thin-provisioning-tools/persistent-data/data-structures/btree_counter.h
2014-02-19 16:08:05 +00:00

96 lines
2.4 KiB
C++

#ifndef PERSISTENT_DATA_DATA_STRUCTURES_BTREE_COUNTER_H
#define PERSISTENT_DATA_DATA_STRUCTURES_BTREE_COUNTER_H
#include "persistent-data/data-structures/btree.h"
#include "persistent-data/block_counter.h"
//----------------------------------------------------------------
namespace persistent_data {
namespace btree_count_detail {
template <unsigned Levels, typename ValueTraits, typename ValueCounter>
class counting_visitor : public btree<Levels, ValueTraits>::visitor {
public:
typedef btree<Levels, ValueTraits> tree;
counting_visitor(block_counter &bc, ValueCounter &vc)
: bc_(bc),
vc_(vc) {
}
virtual bool visit_internal(node_location const &l,
typename tree::internal_node const &n) {
return visit_node(n);
}
virtual bool visit_internal_leaf(node_location const &l,
typename tree::internal_node const &n) {
return visit_node(n);
}
virtual bool visit_leaf(node_location const &l,
typename tree::leaf_node const &n) {
if (visit_node(n)) {
unsigned nr = n.get_nr_entries();
for (unsigned i = 0; i < nr; i++) {
// FIXME: confirm l2 is correct
node_location l2(l);
l2.push_key(i);
vc_.visit(l2, n.value_at(i));
}
return true;
}
return false;
}
private:
template <typename Node>
bool visit_node(Node const &n) {
block_address b = n.get_location();
bool seen = bc_.get_count(b);
bc_.inc(b);
return !seen;
}
block_counter &bc_;
ValueCounter &vc_;
};
}
template <typename T>
struct noop_value_counter {
void visit(btree_detail::node_location const &loc, T const &v) {
}
};
struct block_address_counter {
block_address_counter(block_counter &bc)
: bc_(bc) {
}
void visit(btree_detail::node_location const &loc, block_address b) {
bc_.inc(b);
}
private:
block_counter &bc_;
};
// Counts how many times each metadata block is referenced in the
// tree. Blocks already referenced in the block counter are not
// walked. This walk should only be done once you're sure the tree
// is not corrupt.
template <unsigned Levels, typename ValueTraits, typename ValueCounter>
void count_btree_blocks(btree<Levels, ValueTraits> const &tree, block_counter &bc, ValueCounter &vc) {
btree_count_detail::counting_visitor<Levels, ValueTraits, ValueCounter> v(bc, vc);
tree.visit_depth_first(v);
}
}
//----------------------------------------------------------------
#endif