| // Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| /// This library defines how to read module dependencies from a Yaml |
| /// specification. We expect to find specifications written in this format: |
| /// |
| /// dependencies: |
| /// b: a |
| /// main: [b, expect] |
| /// |
| /// Where: |
| /// - Each name corresponds to a module. |
| /// - Module names correlate to either a file, a folder, or a package. |
| /// - A map entry contains all the dependencies of a module, if any. |
| /// - If a module has a single dependency, it can be written as a single |
| /// value. |
| /// |
| /// The logic in this library mostly treats these names as strings, separately |
| /// `loader.dart` is responsible for validating and attaching this dependency |
| /// information to a set of module definitions. |
| import 'package:yaml/yaml.dart'; |
| |
| /// Parses [contents] containing a module dependencies specification written in |
| /// yaml, and returns a normalized dependency map. |
| /// |
| /// Note: some values in the map may not have a corresponding key. That may be |
| /// the case for modules that have no dependencies and modules that are not |
| /// specified in [contents] (e.g. modules that are supported by default). |
| Map<String, List<String>> parseDependencyMap(String contents) { |
| var spec = loadYaml(contents); |
| if (spec is! YamlMap) { |
| return _invalidSpecification("spec is not a map"); |
| } |
| var dependencies = spec['dependencies']; |
| if (dependencies == null) { |
| return _invalidSpecification("no dependencies section"); |
| } |
| if (dependencies is! YamlMap) { |
| return _invalidSpecification("dependencies is not a map"); |
| } |
| |
| Map<String, List<String>> normalizedMap = {}; |
| dependencies.forEach((key, value) { |
| if (key is! String) { |
| _invalidSpecification("key: '$key' is not a string"); |
| } |
| normalizedMap[key] = []; |
| if (value is String) { |
| normalizedMap[key].add(value); |
| } else if (value is List) { |
| value.forEach((entry) { |
| if (entry is! String) { |
| _invalidSpecification("entry: '$entry' is not a string"); |
| } |
| normalizedMap[key].add(entry); |
| }); |
| } else { |
| _invalidSpecification( |
| "entry: '$value' is not a string or a list of strings"); |
| } |
| }); |
| return normalizedMap; |
| } |
| |
| _invalidSpecification(String message) { |
| throw new InvalidSpecificationError(message); |
| } |
| |
| class InvalidSpecificationError extends Error { |
| final String message; |
| InvalidSpecificationError(this.message); |
| String toString() => "Invalid specification: $message"; |
| } |