URL.swift

//
//  URL.swift
//  aftermath
//
//  Copyright  2022 JAMF Software, LLC
//

import Foundation

extension URL {

    // Get list of all extended attributes.
    func listExtendedAttributes() throws -> [String] {

        let list = try self.withUnsafeFileSystemRepresentation { fileSystemPath -> [String] in
            let length = listxattr(fileSystemPath, nil, 0, 0)
            guard length >= 0 else { throw URL.posixError(errno) }

            // Create buffer with required size:
            var namebuf = Array<CChar>(repeating: 0, count: length)

            // Retrieve attribute list:
            let result = listxattr(fileSystemPath, &namebuf, namebuf.count, 0)
            guard result >= 0 else { throw URL.posixError(errno) }

            // Extract attribute names:
            let list = namebuf.split(separator: 0).compactMap {
                $0.withUnsafeBufferPointer {
                    $0.withMemoryRebound(to: UInt8.self) {
                        String(bytes: $0, encoding: .utf8)
                    }
                }
            }
            return list
        }
        return list
    }

    // Helper function to create an NSError from a Unix errno.
    private static func posixError(_ err: Int32) -> NSError {
        return NSError(domain: NSPOSIXErrorDomain, code: Int(err),
                       userInfo: [NSLocalizedDescriptionKey: String(cString: strerror(err))])
    }
}