SwiftLint/Source/SwiftLintCore/Models/YamlParser.swift

71 lines
2.1 KiB
Swift

import Foundation
import Yams
// MARK: - YamlParser
/// An interface for parsing YAML.
public struct YamlParser {
/// Parses the input YAML string as an untyped dictionary.
///
/// - parameter yaml: YAML-formatted string.
/// - parameter env: The environment to use to expand variables in the YAML.
///
/// - returns: The parsed YAML as an untyped dictionary.
///
/// - throws: Throws if the `yaml` string provided could not be parsed.
public static func parse(_ yaml: String,
env: [String: String] = ProcessInfo.processInfo.environment) throws -> [String: Any] {
do {
return try Yams.load(yaml: yaml, .default,
.swiftlintConstructor(env: env)) as? [String: Any] ?? [:]
} catch {
throw Issue.yamlParsing("\(error)")
}
}
}
private extension Constructor {
static func swiftlintConstructor(env: [String: String]) -> Constructor {
return Constructor(customScalarMap(env: env))
}
static func customScalarMap(env: [String: String]) -> ScalarMap {
var map = defaultScalarMap
map[.str] = String.constructExpandingEnvVars(env: env)
map[.bool] = Bool.constructUsingOnlyTrueAndFalse
return map
}
}
private extension String {
static func constructExpandingEnvVars(env: [String: String]) -> (_ scalar: Node.Scalar) -> String? {
return { (scalar: Node.Scalar) -> String? in
return scalar.string.expandingEnvVars(env: env)
}
}
func expandingEnvVars(env: [String: String]) -> String {
var result = self
for (key, value) in env {
result = result.replacingOccurrences(of: "${\(key)}", with: value)
}
return result
}
}
private extension Bool {
// swiftlint:disable:next discouraged_optional_boolean
static func constructUsingOnlyTrueAndFalse(from scalar: Node.Scalar) -> Bool? {
switch scalar.string.lowercased() {
case "true":
return true
case "false":
return false
default:
return nil
}
}
}