ClickHouse/programs/copier/StatusAccumulator.h

#pragma once


#include <Poco/JSON/Parser.h>
#include <Poco/JSON/JSON.h>
#include <Poco/JSON/Object.h>
#include <Poco/JSON/Stringifier.h>

#include <unordered_map>
#include <memory>
#include <string>
#include <iostream>

namespace DB
{

class StatusAccumulator
{
    public:
        struct TableStatus
        {
            size_t all_partitions_count;
            size_t processed_partitions_count;
        };

        using Map = std::unordered_map<std::string, TableStatus>;
        using MapPtr = std::shared_ptr<Map>;

        static MapPtr fromJSON(std::string state_json)
        {
            Poco::JSON::Parser parser;
            auto state = parser.parse(state_json).extract<Poco::JSON::Object::Ptr>();
            MapPtr result_ptr = std::make_shared<Map>();
            for (const auto & table_name : state->getNames())
            {
                auto table_status_json = state->getValue<std::string>(table_name);
                auto table_status = parser.parse(table_status_json).extract<Poco::JSON::Object::Ptr>();
                /// Map entry will be created if it is absent
                auto & map_table_status = (*result_ptr)[table_name];
                map_table_status.all_partitions_count += table_status->getValue<size_t>("all_partitions_count");
                map_table_status.processed_partitions_count += table_status->getValue<size_t>("processed_partitions_count");
            }
            return result_ptr;
        }

        static std::string serializeToJSON(MapPtr statuses)
        {
            Poco::JSON::Object result_json;
            for (const auto & [table_name, table_status] : *statuses)
            {
                Poco::JSON::Object status_json;
                status_json.set("all_partitions_count", table_status.all_partitions_count);
                status_json.set("processed_partitions_count", table_status.processed_partitions_count);

                result_json.set(table_name, status_json);
            }
            std::ostringstream oss;     // STYLE_CHECK_ALLOW_STD_STRING_STREAM
            oss.exceptions(std::ios::failbit);
            Poco::JSON::Stringifier::stringify(result_json, oss);
            auto result = oss.str();
            return result;
        }
};

}