Class GraphWriter

tensorflow/core/summary/summary_db_writer.cc:216–375

};

class GraphWriter {
 public:
  static Status Save(Sqlite* db, SqliteTransaction* txn, IdAllocator* ids,
                     GraphDef* graph, uint64 now, int64 run_id, int64* graph_id)
      SQLITE_EXCLUSIVE_TRANSACTIONS_REQUIRED(*db) {
    TF_RETURN_IF_ERROR(ids->CreateNewId(graph_id));
    GraphWriter saver{db, txn, graph, now, *graph_id};
    saver.MapNameToNodeId();
    TF_RETURN_WITH_CONTEXT_IF_ERROR(saver.SaveNodeInputs(), "SaveNodeInputs");
    TF_RETURN_WITH_CONTEXT_IF_ERROR(saver.SaveNodes(), "SaveNodes");
    TF_RETURN_WITH_CONTEXT_IF_ERROR(saver.SaveGraph(run_id), "SaveGraph");
    return Status::OK();
  }

 private:
  GraphWriter(Sqlite* db, SqliteTransaction* txn, GraphDef* graph, uint64 now,
              int64 graph_id)
      : db_(db), txn_(txn), graph_(graph), now_(now), graph_id_(graph_id) {}

  void MapNameToNodeId() {
    size_t toto = static_cast<size_t>(graph_->node_size());
    name_copies_.reserve(toto);
    name_to_node_id_.reserve(toto);
    for (int node_id = 0; node_id < graph_->node_size(); ++node_id) {
      // Copy name into memory region, since we call clear_name() later.
      // Then wrap in StringPiece so we can compare slices without copy.
      name_copies_.emplace_back(graph_->node(node_id).name());
      name_to_node_id_.emplace(name_copies_.back(), node_id);
    }
  }

  Status SaveNodeInputs() {
    const char* sql = R"sql(
      INSERT INTO NodeInputs (
        graph_id,
        node_id,
        idx,
        input_node_id,
        input_node_idx,
        is_control
      ) VALUES (?, ?, ?, ?, ?, ?)
    )sql";
    SqliteStatement insert;
    TF_RETURN_IF_ERROR(db_->Prepare(sql, &insert));
    for (int node_id = 0; node_id < graph_->node_size(); ++node_id) {
      const NodeDef& node = graph_->node(node_id);
      for (int idx = 0; idx < node.input_size(); ++idx) {
        StringPiece name = node.input(idx);
        int64 input_node_id;
        int64 input_node_idx = 0;
        int64 is_control = 0;
        size_t i = name.rfind(':');
        if (i != StringPiece::npos) {
          if (!strings::safe_strto64(name.substr(i + 1, name.size() - i - 1),
                                     &input_node_idx)) {
            return errors::DataLoss("Bad NodeDef.input: ", name);
          }
          name.remove_suffix(name.size() - i);