destruction_guard.h

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* Author: Eitan Marder-Eppstein
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#ifndef ACTIONLIB__DESTRUCTION_GUARD_H_
#define ACTIONLIB__DESTRUCTION_GUARD_H_

#include <boost/thread/condition.hpp>
#include <boost/thread/mutex.hpp>

namespace actionlib
{
class DestructionGuard
{
public:
  DestructionGuard()
  : use_count_(0), destructing_(false) {}
  void destruct()
  {
    boost::mutex::scoped_lock lock(mutex_);
    destructing_ = true;
    while (use_count_ > 0) {
      count_condition_.timed_wait(lock, boost::posix_time::milliseconds(1000));
    }
  }

  bool tryProtect()
  {
    boost::mutex::scoped_lock lock(mutex_);
    if (destructing_) {
      return false;
    }
    use_count_++;
    return true;
  }

  void unprotect()
  {
    boost::mutex::scoped_lock lock(mutex_);
    use_count_--;
  }

  class ScopedProtector
  {
public:
    ScopedProtector(DestructionGuard & guard)
    : guard_(guard), protected_(false)
    {
      protected_ = guard_.tryProtect();
    }

    bool isProtected()
    {
      return protected_;
    }

    ~ScopedProtector()
    {
      if (protected_) {
        guard_.unprotect();
      }
    }

private:
    DestructionGuard & guard_;
    bool protected_;
  };

private:
  boost::mutex mutex_;
  int use_count_;
  bool destructing_;
  boost::condition count_condition_;
};

}   // namespace actionlib
#endif  // ACTIONLIB__DESTRUCTION_GUARD_H_