livetrax/libs/pbd/stateful_diff_command.cc

/*
 * Copyright (C) 2010-2016 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2010 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2012-2016 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.
 */

#include "pbd/stateful_diff_command.h"
#include "pbd/demangle.h"
#include "pbd/i18n.h"
#include "pbd/property_list.h"
#include "pbd/types_convert.h"

using namespace std;
using namespace PBD;

/** Create a new StatefulDiffCommand by examining the changes made to a Stateful
 *  since the last time that clear_changes was called on it.
 *  @param s Stateful object.
 */

StatefulDiffCommand::StatefulDiffCommand (boost::shared_ptr<StatefulDestructible> s)
	: _object (s)
	, _changes (0)
{
	_changes = s->get_changes_as_properties (this);

	/* if the stateful object that this command refers to goes away,
           be sure to notify owners of this command.
        */

	s->DropReferences.connect_same_thread (*this, boost::bind (&Destructible::drop_references, this));
}

StatefulDiffCommand::StatefulDiffCommand (boost::shared_ptr<StatefulDestructible> s, XMLNode const& n)
	: _object (s)
	, _changes (0)
{
	const XMLNodeList& children (n.children ());

	for (XMLNodeList::const_iterator i = children.begin (); i != children.end (); ++i) {
		if ((*i)->name () == X_ ("Changes")) {
			_changes = s->property_factory (**i);
		}
	}

	assert (_changes != 0);

	/* if the stateful object that this command refers to goes away,
           be sure to notify owners of this command.
        */

	s->DropReferences.connect_same_thread (*this, boost::bind (&Destructible::drop_references, this));
}

StatefulDiffCommand::~StatefulDiffCommand ()
{
	delete _changes;
}

void
StatefulDiffCommand::operator() ()
{
	boost::shared_ptr<Stateful> s (_object.lock ());

	if (s) {
		s->apply_changes (*_changes);
	}
}

void
StatefulDiffCommand::undo ()
{
	boost::shared_ptr<Stateful> s (_object.lock ());

	if (s) {
		PropertyList p = *_changes;
		p.invert ();
		s->apply_changes (p);
	}
}

XMLNode&
StatefulDiffCommand::get_state ()
{
	boost::shared_ptr<Stateful> s (_object.lock ());

	if (!s) {
		/* XXX should we throw? */
		return *new XMLNode ("");
	}

	XMLNode* node = new XMLNode (X_ ("StatefulDiffCommand"));

	node->set_property ("obj-id", s->id ());
	node->set_property ("type-name", demangled_name (*s.get ()));

	XMLNode* changes = new XMLNode (X_ ("Changes"));

	_changes->get_changes_as_xml (changes);

	node->add_child_nocopy (*changes);

	return *node;
}

bool
StatefulDiffCommand::empty () const
{
	return _changes->empty ();
}