thread_context.hh

#ifndef SUBORDINATION_PPL_THREAD_CONTEXT_HH
#define SUBORDINATION_PPL_THREAD_CONTEXT_HH

#include <mutex>
#include <unistdx/base/simple_lock>
#include <unistdx/ipc/thread_semaphore>

namespace sbn {

    struct Thread_context {

        typedef std::mutex mutex_type;
        typedef sys::thread_semaphore sem_type;

        inline void
        register_thread() noexcept {
            ++this->_nthreads;
            ++this->_saved_nthreads;
        }

        inline void
        lock() {
            this->_mtx.lock();
        }

        inline void
        unlock() {
            this->_mtx.unlock();
        }

        template <class Lock>
        void
        wait(Lock& lock) {
            if (--this->_nthreads == 0) {
                this->_nthreads = this->_saved_nthreads;
                for (int i=0; i<this->_nthreads; ++i) {
                    this->_semaphore.notify_one();
                }
            } else {
                this->_semaphore.wait(lock);
            }
        }

    private:
        volatile int _nthreads = 0;
        volatile int _saved_nthreads = 0;
        mutex_type _mtx;
        sem_type _semaphore;
    };

    typedef sys::simple_lock<Thread_context> Thread_context_guard;

    namespace this_thread {

        extern Thread_context context;

    }

}

#endif // vim:filetype=cpp