117 lines
2.4 KiB
C++
117 lines
2.4 KiB
C++
#ifndef BLOCK_H
|
|
#define BLOCK_H
|
|
|
|
#include <stdint.h>
|
|
#include <map>
|
|
#include <vector>
|
|
|
|
#include <boost/noncopyable.hpp>
|
|
#include <boost/optional.hpp>
|
|
#include <boost/shared_ptr.hpp>
|
|
|
|
//----------------------------------------------------------------
|
|
|
|
namespace persistent_data {
|
|
|
|
typedef uint64_t block_address;
|
|
|
|
template <uint32_t BlockSize>
|
|
class block_manager : private boost::noncopyable {
|
|
public:
|
|
typedef boost::shared_ptr<block_manager> ptr;
|
|
|
|
block_manager(std::string const &path);
|
|
~block_manager();
|
|
|
|
typedef unsigned char buffer[BlockSize];
|
|
typedef unsigned char const const_buffer[BlockSize];
|
|
|
|
class block;
|
|
|
|
class block_validator {
|
|
public:
|
|
virtual ~block_validator() {}
|
|
|
|
virtual void check(block const &b) const = 0;
|
|
virtual void prepare(block &b) const = 0;
|
|
};
|
|
|
|
struct block {
|
|
typedef boost::optional<block_validator> maybe_validator;
|
|
|
|
block(block_address location,
|
|
maybe_validator v = maybe_validator())
|
|
: location_(location),
|
|
validator_(v) {
|
|
}
|
|
|
|
block_address location_;
|
|
buffer data_;
|
|
boost::optional<block_validator> validator_;
|
|
};
|
|
typedef boost::shared_ptr<block> block_ptr;
|
|
|
|
class read_ref {
|
|
public:
|
|
read_ref(block_ptr b);
|
|
virtual ~read_ref() {}
|
|
|
|
block_address get_location() const;
|
|
const_buffer &data() const;
|
|
|
|
protected:
|
|
block_ptr block_;
|
|
};
|
|
|
|
// Inherited from read_ref, since you can read a block that's write
|
|
// locked.
|
|
class write_ref : public read_ref {
|
|
public:
|
|
using read_ref::data;
|
|
buffer &data();
|
|
};
|
|
|
|
// Locking methods
|
|
read_ref
|
|
read_lock(block_address location);
|
|
|
|
boost::optional<read_ref>
|
|
read_try_lock(block_address location);
|
|
|
|
write_ref
|
|
write_lock(block_address location);
|
|
|
|
write_ref
|
|
write_lock_zero(block_address location);
|
|
|
|
// Validator variants
|
|
read_ref
|
|
read_lock(block_address location, block_validator const &v);
|
|
|
|
boost::optional<read_ref>
|
|
read_try_lock(block_address location, block_validator const &v);
|
|
|
|
write_ref
|
|
write_lock(block_address location, block_validator const &v);
|
|
|
|
write_ref
|
|
write_lock_zero(block_address location, block_validator const &v);
|
|
|
|
// Use this to commit changes
|
|
void flush(write_ref super_block);
|
|
|
|
private:
|
|
void read_block(block &b);
|
|
void write_block(block const &b);
|
|
void zero_block(block &b);
|
|
|
|
void write_and_release(block *b);
|
|
|
|
int fd_;
|
|
};
|
|
}
|
|
|
|
//----------------------------------------------------------------
|
|
|
|
#endif
|