: m_exit(false)

, m_jobs(0)

{

assert(!s_instance);

s_instance = this;

assert(workers >= 1);

workers--;

m_workers.reserve(workers);

for (int i = 0; i < workers; i++)

{

m_workers.emplace_back([this]{ Worker(); });

}

{

std::unique_lock<std::mutex> lock(s_instance->m_queueLock);

s_instance->m_queue.emplace(f);

const auto size = s_instance->m_queue.size();

lock.unlock();

if (size > 1)

{

s_instance->m_cvWork.notify_one();

}

{

std::unique_lock<std::mutex> lock(s_instance->m_queueLock);

s_instance->m_queue.emplace(std::move(f));

const auto size = s_instance->m_queue.size();

lock.unlock();

if (size > 1)

{

s_instance->m_cvWork.notify_one();

}

{

std::unique_lock<std::mutex> lock(s_instance->m_queueLock);

while (!s_instance->m_queue.empty())

{

auto f = s_instance->m_queue.front();

s_instance->m_queue.pop();

lock.unlock();

f();

lock.lock();

}

s_instance->m_cvJobs.wait(lock, []{ return s_instance->m_jobs == 0; });

{

for (;;)

{

std::unique_lock<std::mutex> lock(m_queueLock);

m_cvWork.wait(lock, [this]{ return !m_queue.empty() || m_exit; });

if (m_exit) return;

auto f = m_queue.front();

m_queue.pop();

m_jobs++;

lock.unlock();

f();

lock.lock();

m_jobs--;

bool notify = m_jobs == 0 && m_queue.empty();

lock.unlock();

if (notify)

{

m_cvJobs.notify_all();

}

}