Foundation/UserDefaults.swift - third_party/swift-corelibs-foundation - Git at Google

 // This source file is part of the Swift.org open source project
 //
 // Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See http://swift.org/LICENSE.txt for license information
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //

 import CoreFoundation

 private var registeredDefaults = [String: Any]()
 private var sharedDefaults = UserDefaults()

 fileprivate func bridgeFromNSCFTypeIfNeeded(_ value: Any) -> Any {
     // This line will produce a 'Conditional cast always succeeds' warning if compoiled on Darwin, since Darwin has bridging casts of any value to an object,
     // but is required for non-Darwin to work correctly, since that platform _doesn't_ have bridging casts of that kind for now.
     if let object = value as? AnyObject {
         return _SwiftValue.fetch(nonOptional: object)
     } else {
         return value
     }
 }

 open class UserDefaults: NSObject {
     static private func _isValueAllowed(_ nonbridgedValue: Any) -> Bool {
         let value = bridgeFromNSCFTypeIfNeeded(nonbridgedValue)

         if let value = value as? [Any] {
             for innerValue in value {
                 if !_isValueAllowed(innerValue) {
                     return false
                 }
             }

             return true
         }

         if let value = value as? [AnyHashable: Any] {
             for (key, innerValue) in value {
                 if !(key is String) {
                     return false
                 }

                 if !_isValueAllowed(innerValue) {
                     return false
                 }
             }

             return true
         }

         // NSNumber doesn't quite bridge -- treat it specially.
         if value is NSNumber {
             return true
         }

         let isOfCommonTypes =  value is String || value is Data || value is Date || value is Int || value is Bool || value is CGFloat
         if isOfCommonTypes {
             return true
         }

         let isOfUncommonNumericTypes = value is Double || value is Float || value is Float || value is Int8 || value is UInt8 || value is Int16 || value is UInt16 || value is Int32 || value is UInt32 || value is Int64 || value is UInt64
         return isOfUncommonNumericTypes
     }

     static private func _unboxingNSNumbers(_ value: Any?) -> Any? {
         if value == nil {
             return nil
         }

         if let number = value as? NSNumber {
             return number._swiftValueOfOptimalType
         }

         if let value = value as? [Any] {
             return value.map(_unboxingNSNumbers)
         }

         if let value = value as? [AnyHashable: Any] {
             return value.mapValues(_unboxingNSNumbers)
         }

         return value
     }

     private let suite: String?

     open class var standard: UserDefaults {
         return sharedDefaults
     }

     open class func resetStandardUserDefaults() {}

     public convenience override init() {
         self.init(suiteName: nil)!
     }

     /// nil suite means use the default search list that +standardUserDefaults uses
     public init?(suiteName suitename: String?) {
         suite = suitename
         super.init()

         setVolatileDomain(UserDefaults._parsedArgumentsDomain, forName: UserDefaults.argumentDomain)
     }

     open func object(forKey defaultName: String) -> Any? {
         let argumentDomain = volatileDomain(forName: UserDefaults.argumentDomain)
         if let object = argumentDomain[defaultName] {
             return object
         }

         func getFromRegistered() -> Any? {
             return UserDefaults._unboxingNSNumbers(registeredDefaults[defaultName])
         }

         guard let anObj = CFPreferencesCopyAppValue(defaultName._cfObject, suite?._cfObject ?? kCFPreferencesCurrentApplication) else {
             return getFromRegistered()
         }

         if let fetched = _SwiftValue.fetch(anObj) {
             return UserDefaults._unboxingNSNumbers(fetched)
         } else {
             return nil
         }
     }

     open func set(_ value: Any?, forKey defaultName: String) {
         guard let value = value else {
             CFPreferencesSetAppValue(defaultName._cfObject, nil, suite?._cfObject ?? kCFPreferencesCurrentApplication)
             return
         }

         if let url = value as? URL {
             set(url.absoluteURL.path, forKey: defaultName)
             return
         }

         if let url = value as? NSURL, let path = url.absoluteURL?.path {
             set(path, forKey: defaultName)
             return
         }

         guard UserDefaults._isValueAllowed(value) else {
             fatalError("This value is not supported by set(_:forKey:)")
         }

