ClickHouse/dbms/include/DB/DataStreams/AddingDefaultBlockOutputStream.h
2015-01-21 07:17:02 +03:00

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#pragma once
#include <Poco/SharedPtr.h>
#include <DB/DataStreams/IBlockOutputStream.h>
#include <DB/Columns/ColumnConst.h>
#include <DB/Storages/ColumnDefault.h>
#include <DB/Interpreters/Context.h>
#include <DB/Interpreters/evaluateMissingDefaults.h>
namespace DB
{
/** Добавляет в блок недостающие столбцы со значениями по-умолчанию.
* Эти столбцы - материалированные (не константы).
*/
class AddingDefaultBlockOutputStream : public IBlockOutputStream
{
public:
AddingDefaultBlockOutputStream(
BlockOutputStreamPtr output_,
NamesAndTypesListPtr required_columns_,
const ColumnDefaults & column_defaults_,
const Context & context_)
: output(output_), required_columns(required_columns_),
column_defaults(column_defaults_), context(context_)
{
}
AddingDefaultBlockOutputStream(BlockOutputStreamPtr output_, NamesAndTypesListPtr required_columns_, const Context & context_)
: AddingDefaultBlockOutputStream{output_, required_columns_, ColumnDefaults{}, context_}
{
}
void write(const Block & block) override
{
Block res = block;
evaluateMissingDefaults(res, *required_columns, column_defaults, context);
res.addDefaults(*required_columns);
output->write(res);
}
void flush() override { output->flush(); }
void writePrefix() override { output->writePrefix(); }
void writeSuffix() override { output->writeSuffix(); }
private:
BlockOutputStreamPtr output;
NamesAndTypesListPtr required_columns;
const ColumnDefaults & column_defaults;
Context context;
};
}