bees: remove local cruft, throw at github

include/crucible/extentwalker.h

@@ -0,0 +1,101 @@
+#ifndef CRUCIBLE_EXTENTWALKER_H
+#define CRUCIBLE_EXTENTWALKER_H
+
+#include "crucible/fd.h"
+
+namespace crucible {
+	using namespace std;
+
+	// FIXME:  ExtentCursor is probably a better name
+	struct Extent {
+		off_t		m_begin;
+		off_t		m_end;
+		uint64_t	m_physical;
+		uint64_t	m_flags;
+
+		// Btrfs extent reference details
+		off_t		m_physical_len;
+		off_t		m_logical_len;
+		off_t		m_offset;
+
+		// fiemap flags are uint32_t, so bits 32..63 are OK for us
+
+		// no extent here
+		static const uint64_t HOLE      = (1ULL << 32);
+
+		// extent is physical space full of zeros
+		static const uint64_t PREALLOC  = (1ULL << 33);
+
+		// extent's physical (RAM) size does not match logical (can we know this?)
+		static const uint64_t OBSCURED  = (1ULL << 34);
+
+		operator bool() const;
+		off_t size() const;
+		off_t begin() const { return m_begin; }
+		off_t end() const { return m_end; }
+		uint64_t flags() const { return m_flags; }
+		uint64_t physical() const { return m_physical; }
+		off_t physical_len() const { return m_physical_len; }
+		off_t logical_len() const { return m_logical_len; }
+		off_t offset() const { return m_offset; }
+		bool operator==(const Extent &that) const;
+		bool operator!=(const Extent &that) const { return !(*this == that); }
+
+		Extent();
+		Extent(const Extent &e) = default;
+	};
+
+	class ExtentWalker {
+	public:
+		using Vec = vector<Extent>;
+		using Itr = Vec::iterator;
+
+	protected:
+		Fd	m_fd;
+		Stat	m_stat;
+
+		virtual Vec get_extent_map(off_t pos);
+
+		static const unsigned sc_extent_fetch_max = 64;
+		static const unsigned sc_extent_fetch_min = 4;
+		static const off_t sc_step_size = 0x1000 * (sc_extent_fetch_max / 2);
+
+	private:
+		Vec	m_extents;
+		Itr	m_current;
+
+		Itr find_in_cache(off_t pos);
+		void run_fiemap(off_t pos);
+
+	public:
+		ExtentWalker(Fd fd = Fd());
+		ExtentWalker(Fd fd, off_t initial_pos);
+		virtual ~ExtentWalker();
+
+		void reset();
+		Extent current();
+		bool next();
+		bool prev();
+		void seek(off_t new_pos);
+
+	friend ostream & operator<<(ostream &os, const ExtentWalker &ew);
+	};
+
+	class BtrfsExtentWalker : public ExtentWalker {
+		uint64_t m_tree_id;
+		Fd m_root_fd;
+
+	protected:
+		Vec get_extent_map(off_t pos) override;
+
+	public:
+		BtrfsExtentWalker(Fd fd);
+		BtrfsExtentWalker(Fd fd, off_t initial_pos);
+		BtrfsExtentWalker(Fd fd, off_t initial_pos, Fd root_fd);
+		void set_root_fd(Fd fd);
+	};
+
+	ostream &operator<<(ostream &os, const Extent &e);
+};
+
+#endif // CRUCIBLE_EXTENTWALKER_H