Viewing file:  MSVCErrorWorkarounds.h (2.62 KB) -rw-r--r--
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//===--- MSVCErrorWorkarounds.h - Enable future<Error> in MSVC --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// MSVC's promise/future implementation requires types to be default
// constructible, so this header provides analogues of Error an Expected
// that are default constructed in a safely destructible state.
//
// FIXME: Kill off this header and migrate all users to Error/Expected once we
// move to MSVC versions that support non-default-constructible types.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_MSVCERRORWORKAROUNDS_H
#define LLVM_SUPPORT_MSVCERRORWORKAROUNDS_H
#include "llvm/Support/Error.h"
namespace llvm {
// A default-constructible llvm::Error that is suitable for use with MSVC's
// std::future implementation which requires default constructible types.
class MSVCPError : public Error {
public:
MSVCPError() { (void)!!*this; }
MSVCPError(MSVCPError &&Other) : Error(std::move(Other)) {}
MSVCPError &operator=(MSVCPError Other) {
Error::operator=(std::move(Other));
return *this;
}
MSVCPError(Error Err) : Error(std::move(Err)) {}
};
// A default-constructible llvm::Expected that is suitable for use with MSVC's
// std::future implementation, which requires default constructible types.
template <typename T> class MSVCPExpected : public Expected<T> {
public:
MSVCPExpected()
: Expected<T>(make_error<StringError>("", inconvertibleErrorCode())) {
consumeError(this->takeError());
}
MSVCPExpected(MSVCPExpected &&Other) : Expected<T>(std::move(Other)) {}
MSVCPExpected &operator=(MSVCPExpected &&Other) {
Expected<T>::operator=(std::move(Other));
return *this;
}
MSVCPExpected(Error Err) : Expected<T>(std::move(Err)) {}
template <typename OtherT>
MSVCPExpected(
OtherT &&Val,
std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr)
: Expected<T>(std::move(Val)) {}
template <class OtherT>
MSVCPExpected(
Expected<OtherT> &&Other,
std::enable_if_t<std::is_convertible<OtherT, T>::value> * = nullptr)
: Expected<T>(std::move(Other)) {}
template <class OtherT>
explicit MSVCPExpected(
Expected<OtherT> &&Other,
std::enable_if_t<!std::is_convertible<OtherT, T>::value> * = nullptr)
: Expected<T>(std::move(Other)) {}
};
} // end namespace llvm
#endif // LLVM_SUPPORT_MSVCERRORWORKAROUNDS_H
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