[thin_dump] --format custom=<shared lib>

Allow people to use their own emitters held in a shared library.

Put a trivial emitter in contrib/ as an example.

contrib/thin_sexp_emitter.cc

@@ -0,0 +1,120 @@
+#include "base/indented_stream.h"
+#include "thin-provisioning/emitter.h"
+
+using namespace std;
+using namespace thin_provisioning;
+
+//----------------------------------------------------------------
+
+namespace {
+	class sexp_emitter : public emitter {
+	public:
+		sexp_emitter(ostream &out)
+		: out_(out) {
+		}
+
+		virtual void begin_superblock(std::string const &uuid,
+					      uint64_t time,
+					      uint64_t trans_id,
+					      boost::optional<uint32_t> flags,
+					      boost::optional<uint32_t> version,
+					      uint32_t data_block_size,
+					      uint64_t nr_data_blocks,
+					      boost::optional<uint64_t> metadata_snap) {
+			open("superblock");
+			out_.indent();
+			out_ << "((uuid \"" << uuid << "\")\n";
+			kv("time", time);
+			kv("trans_id", trans_id);
+			kv("flags", flags);
+			kv("version", version);
+			kv("data_block_size", data_block_size);
+			kv("nr_data_blocks", nr_data_blocks);
+			kv("metadata_snap", metadata_snap);
+			out_.indent();
+			out_ << ")\n";
+		}
+
+		virtual void end_superblock() {
+			close();
+		}
+
+		virtual void begin_device(uint32_t dev_id,
+					  uint64_t mapped_blocks,
+					  uint64_t trans_id,
+					  uint64_t creation_time,
+					  uint64_t snap_time) {
+			open("device");
+			out_.indent();
+			out_ << "((dev_id " << dev_id << ")\n";
+			kv("mapped_blocks", mapped_blocks);
+			kv("trans_id", trans_id);
+			kv("creation_time", creation_time);
+			kv("snap_time", snap_time);
+			out_.indent();
+			out_ << ")\n";
+		}
+
+		virtual void end_device() {
+			close();
+		}
+
+		virtual void begin_named_mapping(std::string const &name) {
+
+		}
+
+		virtual void end_named_mapping() {
+
+		}
+
+		virtual void identifier(std::string const &name) {
+
+		}
+
+		virtual void range_map(uint64_t origin_begin, uint64_t data_begin, uint32_t time, uint64_t len) {
+			out_.indent();
+			out_ << "(range (origin_begin " << origin_begin
+			     << ") (data_begin " << data_begin
+			     << ") (time " << time
+			     << ") (len " << len << "))\n";
+		}
+
+		virtual void single_map(uint64_t origin_block, uint64_t data_block, uint32_t time) {
+			out_.indent();
+			out_ << "(single (origin_block " << origin_block
+			     << ") (data_block " << data_block
+			     << ") (time " << time << "))\n";
+		}
+
+	private:
+		void open(char const *tag) {
+			out_.indent();
+			out_ << "(" << tag << "\n";
+			out_.inc();
+		}
+
+		void close() {
+			out_.dec();
+			out_.indent();
+			out_ << ")\n";
+		}
+
+		template <typename T>
+		void kv(char const *k, T const &v) {
+			out_.indent();
+			out_ << " (" << k << " " << v << ")\n";
+		}
+
+		indented_stream out_;
+	};
+}
+
+//----------------------------------------------------------------
+
+extern "C" {
+	emitter::ptr create_emitter(ostream &out) {
+		return emitter::ptr(new sexp_emitter(out));
+	}
+}
+
+//----------------------------------------------------------------