ISaveable.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2011 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#pragma once
 
#include "MantidKernel/DllConfig.h"
#include <list>
#include <mutex>
#ifndef Q_MOC_RUN
#include <boost/optional.hpp>
#endif
 
namespace Mantid {
namespace Kernel {
 
// forward declaration
 
class MANTID_KERNEL_DLL ISaveable {
public:
  ISaveable();
  ISaveable(const ISaveable &other);
  virtual ~ISaveable() = default;
 
  virtual uint64_t getFilePosition() const { return m_fileIndexStart; }
  uint64_t getFileSize() const { return m_fileNumEvents; }
  void setFilePosition(uint64_t newPos, size_t newSize, bool wasSaved);
  //-----------------------------------------------------------------------------------------------
  // Saveable functions interface, which controls the logic of working with
  // objects on HDD
 
  bool wasSaved() const // for speed it returns this boolean, but for
                        // relaibility this should be
                        // m_wasSaved&&(m_fileIndexStart!=max())
  {
    return m_wasSaved;
  }
  bool isLoaded() const { return m_isLoaded; }
 
  // protected?
  void setLoaded(bool Yes) { m_isLoaded = Yes; }
 
  bool isBusy() const { return m_Busy; }
  void setBusy(bool On) { m_Busy = On; }
 
  // protected?
 
  bool isDataChanged() const { return m_dataChanged; }
  void setDataChanged() {
    if (this->wasSaved())
      m_dataChanged = true;
  }
  void clearDataChanged() { m_dataChanged = false; }
 
  //-----------------------------------------------------------------------------------------------
  // INTERFACE:
 
  virtual void save() const = 0;
 
  virtual void load() = 0;
 
  virtual void flushData() const = 0;
  virtual void clearDataFromMemory() = 0;
 
  virtual uint64_t getTotalDataSize() const = 0;
  virtual size_t getDataMemorySize() const = 0;
 
protected:
  //--------------
  bool m_Busy;
  bool m_dataChanged;
  // this tracks the history of operations, occuring over the data.
  mutable bool m_wasSaved;
  bool m_isLoaded;
 
private:
  // the iterator which describes the position of this object in the DiskBuffer.
  // Undefined if not placed to buffer
  boost::optional<std::list<ISaveable *>::iterator> m_BufPosition;
  // the size of the object in the memory buffer, used to calculate the total
  // amount of memory the objects occupy
  size_t m_BufMemorySize;
  uint64_t m_fileIndexStart;
  uint64_t m_fileNumEvents;
 
  friend class DiskBuffer;
  void saveAt(uint64_t newPos, uint64_t newSize);
 
  size_t setBufferPosition(std::list<ISaveable *>::iterator bufPosition);
  boost::optional<std::list<ISaveable *>::iterator> &getBufPostion() { return m_BufPosition; }
  size_t getBufferSize() const { return m_BufMemorySize; }
  void setBufferSize(size_t newSize) { m_BufMemorySize = newSize; }
 
  void clearBufferState();
 
  // the mutex to protect changes in this memory
  std::mutex m_setter;
};
 
} // namespace Kernel
} // namespace Mantid