serialization: fix infinite loops and clean up dispatching

Resolves #8687

9 files changed, 87 insertions, 152 deletions

diff --git a/src/cryptonote_basic/tx_extra.h b/src/cryptonote_basic/tx_extra.h
index af6ee5197..a29f126ee 100644
--- a/src/cryptonote_basic/tx_extra.h
+++ b/src/cryptonote_basic/tx_extra.h
@@ -52,7 +52,7 @@ namespace cryptonote
 
     // load
     template <template <bool> class Archive>
-    bool do_serialize(Archive<false>& ar)
+    bool member_do_serialize(Archive<false>& ar)
     {
       // size - 1 - because of variant tag
       for (size = 1; size <= TX_EXTRA_PADDING_MAX_COUNT; ++size)
@@ -73,7 +73,7 @@ namespace cryptonote
 
     // store
     template <template <bool> class Archive>
-    bool do_serialize(Archive<true>& ar)
+    bool member_do_serialize(Archive<true>& ar)
     {
       if(TX_EXTRA_PADDING_MAX_COUNT < size)
         return false;
@@ -129,7 +129,7 @@ namespace cryptonote
 
     // load
     template <template <bool> class Archive>
-    bool do_serialize(Archive<false>& ar)
+    bool member_do_serialize(Archive<false>& ar)
     {
       std::string field;
       if(!::do_serialize(ar, field))
@@ -142,7 +142,7 @@ namespace cryptonote
 
     // store
     template <template <bool> class Archive>
-    bool do_serialize(Archive<true>& ar)
+    bool member_do_serialize(Archive<true>& ar)
     {
       std::ostringstream oss;
       binary_archive<true> oar(oss);
diff --git a/src/serialization/container.h b/src/serialization/container.h
index 80e1892f2..393c66399 100644
--- a/src/serialization/container.h
+++ b/src/serialization/container.h
@@ -42,7 +42,7 @@ namespace serialization
     typename std::enable_if<!use_container_varint<T>(), bool>::type
     serialize_container_element(Archive& ar, T& e)
     {
-      return ::do_serialize(ar, e);
+      return do_serialize(ar, e);
     }
 
     template<typename Archive, typename T>
@@ -52,7 +52,7 @@ namespace serialization
       static constexpr const bool previously_varint = std::is_same<uint64_t, T>() || std::is_same<uint32_t, T>();
 
       if (!previously_varint && ar.varint_bug_backward_compatibility_enabled() && !typename Archive::is_saving())
-        return ::do_serialize(ar, e);
+        return do_serialize(ar, e);
       ar.serialize_varint(e);
       return true;
     }
diff --git a/src/serialization/debug_archive.h b/src/serialization/debug_archive.h
index ef3bb4345..f4df963db 100644
--- a/src/serialization/debug_archive.h
+++ b/src/serialization/debug_archive.h
@@ -42,14 +42,12 @@ struct debug_archive : public json_archive<W> {
 };
 
 template <class T>
-struct serializer<debug_archive<true>, T>
+static inline bool do_serialize(debug_archive<true> &ar, T &v)
 {
-  static void serialize(debug_archive<true> &ar, T &v)
-  {
     ar.begin_object();
     ar.tag(variant_serialization_traits<debug_archive<true>, T>::get_tag());
-    serializer<json_archive<true>, T>::serialize(ar, v);
+    do_serialize(static_cast<json_archive<true>&>(ar), v);
     ar.end_object();
     ar.stream() << std::endl;
-  }
-};
+    return true;
+}
diff --git a/src/serialization/difficulty_type.h b/src/serialization/difficulty_type.h
index 37761839b..c071f287b 100644
--- a/src/serialization/difficulty_type.h
+++ b/src/serialization/difficulty_type.h
@@ -31,8 +31,6 @@
 #include "cryptonote_basic/difficulty.h"
 #include "serialization.h"
 
