mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-23 16:12:01 +00:00
80 lines
2.1 KiB
C++
80 lines
2.1 KiB
C++
#pragma once
|
||
|
||
#include <DB/IO/ReadHelpers.h>
|
||
#include <DB/IO/WriteHelpers.h>
|
||
|
||
#include <iostream>
|
||
|
||
|
||
namespace DB
|
||
{
|
||
|
||
|
||
/** Считывает данные, из формата, состоящего из чанков
|
||
* (идентификатор запроса, признак последнего чанка, размер чанка, часть данных со сжатием или без).
|
||
*/
|
||
class ChunkedReadBuffer : public ReadBuffer
|
||
{
|
||
protected:
|
||
ReadBuffer & in;
|
||
bool all_read;
|
||
size_t read_in_chunk;
|
||
size_t chunk_size;
|
||
UInt64 assert_query_id;
|
||
|
||
bool nextImpl()
|
||
{
|
||
/// Если прочитали ещё не весь блок - получим следующие данные. Если следующих данных нет - ошибка.
|
||
if (read_in_chunk < chunk_size)
|
||
{
|
||
if (!in.next())
|
||
throw Exception("Cannot read all data from chunked input", ErrorCodes::CANNOT_READ_ALL_DATA_FROM_CHUNKED_INPUT);
|
||
|
||
working_buffer = in.buffer();
|
||
if (chunk_size - read_in_chunk < working_buffer.size())
|
||
{
|
||
working_buffer.resize(chunk_size - read_in_chunk);
|
||
read_in_chunk = chunk_size;
|
||
}
|
||
else
|
||
read_in_chunk += working_buffer.size();
|
||
|
||
in.position() += working_buffer.size();
|
||
}
|
||
else
|
||
{
|
||
if (all_read)
|
||
return false;
|
||
|
||
UInt64 query_id = 0;
|
||
readIntBinary(query_id, in);
|
||
|
||
if (query_id != assert_query_id)
|
||
throw Exception("Received data for wrong query id (expected "
|
||
+ toString(assert_query_id) + ", got "
|
||
+ toString(query_id) + ")", ErrorCodes::RECEIVED_DATA_FOR_WRONG_QUERY_ID);
|
||
|
||
/// Флаг конца.
|
||
readIntBinary(all_read, in);
|
||
/// Размер блока.
|
||
readIntBinary(chunk_size, in);
|
||
|
||
read_in_chunk = std::min(chunk_size, in.buffer().size() - in.offset());
|
||
working_buffer = Buffer(in.position(), in.position() + read_in_chunk);
|
||
in.position() += read_in_chunk;
|
||
|
||
if (all_read)
|
||
return false;
|
||
}
|
||
|
||
return true;
|
||
}
|
||
|
||
public:
|
||
ChunkedReadBuffer(ReadBuffer & in_, UInt64 assert_query_id_)
|
||
: ReadBuffer(NULL, 0), in(in_), all_read(false), read_in_chunk(0), chunk_size(0), assert_query_id(assert_query_id_) {}
|
||
};
|
||
|
||
|
||
}
|