Serialization.h

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#ifndef CondCore_CondDB_Serialization_h
#define CondCore_CondDB_Serialization_h
//
// Package:     CondDB
//
//
// Author:      Giacomo Govi
// Created:     October 2013
//
//

#include "CondCore/CondDB/interface/Binary.h"
#include "CondCore/CondDB/interface/Exception.h"
#include "CondCore/CondDB/interface/Utils.h"
//
#include <sstream>
#include <iostream>
#include <memory>
//
// temporarely

#include "CondFormats/Serialization/interface/Archive.h"

namespace cond {

  // default payload factory
  template <typename T>
  T* createPayload(const std::string& payloadTypeName) {
    std::string userTypeName = demangledName(typeid(T));
    if (userTypeName != payloadTypeName)
      throwException(
          std::string("Type mismatch, user type: \"" + userTypeName + "\", target type: \"") + payloadTypeName + "\"",
          "createPayload");
    return new T;
  }

  template <>
  inline std::string* createPayload<std::string>(const std::string& payloadTypeName) {
    std::string userTypeName = demangledName(typeid(std::string));
    if (payloadTypeName != userTypeName && payloadTypeName != "std::string")
      throwException(std::string("Type mismatch, user type: \"std::string\", target type: \"") + payloadTypeName + "\"",
                     "createPayload");
    return new std::string;
  }

  class StreamerInfo {
  public:
    static constexpr char const* TECH_LABEL = "technology";
    static constexpr char const* TECH_VERSION_LABEL = "tech_version";
    static constexpr char const* CMSSW_VERSION_LABEL = "CMSSW_version";
    static constexpr char const* ARCH_LABEL = "architecture";
    //
    static constexpr char const* TECHNOLOGY = "boost/serialization";
    static std::string techVersion();
    static std::string jsonString();
  };

  typedef cond::serialization::InputArchive CondInputArchive;
  typedef cond::serialization::OutputArchive CondOutputArchive;

  // call for the serialization.
  template <typename T>
  std::pair<Binary, Binary> serialize(const T& payload) {
    std::pair<Binary, Binary> ret;
    std::string streamerInfo(StreamerInfo::jsonString());
    try {
      // save data to buffers
      std::ostringstream dataBuffer;
      CondOutputArchive oa(dataBuffer);
      oa << payload;
      //TODO: avoid (2!!) copies
      ret.first.copy(dataBuffer.str());
      ret.second.copy(streamerInfo);
    } catch (const std::exception& e) {
      std::string em(e.what());
      throwException("Serialization failed: " + em + ". Serialization info:" + streamerInfo, "serialize");
    }
    return ret;
  }

  // generates an instance of T from the binary serialized data.
  template <typename T>
  std::unique_ptr<T> default_deserialize(const std::string& payloadType,
                                         const Binary& payloadData,
                                         const Binary& streamerInfoData) {
    std::unique_ptr<T> payload;
    std::stringbuf sstreamerInfoBuf;
    sstreamerInfoBuf.pubsetbuf(static_cast<char*>(const_cast<void*>(streamerInfoData.data())), streamerInfoData.size());
    std::string streamerInfo = sstreamerInfoBuf.str();
    try {
      std::stringbuf sdataBuf;
      sdataBuf.pubsetbuf(static_cast<char*>(const_cast<void*>(payloadData.data())), payloadData.size());
      std::istream dataBuffer(&sdataBuf);
      CondInputArchive ia(dataBuffer);
      payload.reset(createPayload<T>(payloadType));
      ia >> (*payload);
    } catch (const std::exception& e) {
      std::string errorMsg("De-serialization failed: ");
      std::string em(e.what());
      if (em == "unsupported version") {
        errorMsg += "the current boost version (" + StreamerInfo::techVersion() +
                    ") is unable to read the payload. Data might have been serialized with an incompatible version.";
      } else if (em == "input stream error") {
        errorMsg += "data size does not fit with the current class layout. The Class " + payloadType +
                    " might have been changed with respect to the layout used in the upload.";
      } else {
        errorMsg += em;
      }
      if (!streamerInfo.empty())
        errorMsg += " Payload serialization info: " + streamerInfo;
      throwException(errorMsg, "default_deserialize");
    }
    return payload;
  }

  // default specialization
  template <typename T>
  std::unique_ptr<T> deserialize(const std::string& payloadType,
                                 const Binary& payloadData,
                                 const Binary& streamerInfoData) {
    return default_deserialize<T>(payloadType, payloadData, streamerInfoData);
  }

}  // namespace cond

#define DESERIALIZE_BASE_CASE(BASETYPENAME)                                               \
  if (payloadType == #BASETYPENAME) {                                                     \
    return default_deserialize<BASETYPENAME>(payloadType, payloadData, streamerInfoData); \
  }

#define DESERIALIZE_POLIMORPHIC_CASE(BASETYPENAME, DERIVEDTYPENAME)                          \
  if (payloadType == #DERIVEDTYPENAME) {                                                     \
    return default_deserialize<DERIVEDTYPENAME>(payloadType, payloadData, streamerInfoData); \
  }

#endif