fichier_libssh.hpp

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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2025 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// to contact the author, see the AUTHOR file
/*********************************************************************/
 
 
#ifndef FICHIER_LIBSSH_HPP
#define FICHIER_LIBSSH_HPP
 
 
#include "../my_config.h"
 
extern "C"
{
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
} // end extern "C"
 
#include "integers.hpp"
#include "user_interaction.hpp"
#include "fichier_global.hpp"
#include "libssh_connection.hpp"
#include "cygwin_adapt.hpp"
 
#include <string>
 
namespace libdar
{
 
 
 
 
#if LIBSSH_AVAILABLE
 
    class fichier_libssh : public fichier_global
    {
    public:
 
        fichier_libssh(const std::shared_ptr<user_interaction> & dialog,
               const std::shared_ptr<libssh_connection> & ptr,
               const std::string & chemin,
               gf_mode mode,
               U_I permission,
               bool fail_if_exists,
               bool erase);
 
    fichier_libssh(const fichier_libssh & ref) = delete;
 
    fichier_libssh(fichier_libssh && ref) noexcept = delete;
 
    fichier_libssh & operator = (const fichier_libssh & ref) = delete;
 
    fichier_libssh & operator = (fichier_libssh && ref) noexcept = delete;
 
    ~fichier_libssh();
 
 
    virtual void change_ownership(const std::string & user, const std::string & group) override
    { throw Efeature(gettext("user/group ownership not implemented for this repository")); };
        // not implemented, libssh can set ownership based on uid / gid but not based on user/group names
 
    virtual void change_permission(U_I perm) override;
 
        virtual infinint get_size() const override;
 
    virtual void fadvise(advise adv) const override {}; // not supported
 
            // inherited from generic_file
    virtual bool skippable(skippability direction, const infinint & amount) override;
        virtual bool skip(const infinint & pos) override;
        virtual bool skip_to_eof() override;
        virtual bool skip_relative(S_I x) override;
    virtual bool truncatable(const infinint & pos) const override;
        virtual infinint get_position() const override;
 
    protected:
        // inherited from generic_file grand-parent class
    virtual void inherited_truncate(const infinint & pos) override;
    virtual void inherited_read_ahead(const infinint & amount) override;
    virtual void inherited_sync_write() override {};
    virtual void inherited_flush_read() override {};
    virtual void inherited_terminate() override { myclose(); };
 
        // inherited from fichier_global parent class
    virtual U_I fichier_global_inherited_write(const char *a, U_I size) override;
        virtual bool fichier_global_inherited_read(char *a, U_I size, U_I & read, std::string & message) override;
 
    private:
    std::shared_ptr<libssh_connection> connect;
    std::string my_path;
    sftp_file sfd;
    infinint current_pos; 
 
        // read ahead structures
 
    struct rahead
    {
        sftp_aio handle;
 
        rahead(): handle(nullptr) {};
        rahead(const rahead & ref) = delete;
        rahead(rahead && ref) noexcept { handle = ref.handle; ref.handle = nullptr; };
        rahead & operator = (const rahead & ref) = delete;
        rahead & operator = (rahead && ref) noexcept { std::swap(handle, ref.handle); return *this; };
        ~rahead() { if(handle != nullptr) sftp_aio_free(handle); };
    };
 
    static const U_I read_ahead_window_size = 100*1024*1024;
 
    infinint tora; 
 
    std::deque<rahead> rareq; 
    U_I rareq_maxsize;
 
    char* rabuffer; 
    U_I rallocated; 
    U_I rasize;     
    U_I ralu;       
 
        // private methods
 
    void myclose();
    void clear_readahead() { rareq.clear(); ralu = rasize = 0; };
    void update_aio_reqs();
 
 
    void check_pos_from_libssh();
 
    };
 
#endif
 
 
} // end of namespace
 
#endif