ClickHouse/dbms/src/IO/WriteBufferFromFileBase.h

#pragma once

#include <string>
#include <fcntl.h>

#include <IO/WriteBuffer.h>
#include <IO/BufferWithOwnMemory.h>

namespace DB
{

class WriteBufferFromFileBase : public BufferWithOwnMemory<WriteBuffer>
{
public:
    WriteBufferFromFileBase(size_t buf_size, char * existing_memory, size_t alignment);
    virtual ~WriteBufferFromFileBase();

    off_t seek(off_t off, int whence = SEEK_SET);
    void truncate(off_t length = 0);
    virtual off_t getPositionInFile() = 0;
    virtual void sync() = 0;
    virtual std::string getFileName() const = 0;
    virtual int getFD() const = 0;

protected:
    virtual off_t doSeek(off_t off, int whence) = 0;
    virtual void doTruncate(off_t length) = 0;
};

}