flutter/packages/flutter_tools/test/general.shard/asset_bundle_variant_test.dart

// 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.

import 'dart:convert';
import 'dart:typed_data';

import 'package:file/file.dart';
import 'package:file/memory.dart';

import 'package:flutter_tools/src/asset.dart';
import 'package:flutter_tools/src/base/file_system.dart';
import 'package:flutter_tools/src/base/logger.dart';
import 'package:flutter_tools/src/base/platform.dart';
import 'package:flutter_tools/src/base/user_messages.dart';
import 'package:flutter_tools/src/cache.dart';

import 'package:flutter_tools/src/project.dart';
import 'package:standard_message_codec/standard_message_codec.dart';

import '../src/common.dart';

void main() {

  Future<Map<String, List<String>>> extractAssetManifestJsonFromBundle(ManifestAssetBundle bundle) async {
    final String manifestJson = utf8.decode(await bundle.entries['AssetManifest.json']!.contentsAsBytes());
    final Map<String, dynamic> parsedJson = json.decode(manifestJson) as Map<String, dynamic>;
    final Iterable<String> keys = parsedJson.keys;
    final Map<String, List<String>> parsedManifest = <String, List<String>> {
      for (final String key in keys) key: List<String>.from(parsedJson[key] as List<dynamic>),
    };
    return parsedManifest;
  }

  Future<Map<Object?, Object?>> extractAssetManifestSmcBinFromBundle(ManifestAssetBundle bundle) async {
    final List<int> manifest = await bundle.entries['AssetManifest.smcbin']!.contentsAsBytes();
    final ByteData asByteData = ByteData.view(Uint8List.fromList(manifest).buffer);
    final Map<Object?, Object?> decoded = const StandardMessageCodec().decodeMessage(asByteData)! as Map<Object?, Object?>;
    return decoded;
  }

  group('AssetBundle asset variants (with Unix-style paths)', () {
    late Platform platform;
    late FileSystem fs;

    setUp(() {
      platform = FakePlatform();
      fs = MemoryFileSystem.test();
      Cache.flutterRoot = Cache.defaultFlutterRoot(
        platform: platform,
        fileSystem: fs,
        userMessages: UserMessages()
      );

      fs.file('.packages').createSync();
    });

    void createPubspec({
      required List<String> assets,
    }) {
      fs.file('pubspec.yaml').writeAsStringSync(
'''
name: test
dependencies:
  flutter:
    sdk: flutter
flutter:
  assets:
${assets.map((String entry) => '    - $entry').join('\n')}
'''
      );
    }

    testWithoutContext('Only images in folders named with device pixel ratios (e.g. 2x, 3.0x) should be considered as variants of other images', () async {
      createPubspec(assets: <String>['assets/', 'assets/notAVariant/']);

      const String image = 'assets/image.jpg';
      const String image2xVariant = 'assets/2x/image.jpg';
      const String imageNonVariant = 'assets/notAVariant/image.jpg';

      final List<String> assets = <String>[
        image,
        image2xVariant,
        imageNonVariant
      ];

      for (final String asset in assets) {
        final File assetFile = fs.file(asset);
        assetFile.createSync(recursive: true);
        assetFile.writeAsStringSync(asset);
      }

      final ManifestAssetBundle bundle = ManifestAssetBundle(
        logger: BufferLogger.test(),
        fileSystem: fs,
        platform: platform,
      );

      await bundle.build(
        packagesPath: '.packages',
        flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
      );

      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);

      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
        image: <Map<String, Object>>[
          <String, String>{
            'asset': image,
          },
          <String, Object>{
            'asset': image2xVariant,
            'dpr': 2.0,
          }
        ],
        imageNonVariant: <Map<String, String>>[
          <String, String>{
            'asset': imageNonVariant,
          }
        ],
      };

      expect(smcBinManifest, equals(expectedAssetManifest));
      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
    });

    testWithoutContext('Asset directories have their subdirectories searched for asset variants', () async {
      createPubspec(assets: <String>['assets/', 'assets/folder/']);

      const String topLevelImage = 'assets/image.jpg';
      const String secondLevelImage = 'assets/folder/secondLevel.jpg';
      const String secondLevel2xVariant = 'assets/folder/2x/secondLevel.jpg';

      final List<String> assets = <String>[
        topLevelImage,
        secondLevelImage,
        secondLevel2xVariant
      ];

      for (final String asset in assets) {
        final File assetFile = fs.file(asset);
        assetFile.createSync(recursive: true);
        assetFile.writeAsStringSync(asset);
      }

      final ManifestAssetBundle bundle = ManifestAssetBundle(
        logger: BufferLogger.test(),
        fileSystem: fs,
        platform: platform,
      );

      await bundle.build(
        packagesPath: '.packages',
        flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
      );

      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
      expect(jsonManifest, hasLength(2));
      expect(jsonManifest[topLevelImage], equals(<String>[topLevelImage]));
      expect(jsonManifest[secondLevelImage], equals(<String>[secondLevelImage, secondLevel2xVariant]));

      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);

