thin-provisioning-tools/space_map.h
2011-11-16 13:17:23 +00:00

123 lines
2.6 KiB
C++

#ifndef SPACE_MAP_H
#define SPACE_MAP_H
#include "block.h"
#include "block_counter.h"
#include <boost/shared_ptr.hpp>
#include <boost/optional.hpp>
//----------------------------------------------------------------
namespace persistent_data {
typedef uint32_t ref_t;
class space_map {
public:
typedef boost::shared_ptr<space_map> ptr;
virtual ~space_map() {};
virtual block_address get_nr_blocks() const = 0;
virtual block_address get_nr_free() const = 0;
virtual ref_t get_count(block_address b) const = 0;
virtual void set_count(block_address b, ref_t c) = 0;
virtual void commit() = 0;
virtual void inc(block_address b) = 0;
virtual void dec(block_address b) = 0;
// FIXME: change these to return an optional, failure is
// not that rare if we're restricting the area that's
// searched.
typedef boost::optional<block_address> maybe_block;
virtual maybe_block new_block() = 0;
virtual maybe_block new_block(block_address begin, block_address end) = 0;
virtual bool count_possibly_greater_than_one(block_address b) const = 0;
virtual void extend(block_address extra_blocks) = 0;
struct iterator {
virtual ~iterator() {}
virtual void operator() (block_address b, ref_t c) = 0;
};
virtual void iterate(iterator &it) const {
throw std::runtime_error("not implemented");
}
};
class persistent_space_map : public space_map {
public:
typedef boost::shared_ptr<persistent_space_map> ptr;
virtual size_t root_size() const = 0;
virtual void copy_root(void *dest, size_t len) const = 0;
};
class checked_space_map : public persistent_space_map {
public:
typedef boost::shared_ptr<checked_space_map> ptr;
virtual void check(block_counter &counter) const {
throw std::runtime_error("not implemented");
}
virtual ptr clone() const = 0;
};
class sm_adjust {
public:
sm_adjust(space_map::ptr sm, block_address b, int delta)
: sm_(sm),
b_(b),
delta_(delta) {
adjust_count(delta_);
}
~sm_adjust() {
adjust_count(-delta_);
}
void release() {
delta_ = 0;
}
private:
void adjust_count(int delta) {
if (delta == 1)
sm_->inc(b_);
else if (delta == -1)
sm_->dec(b_);
else
sm_->set_count(b_, sm_->get_count(b_) + delta);
}
space_map::ptr sm_;
block_address b_;
int delta_;
};
class sm_decrementer {
public:
sm_decrementer(space_map::ptr sm, block_address b);
~sm_decrementer();
void dont_bother();
private:
space_map::ptr sm_;
block_address b_;
bool released_;
};
}
//----------------------------------------------------------------
#endif