ClickHouse/dbms/include/DB/IO/MySQLxxHelpers.h

#pragma once

#include <mysqlxx/Row.h>
#include <mysqlxx/Null.h>
#include <mysqlxx/Manip.h>

#include <DB/Core/Field.h>
#include <DB/Core/FieldVisitors.h>
#include <DB/IO/WriteHelpers.h>


/// This is for Yandex.Metrica code.

namespace mysqlxx
{
	inline std::ostream & operator<< (mysqlxx::EscapeManipResult res, const DB::Array & value)
	{
		return res.ostr << DB::applyVisitor(DB::FieldVisitorToString(), DB::Field(value));
	}

	inline std::ostream & operator<< (mysqlxx::QuoteManipResult res, const DB::Array & value)
	{
		throw Poco::Exception("Cannot quote Array with mysqlxx::quote.");
	}

	inline std::istream & operator>> (mysqlxx::UnEscapeManipResult res, DB::Array & value)
	{
		throw Poco::Exception("Cannot unescape Array with mysqlxx::unescape.");
	}

	inline std::istream & operator>> (mysqlxx::UnQuoteManipResult res, DB::Array & value)
	{
		throw Poco::Exception("Cannot unquote Array with mysqlxx::unquote.");
	}


	inline std::ostream & operator<< (mysqlxx::EscapeManipResult res, const DB::Tuple & value)
	{
		return res.ostr << DB::applyVisitor(DB::FieldVisitorToString(), DB::Field(value));
	}

	inline std::ostream & operator<< (mysqlxx::QuoteManipResult res, const DB::Tuple & value)
	{
		throw Poco::Exception("Cannot quote Tuple with mysqlxx::quote.");
	}

	inline std::istream & operator>> (mysqlxx::UnEscapeManipResult res, DB::Tuple & value)
	{
		throw Poco::Exception("Cannot unescape Tuple with mysqlxx::unescape.");
	}

	inline std::istream & operator>> (mysqlxx::UnQuoteManipResult res, DB::Tuple & value)
	{
		throw Poco::Exception("Cannot unquote Tuple with mysqlxx::unquote.");
	}
}


namespace DB
{

/// Вывести mysqlxx::Row в tab-separated виде
inline void writeEscapedRow(const mysqlxx::Row & row, WriteBuffer & buf)
{
	for (size_t i = 0; i < row.size(); ++i)
	{
		if (i != 0)
			buf.write('\t');

		if (unlikely(row[i].isNull()))
		{
			buf.write("\\N", 2);
			continue;
		}

		writeAnyEscapedString<'\''>(row[i].data(), row[i].data() + row[i].length(), buf);
	}
}


template <typename T>
inline void writeText(const mysqlxx::Null<T> & x,	WriteBuffer & buf)
{
	if (x.isNull())
		writeCString("\\N", buf);
	else
		writeText(static_cast<const T &>(x), buf);
}


template <typename T>
inline void writeQuoted(const mysqlxx::Null<T> & x,		WriteBuffer & buf)
{
	if (x.isNull())
		writeCString("NULL", buf);
	else
		writeText(static_cast<const T &>(x), buf);
}

}