         CFPreferencesSetAppValue(defaultName._cfObject, _SwiftValue.store(value), suite?._cfObject ?? kCFPreferencesCurrentApplication)
     }
     open func removeObject(forKey defaultName: String) {
         CFPreferencesSetAppValue(defaultName._cfObject, nil, suite?._cfObject ?? kCFPreferencesCurrentApplication)
     }

     open func string(forKey defaultName: String) -> String? {
         return object(forKey: defaultName) as? String
     }

     open func array(forKey defaultName: String) -> [Any]? {
         return object(forKey: defaultName) as? [Any]
     }

     open func dictionary(forKey defaultName: String) -> [String : Any]? {
         return object(forKey: defaultName) as? [String: Any]
     }

     open func data(forKey defaultName: String) -> Data? {
         return object(forKey: defaultName) as? Data
     }

     open func stringArray(forKey defaultName: String) -> [String]? {
         return object(forKey: defaultName) as? [String]
     }

     open func integer(forKey defaultName: String) -> Int {
         guard let aVal = object(forKey: defaultName) else {
             return 0
         }
         if let bVal = aVal as? Int {
             return bVal
         }
         if let bVal = aVal as? String {
             return NSString(string: bVal).integerValue
         }
         return 0
     }

     open func float(forKey defaultName: String) -> Float {
         guard let aVal = object(forKey: defaultName) else {
             return 0
         }
         if let bVal = aVal as? Float {
             return bVal
         }
         if let bVal = aVal as? String {
             return NSString(string: bVal).floatValue
         }
         return 0
     }

     open func double(forKey defaultName: String) -> Double {
         guard let aVal = object(forKey: defaultName) else {
             return 0
         }
         if let bVal = aVal as? Double {
             return bVal
         }
         if let bVal = aVal as? String {
             return NSString(string: bVal).doubleValue
         }
         return 0
     }

     open func bool(forKey defaultName: String) -> Bool {
         guard let aVal = object(forKey: defaultName) else {
             return false
         }
         if let bVal = aVal as? Bool {
             return bVal
         }
         if let bVal = aVal as? Int {
             return bVal != 0
         }
         if let bVal = aVal as? Float {
             return bVal != 0
         }
         if let bVal = aVal as? Double {
             return bVal != 0
         }
         if let bVal = aVal as? String {
             return NSString(string: bVal).boolValue
         }
         return false
     }
     open func url(forKey defaultName: String) -> URL? {
         guard let aVal = object(forKey: defaultName) else {
             return nil
         }

         if let bVal = aVal as? URL {
             return bVal
         } else if let bVal = aVal as? String {
             let cVal = NSString(string: bVal).expandingTildeInPath
             return URL(fileURLWithPath: cVal)
         } else if let bVal = aVal as? Data {
             return NSKeyedUnarchiver.unarchiveObject(with: bVal) as? URL
         }
         return nil
     }

     open func set(_ value: Int, forKey defaultName: String) {
         set(NSNumber(value: value), forKey: defaultName)
     }
     open func set(_ value: Float, forKey defaultName: String) {
         set(NSNumber(value: value), forKey: defaultName)
     }
     open func set(_ value: Double, forKey defaultName: String) {
         set(NSNumber(value: value), forKey: defaultName)
     }
     open func set(_ value: Bool, forKey defaultName: String) {
         set(NSNumber(value: value), forKey: defaultName)
     }
     open func set(_ url: URL?, forKey defaultName: String) {
         if let url = url {
             //FIXME: CFURLIsFileReferenceURL is limited to OS X/iOS
             #if os(OSX) || os(iOS)
                 //FIXME: no SwiftFoundation version of CFURLIsFileReferenceURL at time of writing!
                 if CFURLIsFileReferenceURL(url._cfObject) {
                     let data = NSKeyedArchiver.archivedData(withRootObject: url._nsObject)
                     set(data._nsObject, forKey: defaultName)
                     return
                 }
             #endif

             set(url.path._nsObject, forKey: defaultName)
         } else {
             set(nil, forKey: defaultName)
         }
     }

     open func register(defaults registrationDictionary: [String : Any]) {
         registeredDefaults.merge(registrationDictionary.mapValues(bridgeFromNSCFTypeIfNeeded), uniquingKeysWith: { $1 })
     }

