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  /* Author: Suat Gedikli */
  
  #pragma once
  
  #include <moveit/macros/class_forward.h>
  #include <boost/thread/condition.hpp>
  #include <boost/thread/mutex.hpp>
  #include <boost/thread/locks.hpp>
  
  namespace mesh_filter
  {
  MOVEIT_CLASS_FORWARD(Job);
  
  /**
   * \brief This class is used to execute functions within the thread that holds the OpenGL context.
   */
  
  class Job
  {
  public:
    Job() : done_(false)
    {
    }
    virtual ~Job() = default;
  
    inline void wait() const;
    virtual void execute() = 0;
    inline void cancel();
    inline bool isDone() const;
  
  protected:
    bool done_;
    mutable boost::condition_variable condition_;
    mutable boost::mutex mutex_;
  };
  
  void Job::wait() const
  {
    boost::unique_lock<boost::mutex> lock(mutex_);
    while (!done_)
      condition_.wait(lock);
  }
  
  void Job::cancel()
  {
    boost::unique_lock<boost::mutex> lock(mutex_);
    done_ = true;
    condition_.notify_all();
  }
  
  bool Job::isDone() const
  {
    return done_;
  }
  
  template <typename ReturnType>
  class FilterJob : public Job
  {
  public:
    FilterJob(const boost::function<ReturnType()>& exec) : Job(), exec_(exec)
    {
    }
    void execute() override;
    const ReturnType& getResult() const;
  
  private:
    boost::function<ReturnType()> exec_;
    ReturnType result_;
  };
  
  template <typename ReturnType>
  void FilterJob<ReturnType>::execute()
  {
    boost::unique_lock<boost::mutex> lock(mutex_);
    if (!done_)  // not canceled !
      result_ = exec_();
  
    done_ = true;
    condition_.notify_all();
  }
  
  template <typename ReturnType>
  const ReturnType& FilterJob<ReturnType>::getResult() const
  {
    wait();
    return result_;
  }
  
  template <>
  class FilterJob<void> : public Job
  {
  public:
    FilterJob(const boost::function<void()>& exec) : Job(), exec_(exec)
    {
    }
    void execute() override
    {
      boost::unique_lock<boost::mutex> lock(mutex_);
      if (!done_)  // not canceled !
        exec_();
  
      done_ = true;
      condition_.notify_all();
    }
  
  private:
    boost::function<void()> exec_;
  };
  }
  