFlutterManifest,
	packageBasePath,
	packageName: packageName,
	);

	if (packageAssets == null)
	return 1;
	assetVariants.addAll(packageAssets);

	fonts.addAll(_parseFonts(
	packageFlutterManifest,
	includeDefaultFonts,
	packageMap,
	packageName: packageName,
	));
	}
	}

	// Save the contents of each image, image variant, and font
	// asset in entries.
	for (_Asset asset in assetVariants.keys) {
	if (!asset.assetFileExists && assetVariants[asset].isEmpty) {
	printStatus('Error detected in pubspec.yaml:', emphasis: true);
	printError('No file or variants found for $asset.\n');
	return 1;
	}
	// The file name for an asset's "main" entry is whatever appears in
	// the pubspec.yaml file. The main entry's file must always exist for
	// font assets. It need not exist for an image if resolution-specific
	// variant files exist. An image's main entry is treated the same as a
	// "1x" resolution variant and if both exist then the explicit 1x
	// variant is preferred.
	if (asset.assetFileExists) {
	assert(!assetVariants[asset].contains(asset));
	assetVariants[asset].insert(0, asset);
	}
	for (_Asset variant in assetVariants[asset]) {
	assert(variant.assetFileExists);
	entries[variant.entryUri.path] = new DevFSFileContent(variant.assetFile);
	}
	}

	final List<_Asset> materialAssets = <_Asset>[];
	if (flutterManifest.usesMaterialDesign && includeDefaultFonts) {
	materialAssets.addAll(_getMaterialAssets(_kFontSetMaterial));
	}
	for (_Asset asset in materialAssets) {
	assert(asset.assetFileExists);
	entries[asset.entryUri.path] = new DevFSFileContent(asset.assetFile);
	}

	entries[_kAssetManifestJson] = _createAssetManifest(assetVariants);

	entries[_kFontManifestJson] = new DevFSStringContent(json.encode(fonts));

	// TODO(ianh): Only do the following line if we've changed packages or if our LICENSE file changed
	entries[_kLICENSE] = await _obtainLicenses(packageMap, assetBasePath, reportPackages: reportLicensedPackages);

	return 0;
	}
	}

	class _Asset {
	_Asset({ this.baseDir, this.relativeUri, this.entryUri });

	final String baseDir;

	/// A platform-independent Uri where this asset can be found on disk on the
	/// host system relative to [baseDir].
	final Uri relativeUri;

	/// A platform-independent Uri representing the entry for the asset manifest.
	final Uri entryUri;

	File get assetFile {
	return fs.file(fs.path.join(baseDir, fs.path.fromUri(relativeUri)));
	}

	bool get assetFileExists => assetFile.existsSync();

	/// The delta between what the entryUri is and the relativeUri (e.g.,
	/// packages/flutter_gallery).
	Uri get symbolicPrefixUri {
	if (entryUri == relativeUri)
	return null;
	final int index = entryUri.path.indexOf(relativeUri.path);
	return index == -1 ? null : new Uri(path: entryUri.path.substring(0, index));
	}

	@override
	String toString() => 'asset: $entryUri';

	@override
	bool operator ==(dynamic other) {
	if (identical(other, this))
	return true;
	if (other.runtimeType != runtimeType)
	return false;
	final _Asset otherAsset = other;
	return otherAsset.baseDir == baseDir
	&& otherAsset.relativeUri == relativeUri
	&& otherAsset.entryUri == entryUri;
	}

	@override
	int get hashCode {
	return baseDir.hashCode
	^relativeUri.hashCode
	^ entryUri.hashCode;
	}
	}

	Map<String, dynamic> _readMaterialFontsManifest() {
	final String fontsPath = fs.path.join(fs.path.absolute(Cache.flutterRoot),
	'packages', 'flutter_tools', 'schema', 'material_fonts.yaml');

	return loadYaml(fs.file(fontsPath).readAsStringSync());
	}

	final Map<String, dynamic> _materialFontsManifest = _readMaterialFontsManifest();

	List<Map<String, dynamic>> _getMaterialFonts(String fontSet) {
	return _materialFontsManifest[fontSet];
	}

	List<_Asset> _getMaterialAssets(String fontSet) {
	final List<_Asset> result = <_Asset>[];

	for (Map<String, dynamic> family in _getMaterialFonts(fontSet)) {
	for (Map<String, dynamic> font in family['fonts']) {
	final Uri entryUri = fs.path.toUri(font['asset']);
	result.add(new _Asset(
	baseDir: fs.path.join(Cache.flutterRoot, 'bin', 'cache', 'artifacts', 'material_fonts'),
	relativeUri: new Uri(path: entryUri.pathSegments.last),
	entryUri: entryUri
	));
	}
	}

	return result;
	}

	final String _licenseSeparator = '\n' + ('-' * 80) + '\n';

