Implementation Status

This document lays out the structure of the Foundation project, and provides the current implementation status of each major feature.

Foundation is divided into groups of related functionality. These groups are currently laid out in the Xcode project, even though they are in a flat structure on disk.

As Foundation is a work in progress, not all methods and functionality are present. When implementations are completed, this list should be updated to reflect the current state of the library.

Table Key

Implementation Status

• N/A: This entity is internal or private and implemented ad hoc; there are no guidelines in place to suggest what completion might look like
• Unimplemented: This entity exists, but all functions and methods are NSUnimplemented()
• Incomplete: Implementation of this entity has begun, but critical sections have been left NSUnimplemented()
• Mostly Complete: All critical sections of this entity have been implemented, but some methods might remain NSUnimplemented()
• Complete: No methods are left NSUnimplemented() (though this is not a guarantee that work is complete -- there may be methods that need overriding or extra work)

Test Coverage

• N/A: This entity is internal and public tests are inappropriate, or it is an entity for which testing does not make sense
• None: There are no unit tests specific to this entity; even if it is used indirectly in other unit tests, we should have tests targeting this entity in isolation
• Incomplete: Unit tests exist for this entity, but there are critical paths that are not being tested
• Substantial: Most, if not all, of this entity's critical paths are being tested

There is no Complete status for test coverage because there are always additional tests to be implemented. Even entities with Substantial coverage are missing tests (e.g. NSCoding conformance, NSCopying conformance, descriptions, etc.)

Entities

• Runtime: The basis for interoperability. The classes and methods in this group provide an interface for interoperability between C code and Swift. They also provide common layers used throughout the framework such as the root class NSObject.

  Entity Name	Status	Test Coverage	Notes
  NSEnumerator	Complete	None
  NSGetSizeAndAlignment	Complete	None
  NSStringFromClass	Mostly Complete	None	Only top-level Swift classes are supported
  NSClassFromString	Mostly Complete	None	Only top-level Swift classes are supported; mangled names are not supported
  NSObject	Complete	None
  NSSwiftRuntime	N/A	N/A	For internal use only
  Boxing	N/A	N/A	For internal use only

• URL: Networking primitives

  The classes in this group provide functionality for manipulating URLs and paths via a common model object. The group also has classes for creating and receiving network connections.

  Entity Name	Status	Test Coverage	Notes
  URLAuthenticationChallenge	Unimplemented	None
  URLCache	Unimplemented	None
  URLCredential	Complete	Incomplete
  URLCredentialStorage	Unimplemented	None
  NSURLError*	Complete	N/A
  URLProtectionSpace	Unimplemented	None
  URLProtocol	Unimplemented	None
  URLProtocolClient	Unimplemented	None
  NSURLRequest	Mostly Complete	Incomplete
  NSMutableURLRequest	Mostly Complete	Incomplete
  URLResponse	Mostly Complete	Incomplete
  NSHTTPURLResponse	Mostly Complete	Substantial
  NSURL	Mostly Complete	Substantial	Resource values remain unimplemented
  NSURLQueryItem	Mostly Complete	N/A
  URLResourceKey	Complete	N/A
  URLFileResourceType	Complete	N/A
  URL	Complete	Incomplete
  URLResourceValues	Complete	N/A
  URLComponents	Complete	Incomplete
  URLRequest	Complete	None
  HTTPCookie	Complete	Incomplete
  HTTPCookiePropertyKey	Complete	N/A
  HTTPCookieStorage	Unimplemented	None
  Host	Complete	None
  Configuration	N/A	N/A	For internal use only
  EasyHandle	N/A	N/A	For internal use only
  HTTPBodySource	N/A	N/A	For internal use only
  HTTPMessage	N/A	N/A	For internal use only
  libcurlHelpers	N/A	N/A	For internal use only
  MultiHandle	N/A	N/A	For internal use only
  URLSession	Mostly Complete	Incomplete	shared, invalidation, resetting, flushing, getting tasks, and others remain unimplemented
  URLSessionConfiguration	Mostly Complete	Incomplete	ephemeral and background(withIdentifier:) remain unimplemented
  URLSessionDelegate	Complete	N/A
  URLSessionTask	Mostly Complete	Incomplete	cancel(), createTransferState(url:) with streams, and others remain unimplemented
  URLSessionDataTask	Complete	Incomplete
  URLSessionUploadTask	Complete	None
  URLSessionDownloadTask	Incomplete	Incomplete	cancel(byProducingResumeData:) remains unimplemented
  URLSessionStreamTask	Unimplemented	None
  TaskRegistry	N/A	N/A	For internal use only
  TransferState	N/A	N/A	For internal use only

• Formatters: Locale and language-correct formatted values.