     open func addSuite(named suiteName: String) {
         CFPreferencesAddSuitePreferencesToApp(kCFPreferencesCurrentApplication, suiteName._cfObject)
     }
     open func removeSuite(named suiteName: String) {
         CFPreferencesRemoveSuitePreferencesFromApp(kCFPreferencesCurrentApplication, suiteName._cfObject)
     }

     open func dictionaryRepresentation() -> [String: Any] {
         return _dictionaryRepresentation(includingVolatileDomains: true)
     }

     private func _dictionaryRepresentation(includingVolatileDomains: Bool) -> [String: Any] {
         let registeredDefaultsIfAllowed = includingVolatileDomains ? registeredDefaults : [:]

         guard let defaultsFromDiskCF = CFPreferencesCopyMultiple(nil, suite?._cfObject ?? kCFPreferencesCurrentApplication, kCFPreferencesCurrentUser, kCFPreferencesAnyHost) else {
             return registeredDefaultsIfAllowed
         }

         let defaultsFromDiskWithNumbersBoxed = _SwiftValue.fetch(defaultsFromDiskCF) as? [String: Any] ?? [:]

         if registeredDefaultsIfAllowed.count == 0 {
             return UserDefaults._unboxingNSNumbers(defaultsFromDiskWithNumbersBoxed) as! [String: Any]
         } else {
             var allDefaults = registeredDefaultsIfAllowed

             for (key, value) in defaultsFromDiskWithNumbersBoxed {
                 allDefaults[key] = value
             }

             return UserDefaults._unboxingNSNumbers(allDefaults) as! [String: Any]
         }
     }

     private static let _parsedArgumentsDomain: [String: Any] = UserDefaults._parseArguments(ProcessInfo.processInfo.arguments)

     private var _volatileDomains: [String: [String: Any]] = [:]
     private let _volatileDomainsLock = NSLock()

     open var volatileDomainNames: [String] {
         _volatileDomainsLock.lock()
         let names = Array(_volatileDomains.keys)
         _volatileDomainsLock.unlock()

         return names
     }

     open func volatileDomain(forName domainName: String) -> [String : Any] {
         _volatileDomainsLock.lock()
         let domain = _volatileDomains[domainName]
         _volatileDomainsLock.unlock()

         return domain ?? [:]
     }

     open func setVolatileDomain(_ domain: [String : Any], forName domainName: String) {
         if !UserDefaults._isValueAllowed(domain) {
             fatalError("The content of 'domain' passed to UserDefaults.setVolatileDomain(_:forName:) is not supported.")
         }

         _volatileDomainsLock.lock()
         var storedDomain: [String: Any] = _volatileDomains[domainName] ?? [:]
         storedDomain.merge(domain, uniquingKeysWith: { $1 })
         _volatileDomains[domainName] = storedDomain
         _volatileDomainsLock.unlock()
     }

     open func removeVolatileDomain(forName domainName: String) {
         _volatileDomainsLock.lock()
         _volatileDomains.removeValue(forKey: domainName)
         _volatileDomainsLock.unlock()
     }

     open func persistentDomain(forName domainName: String) -> [String : Any]? {
         return UserDefaults(suiteName: domainName)?._dictionaryRepresentation(includingVolatileDomains: false)
     }

     open func setPersistentDomain(_ domain: [String : Any], forName domainName: String) {
         if let defaults = UserDefaults(suiteName: domainName) {
             for key in defaults._dictionaryRepresentation(includingVolatileDomains: false).keys {
                 defaults.removeObject(forKey: key)
             }

             for (key, value) in domain {
                 defaults.set(value, forKey: key)
             }

             _ = defaults.synchronize()

             NotificationCenter.default.post(name: UserDefaults.didChangeNotification, object: self)
         }
     }

     open func removePersistentDomain(forName domainName: String) {
         if let defaults = UserDefaults(suiteName: domainName) {
             for key in defaults._dictionaryRepresentation(includingVolatileDomains: false).keys {
                 defaults.removeObject(forKey: key)
             }

             _ = defaults.synchronize()

