mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-10-19 15:01:03 +00:00
57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
|
#pragma once
|
|||
|
|
|||
|
#include <unistd.h>
|
|||
|
#include <errno.h>
|
|||
|
|
|||
|
#include <Poco/NumberFormatter.h>
|
|||
|
|
|||
|
#include <DB/Core/Exception.h>
|
|||
|
#include <DB/Core/ErrorCodes.h>
|
|||
|
|
|||
|
#include <DB/IO/WriteBuffer.h>
|
|||
|
#include <DB/IO/BufferWithOwnMemory.h>
|
|||
|
|
|||
|
|
|||
|
namespace DB
|
|||
|
{
|
|||
|
|
|||
|
/** Работает с готовым файловым дескриптором. Не открывает и не закрывает файл.
|
|||
|
*/
|
|||
|
class WriteBufferFromFileDescriptor : public BufferWithOwnMemory<WriteBuffer>
|
|||
|
{
|
|||
|
protected:
|
|||
|
int fd;
|
|||
|
|
|||
|
void nextImpl()
|
|||
|
{
|
|||
|
if (!offset())
|
|||
|
return;
|
|||
|
|
|||
|
ssize_t bytes_written = ::write(fd, working_buffer.begin(), offset());
|
|||
|
if (-1 == bytes_written || 0 == bytes_written)
|
|||
|
throwFromErrno("Cannot write to file " + getFileName(), ErrorCodes::CANNOT_WRITE_TO_FILE_DESCRIPTOR);
|
|||
|
}
|
|||
|
|
|||
|
void throwFromErrno(const std::string & s, int code)
|
|||
|
{
|
|||
|
char buf[128];
|
|||
|
throw Exception(s + ", errno: " + Poco::NumberFormatter::format(errno) + ", strerror: " + std::string(strerror_r(errno, buf, sizeof(buf))), code);
|
|||
|
}
|
|||
|
|
|||
|
/// Имя или описание файла
|
|||
|
virtual std::string getFileName()
|
|||
|
{
|
|||
|
return "(fd = " + Poco::NumberFormatter::format(fd) + ")";
|
|||
|
}
|
|||
|
|
|||
|
public:
|
|||
|
WriteBufferFromFileDescriptor(int fd_) : fd(fd_) {}
|
|||
|
|
|||
|
virtual ~WriteBufferFromFileDescriptor()
|
|||
|
{
|
|||
|
nextImpl();
|
|||
|
}
|
|||
|
};
|
|||
|
|
|||
|
}
|