-template<> struct is_basic_type<cryptonote::difficulty_type> { typedef boost::true_type type; };
-
 template <template <bool> class Archive>
 inline bool do_serialize(Archive<false>& ar, cryptonote::difficulty_type &diff)
 {
diff --git a/src/serialization/pair.h b/src/serialization/pair.h
index f21041fe8..888033fb9 100644
--- a/src/serialization/pair.h
+++ b/src/serialization/pair.h
@@ -47,7 +47,7 @@ namespace serialization
     typename std::enable_if<!use_pair_varint<T>(), bool>::type
     serialize_pair_element(Archive& ar, T& e)
     {
-      return ::do_serialize(ar, e);
+      return do_serialize(ar, e);
     }
 
     template<typename Archive, typename T>
@@ -57,7 +57,7 @@ namespace serialization
       static constexpr const bool previously_varint = std::is_same<uint64_t, T>();
 
       if (!previously_varint && ar.varint_bug_backward_compatibility_enabled() && !typename Archive::is_saving())
-        return ::do_serialize(ar, e);
+        return do_serialize(ar, e);
       ar.serialize_varint(e);
       return true;
     }
diff --git a/src/serialization/serialization.h b/src/serialization/serialization.h
index efe1270a4..2911aecb5 100644
--- a/src/serialization/serialization.h
+++ b/src/serialization/serialization.h
@@ -57,73 +57,30 @@
 template <class T>
 struct is_blob_type { typedef boost::false_type type; };
 
-/*! \struct has_free_serializer
- *
- * \brief a descriptor for dispatching serialize
- */
-template <class T>
-struct has_free_serializer { typedef boost::true_type type; };
-
-/*! \struct is_basic_type
- *
- * \brief a descriptor for dispatching serialize
- */
-template <class T>
-struct is_basic_type { typedef boost::false_type type; };
-
-template<typename F, typename S>
-struct is_basic_type<std::pair<F,S>> { typedef boost::true_type type; };
-template<>
-struct is_basic_type<std::string> { typedef boost::true_type type; };
-
-/*! \struct serializer
+/*! \fn do_serialize(Archive &ar, T &v)
  *
- * \brief ... wouldn't a class be better?
+ * \brief main function for dispatching serialization for a given pair of archive and value types
  * 
- * \detailed The logic behind serializing data. Places the archive
- * data into the supplied parameter. This dispatches based on the
- * supplied \a T template parameter's traits of is_blob_type or it is
- * an integral (as defined by the is_integral trait). Depends on the
- * \a Archive parameter to have overloaded the serialize_blob(T v,
- * size_t size) and serialize_int(T v) base on which trait it
- * applied. When the class has neither types, it falls to the
- * overloaded method do_serialize(Archive ar) in T to do the work.
+ * Types marked true with is_blob_type<T> will be serialized as a blob, integral types will be
+ * serialized as integers, and types who have a `member_do_serialize` method will be serialized
+ * using that method. Booleans are serialized like blobs.
  */
 template <class Archive, class T>
-struct serializer{
-  static bool serialize(Archive &ar, T &v) {
-    return serialize(ar, v, typename boost::is_integral<T>::type(), typename is_blob_type<T>::type(), typename is_basic_type<T>::type());
-  }
-  template<typename A>
-  static bool serialize(Archive &ar, T &v, boost::false_type, boost::true_type, A a) {
-    ar.serialize_blob(&v, sizeof(v));
-    return true;
-  }
-  template<typename A>
-  static bool serialize(Archive &ar, T &v, boost::true_type, boost::false_type, A a) {
-    ar.serialize_int(v);
-    return true;
-  }
-  static bool serialize(Archive &ar, T &v, boost::false_type, boost::false_type, boost::false_type) {
-    //serialize_custom(ar, v, typename has_free_serializer<T>::type());
-    return v.do_serialize(ar);
-  }
-  static bool serialize(Archive &ar, T &v, boost::false_type, boost::false_type, boost::true_type) {
-    //serialize_custom(ar, v, typename has_free_serializer<T>::type());
-    return do_serialize(ar, v);
-  }
-  static void serialize_custom(Archive &ar, T &v, boost::true_type) {
-  }
-};
-
-/*! \fn do_serialize(Archive &ar, T &v)
- *
- * \brief just calls the serialize function defined for ar and v...
- */
+inline std::enable_if_t<is_blob_type<T>::type::value, bool> do_serialize(Archive &ar, T &v)
+{
+  ar.serialize_blob(&v, sizeof(v));
+  return true;
+}
 template <class Archive, class T>
-inline bool do_serialize(Archive &ar, T &v)
+inline std::enable_if_t<boost::is_integral<T>::value, bool> do_serialize(Archive &ar, T &v)
 {
-  return ::serializer<Archive, T>::serialize(ar, v);
+  ar.serialize_int(v);
+  return true;
+}
+template <class Archive, class T>
+inline auto do_serialize(Archive &ar, T &v) -> decltype(v.member_do_serialize(ar), true)
+{
+  return v.member_do_serialize(ar);
 }
 template <class Archive>
 inline bool do_serialize(Archive &ar, bool &v)
@@ -144,16 +101,6 @@ inline bool do_serialize(Archive &ar, bool &v)
     typedef boost::true_type type;					\
   }
 
