REF: Refactor DBN versioning in C++ client

Author: threecgreen

CHANGELOG.md

@@ -5,6 +5,13 @@
 ### Breaking changes
 - Removed deprecated `Packaging` enum and `packaging` field that's no longer supported
   by the API
+- Renamed `VersionUpgradePolicy::Upgrade` to `UpgradeToV2` in preparation for a future
+  DBN version 3
+
+### Enhancements
+- Created separate namespaces for each DBN version to create a consistent way to refer
+  to record types from a particular DBN version regardless of whether the record changed
+  between versions
 
 ## 0.25.0 - 2024-11-12
 

cmake/SourcesAndHeaders.cmake

@@ -31,13 +31,14 @@ set(headers
   include/databento/symbol_map.hpp
   include/databento/symbology.hpp
   include/databento/timeseries.hpp
+  include/databento/v1.hpp
+  include/databento/v2.hpp
   include/databento/with_ts_out.hpp
   src/stream_op_helper.hpp
 )
 
 set(sources
   src/batch.cpp
-  src/compat.cpp
   src/datetime.cpp
   src/dbn.cpp
   src/dbn_constants.hpp
@@ -65,4 +66,5 @@ set(sources
   src/record.cpp
   src/symbol_map.cpp
   src/symbology.cpp
+  src/v1.cpp
 )

include/databento/compat.hpp

@@ -4,201 +4,24 @@
 #include <cstddef>  // size_t
 #include <cstdint>
 
-#include "databento/constants.hpp"  // kSymbolCstrLen
-#include "databento/datetime.hpp"   // UnixNanos
-#include "databento/enums.hpp"
-#include "databento/record.hpp"
+#include "databento/v1.hpp"
+#include "databento/v2.hpp"
 
 namespace databento {
-static constexpr std::size_t kSymbolCstrLenV1 = 22;
-static constexpr std::size_t kSymbolCstrLenV2 = kSymbolCstrLen;
+static constexpr std::size_t kSymbolCstrLenV1 = v1::kSymbolCstrLen;
+static constexpr std::size_t kSymbolCstrLenV2 = v2::kSymbolCstrLen;
 
 constexpr std::size_t VersionSymbolCstrLen(std::uint8_t version) {
   return version < 2 ? kSymbolCstrLenV1 : kSymbolCstrLenV2;
 }
 