  This group contains the is the base NSFormatter class and its subclasses. These formatters can be used for dates, numbers, sizes, energy, and many other types.

  Entity Name	Status	Test Coverage	Notes
  DateComponentFormatter	Unimplemented	None
  DateIntervalFormatter	Unimplemented	None
  EnergyFormatter	Unimplemented	None
  ISO8601DateFormatter	Unimplemented	None
  LengthFormatter	Complete	Substantial
  MassFormatter	Complete	Substantial	Needs localization
  NumberFormatter	Mostly Complete	Substantial	objectValue(_:range:) remains unimplemented
  PersonNameComponentsFormatter	Unimplemented	None
  ByteCountFormatter	Mostly Complete	Substantial	init?(coder:) remains unimplemented
  DateFormatter	Mostly Complete	Incomplete	objectValue(_:range:) remain unimplemented
  Formatter	Complete	N/A
  MeasurementFormatter	Unimplemented	None

• Predicates: Base functionality for building queries.

  This is the base class and subclasses for NSPredicate and NSExpression.

  Entity Name	Status	Test Coverage	Notes
  NSExpression	Unimplemented	N/A
  NSComparisonPredicate	Unimplemented	N/A
  NSCompoundPredicate	Complete	Substantial
  NSPredicate	Incomplete	Incomplete	Only boolean and block evaluations are implemented; all else remains unimplemented

• Serialization: Serialization and deserialization functionality.

  The classes in this group perform tasks like parsing and writing JSON, property lists and binary archives.

  Entity Name	Status	Test Coverage	Notes
  NSJSONSerialization	Mostly Complete	Substantial	jsonObject(with:options:) with streams remains unimplemented
  NSKeyedArchiver	Complete	Substantial
  NSKeyedCoderOldStyleArray	N/A	N/A	For internal use only
  NSKeyedUnarchiver	Mostly Complete	Substantial	decodingFailurePolicy.set remains unimplemented
  NSKeyedArchiverHelpers	N/A	N/A	For internal use only
  NSCoder	Incomplete	N/A	Decoding methods which require a concrete implementation remain unimplemented
  PropertyListSerialization	Complete	Incomplete

• XML: A group of classes for parsing and representing XML documents and elements.

  The classes provided in this group are responsible for parsing and validating XML. They should be an interface for representing libxml2 in a more object-oriented manner.

  Entity Name	Status	Test Coverage	Notes
  XMLDocument	Mostly Complete	Substantial	init(), replacementClass(for:), and object(byApplyingXSLT...) remain unimplemented
  XMLDTD	Mostly Complete	Substantial	init() remains unimplemented
  XMLDTDNode	Complete	Incomplete
  XMLElement	Incomplete	Incomplete	init(xmlString:), elements(forLocalName:uri:), attribute(forLocalName:uri:), namespace support, and others remain unimplemented
  XMLNode	Incomplete	Incomplete	localName(forName:), prefix(forName:), predefinedNamespace(forPrefix:), and others remain unimplemented
  XMLParser	Complete	Incomplete

• Collections: A group of classes to contain objects.

  The classes provided in this group provide basic collections. The primary role for these classes is to provide an interface layer between the CoreFoundation implementations and the standard library implementations. Additionally, they have useful extras like serialization support. There are also additional collection types that the standard library does not support.

  Note: See Known Issues for more information about bridging between Foundation collection types and Swift standard library collection types.

