aria2/src/DiskWriter.h

102 lines
3.1 KiB
C++

/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#ifndef _D_DISK_WRITER_H_
#define _D_DISK_WRITER_H_
#include "BinaryStream.h"
namespace aria2 {
/**
* Interface for writing to a binary stream of bytes.
*
*/
class DiskWriter:public BinaryStream {
protected:
bool _directIOAllowed;
public:
DiskWriter():_directIOAllowed(false) {}
virtual ~DiskWriter() {}
/**
* Creates a file output stream to write to the file with the specified name.
* If the file exists, then it is truncated to 0 length.
* @param filename the file name to be opened.
*/
virtual void initAndOpenFile(const std::string& filename, uint64_t totalLength = 0) = 0;
virtual void openFile(const std::string& filename, uint64_t totalLength = 0) = 0;
/**
* Closes this output stream.
*/
// TODO we have to examine the return value of close()
virtual void closeFile() = 0;
/**
* Opens a file output stream to write to the file with the specified name.
* If the file doesnot exists, an exception may be throwed.
*
* @param filename the file name to be opened.
*/
virtual void openExistingFile(const std::string& filename, uint64_t totalLength = 0) = 0;
virtual void truncate(uint64_t length) = 0;
// Returns file length
virtual uint64_t size() const = 0;
virtual void enableDirectIO() = 0;
virtual void disableDirectIO() = 0;
virtual bool directIOAllowed() const
{
return _directIOAllowed;
}
void setDirectIOAllowed(bool f)
{
_directIOAllowed = f;
}
};
typedef SharedHandle<DiskWriter> DiskWriterHandle;
} // namespace aria2
#endif // _D_DISK_WRITER_H_