2 Copyright (C) 2000-2010 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 __pbd_stateful_h__
21 #define __pbd_stateful_h__
28 #include "pbd/xml++.h"
29 #include "pbd/property_basics.h"
30 #include "pbd/signals.h"
41 class OwnedPropertyList;
43 /** Base class for objects with saveable and undoable state */
49 virtual XMLNode& get_state (void) = 0;
50 virtual int set_state (const XMLNode&, int version) = 0;
51 virtual bool set_property (const PropertyBase&);
53 PropertyChange set_properties (const PropertyList&);
54 const OwnedPropertyList& properties() const { return *_properties; }
56 void add_property (PropertyBase& s);
58 /* Extra XML node: so that 3rd parties can attach state to the XMLNode
59 representing the state of this object.
62 void add_extra_xml (XMLNode&);
63 XMLNode *extra_xml (const std::string& str);
65 const PBD::ID& id() const { return _id; }
67 /* history management */
69 void clear_history ();
70 void diff (PropertyList&, PropertyList&, Command*) const;
73 /* create a property list from an XMLNode
75 virtual PropertyList* property_factory(const XMLNode&) const { return 0; }
77 /* How stateful's notify of changes to their properties
79 PBD::Signal1<void,const PropertyChange&> PropertyChanged;
81 static int current_state_version;
82 static int loading_state_version;
84 virtual void suspend_property_changes ();
85 virtual void resume_property_changes ();
87 void unlock_property_changes () { _no_property_changes = false; }
88 void block_property_changes () { _no_property_changes = true; }
92 void add_instant_xml (XMLNode&, const sys::path& directory_path);
93 XMLNode *instant_xml (const std::string& str, const sys::path& directory_path);
94 void add_properties (XMLNode &);
95 /* derived types can call this from ::set_state() (or elsewhere)
96 to get basic property setting done.
98 PropertyChange set_properties (XMLNode const &);
100 /* derived classes can implement this to do cross-checking
101 of property values after either a PropertyList or XML
102 driven property change.
104 virtual void post_set () { };
107 XMLNode *_instant_xml;
110 bool _no_property_changes;
111 PBD::PropertyChange _pending_changed;
114 std::string _xml_node_name; ///< name of node to use for this object in XML
115 OwnedPropertyList* _properties;
117 virtual void send_change (const PropertyChange&);
118 /** derived classes can implement this in order to process a property change
119 within thaw() just before send_change() is called.
121 virtual void mid_thaw (const PropertyChange&) { }
122 bool property_changes_suspended() const { return g_atomic_int_get (&_frozen) > 0; }
127 #endif /* __pbd_stateful_h__ */