thehub/libs/utils/WorkerThreads.cpp

/*
 * This file is part of the Flowee project
 * Copyright (C) 2016-2025 Tom Zander <tom@flowee.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "WorkerThreads.h"
#include "Logger.h"

WorkerThreads::Work::Work(const std::shared_ptr<boost::asio::io_context> &context)
    : work(boost::asio::make_work_guard(*context))
{
}


// ------------------------------------

WorkerThreads::WorkerThreads(int threadCount)
{
    startThreads(threadCount);
}

void WorkerThreads::startThreads(int threadCount)
{
    if (threadCount < 1)
        threadCount = boost::thread::hardware_concurrency();
    threadCount = std::max(threadCount, 2);
    m_context = std::make_shared<boost::asio::io_context>();
    m_work.reset(new Work(m_context));
    for (int i = threadCount; i > 0; --i) {
        auto context(m_context);
        m_threads.create_thread([context] {
#if defined(PR_SET_NAME)
            // Only the first 15 characters are used (16 - NUL terminator)
            ::prctl(PR_SET_NAME, "Worker-threads", 0, 0, 0);
#endif
            while(true) {
                try {
                    context->run();
                    return;
                } catch (const boost::thread_interrupted&) {
                    return;
                } catch (const std::exception& ex) {
                    logCritical(Log::Flowee) << "Threadgroup: uncaught exception" << ex;
                }
            }
        });
    }
}

WorkerThreads::~WorkerThreads()
{
    stopThreads();
    joinAll();
}

void WorkerThreads::stopThreads()
{
    m_work.reset();
    if (m_context.get()) // it gets reset() by joinAll
        m_context->stop();
}

void WorkerThreads::joinAll()
{
    m_threads.join_all();
    m_context.reset(); // tasks don't get garbage-collected until the destructor is ran
}

boost::asio::io_context& WorkerThreads::ioContext() const
{
    return *m_context;
}