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__
26 #include "pbd/xml++.h"
34 /** A unique identifier for a property of a Stateful object */
35 typedef GQuark PropertyID;
38 struct PropertyDescriptor {
39 PropertyDescriptor () : property_id (0) {}
40 PropertyDescriptor (PropertyID pid) : property_id (pid) {}
42 PropertyID property_id;
46 /** A list of IDs of Properties that have changed in some situation or other */
47 class PropertyChange : public std::set<PropertyID>
52 template<typename T> PropertyChange(PropertyDescriptor<T> p);
54 PropertyChange(const PropertyChange& other) : std::set<PropertyID> (other) {}
56 PropertyChange operator=(const PropertyChange& other) {
58 insert (other.begin (), other.end ());
62 template<typename T> PropertyChange operator=(PropertyDescriptor<T> p);
63 template<typename T> bool contains (PropertyDescriptor<T> p) const;
65 bool contains (const PropertyChange& other) const {
66 for (const_iterator x = other.begin (); x != other.end (); ++x) {
67 if (find (*x) != end ()) {
74 void add (PropertyID id) { insert (id); }
75 void add (const PropertyChange& other) { insert (other.begin (), other.end ()); }
76 template<typename T> void add (PropertyDescriptor<T> p);
79 /** Base (non template) part of Property */
83 PropertyBase (PropertyID pid)
87 virtual ~PropertyBase () {}
89 /** Forget about any old value for this state */
90 virtual void clear_history () = 0;
92 /** Make XML that allows us to get from some previous state to the current state
93 * of this property, and add it to @param history_node
95 virtual void add_history_state (XMLNode* history_node) const = 0;
97 /** Add information to two property lists: one that allows
98 * undo of the changes in this property's state betwen now and
99 * the last call to clear_history, and one that allows redo
102 virtual void diff (PropertyList& undo, PropertyList& redo, Command*) const = 0;
104 virtual PropertyBase* maybe_clone_self_if_found_in_history_node (const XMLNode&) const { return 0; }
106 /** Set state from an XML node previously generated by add_history_state */
107 virtual bool set_state_from_owner_state (XMLNode const&) = 0;
109 /** Add complete current state in XML form to an existing XML node @param node */
110 virtual void add_state_to_owner_state (XMLNode& node) const = 0;
112 /** @return true if this property has changed in value since construction or since
113 * the last call to clear_history(), whichever was more recent.
115 virtual bool changed() const = 0;
117 /** Set the value of this property from another */
118 virtual void set_state_from_property (PropertyBase const *) = 0;
120 const gchar*property_name () const { return g_quark_to_string (_property_id); }
121 PropertyID property_id () const { return _property_id; }
123 bool operator==(PropertyID pid) const {
124 return _property_id == pid;
128 PropertyID _property_id;
133 #endif /* __libpbd_property_basics_h__ */