예제 #1
0
파일: Bridging.cpp 프로젝트: Nirma/swift
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;
}