  Entity Name	Status	Test Coverage	Notes
  NSOrderedSet	Mostly Complete	Substantial	NS[Mutable]Copying, and array & set (and associated indexing methods) remain unimplemented
  NSMutableOrderedSet	Mostly Complete	Substantial	NSCoding and sortRange(_:options:, usingComparator:) with non-empty options remain unimplemented
  NSCFArray	N/A	N/A	For internal use only
  NSIndexSet	Mostly Complete	Incomplete	NSCoding, NSCopying, and concurrent enumerateWithOptions(_:range:paramType:returnType:block:) remain unimplemented
  NSMutableIndexSet	Mostly Complete	Incomplete	shiftIndexesStarting(at:by:) remains unimplemented
  IndexSet	Complete	Incomplete
  NSIndexPath	Mostly Complete	None	NSCoding, NSCopying, getIndexes(_:) remain unimplemented
  IndexPath	Complete	Incomplete
  NSArray	Mostly Complete	Substantial	Reading/writing to files/URLs, concurrent enumerateObjects(at:options:using:), and sortedArray(from:options:usingComparator:) with options remain unimplemented
  NSMutableArray	Mostly Complete	Substantial	exchangeObject(at:withObjectAt:) and replaceObjects(in:withObjectsFromArray:) remain unimplemented for types other than NSMutableArray
  NSDictionary	Mostly Complete	Incomplete	NSCoding with non-keyed-coding archivers, descriptionInStringsFileFormat, sharedKeySet(forKeys:), and reading/writing to files/URLs remain unimplemented
  NSMutableDictionary	Mostly Complete	Incomplete	descriptionInStringsFileFormat, sharedKeySet(forKeys:), and reading/writing to files/URLs remain unimplemented
  NSCFDictionary	N/A	N/A	For internal use only
  NSSet	Mostly Complete	Incomplete	description(withLocale:) and customMirror remain unimplemented
  NSMutableSet	Mostly Complete	Incomplete	init?(coder:) remains unimplemented
  NSCountedSet	Mostly Complete	Incomplete	init?(coder:) remains unimplemented
  NSCFSet	N/A	N/A	For internal use only
  NSCache	Complete	Incomplete
  NSSortDescriptor	Unimplemented	None

• RunLoop: Timers, streams and run loops.

  The classes in this group provide support for scheduling work and acting upon input from external sources.

  Entity Name	Status	Test Coverage	Notes
  Port	Unimplemented	None
  MessagePort	Unimplemented	None
  SocketPort	Unimplemented	None
  PortMessage	Unimplemented	None
  RunLoop	Mostly Complete	Incomplete	add(_: Port, forMode:) and remove(_: Port, forMode:) remain unimplemented
  NSStream	Mostly Complete	Substantial
  Stream	Unimplemented	Substantial	Methods which require a concrete implementation remain unimplemented
  InputStream	Mostly Complete	Substantial	getBuffer(_:length:) remains unimplemented
  NSOutputStream	Complete	Substantial
  Timer	Complete	Substantial

• String: A set of classes for scanning, manipulating and storing string values.

  The NSString implementation is present to provide an interface layer between CoreFoundation and Swift, but it also adds additional functionality on top of the Swift standard library String type. Other classes in this group provide mechanisms to scan, match regular expressions, store attributes in run arrays attached to strings, and represent sets of characters.

  Note: See Known Issues for more information about bridging between the Foundation NSString types and Swift standard library String type.

  Entity Name	Status	Test Coverage	Notes
  NSRegularExpression	Complete	Substantial
  Scanner	Mostly Complete	Incomplete	scanHex<T: _FloatLike>(_:locale:locationToScanFrom:to:) and localizedScannerWithString(_:) remain unimplemented
  NSTextCheckingResult	Mostly Complete	Incomplete	NSCoding, NSCopying, resultType, and range(at:) remain unimplemented
  NSAttributedString	Incomplete	Incomplete	NSCoding, NS[Mutable]Copying, attributedSubstring(from:), isEqual(to:), init(NSAttributedString:) remain unimplemented
  NSMutableAttributedString	Unimplemented	Incomplete	Only addAttribute(_:value:range:) is implemented
  NSCharacterSet	Mostly Complete	Incomplete	NSCoding remains unimplemented
  NSMutableCharacterSet	Mostly Complete	None	Decoding remains unimplemented
  NSCFCharacterSet	N/A	N/A	For internal use only
  CharacterSet	Complete	Incomplete
  NSString	Mostly Complete	Substantial	init(contentsOf:usedEncoding:), init(contentsOfFile:usedEncoding:), enumerateSubstrings(in:options:using:) remain unimplemented
  NSStringEncodings	Complete	N/A	Contains definitions of string encodings
  NSCFString	N/A	N/A	For internal use only
  NSStringAPI	N/A	N/A	Exposes NSString APIs on String
  ExtraStringAPIs	Complete	N/A	Random access for String.UTF16View, only when Foundation is imported; decouples the Swift core from a UTF16 representation.

• Number: A set of classes and methods for representing numeric values and structures.

