diff options
Diffstat (limited to 'absl/types/optional.h')
| -rw-r--r-- | absl/types/optional.h | 19 |
1 files changed, 6 insertions, 13 deletions
diff --git a/absl/types/optional.h b/absl/types/optional.h index c0488797..58906aa4 100644 --- a/absl/types/optional.h +++ b/absl/types/optional.h @@ -114,10 +114,6 @@ namespace absl { // need the inline variable support in C++17 for external linkage. // * Throws `absl::bad_optional_access` instead of // `std::bad_optional_access`. -// * `optional::swap()` and `absl::swap()` relies on -// `std::is_(nothrow_)swappable()`, which has been introduced in C++17. -// As a workaround, we assume `is_swappable()` is always `true` -// and `is_nothrow_swappable()` is the same as `std::is_trivial()`. // * `make_optional()` cannot be declared `constexpr` due to the absence of // guaranteed copy elision. // * The move constructor's `noexcept` specification is stronger, i.e. if the @@ -753,11 +749,10 @@ class optional : private optional_internal::optional_data<T>, // Swap, standard semantics void swap(optional& rhs) noexcept( std::is_nothrow_move_constructible<T>::value&& - std::is_trivial<T>::value) { + type_traits_internal::IsNothrowSwappable<T>::value) { if (*this) { if (rhs) { - using std::swap; - swap(**this, *rhs); + type_traits_internal::Swap(**this, *rhs); } else { rhs.construct(std::move(**this)); this->destruct(); @@ -909,12 +904,10 @@ class optional : private optional_internal::optional_data<T>, // // Performs a swap between two `absl::optional` objects, using standard // semantics. -// -// NOTE: we assume `is_swappable()` is always `true`. A compile error will -// result if this is not the case. -template <typename T, - typename std::enable_if<std::is_move_constructible<T>::value, - bool>::type = false> +template <typename T, typename std::enable_if< + std::is_move_constructible<T>::value && + type_traits_internal::IsSwappable<T>::value, + bool>::type = false> void swap(optional<T>& a, optional<T>& b) noexcept(noexcept(a.swap(b))) { a.swap(b); } |