Type TypeConverter::getLoweredCBridgedType(AbstractionPattern pattern,
Type t,
bool canBridgeBool,
bool bridgedCollectionsAreOptional) {
auto clangTy = pattern.isClangType() ? pattern.getClangType() : nullptr;
// Bridge Bool back to ObjC bool, unless the original Clang type was _Bool
// or the Darwin Boolean type.
auto nativeBoolTy = getBoolType();
if (nativeBoolTy && t->isEqual(nativeBoolTy)) {
if (clangTy) {
if (clangTy->isBooleanType())
return t;
if (clangTy->isSpecificBuiltinType(clang::BuiltinType::UChar))
return getDarwinBooleanType();
}
if (clangTy || canBridgeBool)
return getObjCBoolType();
return t;
}
// Class metatypes bridge to ObjC metatypes.
if (auto metaTy = t->getAs<MetatypeType>()) {
if (metaTy->getInstanceType()->getClassOrBoundGenericClass()) {
return MetatypeType::get(metaTy->getInstanceType(),
MetatypeRepresentation::ObjC);
}
}
// ObjC-compatible existential metatypes.
if (auto metaTy = t->getAs<ExistentialMetatypeType>()) {
if (metaTy->getInstanceType()->isObjCExistentialType()) {
return ExistentialMetatypeType::get(metaTy->getInstanceType(),
MetatypeRepresentation::ObjC);
}
}
// `Any` can bridge to `AnyObject` (`id` in ObjC).
if (t->isAny())
return Context.getAnyObjectType();
if (auto funTy = t->getAs<FunctionType>()) {
switch (funTy->getExtInfo().getSILRepresentation()) {
// Functions that are already represented as blocks or C function pointers
// don't need bridging.
case SILFunctionType::Representation::Block:
case SILFunctionType::Representation::CFunctionPointer:
case SILFunctionType::Representation::Thin:
case SILFunctionType::Representation::Method:
case SILFunctionType::Representation::ObjCMethod:
case SILFunctionType::Representation::WitnessMethod:
case SILFunctionType::Representation::Closure:
return t;
case SILFunctionType::Representation::Thick: {
// Thick functions (TODO: conditionally) get bridged to blocks.
// This bridging is more powerful than usual block bridging, however,
// so we use the ObjCMethod representation.
Type newInput =
getBridgedInputType(SILFunctionType::Representation::ObjCMethod,
pattern.getFunctionInputType(),
funTy->getInput()->getCanonicalType());
Type newResult =
getBridgedResultType(SILFunctionType::Representation::ObjCMethod,
pattern.getFunctionResultType(),
funTy->getResult()->getCanonicalType(),
/*non-optional*/false);
return FunctionType::get(newInput, newResult,
funTy->getExtInfo().withSILRepresentation(
SILFunctionType::Representation::Block));
}
}
}
auto foreignRepresentation =
t->getForeignRepresentableIn(ForeignLanguage::ObjectiveC, M.TheSwiftModule);
switch (foreignRepresentation.first) {
case ForeignRepresentableKind::None:
case ForeignRepresentableKind::Trivial:
case ForeignRepresentableKind::Object:
return t;
case ForeignRepresentableKind::Bridged:
case ForeignRepresentableKind::StaticBridged: {
auto conformance = foreignRepresentation.second;
assert(conformance && "Missing conformance?");
Type bridgedTy =
ProtocolConformanceRef::getTypeWitnessByName(
t, ProtocolConformanceRef(conformance),
M.getASTContext().Id_ObjectiveCType,
nullptr);
assert(bridgedTy && "Missing _ObjectiveCType witness?");
if (bridgedCollectionsAreOptional && clangTy)
bridgedTy = OptionalType::get(bridgedTy);
return bridgedTy;
}
case ForeignRepresentableKind::BridgedError: {
auto nsErrorDecl = M.getASTContext().getNSErrorDecl();
assert(nsErrorDecl && "Cannot bridge when NSError isn't available");
return nsErrorDecl->getDeclaredInterfaceType();
}
}
return t;
}