  Entity Name	Status	Test Coverage	Notes
  NSRange	Complete	Incomplete
  Decimal	Unimplemented	None
  NSDecimalNumber	Unimplemented	None
  NSDecimalNumberHandler	Unimplemented	None
  CGPoint	Complete	Substantial
  CGSize	Complete	Substantial
  CGRect	Complete	Substantial
  NSEdgeInsets	Mostly Complete	None
  NSGeometry	Mostly Complete	Substantial	NSIntegralRectWithOptions .AlignRectFlipped support remains unimplemented
  CGFloat	Complete	Substantial
  AffineTransform	Complete	None
  NSAffineTransform	Complete	Substnatial
  NSNumber	Complete	Incomplete
  NSConcreteValue	N/A	N/A	For internal use only
  NSSpecialValue	N/A	N/A	For internal use only
  NSValue	Complete	Substantial
  NSMeasurement	Unimplemented	None
  Measurement	Complete	None
  UnitConverter	Complete	Incomplete
  UnitConverterLinear	Complete	Incomplete
  Unit	Complete	None
  Dimension	Complete	None
  UnitAcceleration	Complete	None
  UnitAngle	Complete	None
  UnitArea	Complete	None
  UnitConcentrationMass	Complete	None
  UnitDispersion	Complete	None
  UnitDuration	Complete	None
  UnitElectricCharge	Complete	None
  UnitElectricCurrent	Complete	None
  UnitElectricPotentialDifference	Complete	None
  UnitElectricResistance	Complete	None
  UnitEnergy	Complete	None
  UnitFrequency	Complete	None
  UnitFuelEfficiency	Complete	None
  UnitLength	Complete	None
  UnitIlluminance	Complete	None
  UnitMass	Complete	None
  UnitPower	Complete	None
  UnitPressure	Complete	None
  UnitSpeed	Complete	None
  UnitTemperature	Complete	None
  UnitVolume	Complete	None

• UserDefaults: A mechanism for storing values to persist as user settings and local.

  Entity Name	Statues	Test Coverage	Notes
  UserDefaults	Incomplete	None	dictionaryRepresentation(), domain support, and forced objects remain unimplemented. Unit tests are currently commented out
  NSLocale	Complete	Incomplete	Only unit test asserts locale key constant names
  Locale	Complete	Incomplete	Only unit test asserts value copying

• OS: Mechanisms for interacting with the operating system on a file system level as well as process and thread level

  Entity Name	Status	Test Coverage	Notes
  FileHandle	Mostly Complete	Incomplete	NSCoding, and background operations remain unimplemented
  Pipe	Complete	Incomplete
  FileManager	Incomplete	Incomplete	URL searches, relationship lookups, item copying, cross-device moving, recursive linking, and others remain unimplemented
  Process	Mostly Complete	Substantial	interrupt(), terminate(), suspend(), and resume() remain unimplemented
  Bundle	Mostly Complete	Incomplete	allBundles, init(for:), unload(), classNamed(), and principalClass remain unimplemented
  ProcessInfo	Complete	Substantial
  Thread	Complete	Incomplete
  Operation	Complete	Incomplete
  BlockOperation	Complete	Incomplete
  OperationQueue	Complete	Incomplete
  Lock	Complete	Incomplete
  ConditionLock	Complete	None
  RecursiveLock	Complete	None
  Condition	Complete	Incomplete

• DateTime: Classes for representing dates, timezones, and calendars.

  Entity Name	Status	Test Coverage	Notes
  NSCalendar	Complete	None	autoupdatingCurrent, and enumerateDates remain unimplemented
  NSDateComponents	Complete	None
  Calendar	Complete	Incomplete
  DateComponents	Complete	Incomplete
  NSDate	Complete	Incomplete
  NSDateInterval	Complete	None
  DateInterval	Complete	None
  Date	Complete	Incomplete
  NSTimeZone	Mostly Complete	Incomplete	local, timeZoneDataVersion and setting abbreviationDictionary remain unimplemented
  TimeZone	Complete	Incomplete

• Notifications: Classes for loosely coupling events from a set of many observers.

  Entity Name	Status	Test Coverage	Notes
  NSNotification	Complete	N/A
  NotificationCenter	Mostly Complete	Substantial	Adding observers to non-nil queues remains unimplemented
  Notification	Complete	N/A
  NotificationQueue	Complete	Substantial

• Model: Representations for abstract model elements like null, data, and errors.

  Entity Name	Status	Test Coverage	Notes
  NSNull	Complete	Substantial
  NSData	Complete	Substantial
  NSMutableData	Complete	Substantial
  Data	Complete	Substantial
  NSProgress	Complete	Substantial
  NSError	Complete	None
  NSUUID	Complete	Substantial
  UUID	Complete	None
  NSPersonNameComponents	Complete	Incomplete
  PersonNameComponents	Complete	None