[ugc] Template and macro magic for visitors.

3 files changed, 111 insertions, 146 deletions

diff --git a/ugc/serdes.hpp b/ugc/serdes.hpp
index f799403dcf..a6be07e468 100644
--- a/ugc/serdes.hpp
+++ b/ugc/serdes.hpp
@@ -28,63 +28,33 @@ class Serializer
 public:
   Serializer(Sink & sink, HeaderV0 const & header) : m_sink(sink), m_header(header) {}
 
-  void operator()(uint8_t const d) { WriteToSink(m_sink, d); }
-  void operator()(uint32_t const d) { WriteToSink(m_sink, d); }
-  void operator()(uint64_t const d) { WriteToSink(m_sink, d); }
-  void operator()(std::string const & s) { utils::WriteString(m_sink, s); }
+  void operator()(uint8_t const d, char const * /* name */ = nullptr) { WriteToSink(m_sink, d); }
+  void operator()(uint32_t const d, char const * /* name */ = nullptr) { WriteToSink(m_sink, d); }
+  void operator()(uint64_t const d, char const * /* name */ = nullptr) { WriteToSink(m_sink, d); }
+  void operator()(std::string const & s, char const * /* name */ = nullptr)
+  {
+    utils::WriteString(m_sink, s);
+  }
 
-  void SerRating(float const f)
+  void VisitRating(float const f, char const * /* name */ = nullptr)
   {
     CHECK_GREATER_OR_EQUAL(f, 0.0, ());
     auto const d = static_cast<uint32_t>(round(f * 10));
-    SerVarUint(d);
+    VisitVarUint(d);
   }
 
   template <typename T>
-  void SerVarUint(T const & t)
+  void VisitVarUint(T const & t, char const * /* name */ = nullptr)
   {
     WriteVarUint(m_sink, t);
   }
 
-  template <typename T>
-  void operator()(vector<T> const & vs)
-  {
-    SerVarUint(static_cast<uint32_t>(vs.size()));
-    for (auto const & v : vs)
-      (*this)(v);
-  }
-
-  void operator()(RatingRecord const & ratingRecord)
+  void operator()(Time const & t, char const * /* name */ = nullptr)
   {
-    (*this)(ratingRecord.m_key);
-    SerRating(ratingRecord.m_value);
+    VisitVarUint(ToDaysSinceEpoch(t));
   }
 
-  void operator()(Rating const & rating)
-  {
-    (*this)(rating.m_ratings);
-    SerRating(rating.m_aggValue);
-  }
-
-  void operator()(UID const & uid)
-  {
-    (*this)(uid.m_hi);
-    (*this)(uid.m_lo);
-  }
-
-  void operator()(Author const & author)
-  {
-    (*this)(author.m_uid);
-    (*this)(author.m_name);
-  }
-
-  void operator()(Text const & text)
-  {
-    (*this)(text.m_lang);
-    (*this)(text.m_text);
-  }
-
-  void operator()(Sentiment sentiment)
+  void operator()(Sentiment sentiment, char const * /* name */ = nullptr)
   {
     switch (sentiment)
     {
@@ -93,27 +63,18 @@ public:
     }
   }
 
-  void operator()(Review const & review)
-  {
-    (*this)(review.m_id);
-    (*this)(review.m_text);
-    (*this)(review.m_author);
-    SerRating(review.m_rating);
-    (*this)(review.m_sentiment);
-    SerVarUint(review.DaysSinceEpoch());
-  }
-
-  void operator()(Attribute const & attribute)
+  template <typename T>
+  void operator()(vector<T> const & vs, char const * /* name */ = nullptr)
   {
-    (*this)(attribute.m_key);
-    (*this)(attribute.m_value);
+    VisitVarUint(static_cast<uint32_t>(vs.size()));
+    for (auto const & v : vs)
+      (*this)(v);
   }
 
-  void operator()(UGC const & ugc)
+  template <typename R>
+  void operator()(R const & r, char const * /* name */ = nullptr)
   {
-    (*this)(ugc.m_rating);
-    (*this)(ugc.m_reviews);
-    (*this)(ugc.m_attributes);
+    r.Visit(*this);
   }
 
 private:
@@ -127,70 +88,47 @@ class DeserializerV0
 public:
   DeserializerV0(Source & source, HeaderV0 const & header) : m_source(source), m_header(header) {}
 