-using InstrumentDefMsgV2 = InstrumentDefMsg;
-using ErrorMsgV2 = ErrorMsg;
-using SymbolMappingMsgV2 = SymbolMappingMsg;
-using SystemMsgV2 = SystemMsg;
-
+using InstrumentDefMsgV1 = v1::InstrumentDefMsg;
+using InstrumentDefMsgV2 = v2::InstrumentDefMsg;
+using ErrorMsgV1 = v1::ErrorMsg;
+using ErrorMsgV2 = v2::ErrorMsg;
+using SymbolMappingMsgV1 = v1::SymbolMappingMsg;
+using SymbolMappingMsgV2 = v2::SymbolMappingMsg;
+using SystemMsgV1 = v1::SystemMsg;
+using SystemMsgV2 = v2::SystemMsg;
 // DBN version 1 instrument definition.
-struct InstrumentDefMsgV1 {
-  static bool HasRType(RType rtype) { return rtype == RType::InstrumentDef; }
-
-  InstrumentDefMsgV2 ToV2() const;
-  const char* Currency() const { return currency.data(); }
-  const char* SettlCurrency() const { return settl_currency.data(); }
-  const char* SecSubType() const { return secsubtype.data(); }
-  const char* RawSymbol() const { return raw_symbol.data(); }
-  const char* Group() const { return group.data(); }
-  const char* Exchange() const { return exchange.data(); }
-  const char* Asset() const { return asset.data(); }
-  const char* Cfi() const { return cfi.data(); }
-  const char* SecurityType() const { return security_type.data(); }
-  const char* UnitOfMeasure() const { return unit_of_measure.data(); }
-  const char* Underlying() const { return underlying.data(); }
-  const char* StrikePriceCurrency() const {
-    return strike_price_currency.data();
-  }
-
-  RecordHeader hd;
-  UnixNanos ts_recv;
-  std::int64_t min_price_increment;
-  std::int64_t display_factor;
-  UnixNanos expiration;
-  UnixNanos activation;
-  std::int64_t high_limit_price;
-  std::int64_t low_limit_price;
-  std::int64_t max_price_variation;
-  std::int64_t trading_reference_price;
-  std::int64_t unit_of_measure_qty;
-  std::int64_t min_price_increment_amount;
-  std::int64_t price_ratio;
-  std::int32_t inst_attrib_value;
-  std::uint32_t underlying_id;
-  std::uint32_t raw_instrument_id;
-  std::int32_t market_depth_implied;
-  std::int32_t market_depth;
-  std::uint32_t market_segment_id;
-  std::uint32_t max_trade_vol;
-  std::int32_t min_lot_size;
-  std::int32_t min_lot_size_block;
-  std::int32_t min_lot_size_round_lot;
-  std::uint32_t min_trade_vol;
-  std::array<char, 4> _reserved2;
-  std::int32_t contract_multiplier;
-  std::int32_t decay_quantity;
-  std::int32_t original_contract_size;
-  std::array<char, 4> _reserved3;
-  std::uint16_t trading_reference_date;
-  std::int16_t appl_id;
-  std::uint16_t maturity_year;
-  std::uint16_t decay_start_date;
-  std::uint16_t channel_id;
-  std::array<char, 4> currency;
-  std::array<char, 4> settl_currency;
-  std::array<char, 6> secsubtype;
-  std::array<char, kSymbolCstrLenV1> raw_symbol;
-  std::array<char, 21> group;
-  std::array<char, 5> exchange;
-  std::array<char, 7> asset;
-  std::array<char, 7> cfi;
-  std::array<char, 7> security_type;
-  std::array<char, 31> unit_of_measure;
-  std::array<char, 21> underlying;
-  std::array<char, 4> strike_price_currency;
-  InstrumentClass instrument_class;
-  std::array<char, 2> _reserved4;
-  std::int64_t strike_price;
-  std::array<char, 6> _reserved5;
-  MatchAlgorithm match_algorithm;
-  std::uint8_t md_security_trading_status;
-  std::uint8_t main_fraction;
-  std::uint8_t price_display_format;
-  std::uint8_t settl_price_type;
-  std::uint8_t sub_fraction;
-  std::uint8_t underlying_product;
-  SecurityUpdateAction security_update_action;
-  std::uint8_t maturity_month;
-  std::uint8_t maturity_day;
-  std::uint8_t maturity_week;
-  UserDefinedInstrument user_defined_instrument;
-  std::int8_t contract_multiplier_unit;
-  std::int8_t flow_schedule_type;
-  std::uint8_t tick_rule;
-  // padding for alignment
-  std::array<char, 3> dummy;
-};
-static_assert(sizeof(InstrumentDefMsgV1) == 360, "Size must match Rust");
-static_assert(alignof(InstrumentDefMsgV1) == 8, "Must have 8-byte alignment");
-
-// An error message from the Live Subscription Gateway (LSG). This will never
-// be present in historical data.
-struct ErrorMsgV1 {
-  static bool HasRType(RType rtype) { return rtype == RType::Error; }
