Method startThreads

src/ThreadPool.cpp:47–93

}

void ThreadPool::startThreads(size_t num) {
    const scoped_lock lock{mThreadsMutex};
    if (mShuttingDown) {
        return;
    }

    mNumThreads += num;
    for (size_t i = mThreads.size(); i < mNumThreads; ++i) {
        mThreads.emplace_back([this] {
            const auto id = this_thread::get_id();
            // tlog::debug("Spawning thread pool thread {}", id);

            while (true) {
                QueuedTask task = {};
                while (!mTaskQueueSemaphore.wait()) {}

                {
                    const scoped_lock taskQueueLock{mTaskQueueMutex};
                    TEV_ASSERT(!mTaskQueue.empty(), "Task queue was empty after semaphore wait.");

                    task = mTaskQueue.pop();
                }

                task.fun();
                mNumTasksInSystem--;

                if (task.stopToken) {
                    break;
                }
            }

            const scoped_lock threadsLock{mThreadsMutex};

            // Remove oneself from the thread pool. NOTE: at this point, the lock is still held, so modifying mThreads is safe.
            // tlog::debug("Shutting down thread pool thread {}", id);

            const auto it = ranges::find(mThreads, id, [](const auto& t) { return t.get_id(); });
            TEV_ASSERT(it != mThreads.end(), "Thread not found in thread pool.");

            // Thread must be detached, otherwise running our own constructor while still running would result in errors.
            thread self = std::move(*it);
            mThreads.erase(it);

            self.detach();
        });
    }
}

void ThreadPool::shutdownThreads(size_t num) {
    mNumThreads -= num;