-  void operator()(uint8_t & d) { ReadPrimitiveFromSource(m_source, d); }
-  void operator()(uint32_t & d) { ReadPrimitiveFromSource(m_source, d); }
-  void operator()(uint64_t & d) { ReadPrimitiveFromSource(m_source, d); }
-  void operator()(std::string & s) { utils::ReadString(m_source, s); }
-
-  void DesRating(float & f)
-  {
-    uint32_t d = 0;
-    DesVarUint(d);
-    f = static_cast<float>(d) / 10;
-  }
-
-  template <typename T>
-  void DesVarUint(T & t)
+  void operator()(uint8_t & d, char const * /* name */ = nullptr)
   {
-    t = ReadVarUint<T, Source>(m_source);
+    ReadPrimitiveFromSource(m_source, d);
   }
-
-  template <typename T>
-  T DesVarUint()
+  void operator()(uint32_t & d, char const * /* name */ = nullptr)
   {
-    return ReadVarUint<T, Source>(m_source);
+    ReadPrimitiveFromSource(m_source, d);
   }
-
-  void operator()(RatingRecord & ratingRecord)
+  void operator()(uint64_t & d, char const * /* name */ = nullptr)
   {
-    (*this)(ratingRecord.m_key);
-    DesRating(ratingRecord.m_value);
+    ReadPrimitiveFromSource(m_source, d);
   }
-
-  template <typename T>
-  void operator()(vector<T> & vs)
+  void operator()(std::string & s, char const * /* name */ = nullptr)
   {
-    auto const size = DesVarUint<uint32_t>();
-    vs.resize(size);
-    for (auto & v : vs)
-      (*this)(v);
+    utils::ReadString(m_source, s);
   }
 
-  void operator()(Rating & rating)
+  void VisitRating(float & f, char const * /* name */ = nullptr)
   {
-    (*this)(rating.m_ratings);
-    DesRating(rating.m_aggValue);
+    auto const d = DesVarUint<uint32_t>();
+    f = static_cast<float>(d) / 10;
   }
 
-  void operator()(UID & uid)
+  template <typename T>
+  void VisitVarUint(T & t, char const * /* name */ = nullptr)
   {
-    (*this)(uid.m_hi);
-    (*this)(uid.m_lo);
+    t = ReadVarUint<T, Source>(m_source);
   }
 
-  void operator()(Author & author)
+  template <typename T>
+  T DesVarUint()
   {
-    (*this)(author.m_uid);
-    (*this)(author.m_name);
+    return ReadVarUint<T, Source>(m_source);
   }
 
-  void operator()(Text & text)
+  void operator()(Time & t, char const * /* name */ = nullptr)
   {
-    (*this)(text.m_lang);
-    (*this)(text.m_text);
+    t = FromDaysSinceEpoch(DesVarUint<uint32_t>());
   }
 
-  void operator()(Sentiment & sentiment)
+  void operator()(Sentiment & sentiment, char const * /* name */ = nullptr)
   {
     uint8_t s = 0;
     (*this)(s);
@@ -202,27 +140,19 @@ public:
     }
   }
 
-  void operator()(Review & review)
-  {
-    (*this)(review.m_id);
-    (*this)(review.m_text);
-    (*this)(review.m_author);
-    DesRating(review.m_rating);
-    (*this)(review.m_sentiment);
-    review.SetDaysSinceEpoch(DesVarUint<uint32_t>());
-  }
-
-  void operator()(Attribute & attribute)
+  template <typename T>
+  void operator()(vector<T> & vs, char const * /* name */ = nullptr)
   {
-    (*this)(attribute.m_key);
-    (*this)(attribute.m_value);
+    auto const size = DesVarUint<uint32_t>();
+    vs.resize(size);
+    for (auto & v : vs)
+      (*this)(v);
   }
 
-  void operator()(UGC & ugc)
+  template <typename R>
+  void operator()(R & r, char const * /* name */ = nullptr)
   {
-    (*this)(ugc.m_rating);
-    (*this)(ugc.m_reviews);
-    (*this)(ugc.m_attributes);
+    r.Visit(*this);
   }
 
 private:
diff --git a/ugc/types.hpp b/ugc/types.hpp
index 1fffe74d07..32e4e2cd64 100644
--- a/ugc/types.hpp
+++ b/ugc/types.hpp
@@ -4,7 +4,6 @@
 
 #include "coding/hex.hpp"
 
-
 #include <chrono>
 #include <cstdint>
 #include <memory>
@@ -13,6 +12,18 @@
 #include <string>
 #include <vector>
 
