ATTAttributePermissions.swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift open source project
//
// Copyright (c) 2024 Apple Inc. and the Swift project authors.
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
//
//===----------------------------------------------------------------------===//

/// ATT attribute permission bitfield values. Permissions are grouped as
/// "Access", "Encryption", "Authentication", and "Authorization". A bitmask of
/// permissions is a byte that encodes a combination of these.
@frozen
public struct ATTAttributePermissions: OptionSet, Equatable, Hashable, Sendable {
    
    public var rawValue: UInt8
    
    public init(rawValue: UInt8) {
        self.rawValue = rawValue
    }
}

// MARK: - ExpressibleByIntegerLiteral

extension ATTAttributePermissions: ExpressibleByIntegerLiteral {
    
    public init(integerLiteral value: UInt8) {
        self.rawValue = value
    }
}

// MARK: - CustomStringConvertible

extension ATTAttributePermissions: CustomStringConvertible, CustomDebugStringConvertible {
    
    public var description: String {
        "0x" + rawValue.toHexadecimal()
    }

    /// A textual representation of the file permissions, suitable for debugging.
    public var debugDescription: String { self.description }
}

// MARK: - Options

public extension ATTAttributePermissions {
    
    // Access
    static var read: ATTAttributePermissions                     { 0x01 }
    static var write: ATTAttributePermissions                    { 0x02 }
    
    // Encryption
    static var encrypt: ATTAttributePermissions                  { [.readEncrypt, .writeEncrypt] }
    static var readEncrypt: ATTAttributePermissions              { 0x04 }
    static var writeEncrypt: ATTAttributePermissions             { 0x08 }
    
    // The following have no effect on Darwin
    
    // Authentication
    static var authentication: ATTAttributePermissions           { [.readAuthentication, .writeAuthentication] }
    static var readAuthentication: ATTAttributePermissions       { 0x10 }
    static var writeAuthentication: ATTAttributePermissions      { 0x20 }
    
    // Authorization
    static var authorized: ATTAttributePermissions               { 0x40 }
    static var noAuthorization: ATTAttributePermissions          { 0x80 }
}