ClickHouse/src/Formats/TemporaryFileStream.cpp
2021-10-15 23:18:20 +03:00

45 lines
1.4 KiB
C++

#include <Formats/TemporaryFileStream.h>
#include <Formats/NativeReader.h>
#include <Formats/NativeWriter.h>
#include <Processors/Executors/PullingPipelineExecutor.h>
#include <Processors/ISource.h>
#include <Compression/CompressedWriteBuffer.h>
#include <IO/WriteBufferFromFile.h>
#include <Core/ProtocolDefines.h>
namespace DB
{
/// To read the data that was flushed into the temporary data file.
TemporaryFileStream::TemporaryFileStream(const std::string & path)
: file_in(path)
, compressed_in(file_in)
, block_in(std::make_unique<NativeReader>(compressed_in, DBMS_TCP_PROTOCOL_VERSION))
{}
TemporaryFileStream::TemporaryFileStream(const std::string & path, const Block & header_)
: file_in(path)
, compressed_in(file_in)
, block_in(std::make_unique<NativeReader>(compressed_in, header_, 0))
{}
/// Flush data from input stream into file for future reading
void TemporaryFileStream::write(const std::string & path, const Block & header, QueryPipelineBuilder builder, const std::string & codec)
{
WriteBufferFromFile file_buf(path);
CompressedWriteBuffer compressed_buf(file_buf, CompressionCodecFactory::instance().get(codec, {}));
NativeWriter output(compressed_buf, 0, header);
auto pipeline = QueryPipelineBuilder::getPipeline(std::move(builder));
PullingPipelineExecutor executor(pipeline);
Block block;
while (executor.pull(block))
output.write(block);
compressed_buf.finalize();
}
}