+#define DECLARE_VISITOR(...)          \
+  template <typename Visitor>         \
+  void Visit(Visitor & visitor)       \
+  {                                   \
+    __VA_ARGS__;                      \
+  }                                   \
+  template <typename Visitor>         \
+  void Visit(Visitor & visitor) const \
+  {                                   \
+    __VA_ARGS__;                      \
+  }
+
 namespace ugc
 {
 using TranslationKey = std::string;
@@ -33,11 +44,25 @@ inline std::string DebugPrint(Sentiment const & sentiment)
   }
 }
 
+inline uint32_t ToDaysSinceEpoch(Time const & time)
+{
+  auto const hours = std::chrono::duration_cast<std::chrono::hours>(time.time_since_epoch());
+  return static_cast<uint32_t>(hours.count()) / 24;
+}
+
+inline Time FromDaysSinceEpoch(uint32_t days)
+{
+  auto const hours = std::chrono::hours(days * 24);
+  return Time(hours);
+}
+
 struct RatingRecord
 {
   RatingRecord() = default;
   RatingRecord(TranslationKey const & key, float const value) : m_key(key), m_value(value) {}
 
+  DECLARE_VISITOR(visitor(m_key, "key"), visitor.VisitRating(m_value, "value"))
+
   bool operator==(RatingRecord const & rhs) const
   {
     return m_key == rhs.m_key && m_value == rhs.m_value;
@@ -62,6 +87,8 @@ struct Rating
   {
   }
 
+  DECLARE_VISITOR(visitor(m_ratings, "ratings"), visitor.VisitRating(m_aggValue, "aggValue"))
+
   bool operator==(Rating const & rhs) const
   {
     return m_ratings == rhs.m_ratings && m_aggValue == rhs.m_aggValue;
@@ -70,8 +97,8 @@ struct Rating
   friend std::string DebugPrint(Rating const & rating)
   {
     std::ostringstream os;
-    os << "Rating [ ratings:" << ::DebugPrint(rating.m_ratings) << ", aggValue:" << rating.m_aggValue
-       << " ]";
+    os << "Rating [ ratings:" << ::DebugPrint(rating.m_ratings)
+       << ", aggValue:" << rating.m_aggValue << " ]";
     return os.str();
   }
 
@@ -86,8 +113,9 @@ struct UID
 
   std::string ToString() const { return NumToHex(m_hi) + NumToHex(m_lo); }
 
-  bool operator==(UID const & rhs) const { return m_hi == rhs.m_hi && m_lo == rhs.m_lo; }
+  DECLARE_VISITOR(visitor(m_hi, "hi"), visitor(m_lo, "lo"));
 
+  bool operator==(UID const & rhs) const { return m_hi == rhs.m_hi && m_lo == rhs.m_lo; }
   friend std::string DebugPrint(UID const & uid)
   {
     std::ostringstream os;
@@ -104,8 +132,9 @@ struct Author
   Author() = default;
   Author(UID const & uid, std::string const & name) : m_uid(uid), m_name(name) {}
 
-  bool operator==(Author const & rhs) const { return m_uid == rhs.m_uid && m_name == rhs.m_name; }
+  DECLARE_VISITOR(visitor(m_uid, "uid"), visitor(m_name, "name"));
 
+  bool operator==(Author const & rhs) const { return m_uid == rhs.m_uid && m_name == rhs.m_name; }
   friend std::string DebugPrint(Author const & author)
   {
     std::ostringstream os;
@@ -122,8 +151,9 @@ struct Text
   Text() = default;
   Text(std::string const & text, uint8_t const lang) : m_text(text), m_lang(lang) {}
 
-  bool operator==(Text const & rhs) const { return m_lang == rhs.m_lang && m_text == rhs.m_text; }
+  DECLARE_VISITOR(visitor(m_lang, "lang"), visitor(m_text, "text"));
 
+  bool operator==(Text const & rhs) const { return m_lang == rhs.m_lang && m_text == rhs.m_text; }
   friend std::string DebugPrint(Text const & text)
   {
     std::ostringstream os;
@@ -147,24 +177,16 @@ struct Review
   {
   }
 
+  DECLARE_VISITOR(visitor(m_id, "id"), visitor(m_text, "text"), visitor(m_author, "author"),
+                  visitor.VisitRating(m_rating, "rating"), visitor(m_sentiment, "sentiment"),
+                  visitor(m_time, "time"))
+
   bool operator==(Review const & rhs) const
   {
     return m_id == rhs.m_id && m_text == rhs.m_text && m_author == rhs.m_author &&
            m_rating == rhs.m_rating && m_sentiment == rhs.m_sentiment && m_time == rhs.m_time;
   }
 
