diff options
Diffstat (limited to 'absl/container/internal/compressed_tuple.h')
| -rw-r--r-- | absl/container/internal/compressed_tuple.h | 49 |
1 files changed, 41 insertions, 8 deletions
diff --git a/absl/container/internal/compressed_tuple.h b/absl/container/internal/compressed_tuple.h index c29ab41e..7d08e370 100644 --- a/absl/container/internal/compressed_tuple.h +++ b/absl/container/internal/compressed_tuple.h @@ -102,7 +102,9 @@ template <typename T, size_t I, struct Storage { T value; constexpr Storage() = default; - explicit constexpr Storage(T&& v) : value(absl::forward<T>(v)) {} + template <typename V> + explicit constexpr Storage(absl::in_place_t, V&& v) + : value(absl::forward<V>(v)) {} constexpr const T& get() const& { return value; } T& get() & { return value; } constexpr const T&& get() const&& { return absl::move(*this).value; } @@ -112,7 +114,11 @@ struct Storage { template <typename T, size_t I> struct ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC Storage<T, I, true> : T { constexpr Storage() = default; - explicit constexpr Storage(T&& v) : T(absl::forward<T>(v)) {} + + template <typename V> + explicit constexpr Storage(absl::in_place_t, V&& v) + : T(absl::forward<V>(v)) {} + constexpr const T& get() const& { return *this; } T& get() & { return *this; } constexpr const T&& get() const&& { return absl::move(*this); } @@ -132,8 +138,9 @@ struct ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC CompressedTupleImpl< : uses_inheritance, Storage<Ts, std::integral_constant<size_t, I>::value>... { constexpr CompressedTupleImpl() = default; - explicit constexpr CompressedTupleImpl(Ts&&... args) - : Storage<Ts, I>(absl::forward<Ts>(args))... {} + template <typename... Vs> + explicit constexpr CompressedTupleImpl(absl::in_place_t, Vs&&... args) + : Storage<Ts, I>(absl::in_place, absl::forward<Vs>(args))... {} friend CompressedTuple<Ts...>; }; @@ -143,8 +150,9 @@ struct ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC CompressedTupleImpl< // We use the dummy identity function as above... : Storage<Ts, std::integral_constant<size_t, I>::value, false>... { constexpr CompressedTupleImpl() = default; - explicit constexpr CompressedTupleImpl(Ts&&... args) - : Storage<Ts, I, false>(absl::forward<Ts>(args))... {} + template <typename... Vs> + explicit constexpr CompressedTupleImpl(absl::in_place_t, Vs&&... args) + : Storage<Ts, I, false>(absl::in_place, absl::forward<Vs>(args))... {} friend CompressedTuple<Ts...>; }; @@ -159,6 +167,11 @@ constexpr bool ShouldAnyUseBase() { Or({std::integral_constant<bool, ShouldUseBase<Ts>()>()...})){}; } +template <typename T, typename V> +using TupleMoveConstructible = typename std::conditional< + std::is_reference<T>::value, std::is_convertible<V, T>, + std::is_constructible<T, V&&>>::type; + } // namespace internal_compressed_tuple // Helper class to perform the Empty Base Class Optimization. @@ -192,9 +205,29 @@ class ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC CompressedTuple using StorageT = internal_compressed_tuple::Storage<ElemT<I>, I>; public: + // There seems to be a bug in MSVC dealing in which using '=default' here will + // cause the compiler to ignore the body of other constructors. The work- + // around is to explicitly implement the default constructor. +#if defined(_MSC_VER) + constexpr CompressedTuple() : CompressedTuple::CompressedTupleImpl() {} +#else constexpr CompressedTuple() = default; - explicit constexpr CompressedTuple(Ts... base) - : CompressedTuple::CompressedTupleImpl(absl::forward<Ts>(base)...) {} +#endif + explicit constexpr CompressedTuple(const Ts&... base) + : CompressedTuple::CompressedTupleImpl(absl::in_place, base...) {} + + template <typename... Vs, + absl::enable_if_t< + absl::conjunction< + // Ensure we are not hiding default copy/move constructors. + absl::negation<std::is_same<void(CompressedTuple), + void(absl::decay_t<Vs>...)>>, + internal_compressed_tuple::TupleMoveConstructible< + Ts, Vs&&>...>::value, + bool> = true> + explicit constexpr CompressedTuple(Vs&&... base) + : CompressedTuple::CompressedTupleImpl(absl::in_place, + absl::forward<Vs>(base)...) {} template <int I> ElemT<I>& get() & { |