feat(metadata_freezer): log metadata freezing time

include/dwarfs/writer/internal/metadata_freezer.h

@@ -22,11 +22,14 @@
 #pragma once
 
 #include <cstdint>
+#include <memory>
 #include <utility>
 #include <vector>
 
 namespace dwarfs {
 
+class logger;
+
 namespace thrift::metadata {
 class metadata;
 }
@@ -35,8 +38,24 @@ namespace writer::internal {
 
 class metadata_freezer {
  public:
-  static std::pair<std::vector<uint8_t>, std::vector<uint8_t>>
-  freeze(const thrift::metadata::metadata& data);
+  metadata_freezer(logger& lgr);
+  ~metadata_freezer();
+
+  std::pair<std::vector<uint8_t>, std::vector<uint8_t>>
+  freeze(thrift::metadata::metadata const& data) const {
+    return impl_->freeze(data);
+  }
+
+  class impl {
+   public:
+    virtual ~impl() = default;
+
+    virtual std::pair<std::vector<uint8_t>, std::vector<uint8_t>>
+    freeze(thrift::metadata::metadata const& data) const = 0;
+  };
+
+ private:
+  std::unique_ptr<impl> impl_;
 };
 
 } // namespace writer::internal

src/writer/internal/metadata_freezer.cpp

@@ -22,6 +22,8 @@
 #include <thrift/lib/cpp2/frozen/FrozenUtil.h>
 #include <thrift/lib/cpp2/protocol/Serializer.h>
 
+#include <dwarfs/logger.h>
+
 #include <dwarfs/writer/internal/metadata_freezer.h>
 
 #include <dwarfs/gen-cpp2/metadata_layouts.h>
@@ -59,11 +61,33 @@ freeze_to_buffer(const T& x) {
   return {schema_buffer, data_buffer};
 }
 
+template <typename LoggerPolicy>
+class metadata_freezer_ : public metadata_freezer::impl {
+ public:
+  explicit metadata_freezer_(logger& lgr)
+      : LOG_PROXY_INIT(lgr) {}
+
+  std::pair<std::vector<uint8_t>, std::vector<uint8_t>>
+  freeze(thrift::metadata::metadata const& data) const override {
+    auto ti = LOG_TIMED_VERBOSE;
+    auto rv = freeze_to_buffer(data);
+
+    ti << "freezing metadata to " << rv.second.size() << " bytes...";
+
+    return rv;
+  }
+
+ private:
+  LOG_PROXY_DECL(LoggerPolicy);
+};
+
 } // namespace
 
-std::pair<std::vector<uint8_t>, std::vector<uint8_t>>
-metadata_freezer::freeze(const thrift::metadata::metadata& data) {
-  return freeze_to_buffer(data);
-}
+metadata_freezer::metadata_freezer(logger& lgr)
+    : impl_{
+          make_unique_logging_object<impl, metadata_freezer_, logger_policies>(
+              lgr)} {}
+
+metadata_freezer::~metadata_freezer() = default;
 
 } // namespace dwarfs::writer::internal

src/writer/scanner.cpp

@@ -887,7 +887,7 @@ void scanner_<LoggerPolicy>::scan(
   mdb.set_total_hardlink_size(prog.hardlink_size);
   mdb.gather_global_entry_data(ge_data);
 
-  auto [schema, data] = metadata_freezer::freeze(mdb.build());
+  auto [schema, data] = metadata_freezer(LOG_GET_LOGGER).freeze(mdb.build());
 
   LOG_VERBOSE << "uncompressed metadata size: " << size_with_unit(data.size());