KEK/disk_backend.h

48 lines
1.3 KiB
C++

// (C) 2018-2024 by Folkert van Heusden
// Released under MIT license
#pragma once
#include <map>
#include <optional>
#include <stdint.h>
#include <string>
#include <vector>
#include <sys/types.h>
#include "gen.h"
class disk_backend
{
protected:
#if IS_POSIX
bool use_overlay { false };
std::map<off_t, std::vector<uint8_t> > overlay;
void store_object_in_overlay(const off_t id, const std::vector<uint8_t> & data);
bool store_mem_range_in_overlay(const off_t offset, const size_t n, const uint8_t *const from, const size_t sector_size);
std::optional<std::vector<uint8_t> > get_object_from_overlay(const off_t id);
std::optional<std::vector<uint8_t> > get_from_overlay(const off_t offset, const size_t sector_size);
json_t *serialize_overlay() const;
void deserialize_overlay(const json_t *const j);
#endif
public:
disk_backend();
virtual ~disk_backend();
#if IS_POSIX
virtual json_t *serialize() const = 0;
static disk_backend *deserialize(const json_t *const j);
#endif
virtual std::string get_identifier() const = 0;
virtual bool begin(const bool disk_snapshots) = 0;
virtual bool read(const off_t offset, const size_t n, uint8_t *const target, const size_t sector_size) = 0;
virtual bool write(const off_t offset, const size_t n, const uint8_t *const from, const size_t sector_size) = 0;
};