libstdc++-v3/testsuite/20_util/optional/assignment/4.cc

   1 // { dg-options "-std=gnu++17" }
   2 // { dg-do run }
   3
   4 // Copyright (C) 2013-2016 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a moved_to of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 #include <optional>
  22 #include <testsuite_hooks.h>
  23
  24 struct exception {};
  25
  26 int counter = 0;
  27
  28 struct mixin_counter
  29 {
  30   mixin_counter() { ++counter; }
  31   mixin_counter(mixin_counter const&) { ++counter; }
  32   ~mixin_counter() { --counter; }
  33 };
  34
  35 struct value_type : private mixin_counter
  36 {
  37   enum state_type
  38   {
  39     zero,
  40     moved_from,
  41     throwing_construction,
  42     throwing_copy,
  43     throwing_copy_assignment,
  44     throwing_move,
  45     throwing_move_assignment,
  46     threw,
  47   };
  48
  49   value_type() = default;
  50
  51   explicit value_type(state_type state_)
  52   : state(state_)
  53   {
  54     throw_if(throwing_construction);
  55   }
  56
  57   value_type(value_type const& other)
  58   : state(other.state)
  59   {
  60     throw_if(throwing_copy);
  61   }
  62
  63   value_type&
  64   operator=(value_type const& other)
  65   {
  66     state = other.state;
  67     throw_if(throwing_copy_assignment);
  68     return *this;
  69   }
  70
  71   value_type(value_type&& other)
  72   : state(other.state)
  73   {
  74     other.state = moved_from;
  75     throw_if(throwing_move);
  76   }
  77
  78   value_type&
  79   operator=(value_type&& other)
  80   {
  81     state = other.state;
  82     other.state = moved_from;
  83     throw_if(throwing_move_assignment);
  84     return *this;
  85   }
  86
  87   void throw_if(state_type match)
  88   {
  89     if(state == match)
  90     {
  91       state = threw;
  92       throw exception {};
  93     }
  94   }
  95
  96   state_type state = zero;
  97 };
  98
  99 int main()
 100 {
 101   using O = std::optional<value_type>;
 102   using S = value_type::state_type;
 103   auto const make = [](S s = S::zero) { return value_type { s }; };
 104
 105   enum outcome_type { nothrow, caught, bad_catch };
 106
 107   // Check value assignment for engaged optional
 108
 109   {
 110     O o = make();
 111     value_type v = make(S::throwing_copy);
 112     o = v;
 113     VERIFY( o && o->state == S::throwing_copy);
 114   }
 115
 116   {
 117     O o = make();
 118     value_type v = make(S::throwing_move);
 119     o = std::move(v);
 120     VERIFY( o && o->state == S::throwing_move);
 121   }
 122
 123   {
 124     outcome_type outcome {};
 125     O o = make();
 126     value_type v = make(S::throwing_copy_assignment);
 127
 128     try
 129     {
 130       o = v;
 131     }
 132     catch(exception const&)
 133     { outcome = caught; }
 134     catch(...)
 135     { outcome = bad_catch; }
 136
 137     VERIFY( o && o->state == S::threw );
 138   }
 139
 140   {
 141     outcome_type outcome {};
 142     O o = make();
 143     value_type v = make(S::throwing_move_assignment);
 144
 145     try
 146     {
 147       o = std::move(v);
 148     }
 149     catch(exception const&)
 150     { outcome = caught; }
 151     catch(...)
 152     { outcome = bad_catch; }
 153
 154     VERIFY( o && o->state == S::threw );
 155   }
 156
 157   VERIFY( counter == 0 );
 158 }