	/// Returns a DevFSContent representing the license file.
	Future<DevFSContent> _obtainLicenses(
	PackageMap packageMap,
	String assetBase,
	{ bool reportPackages }
	) async {
	// Read the LICENSE file from each package in the .packages file, splitting
	// each one into each component license (so that we can de-dupe if possible).
	//
	// Individual licenses inside each LICENSE file should be separated by 80
	// hyphens on their own on a line.
	//
	// If a LICENSE file contains more than one component license, then each
	// component license must start with the names of the packages to which the
	// component license applies, with each package name on its own line, and the
	// list of package names separated from the actual license text by a blank
	// line. (The packages need not match the names of the pub package. For
	// example, a package might itself contain code from multiple third-party
	// sources, and might need to include a license for each one.)
	final Map<String, Set<String>> packageLicenses = <String, Set<String>>{};
	final Set<String> allPackages = new Set<String>();
	for (String packageName in packageMap.map.keys) {
	final Uri package = packageMap.map[packageName];
	if (package != null && package.scheme == 'file') {
	final File file = fs.file(package.resolve('../LICENSE'));
	if (file.existsSync()) {
	final List<String> rawLicenses =
	(await file.readAsString()).split(_licenseSeparator);
	for (String rawLicense in rawLicenses) {
	List<String> packageNames;
	String licenseText;
	if (rawLicenses.length > 1) {
	final int split = rawLicense.indexOf('\n\n');
	if (split >= 0) {
	packageNames = rawLicense.substring(0, split).split('\n');
	licenseText = rawLicense.substring(split + 2);
	}
	}
	if (licenseText == null) {
	packageNames = <String>[packageName];
	licenseText = rawLicense;
	}
	packageLicenses.putIfAbsent(licenseText, () => new Set<String>())
	..addAll(packageNames);
	allPackages.addAll(packageNames);
	}
	}
	}
	}

	if (reportPackages) {
	final List<String> allPackagesList = allPackages.toList()..sort();
	printStatus('Licenses were found for the following packages:');
	printStatus(allPackagesList.join(', '));
	}

	final List<String> combinedLicensesList = packageLicenses.keys.map(
	(String license) {
	final List<String> packageNames = packageLicenses[license].toList()
	..sort();
	return packageNames.join('\n') + '\n\n' + license;
	}
	).toList();
	combinedLicensesList.sort();

	final String combinedLicenses = combinedLicensesList.join(_licenseSeparator);

	return new DevFSStringContent(combinedLicenses);
	}

	DevFSContent _createAssetManifest(Map<_Asset, List<_Asset>> assetVariants) {
	final Map<String, List<String>> jsonObject = <String, List<String>>{};
	for (_Asset main in assetVariants.keys) {
	final List<String> variants = <String>[];
	for (_Asset variant in assetVariants[main])
	variants.add(variant.entryUri.path);
	jsonObject[main.entryUri.path] = variants;
	}
	return new DevFSStringContent(json.encode(jsonObject));
	}

	List<Map<String, dynamic>> _parseFonts(
	FlutterManifest manifest,
	bool includeDefaultFonts,
	PackageMap packageMap, {
	String packageName
	}) {
	final List<Map<String, dynamic>> fonts = <Map<String, dynamic>>[];
	if (manifest.usesMaterialDesign && includeDefaultFonts) {
	fonts.addAll(_getMaterialFonts(_ManifestAssetBundle._kFontSetMaterial));
	}
	if (packageName == null) {
	fonts.addAll(manifest.fontsDescriptor);
	} else {
	fonts.addAll(_createFontsDescriptor(_parsePackageFonts(
	manifest,
	packageName,
	packageMap,
	)));
	}
	return fonts;
	}

	/// Prefixes family names and asset paths of fonts included from packages with
	/// 'packages/<package_name>'
	List<Font> _parsePackageFonts(
	FlutterManifest manifest,
	String packageName,
	PackageMap packageMap,
	) {
	final List<Font> packageFonts = <Font>[];
	for (Font font in manifest.fonts) {
	final List<FontAsset> packageFontAssets = <FontAsset>[];
	for (FontAsset fontAsset in font.fontAssets) {
	final Uri assetUri = fontAsset.assetUri;
	if (assetUri.pathSegments.first == 'packages' &&
	!fs.isFileSync(fs.path.fromUri(packageMap.map[packageName].resolve('../${assetUri.path}')))) {
	packageFontAssets.add(new FontAsset(
	fontAsset.assetUri,
	weight: fontAsset.weight,
	style: fontAsset.style,
	));
	} else {
	packageFontAssets.add(new FontAsset(
	new Uri(pathSegments: <String>['packages', packageName]..addAll(assetUri.pathSegments)),
	weight: fontAsset.weight,
	style: fontAsset.style,
	));
	}
	}
	packageFonts.add(new Font('packages/$packageName/${font.familyName}', packageFontAssets));
	}
	return packageFonts;
	}

