thin-provisioning-tools/persistent-data/data-structures/btree_counter.h
2016-06-20 00:30:25 +08:00

149 lines
4.3 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/data-structures/btree_node_checker.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 check_internal(l, n) ? visit_node(n) : false;
}
virtual bool visit_internal_leaf(node_location const &l,
typename tree::internal_node const &n) {
return check_leaf(l, n) ? visit_node(n) : false;
}
virtual bool visit_leaf(node_location const &l,
typename tree::leaf_node const &n) {
if (check_leaf(l, n) && 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(n.key_at(i));
vc_.visit(l2, n.value_at(i));
}
return true;
}
return false;
}
typedef typename btree<Levels, ValueTraits>::visitor::error_outcome error_outcome;
error_outcome error_accessing_node(node_location const &l, block_address b,
std::string const &what) {
return btree<Levels, ValueTraits>::visitor::EXCEPTION_HANDLED;
}
private:
bool check_internal(node_location const &l,
btree_detail::node_ref<block_traits> const &n) {
if (l.is_sub_root())
new_root(l.level());
if (!checker_.check_block_nr(n) ||
!checker_.check_value_size(n) ||
!checker_.check_max_entries(n) ||
!checker_.check_nr_entries(n, l.is_sub_root()) ||
!checker_.check_ordered_keys(n) ||
!checker_.check_parent_key(n, l.is_sub_root() ? boost::optional<uint64_t>() : l.key))
return false;
return true;
}
template <typename ValueTraits2>
bool check_leaf(node_location const &l,
btree_detail::node_ref<ValueTraits2> const &n) {
if (l.is_sub_root())
new_root(l.level());
if (!checker_.check_block_nr(n) ||
!checker_.check_value_size(n) ||
!checker_.check_max_entries(n) ||
!checker_.check_nr_entries(n, l.is_sub_root()) ||
!checker_.check_ordered_keys(n) ||
!checker_.check_parent_key(n, l.is_sub_root() ? boost::optional<uint64_t>() : l.key) ||
!checker_.check_leaf_key(n, last_leaf_key_[l.level()]))
return false;
if (n.get_nr_entries() > 0)
last_leaf_key_[l.level()] = n.key_at(n.get_nr_entries() - 1);
return true;
}
void new_root(unsigned level) {
// we're starting a new subtree, so should
// reset the last_leaf value.
last_leaf_key_[level] = boost::optional<uint64_t>();
}
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_;
btree_node_checker checker_;
boost::optional<uint64_t> last_leaf_key_[Levels];
};
}
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