             NotificationCenter.default.post(name: UserDefaults.didChangeNotification, object: self)
         }
     }

     open func synchronize() -> Bool {
         return CFPreferencesAppSynchronize(suite?._cfObject ?? kCFPreferencesCurrentApplication)
     }

     open func objectIsForced(forKey key: String) -> Bool {
         // If you're using this version of Foundation, there is nothing in particular that can force a key.
         // So:
         return false
     }

     open func objectIsForced(forKey key: String, inDomain domain: String) -> Bool {
         // If you're using this version of Foundation, there is nothing in particular that can force a key.
         // So:
         return false
     }
 }

 extension UserDefaults {
     public static let didChangeNotification = NSNotification.Name(rawValue: "NSUserDefaultsDidChangeNotification")
     public static let globalDomain: String = "NSGlobalDomain"
     public static let argumentDomain: String = "NSArgumentDomain"
     public static let registrationDomain: String = "NSRegistrationDomain"
 }

 // MARK: -
 // MARK: Parsing arguments.

 fileprivate let propertyListPrefixes: Set<Character> = [ "{", "[", "(", "<", "\"" ]

 private extension UserDefaults {
     static func _parseArguments(_ arguments: [String]) -> [String: Any] {
         var result: [String: Any] = [:]

         let count = arguments.count

         var index = 0
         while index < count - 1 { // We're looking for pairs, so stop at the second-to-last argument.
             let current = arguments[index]
             let next = arguments[index + 1]
             if current.hasPrefix("-") && !next.hasPrefix("-") {
                 // Match what Darwin does, which is to check whether the first argument is one of the characters that make up a NeXTStep-style or XML property list: open brace, open parens, open bracket, open angle bracket, or double quote. If it is, attempt parsing it as a plist; otherwise, just use the argument value as a String.

                 let keySubstring = current[current.index(after: current.startIndex)...]
                 if !keySubstring.isEmpty {
                     let key = String(keySubstring)
                     let value = next.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)

                     var parsed = false
                     if let prefix = value.first, propertyListPrefixes.contains(prefix) {
                         if let data = value.data(using: .utf8),
                             let plist = try? PropertyListSerialization.propertyList(from: data, format: nil) {

                             // If we can parse that argument as a plist, use the parsed value.
                             parsed = true
                             result[key] = plist

                         }
                     }

                     if !parsed {
                         result[key] = value
                     }
                 }

                 index += 1 // Skip both the key and the value on this loop.
             }

             index += 1
         }

         return result
     }
 }
	// This source file is part of the Swift.org open source project
	//
	// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
	// Licensed under Apache License v2.0 with Runtime Library Exception
	//
	// See http://swift.org/LICENSE.txt for license information
	// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
	//

	import CoreFoundation

	private var registeredDefaults = [String: Any]()
	private var sharedDefaults = UserDefaults()

	fileprivate func bridgeFromNSCFTypeIfNeeded(_ value: Any) -> Any {
	// This line will produce a 'Conditional cast always succeeds' warning if compoiled on Darwin, since Darwin has bridging casts of any value to an object,
	// but is required for non-Darwin to work correctly, since that platform _doesn't_ have bridging casts of that kind for now.
	if let object = value as? AnyObject {
	return _SwiftValue.fetch(nonOptional: object)
	} else {
	return value
	}
	}

	open class UserDefaults: NSObject {
	static private func _isValueAllowed(_ nonbridgedValue: Any) -> Bool {
	let value = bridgeFromNSCFTypeIfNeeded(nonbridgedValue)

	if let value = value as? [Any] {
	for innerValue in value {
	if !_isValueAllowed(innerValue) {
	return false
	}
	}

	return true
	}

	if let value = value as? [AnyHashable: Any] {
	for (key, innerValue) in value {
	if !(key is String) {
	return false
	}

	if !_isValueAllowed(innerValue) {
	return false
	}
	}

	return true
	}

	// NSNumber doesn't quite bridge -- treat it specially.
	if value is NSNumber {
	return true
	}

	let isOfCommonTypes = value is String \|\| value is Data \|\| value is Date \|\| value is Int \|\| value is Bool \|\| value is CGFloat
	if isOfCommonTypes {
	return true
	}

	let isOfUncommonNumericTypes = value is Double \|\| value is Float \|\| value is Float \|\| value is Int8 \|\| value is UInt8 \|\| value is Int16 \|\| value is UInt16 \|\| value is Int32 \|\| value is UInt32 \|\| value is Int64 \|\| value is UInt64
	return isOfUncommonNumericTypes
	}

	static private func _unboxingNSNumbers(_ value: Any?) -> Any? {
	if value == nil {
	return nil
	}

	if let number = value as? NSNumber {
	return number._swiftValueOfOptimalType
	}

	if let value = value as? [Any] {
	return value.map(_unboxingNSNumbers)
	}

	if let value = value as? [AnyHashable: Any] {
	return value.mapValues(_unboxingNSNumbers)
	}

	return value
	}

	private let suite: String?

