uhd

//

// Copyright 2010 Ettus Research LLC

//

// 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 3 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, see <http://www.gnu.org/licenses/>.

//

#include <uhd/wax.hpp>

#include <boost/format.hpp>

#include <stdexcept>

/*!

 * The link args for internal use within this cpp file:

 *

 * It contains a link (in this case a pointer) to a wax object.

 * Only the methods in this file may create or parse link args.

 * The get_link method is the creator of a link args object.

 * The [] operator will resolve the link and make the [] call.

 *

 * TODO: register the link args with the wax obj that it links to.

 * That way, if the obj destructs, the link can be invalidated.

 * The operator() will throw, rather than dereferencing bad memory.

 */

class link_args_t{

public:

    link_args_t(const wax::obj *obj_ptr) : _obj_ptr(obj_ptr){

        /* NOP */

    }

    wax::obj & operator()(void) const{

        //recursively resolve link args to get at original pointer

        if (_obj_ptr->type() == typeid(link_args_t)){

            return _obj_ptr->as<link_args_t>()();

        }

        return *const_cast<wax::obj *>(_obj_ptr);

    }

private:

    const wax::obj *_obj_ptr;

};

/*!

 * The proxy args for internal use within this cpp file:

 *

 * It contains a link and a key for setting/getting a property.

 * Only the methods in this file may create or parse proxy args.

 * Class methods have special handling for the case when the

 * wax obj contains an instance of the proxy args.

 */

class proxy_args_t{

public:

    proxy_args_t(const wax::obj *obj_ptr, const wax::obj &key) : _key(key){

        _obj_link = obj_ptr->get_link();

    }

    wax::obj & operator()(void) const{

        return _obj_link.as<link_args_t>()();

    }

    const wax::obj & key(void) const{

        return _key;

    }

private:

    wax::obj _obj_link;

    const wax::obj _key;

};

/***********************************************************************

 * Structors

 **********************************************************************/

wax::obj::obj(void){

    /* NOP */

}

wax::obj::obj(const obj &o){

    _contents = o._contents;

}

wax::obj::~obj(void){

    /* NOP */

}

/***********************************************************************

 * Special Operators

 **********************************************************************/

wax::obj wax::obj::operator[](const obj &key){

    if (_contents.type() == typeid(proxy_args_t)){

        obj val = resolve();

        //check if its a special link and call

        if (val.type() == typeid(link_args_t)){

            return val.as<link_args_t>()()[key];

        }

        //unknown obj

        throw std::runtime_error("cannot use [] on non wax::obj link");

    }

    else{

        return proxy_args_t(this, key);

    }

}

wax::obj & wax::obj::operator=(const obj &val){

    if (_contents.type() == typeid(proxy_args_t)){

        proxy_args_t proxy_args = boost::any_cast<proxy_args_t>(_contents);

        proxy_args().set(proxy_args.key(), val);

    }

    else{

        _contents = val._contents;

    }

    return *this;

}

/***********************************************************************

 * Public Methods

 **********************************************************************/

wax::obj wax::obj::get_link(void) const{

    return link_args_t(this);

}

const std::type_info & wax::obj::type(void) const{

    return resolve().type();

}

/***********************************************************************

 * Private Methods

 **********************************************************************/

boost::any wax::obj::resolve(void) const{

    if (_contents.type() == typeid(proxy_args_t)){

        obj val;

        proxy_args_t proxy_args = boost::any_cast<proxy_args_t>(_contents);

        proxy_args().get(proxy_args.key(), val);

        return val.resolve();

    }

    else{

        return _contents;

    }

}

void wax::obj::get(const obj &, obj &){

    throw std::runtime_error("Cannot call get on wax obj base class");

}

void wax::obj::set(const obj &, const obj &){

    throw std::runtime_error("Cannot call set on wax obj base class");

}