2 Copyright (C) 2010 Paul Davis
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #ifndef __libpbd_property_basics_h__
21 #define __libpbd_property_basics_h__
27 #include "pbd/xml++.h"
34 class StatefulDiffCommand;
36 /** A unique identifier for a property of a Stateful object */
37 typedef GQuark PropertyID;
40 struct PropertyDescriptor {
41 PropertyDescriptor () : property_id (0) {}
42 PropertyDescriptor (PropertyID pid) : property_id (pid) {}
44 PropertyID property_id;
48 /** A list of IDs of Properties that have changed in some situation or other */
49 class PropertyChange : public std::set<PropertyID>
54 template<typename T> PropertyChange(PropertyDescriptor<T> p);
56 PropertyChange(const PropertyChange& other) : std::set<PropertyID> (other) {}
58 PropertyChange operator=(const PropertyChange& other) {
60 insert (other.begin (), other.end ());
64 template<typename T> PropertyChange operator=(PropertyDescriptor<T> p);
65 template<typename T> bool contains (PropertyDescriptor<T> p) const;
67 bool contains (const PropertyChange& other) const {
68 for (const_iterator x = other.begin (); x != other.end (); ++x) {
69 if (find (*x) != end ()) {
76 void add (PropertyID id) { insert (id); }
77 void add (const PropertyChange& other) { insert (other.begin (), other.end ()); }
78 template<typename T> void add (PropertyDescriptor<T> p);
81 /** Base (non template) part of Property */
85 PropertyBase (PropertyID pid)
89 virtual ~PropertyBase () {}
91 virtual PropertyBase* clone () const = 0;
93 /** Forget about any old changes to this property's value */
94 virtual void clear_changes () = 0;
96 /** Tell any things we own to forget about their old values */
97 virtual void clear_owned_changes () {}
99 /** Get any changes in this property as XML and add them to a node */
100 virtual void get_changes_as_xml (XMLNode *) const = 0;
102 /** Get any changes in this property as Properties and add them to a list */
103 virtual void get_changes_as_properties (PropertyList& changes, Command *) const = 0;
105 /** Collect StatefulDiffCommands for changes to anything that we own */
106 virtual void rdiff (std::vector<Command*> &) const {}
108 /** Look in an XML node written by get_changes_as_xml and, if XML from this property
109 * is found, create a property with the changes from the XML.
111 virtual PropertyBase* clone_from_xml (const XMLNode &) const { return 0; }
113 /** Set our value from an XML node.
114 * @return true if the value was set.
116 virtual bool set_value (XMLNode const &) = 0;
118 /** Get our value and put it into an XML node */
119 virtual void get_value (XMLNode& node) const = 0;
121 /** @return true if this property has changed in value since construction or since
122 * the last call to clear_changes (), whichever was more recent.
124 virtual bool changed() const = 0;
126 /** Apply changes contained in another Property to this one */
127 virtual void apply_changes (PropertyBase const *) = 0;
129 /** Invert the changes in this property */
130 virtual void invert () = 0;
132 const gchar* property_name () const { return g_quark_to_string (_property_id); }
133 PropertyID property_id () const { return _property_id; }
135 bool operator==(PropertyID pid) const {
136 return _property_id == pid;
140 /* copy construction only by subclasses */
141 PropertyBase (PropertyBase const & b)
142 : _property_id (b._property_id)
146 PropertyID _property_id;
152 #endif /* __libpbd_property_basics_h__ */