libstdc++-v3/testsuite/experimental/optional/assignment/4.cc

   1 // { dg-do run { target c++14 } }
   2
   3 // Copyright (C) 2013-2020 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 #include <experimental/optional>
  21 #include <testsuite_hooks.h>
  22
  23 struct exception {};
  24
  25 int counter = 0;
  26
  27 struct mixin_counter
  28 {
  29   mixin_counter() { ++counter; }
  30   mixin_counter(mixin_counter const&) { ++counter; }
  31   ~mixin_counter() { --counter; }
  32 };
  33
  34 struct value_type : private mixin_counter
  35 {
  36   enum state_type
  37   {
  38     zero,
  39     moved_from,
  40     throwing_construction,
  41     throwing_copy,
  42     throwing_copy_assignment,
  43     throwing_move,
  44     throwing_move_assignment,
  45     threw,
  46   };
  47
  48   value_type() = default;
  49
  50   explicit value_type(state_type state_)
  51   : state(state_)
  52   {
  53     throw_if(throwing_construction);
  54   }
  55
  56   value_type(value_type const& other)
  57   : state(other.state)
  58   {
  59     throw_if(throwing_copy);
  60   }
  61
  62   value_type&
  63   operator=(value_type const& other)
  64   {
  65     state = other.state;
  66     throw_if(throwing_copy_assignment);
  67     return *this;
  68   }
  69
  70   value_type(value_type&& other)
  71   : state(other.state)
  72   {
  73     other.state = moved_from;
  74     throw_if(throwing_move);
  75   }
  76
  77   value_type&
  78   operator=(value_type&& other)
  79   {
  80     state = other.state;
  81     other.state = moved_from;
  82     throw_if(throwing_move_assignment);
  83     return *this;
  84   }
  85
  86   void throw_if(state_type match)
  87   {
  88     if(state == match)
  89     {
  90       state = threw;
  91       throw exception {};
  92     }
  93   }
  94
  95   state_type state = zero;
  96 };
  97
  98 int main()
  99 {
 100   using O = std::experimental::optional<value_type>;
 101   using S = value_type::state_type;
 102   auto const make = [](S s = S::zero) { return value_type { s }; };
 103
 104   enum outcome_type { nothrow, caught, bad_catch };
 105
 106   // Check value assignment for engaged optional
 107
 108   {
 109     O o = make();
 110     value_type v = make(S::throwing_copy);
 111     o = v;
 112     VERIFY( o && o->state == S::throwing_copy);
 113   }
 114
 115   {
 116     O o = make();
 117     value_type v = make(S::throwing_move);
 118     o = std::move(v);
 119     VERIFY( o && o->state == S::throwing_move);
 120   }
 121
 122   {
 123     outcome_type outcome {};
 124     O o = make();
 125     value_type v = make(S::throwing_copy_assignment);
 126
 127     try
 128     {
 129       o = v;
 130     }
 131     catch(exception const&)
 132     { outcome = caught; }
 133     catch(...)
 134     { outcome = bad_catch; }
 135
 136     VERIFY( o && o->state == S::threw );
 137   }
 138
 139   {
 140     outcome_type outcome {};
 141     O o = make();
 142     value_type v = make(S::throwing_move_assignment);
 143
 144     try
 145     {
 146       o = std::move(v);
 147     }
 148     catch(exception const&)
 149     { outcome = caught; }
 150     catch(...)
 151     { outcome = bad_catch; }
 152
 153     VERIFY( o && o->state == S::threw );
 154   }
 155
 156   VERIFY( counter == 0 );
 157 }