	open class var standard: UserDefaults {
	return sharedDefaults
	}

	open class func resetStandardUserDefaults() {}

	public convenience override init() {
	self.init(suiteName: nil)!
	}

	/// nil suite means use the default search list that +standardUserDefaults uses
	public init?(suiteName suitename: String?) {
	suite = suitename
	super.init()

	setVolatileDomain(UserDefaults._parsedArgumentsDomain, forName: UserDefaults.argumentDomain)
	}

	open func object(forKey defaultName: String) -> Any? {
	let argumentDomain = volatileDomain(forName: UserDefaults.argumentDomain)
	if let object = argumentDomain[defaultName] {
	return object
	}

	func getFromRegistered() -> Any? {
	return UserDefaults._unboxingNSNumbers(registeredDefaults[defaultName])
	}

	guard let anObj = CFPreferencesCopyAppValue(defaultName._cfObject, suite?._cfObject ?? kCFPreferencesCurrentApplication) else {
	return getFromRegistered()
	}

	if let fetched = _SwiftValue.fetch(anObj) {
	return UserDefaults._unboxingNSNumbers(fetched)
	} else {
	return nil
	}
	}

	open func set(_ value: Any?, forKey defaultName: String) {
	guard let value = value else {
	CFPreferencesSetAppValue(defaultName._cfObject, nil, suite?._cfObject ?? kCFPreferencesCurrentApplication)
	return
	}

	if let url = value as? URL {
	set(url.absoluteURL.path, forKey: defaultName)
	return
	}

	if let url = value as? NSURL, let path = url.absoluteURL?.path {
	set(path, forKey: defaultName)
	return
	}

	guard UserDefaults._isValueAllowed(value) else {
	fatalError("This value is not supported by set(_:forKey:)")
	}

	CFPreferencesSetAppValue(defaultName._cfObject, _SwiftValue.store(value), suite?._cfObject ?? kCFPreferencesCurrentApplication)
	}
	open func removeObject(forKey defaultName: String) {
	CFPreferencesSetAppValue(defaultName._cfObject, nil, suite?._cfObject ?? kCFPreferencesCurrentApplication)
	}

	open func string(forKey defaultName: String) -> String? {
	return object(forKey: defaultName) as? String
	}

	open func array(forKey defaultName: String) -> [Any]? {
	return object(forKey: defaultName) as? [Any]
	}

	open func dictionary(forKey defaultName: String) -> [String : Any]? {
	return object(forKey: defaultName) as? [String: Any]
	}

	open func data(forKey defaultName: String) -> Data? {
	return object(forKey: defaultName) as? Data
	}

	open func stringArray(forKey defaultName: String) -> [String]? {
	return object(forKey: defaultName) as? [String]
	}

	open func integer(forKey defaultName: String) -> Int {
	guard let aVal = object(forKey: defaultName) else {
	return 0
	}
	if let bVal = aVal as? Int {
	return bVal
	}
	if let bVal = aVal as? String {
	return NSString(string: bVal).integerValue
	}
	return 0
	}

	open func float(forKey defaultName: String) -> Float {
	guard let aVal = object(forKey: defaultName) else {
	return 0
	}
	if let bVal = aVal as? Float {
	return bVal
	}
	if let bVal = aVal as? String {
	return NSString(string: bVal).floatValue
	}
	return 0
	}

	open func double(forKey defaultName: String) -> Double {
	guard let aVal = object(forKey: defaultName) else {
	return 0
	}
	if let bVal = aVal as? Double {
	return bVal
	}
	if let bVal = aVal as? String {
	return NSString(string: bVal).doubleValue
	}
	return 0
	}

