generic_file.hpp

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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2052 Denis Corbin
//
// 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//
// to contact the author : http://dar.linux.free.fr/email.html
/*********************************************************************/



// IMPORTANT : THIS FILE MUST ALWAYS BE INCLUDE AFTER infinint.hpp   //
//             (and infinint.hpp must be included too, always)       //
#include "infinint.hpp"



#ifndef GENERIC_FILE_HPP
#define GENERIC_FILE_HPP


#include "../my_config.h"

extern "C"
{
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
} // end extern "C"

#include "path.hpp"
#include "integers.hpp"
#include "thread_cancellation.hpp"
#include "label.hpp"
#include "crc.hpp"
#include "user_interaction.hpp"
#include "mem_ui.hpp"

#include <string>

namespace libdar
{


    enum gf_mode
    {
        gf_read_only,  
        gf_write_only, 
        gf_read_write  
    };


    extern gf_mode generic_file_get_mode(S_I fd);
    extern const char * generic_file_get_name(gf_mode mode);


    class generic_file
    {
    public :
        generic_file(gf_mode m) { rw = m; terminated = false; enable_crc(false); checksum = NULL; };

        generic_file(const generic_file &ref) { copy_from(ref); };



        void terminate() const;

        virtual ~generic_file() { destroy(); };

        const generic_file & operator = (const generic_file & ref) { destroy(); copy_from(ref); return *this; };

        gf_mode get_mode() const { return rw; };


        U_I read(char *a, U_I size);


        void write(const char *a, U_I size);


        void write(const std::string & arg);

        S_I read_back(char &a);

        S_I read_forward(char &a) { if(terminated) throw SRC_BUG; return read(&a, 1); };


        virtual bool skip(const infinint & pos) = 0;

        virtual bool skip_to_eof() = 0;

        virtual bool skip_relative(S_I x) = 0;

        virtual infinint get_position() = 0;

        virtual void copy_to(generic_file &ref);


        virtual void copy_to(generic_file &ref, const infinint & crc_size, crc * & value);

        U_32 copy_to(generic_file &ref, U_32 size); // returns the number of byte effectively copied

        infinint copy_to(generic_file &ref, infinint size); // returns the number of byte effectively copied


        bool diff(generic_file & f, const infinint & crc_size, crc * & value);

        bool diff(generic_file & f, const infinint & crc_size, crc * & value, infinint & err_offset);


        void reset_crc(const infinint & width);

        bool crc_status() const { return active_read == &generic_file::read_crc; };


        crc *get_crc();

        void sync_write();

    protected :
        void set_mode(gf_mode x) { rw = x; };


        virtual U_I inherited_read(char *a, U_I size) = 0;


        virtual void inherited_write(const char *a, U_I size) = 0;



        virtual void inherited_sync_write() = 0;



        virtual void inherited_terminate() = 0;


        bool is_terminated() const { return terminated; };

    private :
        gf_mode rw;
        crc *checksum;
        bool terminated;
        U_I (generic_file::* active_read)(char *a, U_I size);
        void (generic_file::* active_write)(const char *a, U_I size);

        void enable_crc(bool mode);

        U_I read_crc(char *a, U_I size);
        void write_crc(const char *a, U_I size);
        void destroy();
        void copy_from(const generic_file & ref);
    };

#define CONTEXT_INIT "init"
#define CONTEXT_OP   "operation"
#define CONTEXT_LAST_SLICE  "last_slice"



    class label;

    class contextual
    {
    public :
        contextual() { status = ""; };
        virtual ~contextual() {};

        virtual void set_info_status(const std::string & s) { status = s; };
        virtual std::string get_info_status() const { return status; };
        virtual bool is_an_old_start_end_archive() const = 0;

        virtual const label & get_data_name() const = 0;

    private:
        std::string status;
    };


} // end of namespace

#endif