-/*! \macro FREE_SERIALIZER
- *
- * \brief adds the has_free_serializer to the type
- */
-#define FREE_SERIALIZER(T)						\
-  template<>								\
-  struct has_free_serializer<T> {					\
-    typedef boost::true_type type;					\
-  }
-
 /*! \macro VARIANT_TAG
  *
  * \brief Adds the tag \tag to the \a Archive of \a Type
@@ -174,7 +121,7 @@ inline bool do_serialize(Archive &ar, bool &v)
  */
 #define BEGIN_SERIALIZE()						\
   template <bool W, template <bool> class Archive>			\
-  bool do_serialize(Archive<W> &ar) {
+  bool member_do_serialize(Archive<W> &ar) {
 
 /*! \macro BEGIN_SERIALIZE_OBJECT
  *
@@ -183,7 +130,7 @@ inline bool do_serialize(Archive &ar, bool &v)
  */
 #define BEGIN_SERIALIZE_OBJECT()					\
   template <bool W, template <bool> class Archive>			\
-  bool do_serialize(Archive<W> &ar) {					\
+  bool member_do_serialize(Archive<W> &ar) {					\
     ar.begin_object();							\
     bool r = do_serialize_object(ar);					\
     ar.end_object();							\
@@ -197,11 +144,6 @@ inline bool do_serialize(Archive &ar, bool &v)
 #define PREPARE_CUSTOM_VECTOR_SERIALIZATION(size, vec)			\
   ::serialization::detail::prepare_custom_vector_serialization(size, vec, typename Archive<W>::is_saving())
 
-/*! \macro PREPARE_CUSTOM_DEQUE_SERIALIZATION
- */
-#define PREPARE_CUSTOM_DEQUE_SERIALIZATION(size, vec)			\
-  ::serialization::detail::prepare_custom_deque_serialization(size, vec, typename Archive<W>::is_saving())
-
 /*! \macro END_SERIALIZE
  * \brief self-explanatory
  */
@@ -209,16 +151,6 @@ inline bool do_serialize(Archive &ar, bool &v)
   return ar.good();				\
   }
 