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

	// Given an assets directory like this:
	//
	// assets/foo
	// assets/var1/foo
	// assets/var2/foo
	// assets/bar
	//
	// variantsFor('assets/foo') => ['/assets/var1/foo', '/assets/var2/foo']
	// variantsFor('assets/bar') => []
	class _AssetDirectoryCache {
	_AssetDirectoryCache(Iterable<String> excluded) {
	_excluded = excluded.map<String>((String path) => fs.path.absolute(path) + fs.path.separator);
	}

	Iterable<String> _excluded;
	final Map<String, Map<String, List<String>>> _cache = <String, Map<String, List<String>>>{};

	List<String> variantsFor(String assetPath) {
	final String assetName = fs.path.basename(assetPath);
	final String directory = fs.path.dirname(assetPath);

	if (!fs.directory(directory).existsSync())
	return const <String>[];

	if (_cache[directory] == null) {
	final List<String> paths = <String>[];
	for (FileSystemEntity entity in fs.directory(directory).listSync(recursive: true)) {
	final String path = entity.path;
	if (fs.isFileSync(path) && !_excluded.any((String exclude) => path.startsWith(exclude)))
	paths.add(path);
	}

	final Map<String, List<String>> variants = <String, List<String>>{};
	for (String path in paths) {
	final String variantName = fs.path.basename(path);
	if (directory == fs.path.dirname(path))
	continue;
	variants[variantName] ??= <String>[];
	variants[variantName].add(path);
	}
	_cache[directory] = variants;
	}

	return _cache[directory][assetName] ?? const <String>[];
	}
	}

	/// Given an assetBase location and a pubspec.yaml Flutter manifest, return a
	/// map of assets to asset variants.
	///
	/// Returns null on missing assets.
	Map<_Asset, List<_Asset>> _parseAssets(
	PackageMap packageMap,
	FlutterManifest flutterManifest,
	String assetBase, {
	List<String> excludeDirs: const <String>[],
	String packageName
	}) {
	final Map<_Asset, List<_Asset>> result = <_Asset, List<_Asset>>{};

	final _AssetDirectoryCache cache = new _AssetDirectoryCache(excludeDirs);
	for (Uri assetUri in flutterManifest.assets) {
	final _Asset asset = _resolveAsset(
	packageMap,
	assetBase,
	assetUri,
	packageName,
	);
	final List<_Asset> variants = <_Asset>[];
	for (String path in cache.variantsFor(asset.assetFile.path)) {
	final String relativePath = fs.path.relative(path, from: asset.baseDir);
	final Uri relativeUri = fs.path.toUri(relativePath);
	final Uri entryUri = asset.symbolicPrefixUri == null
	? relativeUri
	: asset.symbolicPrefixUri.resolveUri(relativeUri);
	variants.add(new _Asset(
	baseDir: asset.baseDir,
	entryUri: entryUri,
	relativeUri: relativeUri,
	));
	}

	result[asset] = variants;
	}

	// Add assets referenced in the fonts section of the manifest.
	for (Font font in flutterManifest.fonts) {
	for (FontAsset fontAsset in font.fontAssets) {
	final _Asset baseAsset = _resolveAsset(
	packageMap,
	assetBase,
	fontAsset.assetUri,
	packageName,
	);
	if (!baseAsset.assetFileExists) {
	printError('Error: unable to locate asset entry in pubspec.yaml: "${fontAsset.assetUri}".');
	return null;
	}

	result[baseAsset] = <_Asset>[];
	}
	}

	return result;
	}

	_Asset _resolveAsset(
	PackageMap packageMap,
	String assetsBaseDir,
	Uri assetUri,
	String packageName,
	) {
	final String assetPath = fs.path.fromUri(assetUri);
	if (assetUri.pathSegments.first == 'packages' && !fs.isFileSync(fs.path.join(assetsBaseDir, assetPath))) {
	// The asset is referenced in the pubspec.yaml as
	// 'packages/PACKAGE_NAME/PATH/TO/ASSET .
	final _Asset packageAsset = _resolvePackageAsset(assetUri, packageMap);
	if (packageAsset != null)
	return packageAsset;
	}

	return new _Asset(
	baseDir: assetsBaseDir,
	entryUri: packageName == null
	? assetUri // Asset from the current application.
	: new Uri(pathSegments: <String>['packages', packageName]..addAll(assetUri.pathSegments)), // Asset from, and declared in $packageName.
	relativeUri: assetUri,
	);
	}

	_Asset _resolvePackageAsset(Uri assetUri, PackageMap packageMap) {
	assert(assetUri.pathSegments.first == 'packages');
	if (assetUri.pathSegments.length > 1) {
	final String packageName = assetUri.pathSegments[1];
	final Uri packageUri = packageMap.map[packageName];
	if (packageUri != null && packageUri.scheme == 'file') {
	return new _Asset(
	baseDir: fs.path.fromUri(packageUri),
	entryUri: assetUri,
	relativeUri: new Uri(pathSegments: assetUri.pathSegments.sublist(2)),
	);
	}
	}
	printStatus('Error detected in pubspec.yaml:', emphasis: true);
	printError('Could not resolve package for asset $assetUri.\n');
	return null;
	}