SwiftLint/Plugins/SwiftLintPlugin/Path+Helpers.swift

import Foundation
import PackagePlugin

#if os(Linux)
import Glibc
#else
import Darwin
#endif

extension Path {
    /// Scans the receiver, then all of its parents looking for a configuration file with the name ".swiftlint.yml".
    ///
    /// - returns: Path to the configuration file, or nil if one cannot be found.
    func firstConfigurationFileInParentDirectories() -> Path? {
        let defaultConfigurationFileName = ".swiftlint.yml"
        let proposedDirectory = sequence(
            first: self,
            next: { path in
                guard path.stem.count > 1 else {
                    // Check we're not at the root of this filesystem, as `removingLastComponent()`
                    // will continually return the root from itself.
                    return nil
                }

                return path.removingLastComponent()
            }
        ).first { path in
            let potentialConfigurationFile = path.appending(subpath: defaultConfigurationFileName)
            return potentialConfigurationFile.isAccessible()
        }
        return proposedDirectory?.appending(subpath: defaultConfigurationFileName)
    }

    /// Safe way to check if the file is accessible from within the current process sandbox.
    private func isAccessible() -> Bool {
        let result = string.withCString { pointer in
            access(pointer, R_OK)
        }

        return result == 0
    }
}