Add create timestamp

src/dwarfs/metadata_v2.cpp

@@ -24,6 +24,7 @@
 #include <cerrno>
 #include <climits>
 #include <cstring>
+#include <ctime>
 #include <numeric>
 #include <ostream>
 
@@ -574,6 +575,13 @@ void metadata_<LoggerPolicy>::dump(
     os << "created by: " << *version << std::endl;
   }
 
+  if (auto ts = meta_.create_timestamp()) {
+    time_t tp = *ts;
+    std::string str(20, '\0');
+    std::strftime(str.data(), str.size(), "%F %T", std::localtime(&tp));
+    os << "created on: " << str << std::endl;
+  }
+
   if (detail_level > 0) {
     os << "block size: " << stbuf.f_bsize << std::endl;
     os << "inode count: " << stbuf.f_files << std::endl;

src/dwarfs/scanner.cpp

@@ -22,6 +22,7 @@
 #include <algorithm>
 #include <cstdint>
 #include <cstring>
+#include <ctime>
 #include <deque>
 #include <iterator>
 #include <stdexcept>
@@ -726,6 +727,7 @@ void scanner_<LoggerPolicy>::scan(filesystem_writer& fsw,
   mv2.total_hardlink_size_ref() = prog.hardlink_size;
   mv2.options_ref() = fsopts;
   mv2.dwarfs_version_ref() = std::string("libdwarfs ") + PRJ_GIT_ID;
+  mv2.create_timestamp_ref() = std::time(nullptr);
 
   auto [schema, data] = metadata_v2::freeze(mv2);
 

thrift/metadata.thrift

@@ -238,6 +238,6 @@ struct metadata {
   // version
   22: optional string           dwarfs_version,
 
-  // TODO: add timestamp
+  // timestamp
-  // 21: optional UInt64           timestamp,
+  23: optional UInt64           create_timestamp,
 }