149 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			149 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
#ifndef PERSISTENT_DATA_DATA_STRUCTURES_BTREE_COUNTER_H
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#define PERSISTENT_DATA_DATA_STRUCTURES_BTREE_COUNTER_H
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#include "persistent-data/data-structures/btree.h"
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#include "persistent-data/data-structures/btree_node_checker.h"
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#include "persistent-data/block_counter.h"
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//----------------------------------------------------------------
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namespace persistent_data {
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	namespace btree_count_detail {
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		template <unsigned Levels, typename ValueTraits, typename ValueCounter>
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		class counting_visitor : public btree<Levels, ValueTraits>::visitor {
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		public:
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			typedef btree<Levels, ValueTraits> tree;
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			counting_visitor(block_counter &bc, ValueCounter &vc)
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				: bc_(bc),
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				  vc_(vc) {
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			}
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			virtual bool visit_internal(node_location const &l,
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						    typename tree::internal_node const &n) {
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				return check_internal(l, n) ? visit_node(n) : false;
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			}
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			virtual bool visit_internal_leaf(node_location const &l,
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							 typename tree::internal_node const &n) {
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				return check_leaf(l, n) ? visit_node(n) : false;
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			}
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			virtual bool visit_leaf(node_location const &l,
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						typename tree::leaf_node const &n) {
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				if (check_leaf(l, n) && visit_node(n)) {
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					unsigned nr = n.get_nr_entries();
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					for (unsigned i = 0; i < nr; i++) {
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						// FIXME: confirm l2 is correct
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						node_location l2(l);
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						l2.push_key(i);
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						vc_.visit(l2, n.value_at(i));
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					}
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					return true;
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				}
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				return false;
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			}
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			typedef typename btree<Levels, ValueTraits>::visitor::error_outcome error_outcome;
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			error_outcome error_accessing_node(node_location const &l, block_address b,
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							   std::string const &what) {
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				return btree<Levels, ValueTraits>::visitor::EXCEPTION_HANDLED;
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			}
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		private:
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			bool check_internal(node_location const &l,
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					    btree_detail::node_ref<block_traits> const &n) {
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				if (l.is_sub_root())
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					new_root(l.level());
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				if (!checker_.check_block_nr(n) ||
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				    !checker_.check_value_size(n) ||
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				    !checker_.check_max_entries(n) ||
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				    !checker_.check_nr_entries(n, l.is_sub_root()) ||
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				    !checker_.check_ordered_keys(n) ||
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				    !checker_.check_parent_key(n, l.is_sub_root() ? boost::optional<uint64_t>() : l.key))
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					return false;
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				return true;
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			}
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			template <typename ValueTraits2>
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			bool check_leaf(node_location const &l,
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				        btree_detail::node_ref<ValueTraits2> const &n) {
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				if (l.is_sub_root())
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					new_root(l.level());
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				if (!checker_.check_block_nr(n) ||
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				    !checker_.check_value_size(n) ||
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				    !checker_.check_max_entries(n) ||
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				    !checker_.check_nr_entries(n, l.is_sub_root()) ||
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				    !checker_.check_ordered_keys(n) ||
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				    !checker_.check_parent_key(n, l.is_sub_root() ? boost::optional<uint64_t>() : l.key) ||
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				    !checker_.check_leaf_key(n, last_leaf_key_[l.level()]))
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					return false;
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				if (n.get_nr_entries() > 0)
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					last_leaf_key_[l.level()] = n.key_at(n.get_nr_entries() - 1);
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				return true;
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			}
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			void new_root(unsigned level) {
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				// we're starting a new subtree, so should
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				// reset the last_leaf value.
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				last_leaf_key_[level] = boost::optional<uint64_t>();
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			}
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			template <typename Node>
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			bool visit_node(Node const &n) {
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				block_address b = n.get_location();
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				bool seen = bc_.get_count(b);
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				bc_.inc(b);
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				return !seen;
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			}
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			block_counter &bc_;
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			ValueCounter &vc_;
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			btree_node_checker checker_;
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			boost::optional<uint64_t> last_leaf_key_[Levels];
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		};
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	}
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	template <typename T>
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	struct noop_value_counter {
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		void visit(btree_detail::node_location const &loc, T const &v) {
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		}
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	};
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	struct block_address_counter {
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		block_address_counter(block_counter &bc)
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		: bc_(bc) {
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		}
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		void visit(btree_detail::node_location const &loc, block_address b) {
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			bc_.inc(b);
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		}
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	private:
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		block_counter &bc_;
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	};
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	// Counts how many times each metadata block is referenced in the
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	// tree.  Blocks already referenced in the block counter are not
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	// walked.  This walk should only be done once you're sure the tree
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	// is not corrupt.
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	template <unsigned Levels, typename ValueTraits, typename ValueCounter>
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	void count_btree_blocks(btree<Levels, ValueTraits> const &tree, block_counter &bc, ValueCounter &vc) {
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		btree_count_detail::counting_visitor<Levels, ValueTraits, ValueCounter> v(bc, vc);
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		tree.visit_depth_first(v);
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	}
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}
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//----------------------------------------------------------------
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#endif
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