serialization: support passing extra args to fields in DSL

src/common/va_args.h

@@ -0,0 +1,45 @@
+// Copyright (c) 2024, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+// Check for __VA_OPT__ support
+// Apdated from cpplearner's StackOverflow answer: https://stackoverflow.com/a/48045656
+#define PP_THIRD_ARG(a,b,c,...) c
+#define VA_OPT_SUPPORTED_I(...) PP_THIRD_ARG(__VA_OPT__(,),true,false,)
+#define VA_OPT_SUPPORTED VA_OPT_SUPPORTED_I(?)
+
+// VA_ARGS_COMMAPREFIX(): VA_ARGS_COMMAPREFIX(__VA_ARGS__) expands to __VA_ARGS__ with a comma in
+// front if more than one argument, else nothing.
+// If __VA_OPT__ supported, use that. Else, use GCC's ,## hack
+#if VA_OPT_SUPPORTED
+#    define VA_ARGS_COMMAPREFIX(...) __VA_OPT__(,) __VA_ARGS__
+#else
+#    define VA_ARGS_COMMAPREFIX(...) , ## __VA_ARGS__
+#endif
+

src/serialization/serialization.h

@@ -50,6 +50,8 @@
 #include <boost/type_traits/integral_constant.hpp>
 #include <boost/mpl/bool.hpp>
 
+#include "common/va_args.h"
+
 /*! \struct is_blob_type / is_blob_forced
  *
  * \brief descriptors for dispatching serialize: whether to take byte-wise copy/store to type
@@ -93,6 +95,15 @@ inline bool do_serialize(Archive &ar, bool &v)
   ar.serialize_blob(&v, sizeof(v));
   return true;
 }
+template <class Archive, class T, typename... Args>
+inline auto do_serialize(Archive &ar, T &v, Args&&... args)
+  -> decltype(do_serialize_object(ar, v, args...), true)
+{
+  ar.begin_object();
+  const bool r = do_serialize_object(ar, v, args...);
+  ar.end_object();
+  return r && ar.good();
+}
 
 /* the following add a trait to a set and define the serialization DSL*/
 
@@ -180,18 +191,9 @@ inline bool do_serialize(Archive &ar, bool &v)
  * VARINT_FIELD_F(). Otherwise, this macro is similar to
  * BEGIN_SERIALIZE_OBJECT(), as you should list only field serializations.
  */
-#define BEGIN_SERIALIZE_OBJECT_FN(stype)               \
-  template <bool W, template <bool> class Archive>     \
-  bool do_serialize_object(Archive<W> &ar, stype &v);  \
-  template <bool W, template <bool> class Archive>     \
-  bool do_serialize(Archive<W> &ar, stype &v) {        \
-    ar.begin_object();                                 \
-    bool r = do_serialize_object(ar, v);               \
-    ar.end_object();                                   \
-    return r;                                          \
-  }                                                    \
-  template <bool W, template <bool> class Archive>     \
-  bool do_serialize_object(Archive<W> &ar, stype &v) { \
+#define BEGIN_SERIALIZE_OBJECT_FN(stype, ...)                                           \
+  template <bool W, template <bool> class Archive>                                      \
+  bool do_serialize_object(Archive<W> &ar, stype &v VA_ARGS_COMMAPREFIX(__VA_ARGS__)) {
 
 /*! \macro PREPARE_CUSTOM_VECTOR_SERIALIZATION
  */
@@ -209,10 +211,10 @@ inline bool do_serialize(Archive &ar, bool &v)
  *
  * \brief serializes a field \a f tagged \a t  
  */
-#define FIELD_N(t, f)					\
+#define FIELD_N(t, f, ...)                                    \
   do {							\
     ar.tag(t);						\
-    bool r = do_serialize(ar, f);			\
+    bool r = do_serialize(ar, f VA_ARGS_COMMAPREFIX(__VA_ARGS__)); \
     if (!r || !ar.good()) return false;			\
   } while(0);
 
@@ -231,7 +233,7 @@ inline bool do_serialize(Archive &ar, bool &v)
  *
  * \brief tags the field with the variable name and then serializes it (for use in a free function)
  */
-#define FIELD_F(f) FIELD_N(#f, v.f)
+#define FIELD_F(f, ...) FIELD_N(#f, v.f VA_ARGS_COMMAPREFIX(__VA_ARGS__))
 
 /*! \macro FIELDS(f)
  *