-/*! \macro VALUE(f)
- * \brief the same as FIELD(f)
- */
-#define VALUE(f)					\
-  do {							\
-    ar.tag(#f);						\
-    bool r = ::do_serialize(ar, f);			\
-    if (!r || !ar.good()) return false;			\
-  } while(0);
-
 /*! \macro FIELD_N(t,f)
  *
  * \brief serializes a field \a f tagged \a t  
@@ -226,7 +158,7 @@ inline bool do_serialize(Archive &ar, bool &v)
 #define FIELD_N(t, f)					\
   do {							\
     ar.tag(t);						\
-    bool r = ::do_serialize(ar, f);			\
+    bool r = do_serialize(ar, f);			\
     if (!r || !ar.good()) return false;			\
   } while(0);
 
@@ -237,7 +169,7 @@ inline bool do_serialize(Archive &ar, bool &v)
 #define FIELD(f)					\
   do {							\
     ar.tag(#f);						\
-    bool r = ::do_serialize(ar, f);			\
+    bool r = do_serialize(ar, f);			\
     if (!r || !ar.good()) return false;			\
   } while(0);
 
@@ -247,7 +179,7 @@ inline bool do_serialize(Archive &ar, bool &v)
  */
 #define FIELDS(f)							\
   do {									\
-    bool r = ::do_serialize(ar, f);					\
+    bool r = do_serialize(ar, f);					\
     if (!r || !ar.good()) return false;					\
   } while(0);
 
@@ -317,17 +249,6 @@ namespace serialization {
       vec.resize(size);
     }
 
-    template <typename T>
-    void prepare_custom_deque_serialization(size_t size, std::deque<T>& vec, const boost::mpl::bool_<true>& /*is_saving*/)
-    {
-    }
-
-    template <typename T>
-    void prepare_custom_deque_serialization(size_t size, std::deque<T>& vec, const boost::mpl::bool_<false>& /*is_saving*/)
-    {
-      vec.resize(size);
-    }
-
     /*! \fn do_check_stream_state
      *
      * \brief self explanatory
diff --git a/src/serialization/tuple.h b/src/serialization/tuple.h
index e76ca0b99..d9592bc96 100644
--- a/src/serialization/tuple.h
+++ b/src/serialization/tuple.h
@@ -39,7 +39,7 @@ namespace serialization
     template <typename Archive, class T>
     bool serialize_tuple_element(Archive& ar, T& e)
     {
-      return ::do_serialize(ar, e);
+      return do_serialize(ar, e);
     }
 
     template <typename Archive>
diff --git a/src/serialization/variant.h b/src/serialization/variant.h
index 77d767a1c..1cf93c8cf 100644
--- a/src/serialization/variant.h
+++ b/src/serialization/variant.h
@@ -72,7 +72,7 @@ struct variant_reader
   {
     if(variant_serialization_traits<Archive, current_type>::get_tag() == t) {
       current_type x;
-      if(!::do_serialize(ar, x))
+      if(!do_serialize(ar, x))
       {
         ar.set_fail();
         return false;
@@ -100,19 +100,13 @@ struct variant_reader<Archive, Variant, TBegin, TBegin>
   }
 };
 
-
-template <template <bool> class Archive, BOOST_VARIANT_ENUM_PARAMS(typename T)>
-struct serializer<Archive<false>, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>>
-{
-  typedef boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> variant_type;
-  typedef typename Archive<false>::variant_tag_type variant_tag_type;
-  typedef typename variant_type::types types;
-
-  static bool serialize(Archive<false> &ar, variant_type &v) {
-    variant_tag_type t;
+template <template <bool> class Archive, typename... T>
+static bool do_serialize(Archive<false> &ar, boost::variant<T...> &v) {
+    using types = typename boost::variant<T...>::types;
+    typename Archive<false>::variant_tag_type t;
     ar.begin_variant();
     ar.read_variant_tag(t);
-    if(!variant_reader<Archive<false>, variant_type,
+    if(!variant_reader<Archive<false>, boost::variant<T...>,
        typename boost::mpl::begin<types>::type,
        typename boost::mpl::end<types>::type>::read(ar, v, t))
     {
@@ -121,27 +115,21 @@ struct serializer<Archive<false>, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>>
     }
     ar.end_variant();
     return true;
-  }
-};
+}
 
