// return shared pointer to value - which if set to nullptr,
// indicates container was empty at the time of the call.
inline std::shared_ptr<T> try_pop() {
std::lock_guard<std::mutex> lock(mut);
if (data_queue.empty()) {
return std::shared_ptr<T>();
} else {
auto res = std::move(front_or_top(data_queue));
data_queue.pop();
return std::move(res);
}
}
// return value in specified reference indicating whether
// value successfully returned or not
inline bool try_pop(std::shared_ptr<T>& rValue) {
std::lock_guard<std::mutex> lock(mut);
if (data_queue.empty()) {
rValue.reset();
return false;
} else {
rValue = std::move(front_or_top(data_queue));
data_queue.pop();
return true;
}
}
// wait for non empty lambda condition before returning shared pointer to value
inline std::shared_ptr<T> wait_and_pop() {
std::unique_lock<std::mutex> lock(mut);
data_cond.wait(lock, [this]{
return !data_queue.empty() || shutdownFlag;
});
if (!shutdownFlag) {
auto res = std::move(front_or_top(data_queue));
data_queue.pop();
return std::move(res);
}
return nullptr;
}