-  uint32_t DaysSinceEpoch() const
-  {
-    auto const hours = std::chrono::duration_cast<std::chrono::hours>(m_time.time_since_epoch());
-    return static_cast<uint32_t>(hours.count()) / 24;
-  }
-
-  void SetDaysSinceEpoch(uint32_t days)
-  {
-    auto const hours = std::chrono::hours(days * 24);
-    m_time = Time(hours);
-  }
-
   friend std::string DebugPrint(Review const & review)
   {
     std::ostringstream os;
@@ -174,7 +196,7 @@ struct Review
     os << "author:" << DebugPrint(review.m_author) << ", ";
     os << "rating:" << review.m_rating << ", ";
     os << "sentiment:" << DebugPrint(review.m_sentiment) << ", ";
-    os << "days since epoch:" << review.DaysSinceEpoch() << " ]";
+    os << "days since epoch:" << ToDaysSinceEpoch(review.m_time) << " ]";
     return os.str();
   }
 
@@ -196,6 +218,8 @@ struct Attribute
   {
   }
 
+  DECLARE_VISITOR(visitor(m_key, "key"), visitor(m_value, "value"))
+
   bool operator==(Attribute const & rhs) const
   {
     return m_key == rhs.m_key && m_value == rhs.m_value;
@@ -221,7 +245,11 @@ struct UGC
   {
   }
 
-  bool operator==(UGC const & rhs) const {
+  DECLARE_VISITOR(visitor(m_rating, "rating"), visitor(m_reviews, "review"),
+                  visitor(m_attributes, "attributes"))
+
+  bool operator==(UGC const & rhs) const
+  {
     return m_rating == rhs.m_rating && m_reviews == rhs.m_reviews &&
            m_attributes == rhs.m_attributes;
   }
@@ -274,3 +302,5 @@ struct UGCUpdate
   ReviewFeedback m_feedbacks;
 };
 }  // namespace ugc
+
+#undef DECLARE_VISITOR
diff --git a/ugc/ugc_tests/serdes_tests.cpp b/ugc/ugc_tests/serdes_tests.cpp
index 66638655a3..5687570f32 100644
--- a/ugc/ugc_tests/serdes_tests.cpp
+++ b/ugc/ugc_tests/serdes_tests.cpp
@@ -29,6 +29,7 @@ Rating GetTestRating()
 }
 
 MemWriter<Buffer> MakeSink(Buffer & buffer) { return MemWriter<Buffer>(buffer); }
+
 ReaderSource<MemReader> MakeSource(Buffer const & buffer)
 {
   MemReader reader(buffer.data(), buffer.size());
@@ -37,7 +38,7 @@ ReaderSource<MemReader> MakeSource(Buffer const & buffer)
 
 UNIT_TEST(SerDes_Rating)
 {
-  auto const expectedRating = GetTestRating();
+  auto expectedRating = GetTestRating();
   TEST_EQUAL(expectedRating, expectedRating, ());
 
   HeaderV0 header;
@@ -46,14 +47,16 @@ UNIT_TEST(SerDes_Rating)
 
   {
     auto sink = MakeSink(buffer);
-    Ser(sink, header)(expectedRating);
+    Ser ser(sink, header);
+    ser(expectedRating);
   }
 
   Rating actualRating({} /* ratings */, {} /* aggValue */);
 
   {
     auto source = MakeSource(buffer);
-    Des(source, header)(actualRating);
+    Des des(source, header);
+    des(actualRating);
   }
 
   TEST_EQUAL(expectedRating, actualRating, ());
@@ -61,7 +64,7 @@ UNIT_TEST(SerDes_Rating)
 
 UNIT_TEST(SerDes_UGC)
 {
-  auto const expectedUGC = Api::MakeTestUGC1();
+  auto expectedUGC = Api::MakeTestUGC1();
   TEST_EQUAL(expectedUGC, expectedUGC, ());
 
   HeaderV0 header;
@@ -70,13 +73,15 @@ UNIT_TEST(SerDes_UGC)
 
   {
     auto sink = MakeSink(buffer);
-    Ser(sink, header)(expectedUGC);
+    Ser ser(sink, header);
+    ser(expectedUGC);
   }
 
   UGC actualUGC({} /* rating */, {} /* reviews */, {} /* attributes */);
   {
     auto source = MakeSource(buffer);
-    Des(source, header)(actualUGC);
+    Des des(source, header);
+    des(actualUGC);
   }
 
   TEST_EQUAL(expectedUGC, actualUGC, ());