json_template_unnest.h

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/*
  Copyright (c) 2021, 2025, Oracle and/or its affiliates.
 
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 2.0,
  as published by the Free Software Foundation.
 
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  as designated in a particular file or component or in included license
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  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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  You should have received a copy of the GNU General Public License
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*/
 
#ifndef ROUTER_SRC_REST_MRS_SRC_MRS_RESPONSE_ITEMS_FORMATTER_UNNEST_H_
#define ROUTER_SRC_REST_MRS_SRC_MRS_RESPONSE_ITEMS_FORMATTER_UNNEST_H_
 
#include <string>
#include <vector>
 
#include "helper/json/serializer_to_text.h"
#include "helper/mysql_column.h"
#include "mrs/database/json_template.h"
#include "mysqlrouter/mysql_session.h"
 
namespace mrs {
namespace json {
 
class JsonTemplateUnnest : public database::JsonTemplate {
 public:
  using JsonSerializer = helper::json::SerializerToText;
  using ResultRow = mysqlrouter::MySQLSession::ResultRow;
 
 public:
  explicit JsonTemplateUnnest(bool encode_bigints_as_string = false);
 
  void begin_resultset(const std::string &url, const std::string &items_name,
                       const std::vector<helper::Column> &columns) override;
  void begin_resultset_with_limits(
      uint64_t offset, uint64_t limit, bool is_default_limit,
      const std::string &url,
      const std::vector<helper::Column> &columns) override;
  bool push_json_document(const char *document) override;
  bool push_row(const ResultRow &values,
                const char *ignore_column = nullptr) override;
  void end_resultset(const std::optional<bool> &has_more = {}) override;
 
  void begin() override;
  void finish(const CustomMetadata &custom_metadata = {}) override;
 
  void flush() override;
  std::string get_result() override;
 
 private:
  bool count_check_if_push_is_allowed();
 
  // External data needed by the template
  uint64_t offset_{0};
  uint64_t limit_{25};
  bool is_default_limit_{false};
  bool limit_not_set_{false};
  std::string url_;
  bool full_stop_{false};
 
  // Needed for serialization of json document
  JsonSerializer serializer_;
  JsonSerializer::Object json_root_;
  JsonSerializer::Array json_root_items_;
 
  // Internal state, for use case verification and template filling
  bool has_more_{false};
  uint64_t pushed_documents_{0};
  bool began_{false};
  std::vector<helper::Column> columns_;
  bool encode_bigints_as_string_;
};
 
}  // namespace json
}  // namespace mrs
 
#endif  // ROUTER_SRC_REST_MRS_SRC_MRS_RESPONSE_ITEMS_FORMATTER_UNNEST_H_