ClickHouse/dbms/include/DB/IO/WriteBufferFromFile.h

#pragma once

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <DB/IO/WriteBufferFromFileDescriptor.h>


namespace DB
{

/** Принимает имя файла. Самостоятельно открывает и закрывает файл.
  */
class WriteBufferFromFile : public WriteBufferFromFileDescriptor
{
private:
	std::string file_name;
	
public:
	WriteBufferFromFile(const std::string & file_name_, size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE, int flags = -1, mode_t mode = 0666)
		: WriteBufferFromFileDescriptor(-1, buf_size), file_name(file_name_)
	{
		fd = open(file_name.c_str(), flags == -1 ? O_WRONLY | O_TRUNC | O_CREAT : flags, mode);
		
		if (-1 == fd)
			throwFromErrno("Cannot open file " + file_name, errno == ENOENT ? ErrorCodes::FILE_DOESNT_EXIST : ErrorCodes::CANNOT_OPEN_FILE);
	}

    ~WriteBufferFromFile()
	{
		bool uncaught_exception = std::uncaught_exception();

		if (!uncaught_exception)
			next();

		if (0 != close(fd) && !uncaught_exception)
			throwFromErrno("Cannot close file " + file_name, ErrorCodes::CANNOT_CLOSE_FILE);
	}

	virtual std::string getFileName()
	{
		return file_name;
	}
};

}