buffered_file_io.h

/* Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#ifndef BUFFEREDFILEIO_INCLUDED
#define BUFFEREDFILEIO_INCLUDED

#include <my_global.h>
#include <mysql/plugin.h>
#include "i_keyring_io.h"
#include "logger.h"
#include "keyring_memory.h"
#include "buffer.h"
#include "hash_to_buffer_serializer.h"
#include "keyring_stat.h"
#include "file_io.h"

namespace keyring {

class Buffered_file_io : public IKeyring_io
{
public:
  Buffered_file_io(ILogger *logger)
    : eofTAG("EOF")
    , file_version("Keyring file version:1.0")
    , logger(logger)
    , backup_exists(FALSE)
    , memory_needed_for_buffer(0)
    , file_io(logger)
    , keyring_file(-1)
  {
    memset(&saved_keyring_stat, 0, sizeof(MY_STAT));
  }

  my_bool init(std::string *keyring_filename);

  my_bool flush_to_backup(ISerialized_object *serialized_object);
  my_bool flush_to_storage(ISerialized_object *serialized_object);

  ISerializer* get_serializer();
  my_bool get_serialized_object(ISerialized_object **serialized_object);
  my_bool has_next_serialized_object();
protected:
  virtual my_bool remove_backup(myf myFlags);
  virtual my_bool read_keyring_stat(File file);
  virtual my_bool check_keyring_file_stat(File file);
private:
  my_bool recreate_keyring_from_backup_if_backup_exists();

  std::string* get_backup_filename();
  my_bool open_backup_file(File *backup_file);
  my_bool load_file_into_buffer(File file, Buffer *buffer);
  my_bool flush_buffer_to_storage(Buffer *buffer, File file);
  my_bool flush_buffer_to_file(Buffer *buffer, File file);
  inline my_bool check_file_structure(File file, size_t file_size);
  my_bool check_if_keyring_file_can_be_opened_or_created();
  my_bool is_file_tag_correct(File file);
  my_bool is_file_version_correct(File file);

  Keyring_stat saved_keyring_stat;
  std::string keyring_filename;
  std::string backup_filename;
  const std::string eofTAG;
  const std::string file_version;
  ILogger *logger;
  my_bool backup_exists;
  Hash_to_buffer_serializer hash_to_buffer_serializer;
  size_t memory_needed_for_buffer;
  File_io file_io;
  File keyring_file;
};

}//namespace keyring

#endif //BUFFEREDFILEIO_INCLUDED