On Mon, 31 Oct 2022 at 20:33, Patrick Palka via Libstdc++ <libstd...@gcc.gnu.org> wrote: > > Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
OK, thanks. We should update https://gcc.gnu.org/gcc-13/changes.html#libstdcxx again soon. > > libstdc++-v3/ChangeLog: > > * include/std/ranges (as_rvalue_view): Define. > (enable_borrowed_range<as_rvalue_view>): Define. > (views::__detail::__can_as_rvalue_view): Define. > (views::_AsRvalue, views::as_rvalue): Define. > * testsuite/std/ranges/adaptors/as_rvalue/1.cc: New test. > --- > libstdc++-v3/include/std/ranges | 88 +++++++++++++++++++ > .../std/ranges/adaptors/as_rvalue/1.cc | 47 ++++++++++ > 2 files changed, 135 insertions(+) > create mode 100644 libstdc++-v3/testsuite/std/ranges/adaptors/as_rvalue/1.cc > > diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges > index 959886a1a55..239b3b61d30 100644 > --- a/libstdc++-v3/include/std/ranges > +++ b/libstdc++-v3/include/std/ranges > @@ -8486,6 +8486,94 @@ namespace views::__adaptor > > inline constexpr _CartesianProduct cartesian_product; > } > + > + template<input_range _Vp> > + requires view<_Vp> > + class as_rvalue_view : public view_interface<as_rvalue_view<_Vp>> > + { > + _Vp _M_base = _Vp(); > + > + public: > + as_rvalue_view() requires default_initializable<_Vp> = default; > + > + constexpr explicit > + as_rvalue_view(_Vp __base) > + : _M_base(std::move(__base)) > + { } > + > + constexpr _Vp > + base() const& requires copy_constructible<_Vp> { return _M_base; } > + > + constexpr _Vp > + base() && { return std::move(_M_base); } > + > + constexpr auto > + begin() requires (!__detail::__simple_view<_Vp>) > + { return move_iterator(ranges::begin(_M_base)); } > + > + constexpr auto > + begin() const requires range<const _Vp> > + { return move_iterator(ranges::begin(_M_base)); } > + > + constexpr auto > + end() requires (!__detail::__simple_view<_Vp>) > + { > + if constexpr (common_range<_Vp>) > + return move_iterator(ranges::end(_M_base)); > + else > + return move_sentinel(ranges::end(_M_base)); > + } > + > + constexpr auto > + end() const requires range<const _Vp> > + { > + if constexpr (common_range<const _Vp>) > + return move_iterator(ranges::end(_M_base)); > + else > + return move_sentinel(ranges::end(_M_base)); > + } > + > + constexpr auto > + size() requires sized_range<_Vp> > + { return ranges::size(_M_base); } > + > + constexpr auto > + size() const requires sized_range<const _Vp> > + { return ranges::size(_M_base); } > + }; > + > + template<typename _Range> > + as_rvalue_view(_Range&&) -> as_rvalue_view<views::all_t<_Range>>; > + > + template<typename _Tp> > + inline constexpr bool enable_borrowed_range<as_rvalue_view<_Tp>> > + = enable_borrowed_range<_Tp>; > + > + namespace views > + { > + namespace __detail > + { > + template<typename _Tp> > + concept __can_as_rvalue_view = requires { > as_rvalue_view(std::declval<_Tp>()); }; > + } > + > + struct _AsRvalue : __adaptor::_RangeAdaptorClosure > + { > + template<viewable_range _Range> > + requires __detail::__can_as_rvalue_view<_Range> > + constexpr auto > + operator() [[nodiscard]] (_Range&& __r) const > + { > + if constexpr (same_as<range_rvalue_reference_t<_Range>, > + range_reference_t<_Range>>) > + return views::all(std::forward<_Range>(__r)); > + else > + return as_rvalue_view(std::forward<_Range>(__r)); > + } > + }; > + > + inline constexpr _AsRvalue as_rvalue; > + } > #endif // C++23 > } // namespace ranges > > diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/as_rvalue/1.cc > b/libstdc++-v3/testsuite/std/ranges/adaptors/as_rvalue/1.cc > new file mode 100644 > index 00000000000..8ca4f50e9d2 > --- /dev/null > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/as_rvalue/1.cc > @@ -0,0 +1,47 @@ > +// { dg-options "-std=gnu++23" } > +// { dg-do run { target c++23 } } > + > +#include <ranges> > +#include <algorithm> > +#include <memory> > +#include <testsuite_hooks.h> > +#include <testsuite_iterators.h> > + > +namespace ranges = std::ranges; > +namespace views = std::views; > + > +constexpr bool > +test01() > +{ > + > + std::unique_ptr<int> a[3] = { std::make_unique<int>(1), > + std::make_unique<int>(2), > + std::make_unique<int>(3) }; > + std::unique_ptr<int> b[3]; > + auto v = a | views::as_rvalue; > + ranges::copy(v, b); > + VERIFY( ranges::all_of(a, [](auto& p) { return p.get() == nullptr; }) ); > + VERIFY( ranges::equal(b | views::transform([](auto& p) { return *p; }), > (int[]){1, 2, 3}) ); > + > + return true; > +} > + > +void > +test02() > +{ > + std::unique_ptr<int> x = std::make_unique<int>(42); > + std::unique_ptr<int> y; > + __gnu_test::test_input_range rx(&x, &x+1); > + auto v = rx | views::as_rvalue; > + static_assert(!ranges::common_range<decltype(v)>); > + ranges::copy(v, &y); > + VERIFY( x.get() == nullptr ); > + VERIFY( *y == 42 ); > +} > + > +int > +main() > +{ > + static_assert(test01()); > + test02(); > +} > -- > 2.38.1.381.gc03801e19c >