///
//===----------------------------------------------------------------------===//
-#ifndef LLVM_SUPPORT_ERROR_OR_H
-#define LLVM_SUPPORT_ERROR_OR_H
+#ifndef LLVM_SUPPORT_ERROROR_H
+#define LLVM_SUPPORT_ERROROR_H
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/Support/AlignOf.h"
-#include "llvm/Support/system_error.h"
-#include "llvm/Support/type_traits.h"
#include <cassert>
-#if LLVM_HAS_CXX11_TYPETRAITS
+#include <system_error>
#include <type_traits>
-#endif
namespace llvm {
-#if LLVM_HAS_CXX11_TYPETRAITS && LLVM_HAS_RVALUE_REFERENCES
template<class T, class V>
typename std::enable_if< std::is_constructible<T, V>::value
, typename std::remove_reference<V>::type>::type &&
moveIfMoveConstructible(V &Val) {
return Val;
}
-#else
-template<class T, class V>
-V &moveIfMoveConstructible(V &Val) {
- return Val;
-}
-#endif
/// \brief Stores a reference that can be changed.
template <typename T>
/// It is used like the following.
/// \code
/// ErrorOr<Buffer> getBuffer();
-/// void handleError(error_code ec);
///
/// auto buffer = getBuffer();
-/// if (!buffer)
-/// handleError(buffer);
+/// if (error_code ec = buffer.getError())
+/// return ec;
/// buffer->write("adena");
/// \endcode
///
///
-/// An implicit conversion to bool provides a way to check if there was an
-/// error. The unary * and -> operators provide pointer like access to the
-/// value. Accessing the value when there is an error has undefined behavior.
+/// Implicit conversion to bool returns true if there is a usable value. The
+/// unary * and -> operators provide pointer like access to the value. Accessing
+/// the value when there is an error has undefined behavior.
///
/// When T is a reference type the behaivor is slightly different. The reference
/// is held in a std::reference_wrapper<std::remove_reference<T>::type>, and
template<class T>
class ErrorOr {
template <class OtherT> friend class ErrorOr;
- static const bool isRef = is_reference<T>::value;
- typedef ReferenceStorage<typename remove_reference<T>::type> wrap;
+ static const bool isRef = std::is_reference<T>::value;
+ typedef ReferenceStorage<typename std::remove_reference<T>::type> wrap;
public:
- typedef typename
- conditional< isRef
- , wrap
- , T
- >::type storage_type;
+ typedef typename std::conditional<isRef, wrap, T>::type storage_type;
private:
- typedef typename remove_reference<T>::type &reference;
- typedef typename remove_reference<T>::type *pointer;
+ typedef typename std::remove_reference<T>::type &reference;
+ typedef const typename std::remove_reference<T>::type &const_reference;
+ typedef typename std::remove_reference<T>::type *pointer;
public:
template <class E>
- ErrorOr(E ErrorCode, typename enable_if_c<is_error_code_enum<E>::value ||
- is_error_condition_enum<E>::value,
- void *>::type = 0)
+ ErrorOr(E ErrorCode,
+ typename std::enable_if<std::is_error_code_enum<E>::value ||
+ std::is_error_condition_enum<E>::value,
+ void *>::type = 0)
: HasError(true) {
- new (getErrorStorage()) error_code(make_error_code(ErrorCode));
+ new (getErrorStorage()) std::error_code(make_error_code(ErrorCode));
}
- ErrorOr(llvm::error_code EC) : HasError(true) {
- new (getErrorStorage()) error_code(EC);
+ ErrorOr(std::error_code EC) : HasError(true) {
+ new (getErrorStorage()) std::error_code(EC);
}
ErrorOr(T Val) : HasError(false) {
}
template <class OtherT>
- ErrorOr(const ErrorOr<OtherT> &Other) {
+ ErrorOr(
+ const ErrorOr<OtherT> &Other,
+ typename std::enable_if<std::is_convertible<OtherT, T>::value>::type * =
+ nullptr) {
copyConstruct(Other);
}
- ErrorOr &operator =(const ErrorOr &Other) {
- copyAssign(Other);
- return *this;
- }
-
template <class OtherT>
- ErrorOr &operator =(const ErrorOr<OtherT> &Other) {
- copyAssign(Other);
- return *this;
+ explicit ErrorOr(
+ const ErrorOr<OtherT> &Other,
+ typename std::enable_if<
+ !std::is_convertible<OtherT, const T &>::value>::type * = nullptr) {
+ copyConstruct(Other);
}
-#if LLVM_HAS_RVALUE_REFERENCES
ErrorOr(ErrorOr &&Other) {
moveConstruct(std::move(Other));
}
template <class OtherT>
- ErrorOr(ErrorOr<OtherT> &&Other) {
+ ErrorOr(
+ ErrorOr<OtherT> &&Other,
+ typename std::enable_if<std::is_convertible<OtherT, T>::value>::type * =
+ nullptr) {
moveConstruct(std::move(Other));
}
- ErrorOr &operator =(ErrorOr &&Other) {
- moveAssign(std::move(Other));
+ // This might eventually need SFINAE but it's more complex than is_convertible
+ // & I'm too lazy to write it right now.
