src/iohandler/file_io_handler.h

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/*MT*

    MediaTomb - http://www.mediatomb.cc/

    file_io_handler.h - this file is part of MediaTomb.

    Copyright (C) 2005 Gena Batyan <bgeradz@mediatomb.cc>,
                       Sergey 'Jin' Bostandzhyan <jin@mediatomb.cc>

    Copyright (C) 2006-2010 Gena Batyan <bgeradz@mediatomb.cc>,
                            Sergey 'Jin' Bostandzhyan <jin@mediatomb.cc>,
                            Leonhard Wimmer <leo@mediatomb.cc>

    Copyright (C) 2016-2026 Gerbera Contributors

    MediaTomb is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License version 2
    as published by the Free Software Foundation.

    MediaTomb 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
    version 2 along with MediaTomb; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.

    $Id$
*/

/// @file iohandler/file_io_handler.h
/// @brief Definition of the FileIOHandler class.

#ifndef __FILE_IO_HANDLER_H__
#define __FILE_IO_HANDLER_H__

#include "io_handler.h"
#include "util/grb_fs.h"

#include <mutex>

/// @brief Allows the web server to read from a file.
class FileIOHandler : public IOHandler {
protected:
    /// @brief Name of the file.
    GrbFile file;

    /// @brief Handle of the file.
    std::FILE* f {};

    std::mutex mutex;

    /// @brief open file with offset
    off_t offset;

public:
    /// @brief Sets the filename to work with.
    explicit FileIOHandler(const fs::path& filename, off_t offset = 0);

    /// @brief Opens file for reading (writing is not supported)
    void open(enum UpnpOpenFileMode mode) override;

    /// @brief Reads a previously opened file sequentially.
    /// @param buf Data from the file will be copied into this buffer.
    /// @param length Number of bytes to be copied into the buffer.
    grb_read_t read(std::byte* buf, std::size_t length) override;

    /// @brief Writes to a previously opened file.
    /// @param buf Data from the buffer will be written to the file.
    /// @param length Number of bytes to be written from the buffer.
    /// @return number of bytes written.
    std::size_t write(std::byte* buf, std::size_t length) override;

    /// @brief Performs seek on an open file.
    /// @param offset Number of bytes to move in the file. For seeking forwards
    /// positive values are used, for seeking backwards - negative. Offset must
    /// be positive if origin is set to SEEK_SET
    /// @param whence The position to move relative to. SEEK_CUR to move relative
    /// to current position, SEEK_END to move relative to the end of file,
    /// SEEK_SET to specify an absolute offset.
    void seek(off_t offset, int whence) override;

    /// @brief Return the current stream position.
    off_t tell() override;

    /// @brief Close a previously opened file.
    void close() override;
};

/// @brief Allows the web server to read from a temporary zip file.
class ZipIOHandler : public FileIOHandler {
    using FileIOHandler::FileIOHandler;

    /// @brief Close a previously opened file and delete it.
    void close() override;
};

#endif // __FILE_IO_HANDLER_H__