mycurl_param_list.hpp

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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2024 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 MYCURL_PARAM_LIST_HPP
#define MYCURL_PARAM_LIST_HPP

#include "../my_config.h"

extern "C"
{
#if LIBCURL_AVAILABLE
#if HAVE_CURL_CURL_H
#include <curl/curl.h>
#endif
#endif
} // end extern "C"


#include <string>
#include <memory>
#include <map>
#include <list>
#include "integers.hpp"
#include "erreurs.hpp"

namespace libdar
{



    // libcurl uses a list of options to a CURL handle, which argument is of variable type
    // we want to record this list to be able to reset, copy, and do other fancy operations
    // on CURL handle and have all these managed within a single class (mycurl_easyhandle_node)
    // for that we need here a list of association of CURLoption type with variable typed value
    //
    // This is implemented by a ancestor type (mycurl_param_element_generic) which is an pure abstracted
    // class, from which derives many template based classes: mycurl_param_element<T>.




    class mycurl_param_element_generic
    {
    public:
    virtual ~mycurl_param_element_generic() = default;

    virtual bool operator == (const mycurl_param_element_generic & val) const = 0;
    virtual bool operator != (const mycurl_param_element_generic & val) const { return ! (*this == val); };

    virtual std::unique_ptr<mycurl_param_element_generic> clone() const = 0;
    };





    template <class T> class mycurl_param_element: public mycurl_param_element_generic
    {
    public:
    mycurl_param_element(const T & arg): val(arg) {};
    mycurl_param_element(const mycurl_param_element<T> & e): val(e.val) {};
    mycurl_param_element(mycurl_param_element<T> && e) noexcept: val(std::move(e.val)) {};
    mycurl_param_element<T> & operator = (const mycurl_param_element<T> & e) { val = e.val; return this; };
    mycurl_param_element<T> & operator = (mycurl_param_element<T> && e) { val = std::move(e.val); return this; };
    ~mycurl_param_element() = default;

    virtual bool operator == (const mycurl_param_element_generic & arg) const override
    {
        const mycurl_param_element<T>* arg_ptr = dynamic_cast<const mycurl_param_element<T>*>(&arg);
        if(arg_ptr == nullptr)
        return false;
        return arg_ptr->val == val;
    }

    T get_value() const { return val; };
    const T* get_value_address() const { return &val; };
    void set_value(const T & arg) { val = arg; };

    virtual std::unique_ptr<mycurl_param_element_generic> clone() const override
    {
        std::unique_ptr<mycurl_param_element_generic> ret;

        try
        {
        ret = std::make_unique<mycurl_param_element<T> >(val);
        if(!ret)
            throw Ememory("mycurl_param_list::clone");
        }
        catch(...)
        {
        throw Ememory("mycurl_param_list::clone");
        }

        return ret;
    };

    private:
    T val;
    };



    class mycurl_param_list
    {
    public:
#ifndef LIBCURL_AVAILABLE

        // libcurl not available, no field to initialize
    mycurl_param_list() {};

#else

    mycurl_param_list() { reset_read(); }; // fields "element_list" and "cursor" are objects and get initialized by their default constructor

    mycurl_param_list(const mycurl_param_list & ref) { copy_from(ref); };
    mycurl_param_list(mycurl_param_list && ref) noexcept = default;
    mycurl_param_list & operator = (const mycurl_param_list & ref) { element_list.clear(); copy_from(ref); reset_read(); return *this; };
    mycurl_param_list & operator = (mycurl_param_list && ref) = default;
    ~mycurl_param_list() = default;

        // operations with the list

    template<class T> void add(CURLoption opt, const T & val) { element_list[opt] = std::make_unique<mycurl_param_element<T> >(val); reset_read(); }
    void clear(CURLoption opt);
    void clear() { element_list.clear(); reset_read(); };
    U_I size() const { return element_list.size(); };
    void reset_read() const { cursor = element_list.begin(); };
    bool read_next(CURLoption & opt);

    template<class T> void read_opt(const T* & val) const
    {
        if(cursor == element_list.end())
        throw Erange("mycurl_param_list::read_opt", "Cannot read option when no more option is available");

        if(cursor->second)
        {
        const mycurl_param_element<T>* ptr = dynamic_cast<const mycurl_param_element<T>*>(cursor->second.get());

        if(ptr != nullptr)
            val = ptr->get_value_address();
        else
            val = nullptr;
        }
        else
        val = nullptr;

        ++cursor;
    }

    template<class T>bool get_val(CURLoption opt, const T* & val) const
    {
        std::map<CURLoption, std::unique_ptr<mycurl_param_element_generic> >::const_iterator it = element_list.find(opt);

        if(it == element_list.end())
        return false;

        if(it->second)
        {
        const mycurl_param_element<T>* ptr = dynamic_cast<const mycurl_param_element<T>*>(it->second.get());

        if(ptr != nullptr)
            val = ptr->get_value_address();
        else
            val = nullptr;
        }
        else
        val = nullptr;

        return true;
    }

        // operations between lists




    std::list<CURLoption> update_with(const mycurl_param_list & wanted);

    private:
    std::map<CURLoption, std::unique_ptr<mycurl_param_element_generic> > element_list;
    mutable std::map<CURLoption, std::unique_ptr<mycurl_param_element_generic> >::const_iterator cursor;

    void add_clone(CURLoption opt, const mycurl_param_element_generic & val) { element_list[opt] = val.clone(); }
    void copy_from(const mycurl_param_list & ref);

#endif
    };




} // end of namespace

#endif