+ template <class OtherT>
+ explicit ErrorOr(
+ ErrorOr<OtherT> &&Other,
+ typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * =
+ nullptr) {
+ moveConstruct(std::move(Other));
+ }
+
+ ErrorOr &operator=(const ErrorOr &Other) {
+ copyAssign(Other);
return *this;
}
- template <class OtherT>
- ErrorOr &operator =(ErrorOr<OtherT> &&Other) {
+ ErrorOr &operator=(ErrorOr &&Other) {
moveAssign(std::move(Other));
return *this;
}
-#endif
~ErrorOr() {
if (!HasError)
getStorage()->~storage_type();
}
- typedef void (*unspecified_bool_type)();
- static void unspecified_bool_true() {}
-
/// \brief Return false if there is an error.
- operator unspecified_bool_type() const {
- return HasError ? 0 : unspecified_bool_true;
+ explicit operator bool() const {
+ return !HasError;
}
reference get() { return *getStorage(); }
- const reference get() const { return const_cast<ErrorOr<T> >(this)->get(); }
+ const_reference get() const { return const_cast<ErrorOr<T> *>(this)->get(); }
- error_code getError() const {
- return HasError ? *getErrorStorage() : error_code::success();
+ std::error_code getError() const {
+ return HasError ? *getErrorStorage() : std::error_code();
}
pointer operator ->() {
} else {
// Get other's error.
HasError = true;
- new (getErrorStorage()) error_code(Other.getError());
+ new (getErrorStorage()) std::error_code(Other.getError());
}
}
new (this) ErrorOr(Other);
}
-#if LLVM_HAS_RVALUE_REFERENCES
template <class OtherT>
void moveConstruct(ErrorOr<OtherT> &&Other) {
if (!Other.HasError) {
} else {
// Get other's error.
HasError = true;
- new (getErrorStorage()) error_code(Other.getError());
+ new (getErrorStorage()) std::error_code(Other.getError());
}
}
this->~ErrorOr();
new (this) ErrorOr(std::move(Other));
}
-#endif
pointer toPointer(pointer Val) {
return Val;
return reinterpret_cast<const storage_type*>(TStorage.buffer);
}
- error_code *getErrorStorage() {
+ std::error_code *getErrorStorage() {
assert(HasError && "Cannot get error when a value exists!");
- return reinterpret_cast<error_code*>(ErrorStorage.buffer);
+ return reinterpret_cast<std::error_code *>(ErrorStorage.buffer);
}
- const error_code *getErrorStorage() const {
+ const std::error_code *getErrorStorage() const {
return const_cast<ErrorOr<T> *>(this)->getErrorStorage();
}
union {
AlignedCharArrayUnion<storage_type> TStorage;
- AlignedCharArrayUnion<error_code> ErrorStorage;
+ AlignedCharArrayUnion<std::error_code> ErrorStorage;
};
bool HasError : 1;
};
-template<class T, class E>
-typename enable_if_c<is_error_code_enum<E>::value ||
- is_error_condition_enum<E>::value, bool>::type
-operator ==(ErrorOr<T> &Err, E Code) {
- return error_code(Err) == Code;
+template <class T, class E>
+typename std::enable_if<std::is_error_code_enum<E>::value ||
+ std::is_error_condition_enum<E>::value,
+ bool>::type
+operator==(const ErrorOr<T> &Err, E Code) {
+ return Err.getError() == Code;
}
} // end namespace llvm
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