-template <template <bool> class Archive, BOOST_VARIANT_ENUM_PARAMS(typename T)>
-struct serializer<Archive<true>, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>>
+template <template <bool> class Archive>
+struct variant_write_visitor : public boost::static_visitor<bool>
 {
-  typedef boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> variant_type;
-  //typedef typename Archive<true>::variant_tag_type variant_tag_type;
-
-  struct visitor : public boost::static_visitor<bool>
-  {
     Archive<true> &ar;
 
-    visitor(Archive<true> &a) : ar(a) { }
+    variant_write_visitor(Archive<true> &a) : ar(a) { }
 
     template <class T>
     bool operator ()(T &rv) const
     {
       ar.begin_variant();
       ar.write_variant_tag(variant_serialization_traits<Archive<true>, T>::get_tag());
-      if(!::do_serialize(ar, rv))
+      if(!do_serialize(ar, rv))
       {
         ar.set_fail();
         return false;
@@ -149,9 +137,10 @@ struct serializer<Archive<true>, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>>
       ar.end_variant();
       return true;
     }
-  };
-
-  static bool serialize(Archive<true> &ar, variant_type &v) {
-    return boost::apply_visitor(visitor(ar), v);
-  }
 };
+
+template <template <bool> class Archive, typename... T>
+static bool do_serialize(Archive<true> &ar, boost::variant<T...> &v)
+{
+  return boost::apply_visitor(variant_write_visitor<Archive>(ar), v);
+}
diff --git a/tests/unit_tests/serialization.cpp b/tests/unit_tests/serialization.cpp
index 49f1dc310..ab81acefc 100644
--- a/tests/unit_tests/serialization.cpp
+++ b/tests/unit_tests/serialization.cpp
@@ -59,9 +59,7 @@ struct Struct
 };
 
 template <class Archive>
-struct serializer<Archive, Struct>
-{
-  static bool serialize(Archive &ar, Struct &s) {
+static bool do_serialize(Archive &ar, Struct &s) {
     ar.begin_object();
     ar.tag("a");
     ar.serialize_int(s.a);
@@ -71,8 +69,7 @@ struct serializer<Archive, Struct>
     ar.serialize_blob(s.blob, sizeof(s.blob));
     ar.end_object();
     return true;
-  }
-};
+}
 
 struct Struct1
 {
@@ -122,6 +119,23 @@ bool try_parse(const string &blob)
   return serialization::parse_binary(blob, s1);
 }
 
+namespace example_namespace
+{
+  struct ADLExampleStruct
+  {
+    std::string msg;
+  };
+
+  template <class Archive>
+  static bool do_serialize(Archive &ar, ADLExampleStruct &aes)
+  {
+    ar.begin_object();
+    FIELD_N("custom_fieldname", aes.msg);
+    ar.end_object();
+    return ar.good();
+  }
+}
+
 TEST(Serialization, BinaryArchiveInts) {
   uint64_t x = 0xff00000000, x1;
 
@@ -1178,3 +1192,18 @@ TEST(Serialization, difficulty_type)
 
   ASSERT_EQ(v_original, v_unserialized);
 }
+
+TEST(Serialization, adl_free_function)
+{
+  std::stringstream ss;
+  json_archive<true> ar(ss);
+
+  const std::string msg = "Howdy, World!";
+  example_namespace::ADLExampleStruct aes{msg};
+
+  ASSERT_TRUE(serialization::serialize(ar, aes));
+
+  //                                                       VVVVVVVVVVVVVVVVVVVVVVVVVV weird string serialization artifact
+  const std::string expected = "{\"custom_fieldname\": " + std::to_string(msg.size()) + '"' + epee::string_tools::buff_to_hex_nodelimer(msg) + "\"}";
+  EXPECT_EQ(expected, ss.str());
+}