Eric Fiselier | 3c7b801 | 2015-03-09 18:02:16 +0000 | [diff] [blame] | 1 | #ifndef SUPPORT_TRACKED_VALUE_H |
| 2 | #define SUPPORT_TRACKED_VALUE_H |
| 3 | |
| 4 | #include <cassert> |
| 5 | |
| 6 | struct TrackedValue { |
| 7 | enum State { CONSTRUCTED, MOVED_FROM, DESTROYED }; |
| 8 | State state; |
| 9 | |
| 10 | TrackedValue() : state(State::CONSTRUCTED) {} |
| 11 | |
| 12 | TrackedValue(TrackedValue const& t) : state(State::CONSTRUCTED) { |
| 13 | assert(t.state != State::MOVED_FROM && "copying a moved-from object"); |
| 14 | assert(t.state != State::DESTROYED && "copying a destroyed object"); |
| 15 | } |
| 16 | |
| 17 | #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES |
| 18 | TrackedValue(TrackedValue&& t) : state(State::CONSTRUCTED) { |
| 19 | assert(t.state != State::MOVED_FROM && "double moving from an object"); |
| 20 | assert(t.state != State::DESTROYED && "moving from a destroyed object"); |
| 21 | t.state = State::MOVED_FROM; |
| 22 | } |
| 23 | #endif |
| 24 | |
| 25 | TrackedValue& operator=(TrackedValue const& t) { |
| 26 | assert(state != State::DESTROYED && "copy assigning into destroyed object"); |
| 27 | assert(t.state != State::MOVED_FROM && "copying a moved-from object"); |
| 28 | assert(t.state != State::DESTROYED && "copying a destroyed object"); |
| 29 | state = t.state; |
| 30 | return *this; |
| 31 | } |
| 32 | |
| 33 | #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES |
| 34 | TrackedValue& operator=(TrackedValue&& t) { |
| 35 | assert(state != State::DESTROYED && "move assigning into destroyed object"); |
| 36 | assert(t.state != State::MOVED_FROM && "double moving from an object"); |
| 37 | assert(t.state != State::DESTROYED && "moving from a destroyed object"); |
| 38 | state = t.state; |
| 39 | t.state = State::MOVED_FROM; |
| 40 | return *this; |
| 41 | } |
| 42 | #endif |
| 43 | |
| 44 | ~TrackedValue() { |
| 45 | assert(state != State::DESTROYED && "double-destroying an object"); |
| 46 | state = State::DESTROYED; |
| 47 | } |
| 48 | }; |
| 49 | |
| 50 | #endif // SUPPORT_TRACKED_VALUE_H |