[thin_rmap] rmap_visitor

thin-provisioning/rmap_visitor.h

@@ -0,0 +1,68 @@
+#ifndef THIN_RMAP_VISITOR_H
+#define THIN_RMAP_VISITOR_H
+
+#include "persistent-data/range.h"
+#include "thin-provisioning/mapping_tree.h"
+
+//----------------------------------------------------------------
+
+namespace thin_provisioning {
+	// This value visitor (see btree_damage_visitor.h) produces a
+	// reverse mapping for parts of the data device.
+	//
+	// i) Use add_data_region() to specify which areas of the data device you're interested in.
+	// ii) visit the mapping tree
+	// iii) call complete()
+	// iv) get the rmaps with get_rmap();
+	class rmap_visitor {
+	public:
+		typedef range<block_address> region;
+
+		rmap_visitor();
+
+		// Specify which regions of the data device you want the rmap for.
+		void add_data_region(region const &r);
+		void visit(btree_path const &path, mapping_tree_detail::block_time const &bt);
+
+		struct rmap_region {
+			// FIXME: surely we don't need to provide this for
+			// a POD structure?
+			bool operator ==(rmap_region const &rhs) const {
+				return ((data_begin == rhs.data_begin) &&
+					(data_end == rhs.data_end) &&
+					(thin_dev == rhs.thin_dev) &&
+					(thin_begin == rhs.thin_begin));
+			}
+
+			block_address data_begin;
+		        block_address data_end;
+
+			uint32_t thin_dev;
+			block_address thin_begin;
+		};
+
+		void complete();
+		vector<rmap_region> const &get_rmap() const;
+
+	private:
+		bool in_regions(block_address b) const;
+		bool adjacent_block(rmap_region const &rr,
+				    uint32_t thin_dev, block_address thin_block,
+				    block_address data_block) const;
+		void insert_new_region(uint32_t thin_dev, block_address thin_block,
+				       block_address data_block);
+		void push_current();
+
+		void visit_block(uint32_t thin_dev, block_address thin_block,
+				 block_address data_block);
+
+		vector<region> regions_;
+
+		boost::optional<rmap_region> current_rmap_;
+		vector<rmap_region> rmap_;
+	};
+}
+
+//----------------------------------------------------------------
+
+#endif