mclow.lists created this revision.
Implement the `optional` and `any` part of this issue.
This changes the return type of these functions.
https://reviews.llvm.org/D31956
Files:
include/any
include/optional
test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
Index: test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
===================================================================
--- test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
+++ test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
@@ -10,7 +10,7 @@
// UNSUPPORTED: c++98, c++03, c++11, c++14
// <optional>
-// template <class... Args> void optional<T>::emplace(Args&&... args);
+// template <class... Args> T& optional<T>::emplace(Args&&... args);
#include <optional>
#include <type_traits>
@@ -51,27 +51,35 @@
using Opt = std::optional<T>;
{
Opt opt;
- opt.emplace();
+ auto & v = opt.emplace();
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(static_cast<bool>(opt) == true);
assert(*opt == T(0));
+ assert(&v == &*opt);
}
{
Opt opt;
- opt.emplace(1);
+ auto & v = opt.emplace(1);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(static_cast<bool>(opt) == true);
assert(*opt == T(1));
+ assert(&v == &*opt);
}
{
Opt opt(2);
- opt.emplace();
+ auto & v = opt.emplace();
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(static_cast<bool>(opt) == true);
assert(*opt == T(0));
+ assert(&v == &*opt);
}
{
Opt opt(2);
- opt.emplace(1);
+ auto & v = opt.emplace(1);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(static_cast<bool>(opt) == true);
assert(*opt == T(1));
+ assert(&v == &*opt);
}
}
@@ -83,20 +91,26 @@
using Opt = std::optional<T>;
{
Opt opt;
- opt.emplace(101, 41);
+ auto &v = opt.emplace(101, 41);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(static_cast<bool>(opt) == true);
+ assert( v == T(101, 41));
assert(*opt == T(101, 41));
}
{
Opt opt;
- opt.emplace({1, 2, 3, 4});
+ auto &v = opt.emplace({1, 2, 3, 4});
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(static_cast<bool>(opt) == true);
- assert(*opt == T(4)); // T sets its value to the size of the init list
+ assert( v == T(4)); // T sets its value to the size of the init list
+ assert(*opt == T(4));
}
{
Opt opt;
- opt.emplace({1, 2, 3, 4, 5}, 6);
+ auto &v = opt.emplace({1, 2, 3, 4, 5}, 6);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(static_cast<bool>(opt) == true);
+ assert( v == T(5)); // T sets its value to the size of the init list
assert(*opt == T(5)); // T sets its value to the size of the init list
}
}
@@ -109,7 +123,8 @@
assert(T::alive == 0);
{
T::reset_constructors();
- opt.emplace();
+ auto &v = opt.emplace();
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(T::alive == 1);
assert(T::constructed == 1);
assert(T::default_constructed == 1);
@@ -116,10 +131,12 @@
assert(T::destroyed == 0);
assert(static_cast<bool>(opt) == true);
assert(*opt == T());
+ assert(&v == &*opt);
}
{
T::reset_constructors();
- opt.emplace();
+ auto &v = opt.emplace();
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(T::alive == 1);
assert(T::constructed == 1);
assert(T::default_constructed == 1);
@@ -126,10 +143,12 @@
assert(T::destroyed == 1);
assert(static_cast<bool>(opt) == true);
assert(*opt == T());
+ assert(&v == &*opt);
}
{
T::reset_constructors();
- opt.emplace(101);
+ auto &v = opt.emplace(101);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(T::alive == 1);
assert(T::constructed == 1);
assert(T::value_constructed == 1);
@@ -136,10 +155,12 @@
assert(T::destroyed == 1);
assert(static_cast<bool>(opt) == true);
assert(*opt == T(101));
+ assert(&v == &*opt);
}
{
T::reset_constructors();
- opt.emplace(-10, 99);
+ auto &v = opt.emplace(-10, 99);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(T::alive == 1);
assert(T::constructed == 1);
assert(T::value_constructed == 1);
@@ -146,10 +167,12 @@
assert(T::destroyed == 1);
assert(static_cast<bool>(opt) == true);
assert(*opt == T(-10, 99));
+ assert(&v == &*opt);
}
{
T::reset_constructors();
- opt.emplace(-10, 99);
+ auto &v = opt.emplace(-10, 99);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(T::alive == 1);
