libstdc++-v3/testsuite/23_containers/vector/modifiers/push_back/strong_guarantee.cc

   1 // Copyright (C) 2015-2019 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do run { target c++11 } }
  19
  20 #include <vector>
  21 #include <testsuite_hooks.h>
  22
  23 template<typename T>
  24 void check(const T& t)
  25 {
  26   for (auto& e : t)
  27     VERIFY( !e.moved_from);
  28 }
  29
  30 // This type is CopyInsertable into std::vector<Bomb> so push_back should
  31 // have the strong exception-safety guarantee.
  32 struct Bomb
  33 {
  34   Bomb() = default;
  35
  36   Bomb(const Bomb& b)
  37   : armed(b.armed)
  38   {
  39     tick();
  40   }
  41
  42   Bomb(Bomb&& b) noexcept(false)
  43   : armed(b.armed)
  44   {
  45     tick();
  46     b.moved_from = true;
  47   }
  48
  49   // std::vector in GCC 4.x tries to use this constructor
  50   template<typename T> Bomb(T&) = delete;
  51
  52   bool moved_from = false;
  53   bool armed = true;
  54
  55 private:
  56   void tick()
  57   {
  58     if (armed && ticks++)
  59       throw 1;
  60   }
  61
  62   static int ticks;
  63 };
  64
  65 int Bomb::ticks = 0;
  66
  67 void test01()
  68 {
  69   std::vector<Bomb> v(2); // fill with armed bombs
  70   v.resize(v.capacity()); // ensure no unused capacity
  71   check(v);               // sanity check
  72
  73   try {
  74     Bomb defused;
  75     // don't want any copies/moves of this object to throw
  76     defused.armed = false;
  77     // insert new element, existing elements will be relocated and explode
  78     v.push_back(defused);
  79     VERIFY(false); // should be unreachable
  80   } catch (int) {
  81     check(v);  // make sure no elements have been moved from
  82   }
  83 }
  84
  85 int main()
  86 {
  87   test01();
  88 }