[Support] Add conversions between Expected<T> and ErrorOr<T>.

More utilities to help with std::error_code -> Error transitions.

llvm-svn: 264238
This commit is contained in:
Lang Hames 2016-03-24 02:00:10 +00:00
parent 0cd69a5030
commit fc3b132a68
2 changed files with 40 additions and 1 deletions

View File

@ -753,6 +753,22 @@ inline std::error_code errorToErrorCode(Error Err) {
return EC;
}
/// Convert an ErrorOr<T> to an Expected<T>.
template <typename T>
Expected<T> errorOrToExpected(ErrorOr<T> &&EO) {
if (auto EC = EO.getError())
return errorCodeToError(EC);
return std::move(*EO);
}
/// Convert an Expected<T> to an ErrorOr<T>.
template <typename T>
ErrorOr<T> expectedToErrorOr(Expected<T> &&E) {
if (auto Err = E.takeError())
return errorToErrorCode(std::move(Err));
return std::move(*E);
}
/// Helper for check-and-exit error handling.
///
/// For tool use only. NOT FOR USE IN LIBRARY CODE.

View File

@ -416,7 +416,7 @@ TEST(Error, ExpectedCovariance) {
A2 = Expected<std::unique_ptr<D>>(nullptr);
}
TEST(Error, ECError) {
TEST(Error, ErrorCodeConversions) {
// Round-trip a success value to check that it converts correctly.
EXPECT_EQ(errorToErrorCode(errorCodeToError(std::error_code())),
std::error_code())
@ -427,6 +427,29 @@ TEST(Error, ECError) {
errc::invalid_argument)
<< "std::error_code error value should round-trip via Error "
"conversions";
// Round-trip a success value through ErrorOr/Expected to check that it
// converts correctly.
{
auto Orig = ErrorOr<int>(42);
auto RoundTripped =
expectedToErrorOr(errorOrToExpected(ErrorOr<int>(42)));
EXPECT_EQ(*Orig, *RoundTripped)
<< "ErrorOr<T> success value should round-trip via Expected<T> "
"conversions.";
}
// Round-trip a failure value through ErrorOr/Expected to check that it
// converts correctly.
{
auto Orig = ErrorOr<int>(errc::invalid_argument);
auto RoundTripped =
expectedToErrorOr(
errorOrToExpected(ErrorOr<int>(errc::invalid_argument)));
EXPECT_EQ(Orig.getError(), RoundTripped.getError())
<< "ErrorOr<T> failure value should round-trip via Expected<T> "
"conversions.";
}
}
} // end anon namespace