ClickHouse/src/Processors/Formats/Impl/JSONCompactEachRowRowInputFormat.h

#pragma once

#include <Core/Block.h>
#include <Processors/Formats/IRowInputFormat.h>
#include <Formats/FormatSettings.h>
#include <Common/HashTable/HashMap.h>

namespace DB
{

class ReadBuffer;

/** A stream for reading data in a bunch of formats:
 *  - JSONCompactEachRow
 *  - JSONCompactEachRowWithNamesAndTypes
 *  - JSONCompactStringsEachRow
 *  - JSONCompactStringsEachRowWithNamesAndTypes
 *
*/
class JSONCompactEachRowRowInputFormat : public IRowInputFormat
{
public:
    JSONCompactEachRowRowInputFormat(
        ReadBuffer & in_,
        const Block & header_,
        Params params_,
        const FormatSettings & format_settings_,
        bool with_names_,
        bool yield_strings_);

    String getName() const override { return "JSONCompactEachRowRowInputFormat"; }


    void readPrefix() override;
    bool readRow(MutableColumns & columns, RowReadExtension & ext) override;
    bool allowSyncAfterError() const override { return true; }
    void syncAfterError() override;
    void resetParser() override;

private:
    void addInputColumn(const String & column_name);
    void skipEndOfLine();
    void readField(size_t index, MutableColumns & columns);

    const FormatSettings format_settings;

    using IndexesMap = std::unordered_map<String, size_t>;
    IndexesMap column_indexes_by_names;

    using OptionalIndexes = std::vector<std::optional<size_t>>;
    OptionalIndexes column_indexes_for_input_fields;

    DataTypes data_types;
    std::vector<UInt8> read_columns;
    std::vector<size_t> not_seen_columns;

    /// This is for the correct exceptions in skipping unknown fields.
    std::vector<String> names_of_columns;

    /// For *WithNamesAndTypes formats.
    bool with_names;
    /// For JSONCompactString* formats.
    bool yield_strings;
};

}