assert(T::constructed == 1);
assert(T::value_constructed == 1);
@@ -156,10 +179,12 @@
assert(T::destroyed == 1);
assert(static_cast<bool>(opt) == true);
assert(*opt == T(-10, 99));
+ assert(&v == &*opt);
}
{
T::reset_constructors();
- opt.emplace({-10, 99, 42, 1});
+ auto &v = opt.emplace({-10, 99, 42, 1});
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(T::alive == 1);
assert(T::constructed == 1);
assert(T::value_constructed == 1);
@@ -166,10 +191,12 @@
assert(T::destroyed == 1);
assert(static_cast<bool>(opt) == true);
assert(*opt == T(4)); // size of the initializer list
+ assert(&v == &*opt);
}
{
T::reset_constructors();
- opt.emplace({-10, 99, 42, 1}, 42);
+ auto &v = opt.emplace({-10, 99, 42, 1}, 42);
+ static_assert( std::is_same_v<T&, decltype(v)>, "" );
assert(T::alive == 1);
assert(T::constructed == 1);
assert(T::value_constructed == 1);
@@ -176,6 +203,7 @@
assert(T::destroyed == 1);
assert(static_cast<bool>(opt) == true);
assert(*opt == T(4)); // size of the initializer list
+ assert(&v == &*opt);
}
}
@@ -210,8 +238,10 @@
}
{
optional<const int> opt;
- opt.emplace(42);
+ auto &v = opt.emplace(42);
+ static_assert( std::is_same_v<const int&, decltype(v)>, "" );
assert(*opt == 42);
+ assert( v == 42);
opt.emplace();
assert(*opt == 0);
}
Index: test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
===================================================================
--- test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
+++ test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
@@ -11,9 +11,9 @@
// <any>
-// template <class T, class ...Args> emplace(Args&&...);
+// template <class T, class ...Args> T& emplace(Args&&...);
// template <class T, class U, class ...Args>
-// void emplace(initializer_list<U>, Args&&...);
+// T& emplace(initializer_list<U>, Args&&...);
#include <any>
#include <cassert>
@@ -42,7 +42,9 @@
any a(std::in_place_type<Tracked>);
assert(Tracked::count == 1);
- a.emplace<Type>();
+ auto &v = a.emplace<Type>();
+ static_assert( std::is_same_v<Type&, decltype(v)>, "" );
+ assert(&v == std::any_cast<Type>(&a));
assert(Tracked::count == 0);
assert(Type::count == 1);
@@ -56,7 +58,9 @@
any a(std::in_place_type<Tracked>);
assert(Tracked::count == 1);
- a.emplace<Type>(101);
+ auto &v = a.emplace<Type>(101);
+ static_assert( std::is_same_v<Type&, decltype(v)>, "" );
+ assert(&v == std::any_cast<Type>(&a));
assert(Tracked::count == 0);
assert(Type::count == 1);
@@ -70,7 +74,9 @@
any a(std::in_place_type<Tracked>);
assert(Tracked::count == 1);
- a.emplace<Type>(-1, 42, -1);
+ auto &v = a.emplace<Type>(-1, 42, -1);
+ static_assert( std::is_same_v<Type&, decltype(v)>, "" );
+ assert(&v == std::any_cast<Type>(&a));
assert(Tracked::count == 0);
assert(Type::count == 1);
@@ -89,7 +95,10 @@
{
any a(std::in_place_type<Tracked>);
assert(Tracked::count == 1);
- a.emplace<Type>();
+ auto &v = a.emplace<Type>();
+ static_assert( std::is_same_v<Type&, decltype(v)>, "" );
+ assert(&v == std::any_cast<Type>(&a));
+
assert(Tracked::count == 0);
assertArgsMatch<Type>(a);
}
@@ -96,7 +105,10 @@
{
any a(std::in_place_type<Tracked>);
assert(Tracked::count == 1);
- a.emplace<Type>(-1, 42, -1);
+ auto &v = a.emplace<Type>(-1, 42, -1);
+ static_assert( std::is_same_v<Type&, decltype(v)>, "" );
+ assert(&v == std::any_cast<Type>(&a));
+
assert(Tracked::count == 0);
assertArgsMatch<Type, int, int, int>(a);
}
@@ -104,7 +116,10 @@
{
any a(std::in_place_type<Tracked>);
assert(Tracked::count == 1);
- a.emplace<Type>({-1, 42, -1});
+ auto &v = a.emplace<Type>({-1, 42, -1});
+ static_assert( std::is_same_v<Type&, decltype(v)>, "" );
+ assert(&v == std::any_cast<Type>(&a));
+
assert(Tracked::count == 0);
assertArgsMatch<Type, std::initializer_list<int>>(a);
}
@@ -112,7 +127,10 @@
int x = 42;
any a(std::in_place_type<Tracked>);
assert(Tracked::count == 1);
- a.emplace<Type>({-1, 42, -1}, x);
+ auto &v = a.emplace<Type>({-1, 42, -1}, x);
+ static_assert( std::is_same_v<Type&, decltype(v)>, "" );
+ assert(&v == std::any_cast<Type>(&a));
+
assert(Tracked::count == 0);
assertArgsMatch<Type, std::initializer_list<int>, int&>(a);
}