-
-  ErrorMsgV2 ToV2() const;
-  UnixNanos IndexTs() const { return hd.ts_event; }
-  const char* Err() const { return err.data(); }
-
-  RecordHeader hd;
-  std::array<char, 64> err;
-};
-static_assert(sizeof(ErrorMsgV1) == 80, "ErrorMsg size must match Rust");
-static_assert(alignof(ErrorMsgV1) == 8, "Must have 8-byte alignment");
-
-/// A symbol mapping message.
-struct SymbolMappingMsgV1 {
-  static bool HasRType(RType rtype) { return rtype == RType::SymbolMapping; }
-
-  SymbolMappingMsgV2 ToV2() const;
-  const char* STypeInSymbol() const { return stype_in_symbol.data(); }
-  const char* STypeOutSymbol() const { return stype_out_symbol.data(); }
-
-  RecordHeader hd;
-  std::array<char, kSymbolCstrLenV1> stype_in_symbol;
-  std::array<char, kSymbolCstrLenV1> stype_out_symbol;
-  // padding for alignment
-  std::array<char, 4> dummy;
-  UnixNanos start_ts;
-  UnixNanos end_ts;
-};
-static_assert(sizeof(SymbolMappingMsgV1) == 80, "Size must match Rust");
-static_assert(alignof(SymbolMappingMsgV1) == 8, "Must have 8-byte alignment");
-
-struct SystemMsgV1 {
-  static bool HasRType(RType rtype) { return rtype == RType::System; }
-
-  SystemMsgV2 ToV2() const;
-  UnixNanos IndexTs() const { return hd.ts_event; }
-  const char* Msg() const { return msg.data(); }
-  bool IsHeartbeat() const {
-    return std::strncmp(msg.data(), "Heartbeat", 9) == 0;
-  }
-
-  RecordHeader hd;
-  std::array<char, 64> msg;
-};
-static_assert(sizeof(SystemMsgV1) == 80, "SystemMsg size must match Rust");
-static_assert(alignof(SystemMsgV1) == 8, "Must have 8-byte alignment");
-
-bool operator==(const InstrumentDefMsgV1& lhs, const InstrumentDefMsgV1& rhs);
-inline bool operator!=(const InstrumentDefMsgV1& lhs,
-                       const InstrumentDefMsgV1& rhs) {
-  return !(lhs == rhs);
-}
-inline bool operator==(const ErrorMsgV1& lhs, const ErrorMsgV1& rhs) {
-  return std::tie(lhs.hd, lhs.err) == std::tie(rhs.hd, rhs.err);
-}
-inline bool operator!=(const ErrorMsgV1& lhs, const ErrorMsgV1& rhs) {
-  return !(lhs == rhs);
-}
-inline bool operator==(const SymbolMappingMsgV1& lhs,
-                       const SymbolMappingMsgV1& rhs) {
-  return std::tie(lhs.hd, lhs.stype_in_symbol, lhs.stype_out_symbol,
-                  lhs.start_ts, lhs.end_ts) ==
-         std::tie(rhs.hd, rhs.stype_in_symbol, rhs.stype_out_symbol,
-                  rhs.start_ts, rhs.end_ts);
-}
-inline bool operator!=(const SymbolMappingMsgV1& lhs,
-                       const SymbolMappingMsgV1& rhs) {
-  return !(lhs == rhs);
-}
-inline bool operator==(const SystemMsgV1& lhs, const SystemMsgV1& rhs) {
-  return std::tie(lhs.hd, lhs.msg) == std::tie(rhs.hd, rhs.msg);
-}
-inline bool operator!=(const SystemMsgV1& lhs, const SystemMsgV1& rhs) {
-  return !(lhs == rhs);
-}
-std::string ToString(const InstrumentDefMsgV1& instr_def_msg);
-std::ostream& operator<<(std::ostream& stream,
-                         const InstrumentDefMsgV1& instr_def_msg);
-std::string ToString(const ErrorMsgV1& err_msg);
-std::ostream& operator<<(std::ostream& stream, const ErrorMsgV1& err_msg);
-std::string ToString(const SymbolMappingMsgV1& symbol_mapping_msg);
-std::ostream& operator<<(std::ostream& stream,
-                         const SymbolMappingMsgV1& symbol_mapping_msg);
-std::string ToString(const SystemMsgV1& sys_msg);
-std::ostream& operator<<(std::ostream& stream, const SystemMsgV1& sys_msg);
 }  // namespace databento

include/databento/enums.hpp

@@ -297,7 +297,7 @@ enum class StatUpdateAction : std::uint8_t {
 // How to handle decoding DBN data from a prior version.
 enum class VersionUpgradePolicy : std::uint8_t {
   AsIs = 0,
-  Upgrade = 1,
+  UpgradeToV2 = 1,
 };
 
 namespace status_action {

include/databento/live.hpp

@@ -52,7 +52,7 @@ class LiveBuilder {
   std::string key_;
   std::string dataset_;
   bool send_ts_out_{false};
-  VersionUpgradePolicy upgrade_policy_{VersionUpgradePolicy::Upgrade};
+  VersionUpgradePolicy upgrade_policy_{VersionUpgradePolicy::UpgradeToV2};
   std::chrono::seconds heartbeat_interval_{};
 };
 }  // namespace databento