ClickHouse/dbms/include/DB/DataStreams/JSONRowOutputStream.h
2013-09-07 02:03:13 +00:00

58 lines
1.2 KiB
C++

#pragma once
#include <Poco/SharedPtr.h>
#include <DB/Core/Block.h>
#include <DB/IO/WriteBuffer.h>
#include <DB/IO/WriteBufferValidUTF8.h>
#include <DB/DataStreams/IRowOutputStream.h>
#include <DB/DataStreams/IProfilingBlockInputStream.h>
namespace DB
{
/** Поток для вывода данных в формате JSON.
*/
class JSONRowOutputStream : public IRowOutputStream
{
public:
JSONRowOutputStream(WriteBuffer & ostr_, const Block & sample_);
void writeField(const Field & field);
void writeFieldDelimiter();
void writeRowStartDelimiter();
void writeRowEndDelimiter();
void writePrefix();
void writeSuffix();
void setRowsBeforeLimit(size_t rows_before_limit_)
{
applied_limit = true;
rows_before_limit = rows_before_limit_;
}
void setTotals(const Block & totals_) { totals = totals_; }
void setExtremes(const Block & extremes_) { extremes = extremes_; }
protected:
void writeRowsBeforeLimitAtLeast();
virtual void writeTotals();
virtual void writeExtremes();
typedef std::vector<NameAndTypePair> NamesAndTypesVector;
WriteBufferValidUTF8 ostr;
size_t field_number;
size_t row_count;
bool applied_limit;
size_t rows_before_limit;
NamesAndTypesVector fields;
Block totals;
Block extremes;
};
}