Index: include/optional
===================================================================
--- include/optional
+++ include/optional
@@ -108,9 +108,9 @@
template <class U = T> optional &operator=(U &&);
template <class U> optional &operator=(const optional<U> &);
template <class U> optional &operator=(optional<U> &&);
- template <class... Args> void emplace(Args &&...);
+ template <class... Args> T& emplace(Args &&...);
template <class U, class... Args>
- void emplace(initializer_list<U>, Args &&...);
+ T& emplace(initializer_list<U>, Args &&...);
// 20.6.3.4, swap
void swap(optional &) noexcept(see below );
@@ -729,11 +729,12 @@
>
>
_LIBCPP_INLINE_VISIBILITY
- void
+ _Tp &
emplace(_Args&&... __args)
{
reset();
this->__construct(_VSTD::forward<_Args>(__args)...);
+ return this->__get();
}
template <class _Up, class... _Args,
@@ -743,11 +744,12 @@
>
>
_LIBCPP_INLINE_VISIBILITY
- void
+ _Tp &
emplace(initializer_list<_Up> __il, _Args&&... __args)
{
reset();
this->__construct(__il, _VSTD::forward<_Args>(__args)...);
+ return this->__get();
}
_LIBCPP_INLINE_VISIBILITY
Index: include/any
===================================================================
--- include/any
+++ include/any
@@ -45,6 +45,10 @@
any& operator=(ValueType&& rhs);
// 6.3.3 any modifiers
+ template <class ValueType, class... Args>
+ decay_t<ValueType>& emplace(Args&&... args);
+ template <class ValueType, class U, class... Args>
+ decay_t<ValueType>& emplace(initializer_list<U>, Args&&...);
void reset() noexcept;
void swap(any& rhs) noexcept;
@@ -73,8 +77,6 @@
template<class ValueType>
ValueType* any_cast(any* operand) noexcept;
-} // namespace fundamentals_v1
-} // namespace experimental
} // namespace std
*/
@@ -258,7 +260,7 @@
is_copy_constructible<_Tp>::value>
>
_LIBCPP_INLINE_VISIBILITY
- void emplace(_Args&&... args);
+ _Tp& emplace(_Args&&... args);
template <class _ValueType, class _Up, class ..._Args,
class _Tp = decay_t<_ValueType>,
@@ -267,7 +269,7 @@
is_copy_constructible<_Tp>::value>
>
_LIBCPP_INLINE_VISIBILITY
- void emplace(initializer_list<_Up>, _Args&&...);
+ _Tp& emplace(initializer_list<_Up>, _Args&&...);
// 6.3.3 any modifiers
_LIBCPP_INLINE_VISIBILITY
@@ -364,9 +366,10 @@
template <class ..._Args>
_LIBCPP_INLINE_VISIBILITY
- static void __create(any & __dest, _Args&&... __args) {
- ::new (static_cast<void*>(&__dest.__s.__buf)) _Tp(_VSTD::forward<_Args>(__args)...);
+ static _Tp& __create(any & __dest, _Args&&... __args) {
+ _Tp* __ret = ::new (static_cast<void*>(&__dest.__s.__buf)) _Tp(_VSTD::forward<_Args>(__args)...);
__dest.__h = &_SmallHandler::__handle;
+ return *__ret;
}
private:
@@ -439,14 +442,15 @@
template <class ..._Args>
_LIBCPP_INLINE_VISIBILITY
- static void __create(any & __dest, _Args&&... __args) {
+ static _Tp& __create(any & __dest, _Args&&... __args) {
typedef allocator<_Tp> _Alloc;
typedef __allocator_destructor<_Alloc> _Dp;
_Alloc __a;
unique_ptr<_Tp, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
- ::new ((void*)__hold.get()) _Tp(_VSTD::forward<_Args>(__args)...);
+ _Tp* __ret = ::new ((void*)__hold.get()) _Tp(_VSTD::forward<_Args>(__args)...);
__dest.__s.__ptr = __hold.release();
__dest.__h = &_LargeHandler::__handle;
+ return *__ret;
}
private:
@@ -519,16 +523,16 @@
template <class _ValueType, class ..._Args, class _Tp, class>
inline _LIBCPP_INLINE_VISIBILITY
-void any::emplace(_Args&&... __args) {
+_Tp& any::emplace(_Args&&... __args) {
reset();
- __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_Args>(__args)...);
+ return __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_Args>(__args)...);
}
template <class _ValueType, class _Up, class ..._Args, class _Tp, class>
inline _LIBCPP_INLINE_VISIBILITY
-void any::emplace(initializer_list<_Up> __il, _Args&&... __args) {
+_Tp& any::emplace(initializer_list<_Up> __il, _Args&&... __args) {
reset();
- __any_imp::_Handler<_Tp>::__create(*this, __il, _VSTD::forward<_Args>(__args)...);
+ return __any_imp::_Handler<_Tp>::__create(*this, __il, _VSTD::forward<_Args>(__args)...);
}
inline _LIBCPP_INLINE_VISIBILITY
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