pubspec_lock  
  
 
Dart library to access and manipulate content of pubpec.lock files
Data classes
PubspecLock represents data stored in pubspec.lock files.
https://pub.flutter-io.cn/packages/functional_data is used to provide data type facilities
class PubspecLock {
  final Iterable<SdkDependency> sdks;
  final Iterable<PackageDependency> packages;
}
SdkDependency provides sdk name and version:
@immutable
@FunctionalData()
class SdkDependency {
  /// Default constructor
  const SdkDependency({
    @required this.sdk,
    @required this.version,
  });
  final String sdk;
  final String version;
}
PackageDependency represents a package dependency, which can be:
- a hosted dependency,
- an SDK dependency,
- a Git dependency, or
- a path dependency
Please checkout https://dart.cn/tools/pub/dependencies for details.
https://pub.flutter-io.cn/packages/sum_types is used to deal with variations of different package dependency types in a type-safe and concise manner.
@immutable
@SumType()
class PackageDependency extends _$PackageDependency {
  const PackageDependency.sdk(SdkPackageDependency sdk) : super(sdk: sdk);
  const PackageDependency.hosted(HostedPackageDependency hosted) : super(hosted: hosted);
  const PackageDependency.git(GitPackageDependency git) : super(git: git);
  const PackageDependency.path(PathPackageDependency path) : super(path: path);
  /// Provides package dependency name
  String package() => iswitch(
        sdk: (d) => d.package,
        hosted: (d) => d.package,
        git: (d) => d.package,
        path: (d) => d.package,
      );
  /// Provides package dependency version
  String version() => iswitch(
        sdk: (d) => d.version,
        hosted: (d) => d.version,
        git: (d) => d.version,
        path: (d) => d.version,
      );
  /// Provides package dependency type -- direct, development, or transitive
  DependencyType type() => iswitch(
        sdk: (d) => d.type,
        hosted: (d) => d.type,
        git: (d) => d.type,
        path: (d) => d.type,
      );
}
Import from YAML
The String extension method loadPubspecLockFromYaml() can be used to create a PubspecLock instance from a YAML string:
final pubspecLock = File('pubspec.lock').readAsStringSync().loadPubspecLockFromYaml();
Export to YAML
PubspecLock.toYamlString() can be used to export PubspecLock object to a YAML string:
File('pubspec.lock').writeAsStringSync(pubspecLock.toYamlString());
Full example
The following Dart script checks whether all Dart dependencies are taken from pub.flutter-io.cn.
import 'dart:io';
import 'package:pubspec_lock/pubspec_lock.dart';
// ignore_for_file: avoid_print
void main() {
  final pubspecLock = File('pubspec.lock').readAsStringSync().loadPubspecLockFromYaml();
  print('Loaded pubspec.lock with ${pubspecLock.packages.length} package dependencies:');
  final depsNotHostedByPubDev = [
    for (final package in pubspecLock.packages)
      if (!isHostedByPubDev(package))
        package
  ];
  if (depsNotHostedByPubDev.isEmpty) {
    print('SUCCESS: All dependencies are hosted by pub.flutter-io.cn');
  } else {
    print('WARNING: Dependencies hosted outside of pub.flutter-io.cn:');
    depsNotHostedByPubDev.forEach(print);
  }
  File('pubspec.lock').writeAsStringSync(pubspecLock.toYamlString());
}
bool isHostedByPubDev(PackageDependency package) => package.iswitcho(
      hosted: (package) => package.url == 'https://pub.flutter-io.cn',
      otherwise: () => false,
    );