	open func bool(forKey defaultName: String) -> Bool {
	guard let aVal = object(forKey: defaultName) else {
	return false
	}
	if let bVal = aVal as? Bool {
	return bVal
	}
	if let bVal = aVal as? Int {
	return bVal != 0
	}
	if let bVal = aVal as? Float {
	return bVal != 0
	}
	if let bVal = aVal as? Double {
	return bVal != 0
	}
	if let bVal = aVal as? String {
	return NSString(string: bVal).boolValue
	}
	return false
	}
	open func url(forKey defaultName: String) -> URL? {
	guard let aVal = object(forKey: defaultName) else {
	return nil
	}

	if let bVal = aVal as? URL {
	return bVal
	} else if let bVal = aVal as? String {
	let cVal = NSString(string: bVal).expandingTildeInPath
	return URL(fileURLWithPath: cVal)
	} else if let bVal = aVal as? Data {
	return NSKeyedUnarchiver.unarchiveObject(with: bVal) as? URL
	}
	return nil
	}

	open func set(_ value: Int, forKey defaultName: String) {
	set(NSNumber(value: value), forKey: defaultName)
	}
	open func set(_ value: Float, forKey defaultName: String) {
	set(NSNumber(value: value), forKey: defaultName)
	}
	open func set(_ value: Double, forKey defaultName: String) {
	set(NSNumber(value: value), forKey: defaultName)
	}
	open func set(_ value: Bool, forKey defaultName: String) {
	set(NSNumber(value: value), forKey: defaultName)
	}
	open func set(_ url: URL?, forKey defaultName: String) {
	if let url = url {
	//FIXME: CFURLIsFileReferenceURL is limited to OS X/iOS
	#if os(OSX) \|\| os(iOS)
	//FIXME: no SwiftFoundation version of CFURLIsFileReferenceURL at time of writing!
	if CFURLIsFileReferenceURL(url._cfObject) {
	let data = NSKeyedArchiver.archivedData(withRootObject: url._nsObject)
	set(data._nsObject, forKey: defaultName)
	return
	}
	#endif

	set(url.path._nsObject, forKey: defaultName)
	} else {
	set(nil, forKey: defaultName)
	}
	}

	open func register(defaults registrationDictionary: [String : Any]) {
	registeredDefaults.merge(registrationDictionary.mapValues(bridgeFromNSCFTypeIfNeeded), uniquingKeysWith: { $1 })
	}

	open func addSuite(named suiteName: String) {
	CFPreferencesAddSuitePreferencesToApp(kCFPreferencesCurrentApplication, suiteName._cfObject)
	}
	open func removeSuite(named suiteName: String) {
	CFPreferencesRemoveSuitePreferencesFromApp(kCFPreferencesCurrentApplication, suiteName._cfObject)
	}

	open func dictionaryRepresentation() -> [String: Any] {
	return _dictionaryRepresentation(includingVolatileDomains: true)
	}

	private func _dictionaryRepresentation(includingVolatileDomains: Bool) -> [String: Any] {
	let registeredDefaultsIfAllowed = includingVolatileDomains ? registeredDefaults : [:]

	guard let defaultsFromDiskCF = CFPreferencesCopyMultiple(nil, suite?._cfObject ?? kCFPreferencesCurrentApplication, kCFPreferencesCurrentUser, kCFPreferencesAnyHost) else {
	return registeredDefaultsIfAllowed
	}

	let defaultsFromDiskWithNumbersBoxed = _SwiftValue.fetch(defaultsFromDiskCF) as? [String: Any] ?? [:]

	if registeredDefaultsIfAllowed.count == 0 {
	return UserDefaults._unboxingNSNumbers(defaultsFromDiskWithNumbersBoxed) as! [String: Any]
	} else {
	var allDefaults = registeredDefaultsIfAllowed

	for (key, value) in defaultsFromDiskWithNumbersBoxed {
	allDefaults[key] = value
	}

	return UserDefaults._unboxingNSNumbers(allDefaults) as! [String: Any]
	}
	}

	private static let _parsedArgumentsDomain: [String: Any] = UserDefaults._parseArguments(ProcessInfo.processInfo.arguments)

	private var _volatileDomains: [String: [String: Any]] = [:]
	private let _volatileDomainsLock = NSLock()

	open var volatileDomainNames: [String] {
	_volatileDomainsLock.lock()
	let names = Array(_volatileDomains.keys)
	_volatileDomainsLock.unlock()

	return names
	}

	open func volatileDomain(forName domainName: String) -> [String : Any] {
	_volatileDomainsLock.lock()
	let domain = _volatileDomains[domainName]
	_volatileDomainsLock.unlock()

	return domain ?? [:]
	}

	open func setVolatileDomain(_ domain: [String : Any], forName domainName: String) {
	if !UserDefaults._isValueAllowed(domain) {
	fatalError("The content of 'domain' passed to UserDefaults.setVolatileDomain(_:forName:) is not supported.")
	}

