memento_command.h

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/*
 * Copyright (C) 2006-2015 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2006 Hans Fugal <hans@fugal.net>
 * Copyright (C) 2007-2009 David Robillard <d@drobilla.net>
 * Copyright (C) 2009-2011 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2016-2017 Tim Mayberry <mojofunk@gmail.com>
 *
 * 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.
 */
 
#pragma once
 
#include <iostream>
 
#include "pbd/libpbd_visibility.h"
#include "pbd/command.h"
#include "pbd/xml++.h"
#include "pbd/demangle.h"
 
#include <sigc++/slot.h>
#include <typeinfo>
 
template <class obj_T>
class LIBPBD_TEMPLATE_API MementoCommandBinder : public PBD::Destructible
{
public:
        virtual void set_state (XMLNode const &, int version) const = 0;
        virtual XMLNode& get_state () const = 0;
 
        virtual std::string type_name () const = 0;
 
        virtual void add_state (XMLNode *) = 0;
};
 
template <class obj_T>
class LIBPBD_TEMPLATE_API SimpleMementoCommandBinder : public MementoCommandBinder<obj_T>
{
public:
        SimpleMementoCommandBinder (obj_T& o)
                : _object (o)
        {
                _object.Destroyed.connect_same_thread (_object_death_connection, std::bind (&SimpleMementoCommandBinder::object_died, this));
        }
 
        void set_state (XMLNode const & node , int version) const { _object.set_state (node, version); }
        XMLNode& get_state () const { return _object.get_state(); }
        std::string type_name() const {
                return PBD::demangled_name (_object);
        }
 
        void add_state (XMLNode* node) {
                node->set_property ("obj-id", _object.id().to_s());
        }
 
        void object_died () {
                /* The object we are binding died, so drop references to ourselves */
                this->drop_references ();
        }
 
private:
        obj_T& _object;
        PBD::ScopedConnection _object_death_connection;
};
 
template <class obj_T>
class LIBPBD_TEMPLATE_API MementoCommand : public PBD::Command
{
public:
        MementoCommand (obj_T& a_object, XMLNode* a_before, XMLNode* a_after)
                : _binder (new SimpleMementoCommandBinder<obj_T> (a_object)), before (a_before), after (a_after)
        {
                /* The binder's object died, so we must die */
                _binder->DropReferences.connect_same_thread (_binder_death_connection, std::bind (&MementoCommand::binder_dying, this));
        }
 
        MementoCommand (MementoCommandBinder<obj_T>* b, XMLNode* a_before, XMLNode* a_after)
                : _binder (b), before (a_before), after (a_after)
        {
                /* The binder's object died, so we must die */
                _binder->DropReferences.connect_same_thread (_binder_death_connection, std::bind (&MementoCommand::binder_dying, this));
        }
 
        ~MementoCommand () {
                delete before;
                delete after;
                delete _binder;
        }
 
        void binder_dying () {
                /* delegate to UndoTransaction::command_death */
                drop_references ();
        }
 
        void operator() () {
                if (after) {
                        _binder->set_state(*after, Stateful::current_state_version);
                }
        }
 
        void undo() {
                if (before) {
                        _binder->set_state(*before, Stateful::current_state_version);
                }
        }
 
        virtual XMLNode &get_state() const {
                std::string name;
                if (before && after) {
                        name = "MementoCommand";
                } else if (before) {
                        name = "MementoUndoCommand";
                } else {
                        name = "MementoRedoCommand";
                }
 
                XMLNode* node = new XMLNode(name);
                _binder->add_state (node);
 
                node->set_property ("type-name", _binder->type_name ());
 
                if (before) {
                        node->add_child_copy(*before);
                }
 
                if (after) {
                        node->add_child_copy(*after);
                }
 
                return *node;
        }
 
protected:
        MementoCommandBinder<obj_T>* _binder;
        XMLNode* before;
        XMLNode* after;
        PBD::ScopedConnection _binder_death_connection;
};