SE-0139: Bridge Cocoa framework structs to NSValue.

For every struct type for which the frameworks provides an NSValue category for boxing and unboxing values of that type, provide an _ObjectiveCBridgeable conformance in the Swift overlay that bridges that struct to NSValue, allowing the structs to be used naturally with id-as-Any APIs and Cocoa container classes. This is mostly a matter of gyb-ing out boilerplate using `NSValue.init(bytes:objCType:)` to construct the instance, `NSValue.objCType` to check its type when casting, and `NSValue.getValue(_:)` to extract the unboxed value, though there are a number of special snowflake cases that need special accommodation:

- To maintain proper layering, CoreGraphics structs need to be bridged in the Foundation overlay.
- AVFoundation provides the NSValue boxing categories for structs owned by CoreMedia, but it does so using its own internal subclasses of NSValue, and these subclasses do not interop properly with the standard `NSValue` subclasses instantiated by Foundation. To do the right thing, we therefore have to let AVFoundation provide the bridging implementation for the CoreMedia types, and we have to use its category methods to do so.
- SceneKit provides NSValue categories to box and unbox SCNVector3, SCNVector4, and SCNMatrix4; however, the methods it provides do so in an unusual way. SCNVector3 and SCNVector4 are packaged into `CGRect`s and then the CGRect is boxed using `valueWithCGRect:`. SCNMatrix4 is copied into a CATransform3D, which is then boxed using `valueWithCATransform3D:` from CoreAnimation. To be consistent with what SceneKit does, use its category methods for these types as well, and when casting, check the type against the type encoding SceneKit uses rather than the type encoding of the expected type.

Author: jckarter

include/swift/AST/ASTContext.h

@@ -514,9 +514,9 @@ class ASTContext {
   ProtocolDecl *getProtocol(KnownProtocolKind kind) const;
 
   /// Determine whether the given nominal type is one of the standard
-  /// library types that is known a priori to be bridged to a
-  /// Foundation.
-  bool isStandardLibraryTypeBridgedInFoundation(NominalTypeDecl *nominal) const;
+  /// library or Cocoa framework types that is known to be bridged by another
+  /// module's overlay, for layering or implementation detail reasons.
+  bool isTypeBridgedInExternalModule(NominalTypeDecl *nominal) const;
 
   /// Get the Objective-C type that a Swift type bridges to, if any.
   /// 

include/swift/AST/KnownIdentifiers.def

@@ -29,6 +29,8 @@ IDENTIFIER(Any)
 IDENTIFIER(atIndexedSubscript)
 IDENTIFIER_(bridgeToObjectiveC)
 IDENTIFIER_WITH_NAME(code_, "_code")
+IDENTIFIER(CoreGraphics)
+IDENTIFIER(CoreMedia)
 IDENTIFIER(CGFloat)
 IDENTIFIER(CVarArg)
 IDENTIFIER(Darwin)

lib/AST/ASTContext.cpp

@@ -3982,7 +3982,7 @@ ASTContext::getForeignRepresentationInfo(NominalTypeDecl *nominal,
   }
 }
 
-bool ASTContext::isStandardLibraryTypeBridgedInFoundation(
+bool ASTContext::isTypeBridgedInExternalModule(
      NominalTypeDecl *nominal) const {
   return (nominal == getBoolDecl() ||
           nominal == getIntDecl() ||
@@ -3995,8 +3995,18 @@ bool ASTContext::isStandardLibraryTypeBridgedInFoundation(
           nominal == getStringDecl() ||
           nominal == getErrorDecl() ||
           nominal == getAnyHashableDecl() ||
-          // Weird one-off case where CGFloat is bridged to NSNumber.
-          nominal->getName() == Id_CGFloat);
+          // Foundation's overlay depends on the CoreGraphics overlay, but
+          // CoreGraphics value types bridge to Foundation objects such as
+          // NSValue and NSNumber, so to avoid circular dependencies, the
+          // bridging implementations of CG types appear in the Foundation
+          // module.
+          nominal->getParentModule()->getName() == Id_CoreGraphics ||
+          // CoreMedia is a dependency of AVFoundation, but the bridged
+          // NSValue implementations for CMTime, CMTimeRange, and
+          // CMTimeMapping are provided by AVFoundation, and AVFoundation
+          // gets upset if you don't use the NSValue subclasses its factory
+          // methods instantiate.
+          nominal->getParentModule()->getName() == Id_CoreMedia);
 }
 
 Optional<Type>
@@ -4018,7 +4028,7 @@ ASTContext::getBridgedToObjC(const DeclContext *dc, Type type,
   // optimizer will be guaranteed to see the conformance if it exists.
   bool knownBridgedToObjC = false;
   if (auto ntd = type->getAnyNominal())
-    knownBridgedToObjC = isStandardLibraryTypeBridgedInFoundation(ntd);
+    knownBridgedToObjC = isTypeBridgedInExternalModule(ntd);
 
   // TODO: Under id-as-any, container bridging is unconstrained. This check can
   // go away.

lib/SIL/DynamicCasts.cpp

@@ -55,10 +55,11 @@ mustBridgeToSwiftValueBox(Module *M, CanType T) {
   if (T->isAnyExistentialType())
     return false;
 
