Branch.hpp

/* Copyright (C) 2019-2021 GSI, MEPhI, Universität Tübingen
   SPDX-License-Identifier: GPL-3.0-only
   Authors: Eugeny Kashirin, Viktor Klochkov, Ilya Selyuzhenkov */
#ifndef ANALYSISTREE_INFRA_BRANCH_HPP_
#define ANALYSISTREE_INFRA_BRANCH_HPP_
 
#include <cassert>
#include <map>
#include <utility>
#include <vector>
 
#include "BranchChannel.hpp"
#include "BranchConfig.hpp"
#include "Configuration.hpp"
#include "EventHeader.hpp"
#include "Field.hpp"
#include "VariantMagic.hpp"
 
class TTree;
 
namespace AnalysisTree {
 
class Branch {
 public:
  /* c-tors */
  Branch() = default;
  Branch(const Branch&) = default;
  Branch(Branch&&) = default;
  Branch& operator=(Branch&&) = default;
  Branch& operator=(const Branch&) = default;
 
  explicit Branch(BranchConfig config) : config_(std::move(config)) {
    InitDataPtr();
    UpdateConfigHash();
  }
 
  template<class T>
  Branch(BranchConfig config, T* data) : config_(std::move(config)), data_(data) {
    UpdateConfigHash();
  }
 
  Branch(BranchConfig config, BranchPointer ptr) : config_(std::move(config)), data_(std::move(ptr)) {
    UpdateConfigHash();
  }
 
  ~Branch();
 
  struct FieldsMapping {
    std::vector<std::pair<Field /* src */, Field /* dst */>> field_pairs;
  };
 
  /* Accessors to branch' main parameters, used very often */
  [[nodiscard]] std::string GetBranchName() const { return config_.GetName(); }
  [[nodiscard]] DetType GetBranchType() const { return config_.GetType(); }
  [[nodiscard]] const BranchConfig& GetConfig() const { return config_; }
 
  void InitDataPtr();
 
  BranchChannel NewChannel();
  BranchChannel NullChannel();
  void ClearChannels();
  Field NewVariable(const std::string& field_name, const std::string& title, AnalysisTree::Types type);
  void CloneVariables(const AnalysisTree::BranchConfig& other);
 
  //  /* iterating */
  [[nodiscard]] size_t size() const;
 
  BranchChannel operator[](size_t i_channel) const {
    return BranchChannel(this, i_channel);
  }
 
  std::vector<std::string> GetFieldNames() const;
 
  [[nodiscard]] size_t GetId() const {
    return ANALYSISTREE_UTILS_VISIT(get_id_struct(), data_);
  }
 
  [[nodiscard]] BranchPointer GetData() const { return data_; }
  template<class T>
  [[nodiscard]] T& GetDataRaw() { return ANALYSISTREE_UTILS_GET<T>(data_); }
 
  [[nodiscard]] Field GetField(std::string field_name) const {
    Field field(config_.GetName(), std::move(field_name));
    field.Init(config_);
    return field;
  }
 
 private:
  AnalysisTree::BranchConfig config_;
  BranchPointer data_;
  bool is_mutable_{false};
  bool is_frozen_{false};
  std::size_t config_hash_{0};
 
 public:
  AnalysisTree::Configuration* parent_config{nullptr};
  mutable std::map<const Branch* /* other branch */, FieldsMapping> copy_fields_mapping;
 
  /* Modification */
  void Freeze(bool freeze = true) { is_frozen_ = freeze; };
  void SetMutable(bool is_mutable = true) { Branch::is_mutable_ = is_mutable; }
 
  /* Checks are used very often */
  inline void CheckFrozen(bool expected = true) const {
    if (is_frozen_ != expected) {
      const std::string prefix = expected ? "un" : "";
      const std::string message = "Branch " + config_.GetName() + " is " + prefix + "frozen while the opposite was expected";
      throw std::runtime_error(message);
    }
  }
  inline void CheckMutable(bool expected = true) const {
    if (is_mutable_ != expected) {
      const std::string prefix = expected ? "im" : "";
      const std::string message = "Branch " + config_.GetName() + " is " + prefix + "mutable while the opposite was expected";
      throw std::runtime_error(message);
    }
  }
#ifdef cpp17
  template<typename... Args>
  auto GetVars(Args... field_name) {
    return GetVarsImpl(std::array<std::string, sizeof...(Args)>{{std::string(field_name)...}},
                       std::make_index_sequence<sizeof...(Args)>());
  }
  void UseFields(std::vector<std::pair<std::string, std::reference_wrapper<Field>>>&& vars, bool ignore_missing = false);
  //  [[nodiscard]] std::vector<std::string> GetFieldNames() const;

  template<typename EntityPtr>
  constexpr static const bool is_event_header_v =
      std::is_same_v<AnalysisTree::EventHeader, std::remove_const_t<std::remove_pointer_t<EntityPtr>>>;
#endif
 
  void CopyContentsRaw(Branch* other);
 
  void CreateMapping(const Branch* other, std::string branch_name_prefix = "") const;
 
  void UpdateConfigHash();
 
  [[nodiscard]] AnalysisTree::ShortInt_t Hash() const {
    const auto hasher = std::hash<std::string>();
    return AnalysisTree::ShortInt_t(hasher(config_.GetName()));
  }
 
 private:
  //  template<size_t... Idx>
  //  auto GetVarsImpl(std::array<std::string, sizeof...(Idx)>&& field_names, std::index_sequence<Idx...>) {
  //    return std::make_tuple(GetFieldVar(field_names[Idx])...);
  //  }
};
 
}// namespace AnalysisTree
 
#endif//ANALYSISTREE_INFRA_BRANCH_HPP_