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 __pbd_properties_h__
21 #define __pbd_properties_h__
29 #include "pbd/xml++.h"
30 #include "pbd/property_basics.h"
31 #include "pbd/property_list.h"
32 #include "pbd/enumwriter.h"
36 /** Parent class for classes which represent a single scalar property in a Stateful object
39 class PropertyTemplate : public PropertyBase
42 PropertyTemplate (PropertyDescriptor<T> p, T const& v)
43 : PropertyBase (p.property_id)
48 PropertyTemplate (PropertyDescriptor<T> p, T const& o, T const& c)
49 : PropertyBase (p.property_id)
55 PropertyTemplate (PropertyDescriptor<T> p, PropertyTemplate<T> const & s)
56 : PropertyBase (p.property_id)
58 , _current (s._current)
61 T & operator=(T const& v) {
66 /* This will mean that, if fred and jim are both PropertyTemplates,
67 * fred = jim will result in fred taking on jim's current value,
68 * but NOT jim's property ID.
70 PropertyTemplate<T> & operator= (PropertyTemplate<T> const & p) {
75 T & operator+=(T const& v) {
80 bool operator==(const T& other) const {
81 return _current == other;
84 bool operator!=(const T& other) const {
85 return _current != other;
88 operator T const &() const {
92 T const& val () const {
96 void clear_changes () {
100 void get_changes_as_xml (XMLNode* history_node) const {
101 XMLNode* node = history_node->add_child (property_name());
102 node->add_property ("from", to_string (_old));
103 node->add_property ("to", to_string (_current));
106 bool set_value (XMLNode const & node) {
108 XMLProperty const* p = node.property (property_name());
111 T const v = from_string (p->value ());
122 void get_value (XMLNode & node) const {
123 node.add_property (property_name(), to_string (_current));
126 bool changed () const { return _have_old; }
128 void apply_changes (PropertyBase const * p) {
129 T v = dynamic_cast<const PropertyTemplate<T>* > (p)->val ();
136 T const tmp = _current;
141 void get_changes_as_properties (PropertyList& changes, Command *) const {
142 if (this->_have_old) {
143 changes.add (clone ());
149 void set (T const& v) {
156 /* value has been reset to the value
157 at the start of a history transaction,
158 before clear_changes() is called.
159 thus there is effectively no apparent
160 history for this property.
170 virtual std::string to_string (T const& v) const = 0;
171 virtual T from_string (std::string const& s) const = 0;
178 /* disallow copy-construction; it's not obvious whether it should mean
179 a copy of just the value, or the value and property ID.
181 PropertyTemplate (PropertyTemplate<T> const &);
185 std::ostream & operator<<(std::ostream& os, PropertyTemplate<T> const& s)
187 return os << s.val ();
190 /** Representation of a single piece of scalar state in a Stateful; for use
191 * with types that can be written to / read from stringstreams.
194 class Property : public PropertyTemplate<T>
197 Property (PropertyDescriptor<T> q, T const& v)
198 : PropertyTemplate<T> (q, v)
201 Property (PropertyDescriptor<T> q, T const& o, T const& c)
202 : PropertyTemplate<T> (q, o, c)
205 Property (PropertyDescriptor<T> q, Property<T> const& v)
206 : PropertyTemplate<T> (q, v)
209 Property<T>* clone () const {
210 return new Property<T> (this->property_id(), this->_old, this->_current);
213 Property<T>* clone_from_xml (const XMLNode& node) const {
214 XMLNodeList const & children = node.children ();
215 XMLNodeList::const_iterator i = children.begin();
216 while (i != children.end() && (*i)->name() != this->property_name()) {
220 if (i == children.end()) {
223 XMLProperty* from = (*i)->property ("from");
224 XMLProperty* to = (*i)->property ("to");
230 return new Property<T> (this->property_id(), from_string (from->value()), from_string (to->value ()));
233 T & operator=(T const& v) {
235 return this->_current;
239 friend class PropertyFactory;
241 /* no copy-construction */
242 Property (Property<T> const &);
244 /* Note that we do not set a locale for the streams used
245 * in to_string() or from_string(), because we want the
246 * format to be portable across locales (i.e. C or
247 * POSIX). Also, there is the small matter of
248 * std::locale aborting on OS X if used with anything
249 * other than C or POSIX locales.
251 virtual std::string to_string (T const& v) const {
253 s.precision (12); // in case its floating point
258 virtual T from_string (std::string const& s) const {
259 std::stringstream t (s);
267 /** Specialization, for std::string which is common and special (see to_string() and from_string()
268 * Using stringstream to read from a std::string is easy to get wrong because of whitespace
272 class Property<std::string> : public PropertyTemplate<std::string>
275 Property (PropertyDescriptor<std::string> d, std::string const & v)
276 : PropertyTemplate<std::string> (d, v)
279 Property (PropertyDescriptor<std::string> d, std::string const & o, std::string const & c)
280 : PropertyTemplate<std::string> (d, o, c)
283 Property<std::string>* clone () const {
284 return new Property<std::string> (this->property_id(), _old, _current);
287 std::string & operator= (std::string const& v) {
289 return this->_current;
293 std::string to_string (std::string const& v) const {
297 std::string from_string (std::string const& s) const {
301 /* no copy-construction */
302 Property (Property<std::string> const &);
306 class EnumProperty : public Property<T>
309 EnumProperty (PropertyDescriptor<T> q, T const& v)
313 T & operator=(T const& v) {
315 return this->_current;
319 std::string to_string (T const & v) const {
320 return enum_2_string (v);
323 T from_string (std::string const & s) const {
324 return static_cast<T> (string_2_enum (s, this->_current));
327 /* no copy-construction */
328 EnumProperty (EnumProperty const &);
331 } /* namespace PBD */
333 #include "pbd/property_list_impl.h"
334 #include "pbd/property_basics_impl.h"
336 #endif /* __pbd_properties_h__ */