-  // getBridgedToObjC() might return a null-type for bridged foundation types
-  // during compiling the standard library. Exclude this case here.
+  // getBridgedToObjC() might return a null-type for some types
+  // whose bridging implementation is allowed to live elsewhere. Exclude this
+  // case here.
   if (auto N = T->getAnyNominal())
-    if (M->getASTContext().isStandardLibraryTypeBridgedInFoundation(N))
+    if (M->getASTContext().isTypeBridgedInExternalModule(N))
       return false;
 
   auto bridgeTy  = M->getASTContext().getBridgedToObjC(M, T, nullptr);

lib/Sema/TypeCheckProtocol.cpp

@@ -3904,7 +3904,7 @@ void ConformanceChecker::checkConformance() {
   // between an imported Objective-C module and its overlay.
   if (Proto->isSpecificProtocol(KnownProtocolKind::ObjectiveCBridgeable)) {
     if (auto nominal = Adoptee->getAnyNominal()) {
-      if (!TC.Context.isStandardLibraryTypeBridgedInFoundation(nominal)) {
+      if (!TC.Context.isTypeBridgedInExternalModule(nominal)) {
         auto nominalModule = nominal->getParentModule();
         auto conformanceModule = DC->getParentModule();
         if (nominalModule->getName() != conformanceModule->getName()) {

stdlib/private/StdlibUnittestFoundationExtras/CMakeLists.txt

@@ -4,6 +4,6 @@ add_swift_library(swiftStdlibUnittestFoundationExtras ${SWIFT_STDLIB_LIBRARY_BUI
   StdlibUnittestFoundationExtras.swift
   UnavailableFoundationMethodThunks.mm
 
-  SWIFT_MODULE_DEPENDS Foundation
+  SWIFT_MODULE_DEPENDS Foundation StdlibUnittest
   INSTALL_IN_COMPONENT stdlib-experimental)
 

stdlib/private/StdlibUnittestFoundationExtras/StdlibUnittestFoundationExtras.swift

@@ -12,6 +12,7 @@
 
 import ObjectiveC
 import Foundation
+import StdlibUnittest
 
 internal var _temporaryLocaleCurrentLocale: NSLocale? = nil
 
@@ -111,3 +112,20 @@ extension NSDictionary {
       andKeys: keys)
   }
 }
+
+public func expectBridgeToNSValue<T>(_ value: T,
+                                     nsValueInitializer: ((T) -> NSValue)? = nil,
+                                     nsValueGetter: ((NSValue) -> T)? = nil,
+                                     equal: (T, T) -> Bool) {
+  let object = value as AnyObject
+  let nsValue = object as! NSValue
+  if let nsValueInitializer = nsValueInitializer {
+    expectEqual(nsValueInitializer(value), nsValue)
+  }
+  if let nsValueGetter = nsValueGetter {
+    expectTrue(equal(value, nsValueGetter(nsValue)))
+  }
+  expectTrue(equal(value, object as! T))
+
+}
+

stdlib/public/SDK/AVFoundation/AVFoundation.swift renamed to stdlib/public/SDK/AVFoundation/AVFoundation.swift.gyb

@@ -1,6 +1,11 @@
 @_exported import AVFoundation // Clang module
+import CoreMedia
 import Foundation
 
+%{
+from gyb_foundation_support import \
+  ObjectiveCBridgeableImplementationForNSValueWithCategoryMethods
+}%
 
 extension AVError {
   /// The device name.
@@ -39,3 +44,23 @@ extension AVError {
   }
 }
 
+// Bridge CoreMedia structs to NSValue.
+// AVFoundation provides internal NSValue subclasses for these structures that
+// are incompatible with the NSConcreteValue subclasses you get using
+// -[NSValue valueWithBytes:objCType:].
+
+${ ObjectiveCBridgeableImplementationForNSValueWithCategoryMethods(
+  Type="CMTime",
+  initializer="{ NSValue(time: $0) }",
+  getter="{ $0.timeValue }",
+) }
+${ ObjectiveCBridgeableImplementationForNSValueWithCategoryMethods(
+  Type="CMTimeRange",
+  initializer="{ NSValue(timeRange: $0) }",
+  getter="{ $0.timeRangeValue }",
+) }
+${ ObjectiveCBridgeableImplementationForNSValueWithCategoryMethods(
+  Type="CMTimeMapping",
+  initializer="{ NSValue(timeMapping: $0) }",
+  getter="{ $0.timeMappingValue }",
+) }

stdlib/public/SDK/AVFoundation/CMakeLists.txt

@@ -1,5 +1,5 @@
 add_swift_library(swiftAVFoundation ${SWIFT_SDK_OVERLAY_LIBRARY_BUILD_TYPES} IS_SDK_OVERLAY
-  AVFoundation.swift
+  AVFoundation.swift.gyb
   TARGET_SDKS OSX IOS IOS_SIMULATOR TVOS TVOS_SIMULATOR
   SWIFT_MODULE_DEPENDS Foundation CoreMedia
   SWIFT_MODULE_DEPENDS_OSX AppKit

stdlib/public/SDK/CMakeLists.txt

@@ -29,10 +29,12 @@ add_subdirectory(GLKit)
 add_subdirectory(HomeKit)
 add_subdirectory(IOKit)
 add_subdirectory(Intents)
+add_subdirectory(MapKit)
 add_subdirectory(ObjectiveC)
 add_subdirectory(OpenCL)
 add_subdirectory(os)
 add_subdirectory(Photos)
+add_subdirectory(QuartzCore)
 add_subdirectory(SafariServices)
 add_subdirectory(SceneKit)
 add_subdirectory(simd)