callback_queue.h

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#ifndef ROSCPP_CALLBACK_QUEUE_H
#define ROSCPP_CALLBACK_QUEUE_H

// check if we might need to include our own backported version boost::condition_variable
// in order to use CLOCK_MONOTONIC for the condition variable
// the include order here is important!
#ifdef BOOST_THREAD_HAS_CONDATTR_SET_CLOCK_MONOTONIC
#include <boost/version.hpp>
#if BOOST_VERSION < 106100
// use backported version of boost condition variable, see https://svn.boost.org/trac/boost/ticket/6377
#include "boost_161_condition_variable.h"
#else // Boost version is 1.61 or greater and has the steady clock fixes
#include <boost/thread/condition_variable.hpp>
#endif
#else // !BOOST_THREAD_HAS_CONDATTR_SET_CLOCK_MONOTONIC
#include <boost/thread/condition_variable.hpp>
#endif // BOOST_THREAD_HAS_CONDATTR_SET_CLOCK_MONOTONIC

#include "ros/callback_queue_interface.h"
#include "ros/time.h"
#include "common.h"

#include <boost/shared_ptr.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/shared_mutex.hpp>
#include <boost/thread/tss.hpp>

#include <list>
#include <deque>

namespace ros
{

class ROSCPP_DECL CallbackQueue : public CallbackQueueInterface
{
public:
  CallbackQueue(bool enabled = true);
  virtual ~CallbackQueue();

  virtual void addCallback(const CallbackInterfacePtr& callback, uint64_t removal_id = 0);
  virtual void removeByID(uint64_t removal_id);

  enum CallOneResult
  {
    Called,
    TryAgain,
    Disabled,
    Empty,
  };

  CallOneResult callOne()
  {
    return callOne(ros::WallDuration());
  }

  CallOneResult callOne(ros::WallDuration timeout);

  void callAvailable()
  {
    callAvailable(ros::WallDuration());
  }
  void callAvailable(ros::WallDuration timeout);

  bool empty() { return isEmpty(); }
  bool isEmpty();
  void clear();

  void enable();
  void disable();
  bool isEnabled();

protected:
  void setupTLS();

  struct TLS;
  CallOneResult callOneCB(TLS* tls);

  struct IDInfo
  {
    uint64_t id;
    boost::shared_mutex calling_rw_mutex;
  };
  typedef boost::shared_ptr<IDInfo> IDInfoPtr;
  typedef std::map<uint64_t, IDInfoPtr> M_IDInfo;

  IDInfoPtr getIDInfo(uint64_t id);

  struct CallbackInfo
  {
    CallbackInfo()
    : removal_id(0)
    , marked_for_removal(false)
    {}
    CallbackInterfacePtr callback;
    uint64_t removal_id;
    bool marked_for_removal;
  };
  typedef std::list<CallbackInfo> L_CallbackInfo;
  typedef std::deque<CallbackInfo> D_CallbackInfo;
  D_CallbackInfo callbacks_;
  size_t calling_;
  boost::mutex mutex_;
  boost::condition_variable condition_;

  boost::mutex id_info_mutex_;
  M_IDInfo id_info_;

  struct TLS
  {
    TLS()
    : calling_in_this_thread(0xffffffffffffffffULL)
    , cb_it(callbacks.end())
    {}
    uint64_t calling_in_this_thread;
    D_CallbackInfo callbacks;
    D_CallbackInfo::iterator cb_it;
  };
  boost::thread_specific_ptr<TLS> tls_;

  bool enabled_;
};
typedef boost::shared_ptr<CallbackQueue> CallbackQueuePtr;

}

#endif