Add metadata-as-JSON support to dwarfsck

include/dwarfs/filesystem_v2.h

@@ -33,6 +33,7 @@
 
 #include <sys/types.h>
 
+#include <folly/dynamic.h>
 #include <folly/Expected.h>
 
 #include "dwarfs/metadata_types.h"
@@ -69,6 +70,10 @@ class filesystem_v2 {
     impl_->dump(os, detail_level);
   }
 
+  folly::dynamic metadata_as_dynamic() const {
+    return impl_->metadata_as_dynamic();
+  }
+
   void walk(std::function<void(entry_view)> const& func) const {
     impl_->walk(func);
   }
@@ -128,6 +133,7 @@ class filesystem_v2 {
     virtual ~impl() = default;
 
     virtual void dump(std::ostream& os, int detail_level) const = 0;
+    virtual folly::dynamic metadata_as_dynamic() const = 0;
     virtual void walk(std::function<void(entry_view)> const& func) const = 0;
     virtual std::optional<entry_view> find(const char* path) const = 0;
     virtual std::optional<entry_view> find(int inode) const = 0;

include/dwarfs/metadata_v2.h

@@ -34,6 +34,7 @@
 
 #include <sys/types.h>
 
+#include <folly/dynamic.h>
 #include <folly/Expected.h>
 #include <folly/Range.h>
 
@@ -68,6 +69,10 @@ class metadata_v2 {
     impl_->dump(os, detail_level, icb);
   }
 
+  folly::dynamic as_dynamic() const {
+    return impl_->as_dynamic();
+  }
+
   static void get_stat_defaults(struct ::stat* defaults);
 
   // TODO: check if this is needed
@@ -138,6 +143,8 @@ class metadata_v2 {
         std::ostream& os, int detail_level,
         std::function<void(const std::string&, uint32_t)> const& icb) const = 0;
 
+    virtual folly::dynamic as_dynamic() const = 0;
+
     virtual size_t size() const = 0;
     virtual bool empty() const = 0;
 

src/dwarfs/filesystem_v2.cpp

@@ -195,6 +195,7 @@ class filesystem_ : public filesystem_v2::impl {
               const struct ::stat* stat_defaults, int inode_offset);
 
   void dump(std::ostream& os, int detail_level) const override;
+  folly::dynamic metadata_as_dynamic() const override;
   void walk(std::function<void(entry_view)> const& func) const override;
   std::optional<entry_view> find(const char* path) const override;
   std::optional<entry_view> find(int inode) const override;
@@ -273,6 +274,11 @@ void filesystem_<LoggerPolicy>::dump(std::ostream& os, int detail_level) const {
   });
 }
 
+template <typename LoggerPolicy>
+folly::dynamic filesystem_<LoggerPolicy>::metadata_as_dynamic() const {
+  return meta_.as_dynamic();
+}
+
 template <typename LoggerPolicy>
 void filesystem_<LoggerPolicy>::walk(
     std::function<void(entry_view)> const& func) const {

src/dwarfs/metadata_v2.cpp

@@ -158,6 +158,8 @@ class metadata_ : public metadata_v2::impl {
             std::function<void(const std::string&, uint32_t)> const& icb)
       const override;
 
+  folly::dynamic as_dynamic() const override;
+
   size_t size() const override { return data_.size(); }
 
   bool empty() const override { return data_.empty(); }
@@ -275,6 +277,9 @@ class metadata_ : public metadata_v2::impl {
             int detail_level,
             std::function<void(const std::string&, uint32_t)> const& icb) const;
 
+  folly::dynamic as_dynamic(entry_view entry) const;
+  folly::dynamic as_dynamic(directory_view dir) const;
+
   std::optional<entry_view>
   find(directory_view dir, std::string_view name) const;
 
