ceph/src/boost/libs/hana/test/pair/cnstr.move.cpp

   1 // Copyright Louis Dionne 2013-2017
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   4
   5 #include <boost/hana/assert.hpp>
   6 #include <boost/hana/first.hpp>
   7 #include <boost/hana/pair.hpp>
   8 #include <boost/hana/second.hpp>
   9
  10 #include <type_traits>
  11 #include <utility>
  12 namespace hana = boost::hana;
  13
  14
  15 struct MoveOnly {
  16     int data_;
  17     MoveOnly(MoveOnly const&) = delete;
  18     MoveOnly& operator=(MoveOnly const&) = delete;
  19     MoveOnly(int data) : data_(data) { }
  20     MoveOnly(MoveOnly&& x) : data_(x.data_) { x.data_ = 0; }
  21
  22     MoveOnly& operator=(MoveOnly&& x)
  23     { data_ = x.data_; x.data_ = 0; return *this; }
  24
  25     bool operator==(const MoveOnly& x) const { return data_ == x.data_; }
  26 };
  27
  28 struct MoveOnlyDerived : MoveOnly {
  29     MoveOnlyDerived(MoveOnlyDerived&&) = default;
  30     MoveOnlyDerived(int data = 1) : MoveOnly(data) { }
  31 };
  32
  33 template <typename Target>
  34 struct implicit_to {
  35     constexpr operator Target() const { return Target{}; }
  36 };
  37
  38 struct NoMove {
  39     NoMove() = default;
  40     NoMove(NoMove const&) = delete;
  41     NoMove(NoMove&&) = delete;
  42 };
  43
  44 // Note: It is also useful to check with a non-empty class, because that
  45 //       triggers different instantiations due to EBO.
  46 struct NoMove_nonempty {
  47     NoMove_nonempty() = default;
  48     NoMove_nonempty(NoMove_nonempty const&) = delete;
  49     NoMove_nonempty(NoMove_nonempty&&) = delete;
  50     int i;
  51 };
  52
  53 int main() {
  54     {
  55         hana::pair<MoveOnly, short> p1(MoveOnly{3}, 4);
  56         hana::pair<MoveOnly, short> p2(std::move(p1));
  57         BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3});
  58         BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
  59     }
  60
  61     // Make sure it works across pair types
  62     {
  63         hana::pair<MoveOnlyDerived, short> p1(MoveOnlyDerived{3}, 4);
  64         hana::pair<MoveOnly, long> p2 = std::move(p1);
  65         BOOST_HANA_RUNTIME_CHECK(hana::first(p2) == MoveOnly{3});
  66         BOOST_HANA_RUNTIME_CHECK(hana::second(p2) == 4);
  67     }
  68     {
  69         struct target1 {
  70             target1() = default;
  71             target1(target1 const&) = delete;
  72             target1(target1&&) = default;
  73         };
  74
  75         struct target2 {
  76             target2() = default;
  77             target2(target2 const&) = delete;
  78             target2(target2&&) = default;
  79         };
  80         using Target = hana::pair<target1, target2>;
  81         Target p1(hana::make_pair(target1{}, target2{})); (void)p1;
  82         Target p2(hana::make_pair(implicit_to<target1>{}, target2{})); (void)p2;
  83         Target p3(hana::make_pair(target1{}, implicit_to<target2>{})); (void)p3;
  84         Target p4(hana::make_pair(implicit_to<target1>{}, implicit_to<target2>{})); (void)p4;
  85     }
  86
  87     // Make sure we don't define the move constructor when it shouldn't be defined.
  88     {
  89         using Pair1 = hana::pair<NoMove, NoMove>;
  90         Pair1 pair1; (void)pair1;
  91         static_assert(!std::is_move_constructible<Pair1>::value, "");
  92
  93         using Pair2 = hana::pair<NoMove_nonempty, NoMove_nonempty>;
  94         Pair2 pair2; (void)pair2;
  95         static_assert(!std::is_move_constructible<Pair2>::value, "");
  96     }
  97 }