ClickHouse/src/IO/WriteBufferFromTemporaryFile.h
2020-04-03 18:14:31 +03:00

35 lines
817 B
C++

#include <IO/WriteBuffer.h>
#include <IO/IReadableWriteBuffer.h>
#include <IO/WriteBufferFromFile.h>
#include <Common/filesystemHelpers.h>
namespace DB
{
/// Rereadable WriteBuffer, could be used as disk buffer
/// Creates unique temporary in directory (and directory itself)
class WriteBufferFromTemporaryFile : public WriteBufferFromFile, public IReadableWriteBuffer
{
public:
using Ptr = std::shared_ptr<WriteBufferFromTemporaryFile>;
static Ptr create(const std::string & tmp_dir);
~WriteBufferFromTemporaryFile() override;
protected:
WriteBufferFromTemporaryFile(std::unique_ptr<TemporaryFile> && tmp_file);
std::shared_ptr<ReadBuffer> getReadBufferImpl() override;
protected:
std::unique_ptr<TemporaryFile> tmp_file;
friend class ReadBufferFromTemporaryWriteBuffer;
};
}