subscriptor.h

// ---------------------------------------------------------------------
//
// Copyright (C) 1998 - 2018 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE.md at
// the top level directory of deal.II.
//
// ---------------------------------------------------------------------

#ifndef dealii_subscriptor_h
#define dealii_subscriptor_h


#include <deal.II/base/config.h>

#include <deal.II/base/exceptions.h>

#include <atomic>
#include <map>
#include <string>
#include <typeinfo>

#ifdef DEAL_II_WITH_THREADS
#  include <mutex>
#endif

DEAL_II_NAMESPACE_OPEN

class Subscriptor
{
public:
  Subscriptor();

  Subscriptor(const Subscriptor &);

  Subscriptor(Subscriptor &&) noexcept;

  virtual ~Subscriptor();

  Subscriptor &
  operator=(const Subscriptor &);

  Subscriptor &
  operator=(Subscriptor &&) noexcept;

  void
  subscribe(const char *identifier = nullptr) const;

  void
  unsubscribe(const char *identifier = nullptr) const;

  unsigned int
  n_subscriptions() const;

  template <typename StreamType>
  void
  list_subscribers(StreamType &stream) const;

  void
  list_subscribers() const;

  DeclException3(ExcInUse,
                 int,
                 std::string,
                 std::string,
                 << "Object of class " << arg2 << " is still used by " << arg1
                 << " other objects."
                 << "\n\n"
                 << "(Additional information: " << arg3 << ")\n\n"
                 << "See the entry in the Frequently Asked Questions of "
                 << "deal.II (linked to from http://www.dealii.org/) for "
                 << "a lot more information on what this error means and "
                 << "how to fix programs in which it happens.");

  DeclException2(ExcNoSubscriber,
                 std::string,
                 std::string,
                 << "No subscriber with identifier <" << arg2
                 << "> subscribes to this object of class " << arg1
                 << ". Consequently, it cannot be unsubscribed.");

  template <class Archive>
  void
  serialize(Archive &ar, const unsigned int version);

private:
  using map_value_type = std::map<const char *, unsigned int>::value_type;

  using map_iterator = std::map<const char *, unsigned int>::iterator;

  mutable std::atomic<unsigned int> counter;

  mutable std::map<const char *, unsigned int> counter_map;

  mutable const std::type_info *object_info;

  void
  check_no_subscribers() const noexcept;

#ifdef DEAL_II_WITH_THREADS

  static std::mutex mutex;

#endif
};

//---------------------------------------------------------------------------

template <class Archive>
inline void
Subscriptor::serialize(Archive &, const unsigned int)
{
  // do nothing, as explained in the
  // documentation of this function
}

template <typename StreamType>
inline void
Subscriptor::list_subscribers(StreamType &stream) const
{
#ifdef DEAL_II_WITH_THREADS
  std::lock_guard<std::mutex> lock(mutex);
#endif

  for (map_iterator it = counter_map.begin(); it != counter_map.end(); ++it)
    stream << it->second << '/' << counter << " subscriptions from \""
           << it->first << '\"' << std::endl;
}

DEAL_II_NAMESPACE_CLOSE

#endif