Add support for category metadata

include/dwarfs/categorizer.h

@@ -30,6 +30,8 @@
 #include <span>
 #include <string_view>
 
+#include <folly/dynamic.h>
+
 #include "dwarfs/inode_fragments.h"
 
 namespace boost::program_options {
@@ -50,6 +52,7 @@ class categorizer {
 
   virtual std::span<std::string_view const> categories() const = 0;
   virtual bool is_single_fragment() const = 0;
+  virtual folly::dynamic category_metadata(fragment_category c) const = 0;
 };
 
 class random_access_categorizer : public categorizer {
@@ -132,6 +135,10 @@ class categorizer_manager {
     return impl_->category_name(c);
   }
 
+  folly::dynamic category_metadata(fragment_category c) const {
+    return impl_->category_metadata(c);
+  }
+
   class impl {
    public:
     virtual ~impl() = default;
@@ -140,6 +147,7 @@ class categorizer_manager {
     virtual categorizer_job job(std::filesystem::path const& path) const = 0;
     virtual std::string_view
     category_name(fragment_category::value_type c) const = 0;
+    virtual folly::dynamic category_metadata(fragment_category c) const = 0;
   };
 
  private:

src/dwarfs/categorizer.cpp

@@ -185,6 +185,8 @@ class categorizer_manager_ final : public categorizer_manager_private {
   std::string_view
   category_name(fragment_category::value_type c) const override;
 
+  folly::dynamic category_metadata(fragment_category c) const override;
+
   std::vector<std::shared_ptr<categorizer const>> const&
   categorizers() const override {
     return categorizers_;
@@ -201,9 +203,9 @@ class categorizer_manager_ final : public categorizer_manager_private {
   }
 
  private:
-  void add_category(std::string_view cat) {
+  void add_category(std::string_view cat, size_t categorizer_index) {
     if (catmap_.emplace(cat, categories_.size()).second) {
-      categories_.emplace_back(cat);
+      categories_.emplace_back(cat, categorizer_index);
     } else {
       LOG_WARN << "duplicate category: " << cat;
     }
@@ -212,7 +214,7 @@ class categorizer_manager_ final : public categorizer_manager_private {
   logger& lgr_;
   LOG_PROXY_DECL(LoggerPolicy);
   std::vector<std::shared_ptr<categorizer const>> categorizers_;
-  std::vector<std::string_view> categories_;
+  std::vector<std::pair<std::string_view, size_t>> categories_;
   std::unordered_map<std::string_view, fragment_category::value_type> catmap_;
   bool has_multi_fragment_sequential_categorizers_{false};
 };
@@ -221,7 +223,7 @@ template <typename LoggerPolicy>
 void categorizer_manager_<LoggerPolicy>::add(
     std::shared_ptr<categorizer const> c) {
   for (auto const& c : c->categories()) {
-    add_category(c);
+    add_category(c, categorizers_.size());
   }
 
   if (!c->is_single_fragment() &&
@@ -243,7 +245,15 @@ categorizer_job categorizer_manager_<LoggerPolicy>::job(
 template <typename LoggerPolicy>
 std::string_view categorizer_manager_<LoggerPolicy>::category_name(
     fragment_category::value_type c) const {
-  return DWARFS_NOTHROW(categories_.at(c));
+  return DWARFS_NOTHROW(categories_.at(c)).first;
+}
+
+template <typename LoggerPolicy>
+folly::dynamic categorizer_manager_<LoggerPolicy>::category_metadata(
+    fragment_category c) const {
+  auto categorizer =
+      DWARFS_NOTHROW(categorizers_.at(categories_.at(c.value()).second));
+  return categorizer->category_metadata(c);
 }
 
 categorizer_manager::categorizer_manager(logger& lgr)

src/dwarfs/categorizer/binary_categorizer.cpp

@@ -64,6 +64,10 @@ class binary_categorizer_ final : public binary_categorizer_base {
 
   bool is_single_fragment() const override { return false; }
 
+  folly::dynamic category_metadata(fragment_category) const override {
+    return folly::dynamic();
+  }
+
  private:
   LOG_PROXY_DECL(LoggerPolicy);
 };

src/dwarfs/categorizer/incompressible_categorizer.cpp

@@ -156,8 +156,13 @@ class incompressible_categorizer_ final : public sequential_categorizer {
   std::unique_ptr<sequential_categorizer_job>
   job(std::filesystem::path const& path, size_t total_size,
       category_mapper const& mapper) const override;
+
   bool is_single_fragment() const override { return true; }
 
+  folly::dynamic category_metadata(fragment_category) const override {
+    return folly::dynamic();
+  }
+
  private:
   logger& lgr_;
   incompressible_categorizer_config const config_;

src/dwarfs/categorizer/libmagic_categorizer.cpp

@@ -149,6 +149,10 @@ class libmagic_categorizer_ final : public libmagic_categorizer_base {
 
   bool is_single_fragment() const override { return true; }
 
+  folly::dynamic category_metadata(fragment_category) const override {
+    return folly::dynamic();
+  }
+
  private:
   LOG_PROXY_DECL(LoggerPolicy);
   magic_wrapper m_;