storage.h

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// See the end of this file for license information.

#ifndef TORSION_STORAGE_H
#define TORSION_STORAGE_H

#include "blockdev.h"
#include "blockmap.h"
#include "segment.h"
#include "virtmem.h"
#include "addrmap.h"
#include "types.h"
#include "screen.h"

class Storage_system;
extern Storage_system storage_system;


class Superblock {
public:
  unsigned signature;     
  unsigned checkpoint_counter;    
  unsigned block_directory;   
  unsigned segment_directory;   
  Size blocks_per_segment;    
  unsigned curr_empty_segment;    
  static const unsigned CORRECT_SIGNATURE = 0xbb66;

  void
  print();
};


class Storage_system {
protected:
  Block_device* disk;     
  Segment curr_segment;     

  unsigned first_block;     
  Size blocks_per_segment;    
  Size blocks_per_page;     
  unsigned checkpoint_counter;    
  unsigned curr_superblock;   
  Block_map block_map;      
  Segment_map segment_map;    
  Array<unsigned> cleaned_segments; 
  bool checkpointing_dirty_pages; 
  bool enabled;       

  static const unsigned block_map_id_mask = 1 << 11;

public:
  void
  format(unsigned first_block_to_use = 0, Size segment_size = 0);

  bool
  is_formatted(unsigned first_block_to_use = 0);

  void
  init(unsigned first_block_to_use = 0);

  void
  write_superblock(unsigned block_directory = 0,
                   unsigned segment_directory = 0,
                   unsigned curr_empty_segment = 0);

  void
  checkpoint();

  unsigned
  log_page(void* page, bool update_block_map = true,
           void* actual_page_addr = NULL);

  inline void
  free_page(void* page) {
    block_map.set_block_number(page, 0);
  }

  unsigned
  log_map(Address_map& map);

  unsigned*
  load_table(Address_map& map, unsigned dir_index, void* virtual_table);

  void
  load_page(void* virtual_page);

  void
  write_segment();

  void
  write_segment_if_full();

  bool
  clean(unsigned segments_to_clean);

  void
  get_live_pages(Segment& segment, Array<void*>& live_pages);

  inline void
  set_device(Block_device* device) {
    disk = device;
  }

  inline unsigned
  block_to_segment_index(unsigned segment_block) {
              // - 2 because of the two superblocks
    return (segment_block - first_block - 2) / blocks_per_segment;
  }

  inline unsigned
  segment_index_to_block(unsigned segment_index) {
              // + 2 because of the two superblocks
    return segment_index * blocks_per_segment + first_block + 2;
  }

  inline void
  enable() {
    enabled = true;
  }
  
  inline void
  disable() {
    enabled = false;
  }

  inline bool
  is_checkpointing_dirty_pages() {
    return checkpointing_dirty_pages;
  }

  void
  print();
};

#endif

/* Torsion Operating System, Copyright (C) 2000-2004 Dan Helfman
 *
 * 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; either version 2 of the License, or (at your
 * option) any later version.
 * 
 * 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 (in the COPYING file).
 * 
 * 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.,
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

---

Torsion Operating System, Copyright (C) 2000-2004 Dan Helfman