time_trigger.h

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#pragma once
 
#include <pcl/pcl_macros.h>
 
#include <boost/signals2.hpp>
 
#include <condition_variable>
#include <functional>
#include <mutex>
#include <thread>
 
namespace pcl
{
  /** \brief Timer class that invokes registered callback methods periodically.
    * \ingroup common
    */
  class PCL_EXPORTS TimeTrigger
  {
    public:
      using callback_type = std::function<void ()>;
 
      /** \brief Timer class that calls a callback method periodically. Due to possible blocking calls, only one callback method can be registered per instance.
        * \param[in] interval_seconds interval in seconds
        * \param[in] callback callback to be invoked periodically
        */
      TimeTrigger (double interval_seconds, const callback_type& callback);
 
      /** \brief Timer class that calls a callback method periodically. Due to possible blocking calls, only one callback method can be registered per instance.
        * \param[in] interval_seconds interval in seconds
        */
      TimeTrigger (double interval_seconds = 1.0);
 
      /** \brief Destructor. */
      ~TimeTrigger ();
 
      /** \brief registers a callback
        * \param[in] callback callback function to the list of callbacks. signature has to be std::function<void()>
        * \return connection the connection, which can be used to disable/enable and remove callback from list
        */
      boost::signals2::connection registerCallback (const callback_type& callback);
 
      /** \brief Resets the timer interval
        * \param[in] interval_seconds interval in seconds
        */
      void 
      setInterval (double interval_seconds);
 
      /** \brief Start the Trigger. */
      void 
      start ();
 
      /** \brief Stop the Trigger. */
      void 
      stop ();
    private:
      void 
      thread_function ();
      boost::signals2::signal <void() > callbacks_;
 
      double interval_;
 
      bool quit_;
      bool running_;
 
      std::thread timer_thread_;
      std::condition_variable condition_;
      std::mutex condition_mutex_;
  };
}