	_volatileDomainsLock.lock()
	var storedDomain: [String: Any] = _volatileDomains[domainName] ?? [:]
	storedDomain.merge(domain, uniquingKeysWith: { $1 })
	_volatileDomains[domainName] = storedDomain
	_volatileDomainsLock.unlock()
	}

	open func removeVolatileDomain(forName domainName: String) {
	_volatileDomainsLock.lock()
	_volatileDomains.removeValue(forKey: domainName)
	_volatileDomainsLock.unlock()
	}

	open func persistentDomain(forName domainName: String) -> [String : Any]? {
	return UserDefaults(suiteName: domainName)?._dictionaryRepresentation(includingVolatileDomains: false)
	}

	open func setPersistentDomain(_ domain: [String : Any], forName domainName: String) {
	if let defaults = UserDefaults(suiteName: domainName) {
	for key in defaults._dictionaryRepresentation(includingVolatileDomains: false).keys {
	defaults.removeObject(forKey: key)
	}

	for (key, value) in domain {
	defaults.set(value, forKey: key)
	}

	_ = defaults.synchronize()

	NotificationCenter.default.post(name: UserDefaults.didChangeNotification, object: self)
	}
	}

	open func removePersistentDomain(forName domainName: String) {
	if let defaults = UserDefaults(suiteName: domainName) {
	for key in defaults._dictionaryRepresentation(includingVolatileDomains: false).keys {
	defaults.removeObject(forKey: key)
	}

	_ = defaults.synchronize()

	NotificationCenter.default.post(name: UserDefaults.didChangeNotification, object: self)
	}
	}

	open func synchronize() -> Bool {
	return CFPreferencesAppSynchronize(suite?._cfObject ?? kCFPreferencesCurrentApplication)
	}

	open func objectIsForced(forKey key: String) -> Bool {
	// If you're using this version of Foundation, there is nothing in particular that can force a key.
	// So:
	return false
	}

	open func objectIsForced(forKey key: String, inDomain domain: String) -> Bool {
	// If you're using this version of Foundation, there is nothing in particular that can force a key.
	// So:
	return false
	}
	}

	extension UserDefaults {
	public static let didChangeNotification = NSNotification.Name(rawValue: "NSUserDefaultsDidChangeNotification")
	public static let globalDomain: String = "NSGlobalDomain"
	public static let argumentDomain: String = "NSArgumentDomain"
	public static let registrationDomain: String = "NSRegistrationDomain"
	}

	// MARK: -
	// MARK: Parsing arguments.

	fileprivate let propertyListPrefixes: Set<Character> = [ "{", "[", "(", "<", "\"" ]

	private extension UserDefaults {
	static func _parseArguments(_ arguments: [String]) -> [String: Any] {
	var result: [String: Any] = [:]

	let count = arguments.count

	var index = 0
	while index < count - 1 { // We're looking for pairs, so stop at the second-to-last argument.
	let current = arguments[index]
	let next = arguments[index + 1]
	if current.hasPrefix("-") && !next.hasPrefix("-") {
	// Match what Darwin does, which is to check whether the first argument is one of the characters that make up a NeXTStep-style or XML property list: open brace, open parens, open bracket, open angle bracket, or double quote. If it is, attempt parsing it as a plist; otherwise, just use the argument value as a String.

	let keySubstring = current[current.index(after: current.startIndex)...]
	if !keySubstring.isEmpty {
	let key = String(keySubstring)
	let value = next.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)

	var parsed = false
	if let prefix = value.first, propertyListPrefixes.contains(prefix) {
	if let data = value.data(using: .utf8),
	let plist = try? PropertyListSerialization.propertyList(from: data, format: nil) {

	// If we can parse that argument as a plist, use the parsed value.
	parsed = true
	result[key] = plist

	}
	}

	if !parsed {
	result[key] = value
	}
	}

	index += 1 // Skip both the key and the value on this loop.
	}

	index += 1
	}

	return result
	}
	}