      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
        topLevelImage: <Map<String, Object>>[
          <String, String>{
            'asset': topLevelImage,
          },
        ],
        secondLevelImage: <Map<String, Object>>[
          <String, String>{
            'asset': secondLevelImage,
          },
          <String, Object>{
            'asset': secondLevel2xVariant,
            'dpr': 2.0,
          },
        ],
      };
      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
      expect(smcBinManifest, equals(expectedAssetManifest));
    });

    testWithoutContext('Asset paths should never be URI-encoded', () async {
      createPubspec(assets: <String>['assets/normalFolder/']);

      const String image = 'assets/normalFolder/i have URI-reserved_characters.jpg';
      const String imageVariant = 'assets/normalFolder/3x/i have URI-reserved_characters.jpg';

      final List<String> assets = <String>[
        image,
        imageVariant
      ];

      for (final String asset in assets) {
        final File assetFile = fs.file(asset);
        assetFile.createSync(recursive: true);
        assetFile.writeAsStringSync(asset);
      }

      final ManifestAssetBundle bundle = ManifestAssetBundle(
        logger: BufferLogger.test(),
        fileSystem: fs,
        platform: platform,
      );

      await bundle.build(
        packagesPath: '.packages',
        flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
      );

      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);

      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
        image: <Map<String, Object>>[
          <String, Object>{
            'asset': image,
          },
          <String, Object>{
            'asset': imageVariant,
            'dpr': 3.0
          },
        ],
      };

      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
      expect(smcBinManifest, equals(expectedAssetManifest));
    });

    testWithoutContext('Main assets are not included if the file does not exist', () async {
      createPubspec(assets: <String>['assets/image.png']);

      // We intentionally do not add a 'assets/image.png'.
      const String imageVariant = 'assets/2x/image.png';
      final List<String> assets = <String>[
        imageVariant,
      ];

      for (final String asset in assets) {
        final File assetFile = fs.file(asset);
        assetFile.createSync(recursive: true);
        assetFile.writeAsStringSync(asset);
      }

      final ManifestAssetBundle bundle = ManifestAssetBundle(
        logger: BufferLogger.test(),
        fileSystem: fs,
        platform: platform,
      );

      await bundle.build(
        packagesPath: '.packages',
        flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
      );

      final Map<String, List<Map<String, Object>>> expectedManifest = <String, List<Map<String, Object>>>{
        'assets/image.png': <Map<String, Object>>[
          <String, Object>{
            'asset': imageVariant,
            'dpr': 2.0
          },
        ],
      };
      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);

      expect(jsonManifest, equals(_assetManifestBinToJson(expectedManifest)));
      expect(smcBinManifest, equals(expectedManifest));
    });
  });

  group('AssetBundle asset variants (with Windows-style filepaths)', () {
    late final Platform platform;
    late final FileSystem fs;

    setUp(() {
      platform = FakePlatform(operatingSystem: 'windows');
      fs = MemoryFileSystem.test(style: FileSystemStyle.windows);
      Cache.flutterRoot = Cache.defaultFlutterRoot(
        platform: platform,
        fileSystem: fs,
        userMessages: UserMessages()
      );

      fs.file('.packages').createSync();

      fs.file('pubspec.yaml').writeAsStringSync(
'''
name: test
dependencies:
  flutter:
    sdk: flutter
flutter:
  assets:
    - assets/
    - assets/somewhereElse/
'''
      );
    });

    testWithoutContext('Variant detection works with windows-style filepaths', () async {
      const List<String> assets = <String>[
        r'assets\foo.jpg',
        r'assets\2x\foo.jpg',
        r'assets\somewhereElse\bar.jpg',
        r'assets\somewhereElse\2x\bar.jpg',
      ];

      for (final String asset in assets) {
        final File assetFile = fs.file(asset);
        assetFile.createSync(recursive: true);
        assetFile.writeAsStringSync(asset);
      }

      final ManifestAssetBundle bundle = ManifestAssetBundle(
        logger: BufferLogger.test(),
        fileSystem: fs,
        platform: platform,
      );

      await bundle.build(
        packagesPath: '.packages',
        flutterProject:  FlutterProject.fromDirectoryTest(fs.currentDirectory),
      );

      final Map<String, List<Map<String, Object>>> expectedAssetManifest = <String, List<Map<String, Object>>>{
        'assets/foo.jpg': <Map<String, Object>>[
          <String, Object>{
            'asset': 'assets/foo.jpg',
          },
          <String, Object>{
            'asset': 'assets/2x/foo.jpg',
            'dpr': 2.0,
          },
        ],
        'assets/somewhereElse/bar.jpg': <Map<String, Object>>[
          <String, Object>{
            'asset': 'assets/somewhereElse/bar.jpg',
          },
          <String, Object>{
            'asset': 'assets/somewhereElse/2x/bar.jpg',
            'dpr': 2.0,
          },
        ],
      };

      final Map<String, List<String>> jsonManifest = await extractAssetManifestJsonFromBundle(bundle);
      final Map<Object?, Object?> smcBinManifest = await extractAssetManifestSmcBinFromBundle(bundle);

      expect(jsonManifest, equals(_assetManifestBinToJson(expectedAssetManifest)));
      expect(smcBinManifest, equals(expectedAssetManifest));
    });
  });
}

Map<Object, Object> _assetManifestBinToJson(Map<Object, Object> manifest) {
  List<Object> convertList(List<Object> variants) => variants
    .map((Object variant) => (variant as Map<Object?, Object?>)['asset']!)
    .toList();

  return manifest.map((Object key, Object value) => MapEntry<Object, Object>(key, convertList(value as List<Object>)));
}