ceph/src/boost/libs/hana/test/_include/support/tracked.hpp

   1 // Copyright Louis Dionne 2013-2016
   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 #ifndef TEST_SUPPORT_TRACKED_HPP
   6 #define TEST_SUPPORT_TRACKED_HPP
   7
   8 // Define this if you want Tracked objects to print information to stderr.
   9 // #define TRACKED_PRINT_STUFF
  10
  11 #include <boost/hana/assert.hpp>
  12
  13 #ifdef TRACKED_PRINT_STUFF
  14 #   include <iostream>
  15 #endif
  16
  17 #include <iosfwd>
  18
  19
  20 struct Tracked {
  21     enum class State { CONSTRUCTED, MOVED_FROM, DESTROYED };
  22
  23     int value;
  24     State state;
  25
  26     explicit Tracked(int k) : value{k}, state{State::CONSTRUCTED} {
  27 #ifdef TRACKED_PRINT_STUFF
  28         std::cerr << "constructing " << *this << '\n';
  29 #endif
  30     }
  31
  32     Tracked(Tracked const& t) : value{t.value}, state{State::CONSTRUCTED} {
  33         BOOST_HANA_RUNTIME_CHECK(t.state != State::MOVED_FROM &&
  34             "copying a moved-from object");
  35
  36         BOOST_HANA_RUNTIME_CHECK(t.state != State::DESTROYED &&
  37             "copying a destroyed object");
  38
  39 #ifdef TRACKED_PRINT_STUFF
  40         std::cerr << "copying " << *this << '\n';
  41 #endif
  42     }
  43
  44     Tracked(Tracked&& t) : value{t.value}, state{State::CONSTRUCTED} {
  45         BOOST_HANA_RUNTIME_CHECK(t.state != State::MOVED_FROM &&
  46             "double moving from an object");
  47
  48         BOOST_HANA_RUNTIME_CHECK(t.state != State::DESTROYED &&
  49             "moving from a destroyed object");
  50
  51 #ifdef TRACKED_PRINT_STUFF
  52         std::cerr << "moving " << t << '\n';
  53 #endif
  54         t.state = State::MOVED_FROM;
  55     }
  56
  57     Tracked& operator=(Tracked const& other) {
  58         BOOST_HANA_RUNTIME_CHECK(this->state != State::DESTROYED &&
  59             "assigning to a destroyed object");
  60
  61         BOOST_HANA_RUNTIME_CHECK(other.state != State::MOVED_FROM &&
  62             "assigning a moved-from object");
  63
  64         BOOST_HANA_RUNTIME_CHECK(other.state != State::DESTROYED &&
  65             "assigning a destroyed object");
  66
  67 #ifdef TRACKED_PRINT_STUFF
  68         std::cerr << "assigning " << other << " to " << *this << '\n';
  69 #endif
  70         this->value = other.value;
  71         return *this;
  72     }
  73
  74     Tracked& operator=(Tracked&& other) {
  75         BOOST_HANA_RUNTIME_CHECK(this->state != State::DESTROYED &&
  76             "assigning to a destroyed object");
  77
  78         BOOST_HANA_RUNTIME_CHECK(other.state != State::MOVED_FROM &&
  79             "double-moving from an object");
  80
  81         BOOST_HANA_RUNTIME_CHECK(other.state != State::DESTROYED &&
  82             "assigning a destroyed object");
  83
  84 #ifdef TRACKED_PRINT_STUFF
  85         std::cerr << "assigning " << other << " to " << *this << '\n';
  86 #endif
  87         this->value = other.value;
  88         other.state = State::MOVED_FROM;
  89         return *this;
  90     }
  91
  92     ~Tracked() {
  93         BOOST_HANA_RUNTIME_CHECK(state != State::DESTROYED &&
  94             "double-destroying an object");
  95
  96 #ifdef TRACKED_PRINT_STUFF
  97         std::cerr << "destructing " << *this << '\n';
  98 #endif
  99         state = State::DESTROYED;
 100     }
 101
 102     template <typename CharT, typename Traits>
 103     friend std::basic_ostream<CharT, Traits>&
 104     operator<<(std::basic_ostream<CharT, Traits>& os, Tracked const& t) {
 105         os << "Tracked{" << t.value << "}";
 106         switch (t.state) {
 107         case State::CONSTRUCTED:
 108             os << "[ok]"; break;
 109         case State::MOVED_FROM:
 110             os << "[moved from]"; break;
 111         case State::DESTROYED:
 112             os << "[destroyed]"; break;
 113         default:
 114             BOOST_HANA_RUNTIME_CHECK(false && "never reached");
 115         }
 116         return os;
 117     }
 118 };
 119
 120 #endif // !TEST_SUPPORT_TRACKED_HPP