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"
33 #include "pbd/stateful.h"
37 /** 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)
62 /* OPERATORS / ACCESSORS */
64 T & operator=(T const& v) {
69 /* This will mean that, if fred and jim are both PropertyTemplates,
70 * fred = jim will result in fred taking on jim's current value,
71 * but NOT jim's property ID.
73 PropertyTemplate<T> & operator= (PropertyTemplate<T> const & p) {
78 T & operator+=(T const& v) {
83 bool operator==(const T& other) const {
84 return _current == other;
87 bool operator!=(const T& other) const {
88 return _current != other;
91 operator T const &() const {
95 T const& val () const {
100 /* MANAGEMENT OF Stateful State */
102 bool set_value (XMLNode const & node) {
104 XMLProperty const* p = node.property (property_name());
107 T const v = from_string (p->value ());
118 void get_value (XMLNode & node) const {
119 node.add_property (property_name(), to_string (_current));
123 /* MANAGEMENT OF HISTORY */
125 void clear_changes () {
129 bool changed () const { return _have_old; }
132 T const tmp = _current;
138 /* TRANSFERRING HISTORY TO / FROM A StatefulDiffCommand */
140 void get_changes_as_xml (XMLNode* history_node) const {
141 XMLNode* node = history_node->add_child (property_name());
142 node->add_property ("from", to_string (_old));
143 node->add_property ("to", to_string (_current));
146 void get_changes_as_properties (PropertyList& changes, Command *) const {
147 if (this->_have_old) {
148 changes.add (clone ());
155 void apply_changes (PropertyBase const * p) {
156 T v = dynamic_cast<const PropertyTemplate<T>* > (p)->val ();
164 void set (T const& v) {
171 /* value has been reset to the value
172 at the start of a history transaction,
173 before clear_changes() is called.
174 thus there is effectively no apparent
175 history for this property.
185 virtual std::string to_string (T const& v) const = 0;
186 virtual T from_string (std::string const& s) const = 0;
193 /* disallow copy-construction; it's not obvious whether it should mean
194 a copy of just the value, or the value and property ID.
196 PropertyTemplate (PropertyTemplate<T> const &);
200 std::ostream & operator<<(std::ostream& os, PropertyTemplate<T> const& s)
202 return os << s.val ();
205 /** Representation of a single piece of scalar state in a Stateful; for use
206 * with types that can be written to / read from stringstreams.
209 class Property : public PropertyTemplate<T>
212 Property (PropertyDescriptor<T> q, T const& v)
213 : PropertyTemplate<T> (q, v)
216 Property (PropertyDescriptor<T> q, T const& o, T const& c)
217 : PropertyTemplate<T> (q, o, c)
220 Property (PropertyDescriptor<T> q, Property<T> const& v)
221 : PropertyTemplate<T> (q, v)
224 Property<T>* clone () const {
225 return new Property<T> (this->property_id(), this->_old, this->_current);
228 Property<T>* clone_from_xml (const XMLNode& node) const {
229 XMLNodeList const & children = node.children ();
230 XMLNodeList::const_iterator i = children.begin();
231 while (i != children.end() && (*i)->name() != this->property_name()) {
235 if (i == children.end()) {
238 XMLProperty* from = (*i)->property ("from");
239 XMLProperty* to = (*i)->property ("to");
245 return new Property<T> (this->property_id(), from_string (from->value()), from_string (to->value ()));
248 T & operator=(T const& v) {
250 return this->_current;
254 friend class PropertyFactory;
256 /* no copy-construction */
257 Property (Property<T> const &);
259 /* Note that we do not set a locale for the streams used
260 * in to_string() or from_string(), because we want the
261 * format to be portable across locales (i.e. C or
262 * POSIX). Also, there is the small matter of
263 * std::locale aborting on OS X if used with anything
264 * other than C or POSIX locales.
266 virtual std::string to_string (T const& v) const {
268 s.precision (12); // in case its floating point
273 virtual T from_string (std::string const& s) const {
274 std::stringstream t (s);
282 /** Specialization, for std::string which is common and special (see to_string() and from_string()
283 * Using stringstream to read from a std::string is easy to get wrong because of whitespace
287 class Property<std::string> : public PropertyTemplate<std::string>
290 Property (PropertyDescriptor<std::string> d, std::string const & v)
291 : PropertyTemplate<std::string> (d, v)
294 Property (PropertyDescriptor<std::string> d, std::string const & o, std::string const & c)
295 : PropertyTemplate<std::string> (d, o, c)
298 Property<std::string>* clone () const {
299 return new Property<std::string> (this->property_id(), _old, _current);
302 std::string & operator= (std::string const& v) {
304 return this->_current;
308 std::string to_string (std::string const& v) const {
312 std::string from_string (std::string const& s) const {
316 /* no copy-construction */
317 Property (Property<std::string> const &);
321 class EnumProperty : public Property<T>
324 EnumProperty (PropertyDescriptor<T> q, T const& v)
328 T & operator=(T const& v) {
330 return this->_current;
334 std::string to_string (T const & v) const {
335 return enum_2_string (v);
338 T from_string (std::string const & s) const {
339 return static_cast<T> (string_2_enum (s, this->_current));
342 /* no copy-construction */
343 EnumProperty (EnumProperty const &);
346 /** A Property which holds a shared_ptr to a Stateful object,
347 * and handles undo using the somewhat inefficient approach
348 * of saving the complete XML state of its object before and
349 * after changes. A sort of half-way house between the old
350 * complete-state undo system and the new difference-based
354 class SharedStatefulProperty : public PropertyBase
357 typedef boost::shared_ptr<T> Ptr;
359 SharedStatefulProperty (PropertyID d, Ptr p)
366 SharedStatefulProperty (PropertyID d, Ptr o, Ptr c)
374 bool set_value (XMLNode const & node) {
376 /* Look for our node */
377 XMLNode* n = node.child (property_name ());
382 /* And there should be one child which is the state of our T */
383 XMLNodeList const & children = n->children ();
384 if (children.size() != 1) {
388 _current->set_state (*children.front (), Stateful::current_state_version);
392 void get_value (XMLNode & node) const {
393 XMLNode* n = node.add_child (property_name ());
394 n->add_child_nocopy (_current->get_state ());
397 void clear_changes () {
398 /* We are starting to change things, so _old gets set up
399 with the current state.
401 _old.reset (new T (*_current.get()));
404 bool changed () const {
405 /* Expensive, but, hey; this requires operator!= in
408 return (*_old != *_current);
412 _current.swap (_old);
415 void get_changes_as_xml (XMLNode* history_node) const {
416 /* We express the diff as before and after state, just
417 as MementoCommand does.
419 XMLNode* p = history_node->add_child (property_name ());
420 XMLNode* from = p->add_child ("from");
421 from->add_child_nocopy (_old->get_state ());
422 XMLNode* to = p->add_child ("to");
423 to->add_child_nocopy (_current->get_state ());
426 void get_changes_as_properties (PropertyList& changes, Command *) const {
428 changes.add (clone ());
432 void apply_changes (PropertyBase const * p) {
433 *_current = *(dynamic_cast<SharedStatefulProperty const *> (p))->val ();
440 T* operator-> () const {
441 return _current.operator-> ();
444 operator bool () const {
455 /* No copy-construction nor assignment */
456 SharedStatefulProperty (SharedStatefulProperty<T> const &);
457 SharedStatefulProperty<T>& operator= (SharedStatefulProperty<T> const &);
460 } /* namespace PBD */
462 #include "pbd/property_list_impl.h"
463 #include "pbd/property_basics_impl.h"
465 #endif /* __pbd_properties_h__ */