AutoSyncFileFlow.hxx

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#ifndef _UTILS_AUTOSYNCFILEFLOW_H_
#define _UTILS_AUTOSYNCFILEFLOW_H_
 
#include "executor/Service.hxx"
#include "executor/StateFlow.hxx"
#include "utils/StringPrintf.hxx"
 
class AutoSyncFileFlow : public StateFlowBase
{
public:
    AutoSyncFileFlow(Service *service
                   , int sync_fd
                   , uint64_t interval=SEC_TO_NSEC(1))
                   : StateFlowBase(service)
                   , fd_(sync_fd)
                   , interval_(interval)
                   , name_(StringPrintf("AutoSyncFileFlow(%d)", fd_))
    {
      HASSERT(fd_ >= 0);
      HASSERT(interval_ > 0);
      start_flow(STATE(sleep_and_call_sync));
    }
 
    void shutdown(Notifiable *n)
    {
        shutdown_ = true;
        std::swap(shutdownDone_, n);
        if (n)
        {
            n->notify();
        }
        timer_.ensure_triggered();
    }
 
private:
    const int fd_;
    const uint64_t interval_;
    const std::string name_;
    StateFlowTimer timer_{this};
    bool shutdown_{false};
    Notifiable *shutdownDone_{nullptr};
 
    Action sleep_and_call_sync()
    {
        return sleep_and_call(&timer_, interval_, STATE(sync));
    }
 
    Action sync()
    {
        if (shutdown_)
        {
            AutoNotify n(shutdownDone_);
            return exit();
        }
        ERRNOCHECK(name_.c_str(), fsync(fd_));
        return call_immediately(STATE(sleep_and_call_sync));
    }
};
 
#endif // _UTILS_AUTOSYNCFILEFLOW_H_