| 48 | } |
| 49 | |
| 50 | void unlock() |
| 51 | { |
| 52 | // NOTE: We need to grab the promise 'date->promises.front()' but |
| 53 | // set it outside of the critical section because setting it might |
| 54 | // trigger callbacks that try to reacquire the lock. |
| 55 | Option<Promise<Nothing>> waiter; |
| 56 | |
| 57 | synchronized (data->lock) { |
| 58 | if (!data->waiters.empty()) { |
| 59 | // TODO(benh): Skip a future that has been discarded? |
| 60 | waiter = std::move(data->waiters.front()); |
| 61 | data->waiters.pop(); |
| 62 | } else { |
| 63 | data->locked = false; |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | if (waiter.isSome()) { |
| 68 | waiter->set(Nothing()); |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | private: |
| 73 | struct Data |