ClickHouse/src/Common/JSONBuilder.cpp

#include <Common/JSONBuilder.h>
#include <IO/WriteHelpers.h>
#include <Common/typeid_cast.h>

namespace DB::JSONBuilder
{

static bool isArrayOrMap(const IItem & item)
{
    return typeid_cast<const JSONArray *>(&item) || typeid_cast<const JSONMap *>(&item);
}

static bool isSimpleArray(const std::vector<ItemPtr> & values)
{
    for (const auto & value : values)
        if (isArrayOrMap(*value))
            return false;

    return true;
}

void JSONString::format(const FormatSettings & settings, FormatContext & context)
{
    writeJSONString(value, context.out, settings.settings);
}

void JSONBool::format(const FormatSettings &, FormatContext & context)
{
    writeString(value ? "true" : "false", context.out);
}

void JSONArray::format(const FormatSettings & settings, FormatContext & context)
{
    writeChar('[', context.out);

    context.offset += settings.indent;

    bool single_row = settings.print_simple_arrays_in_single_row && isSimpleArray(values);
    bool first = true;

    for (const auto & value : values)
    {
        if (!first)
            writeChar(',', context.out);

        if (!single_row)
        {
            writeChar('\n', context.out);
            writeChar(' ', context.offset, context.out);
        }
        else if (!first)
            writeChar(' ', context.out);

        first = false;
        value->format(settings, context);
    }

    context.offset -= settings.indent;

    if (!single_row)
    {
        writeChar('\n', context.out);
        writeChar(' ', context.offset, context.out);
    }

    writeChar(']', context.out);
}

void JSONMap::format(const FormatSettings & settings, FormatContext & context)
{
    writeChar('{', context.out);

    context.offset += settings.indent;

    bool first = true;

    for (const auto & value : values)
    {
        if (!first)
            writeChar(',', context.out);
        first = false;

        writeChar('\n', context.out);
        writeChar(' ', context.offset, context.out);
        writeJSONString(value.key, context.out, settings.settings);

        writeChar(':', context.out);
        writeChar(' ', context.out);
        value.value->format(settings, context);
    }

    context.offset -= settings.indent;

    writeChar('\n', context.out);
    writeChar(' ', context.offset, context.out);
    writeChar('}', context.out);
}

}