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/*
Copyright (C) 2010 Paul Davis
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __pbd_properties_h__
#define __pbd_properties_h__
#include <string>
#include <list>
#include <glib/glib.h>
class XMLNode;
namespace PBD {
enum PropertyChange {
range_guarantee = ~0
};
PropertyChange new_change ();
/** Base (non template) part of Property */
class PropertyBase
{
public:
PropertyBase (GQuark quark, PropertyChange c)
: _have_old (false)
, _property_quark (q)
, _change (c)
{
}
/** Forget about any old value for this state */
void clear_history () {
_have_old = false;
}
virtual void diff (XMLNode *, XMLNode *) const = 0;
virtual PropertyChange set_state (XMLNode const &) = 0;
virtual void add_state (XMLNode &) const = 0;
std::string property_name() const { return g_quark_to_string (_property_quark); }
PropertyChange change() const { return _change; }
bool operator== (GQuark q) const {
return _property_quark == q;
}
protected:
bool _have_old;
GQuark _property_quark;
PropertyChange _change;
};
/** Parent class for classes which represent a single property in a Stateful object */
template <class T>
class PropertyTemplate : public PropertyBase
{
public:
PropertyTemplate (GQuark q, PropertyChange c, T const & v)
: PropertyBase (q, c)
, _current (v)
{
}
PropertyTemplate<T> & operator= (PropertyTemplate<T> const & s) {
/* XXX: isn't there a nicer place to do this? */
_have_old = s._have_old;
_property_quark = s._property_quark;
_change = s._change;
_current = s._current;
_old = s._old;
return *this;
}
T & operator= (T const & v) {
set (v);
return _current;
}
T & operator+= (T const & v) {
set (_current + v);
return _current;
}
bool operator== (const T& other) const {
return _current == other;
}
bool operator!= (const T& other) const {
return _current != other;
}
operator T const & () const {
return _current;
}
T const & val () const {
return _current;
}
void diff (XMLNode* old, XMLNode* current) const {
if (_have_old) {
old->add_property (g_quark_to_string (_property_quark), to_string (_old));
current->add_property (g_quark_to_string (_property_quark), to_string (_current));
}
}
/** Try to set state from the property of an XML node.
* @param node XML node.
* @return PropertyChange effected, or 0.
*/
PropertyChange set_state (XMLNode const & node) {
XMLProperty const * p = node.property (g_quark_to_string (_property_quark));
if (p) {
T const v = from_string (p->value ());
if (v == _current) {
return PropertyChange (0);
}
set (v);
return _change;
}
return PropertyChange (0);
}
void add_state (XMLNode & node) const {
node.add_property (g_quark_to_string (_property_quark), to_string (_current));
}
protected:
void set (T const & v) {
_old = _current;
_have_old = true;
_current = v;
}
virtual std::string to_string (T const & v) const = 0;
virtual T from_string (std::string const & s) const = 0;
T _current;
T _old;
};
template<class T>
std::ostream& operator<< (std::ostream& os, PropertyTemplate<T> const & s)
{
return os << s.val();
}
/** Representation of a single piece of state in a Stateful; for use
* with types that can be written to / read from stringstreams.
*/
template <class T>
class Property : public PropertyTemplate<T>
{
public:
Property (GQuark q, PropertyChange c, T const & v)
: PropertyTemplate<T> (q, c, v)
{
}
T & operator= (T const & v) {
this->set (v);
return this->_current;
}
private:
std::string to_string (T const & v) const {
// XXX LocaleGuard
std::stringstream s;
s.precision (12); // in case its floating point
s << v;
return s.str ();
}
T from_string (std::string const & s) const {
// XXX LocaleGuard
std::stringstream t (s);
T v;
t.precision (12); // in case its floating point
t >> v;
return v;
}
};
} /* namespace PBD */
#endif /* __pbd_properties_h__ */
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