@@ -439,6 +444,76 @@ void metadata_<LoggerPolicy>::dump(
   }
 }
 
+template <typename LoggerPolicy>
+folly::dynamic metadata_<LoggerPolicy>::as_dynamic(directory_view dir) const {
+  folly::dynamic obj = folly::dynamic::array;
+
+  auto count = dir.entry_count();
+  auto first = dir.first_entry();
+
+  for (size_t i = 0; i < count; ++i) {
+    obj.push_back(as_dynamic(make_entry_view(first + i)));
+  }
+
+  return obj;
+}
+
+template <typename LoggerPolicy>
+folly::dynamic metadata_<LoggerPolicy>::as_dynamic(entry_view entry) const {
+  folly::dynamic obj = folly::dynamic::object;
+
+  auto mode = entry.mode();
+  auto inode = entry.inode();
+
+  obj["mode"] = mode;
+  obj["modestring"] = modestring(mode);
+  obj["inode"] = inode;
+
+  if (inode > 0) {
+    obj["name"] = std::string(entry.name());
+  }
+
+  if (S_ISREG(mode)) {
+    obj["type"] = "file";
+    obj["size"] = file_size(entry, mode);
+  } else if (S_ISDIR(mode)) {
+    obj["type"] = "directory";
+    obj["entries"] = as_dynamic(make_directory_view(entry));
+  } else if (S_ISLNK(mode)) {
+    obj["type"] = "link";
+    obj["target"] = std::string(link_value(entry));
+  } else if (S_ISBLK(mode)) {
+    obj["type"] = "blockdev";
+    obj["device_id"] = get_device_id(inode);
+  } else if (S_ISCHR(mode)) {
+    obj["type"] = "chardev";
+    obj["device_id"] = get_device_id(inode);
+  } else if (S_ISFIFO(mode)) {
+    obj["type"] = "fifo";
+  } else if (S_ISSOCK(mode)) {
+    obj["type"] = "socket";
+  }
+
+  return obj;
+}
+
+template <typename LoggerPolicy>
+folly::dynamic metadata_<LoggerPolicy>::as_dynamic() const {
+  folly::dynamic obj = folly::dynamic::object;
+
+  struct ::statvfs stbuf;
+  statvfs(&stbuf);
+
+  obj["statvfs"] = folly::dynamic::object
+    ("f_bsize", stbuf.f_bsize)
+    ("f_files", stbuf.f_files)
+    ("f_blocks", stbuf.f_blocks);
+
+  obj["root"] = as_dynamic(root_);
+
+  return obj;
+}
+
 template <typename LoggerPolicy>
 std::string metadata_<LoggerPolicy>::modestring(uint16_t mode) const {
   std::ostringstream oss;

src/dwarfsck.cpp

@@ -24,6 +24,7 @@
 
 #include <boost/program_options.hpp>
 
+#include <folly/json.h>
 #include <folly/String.h>
 
 #include "dwarfs/filesystem_v2.h"
@@ -38,6 +39,7 @@ namespace po = boost::program_options;
 int dwarfsck(int argc, char** argv) {
   std::string log_level, input;
   int detail;
+  bool json;
 
   // clang-format off
   po::options_description opts("Command line options");
@@ -48,6 +50,9 @@ int dwarfsck(int argc, char** argv) {
     ("detail,d",
         po::value<int>(&detail)->default_value(1),
         "detail level")
+    ("json",
+        po::value<bool>(&json)->zero_tokens(),
+        "print metadata in JSON format")
     ("log-level",
         po::value<std::string>(&log_level)->default_value("info"),
         "log level (error, warn, info, debug, trace)")
@@ -74,7 +79,12 @@ int dwarfsck(int argc, char** argv) {
 
   auto mm = std::make_shared<dwarfs::mmap>(input);
 
+  if (json) {
+    dwarfs::filesystem_v2 fs(lgr, mm);
+    std::cout << folly::toPrettyJson(fs.metadata_as_dynamic()) << std::endl;
+  } else {
     dwarfs::filesystem_v2::identify(lgr, mm, std::cout, detail);
+  }
 
   return 0;
 }