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Clarify commentary slightly. No functional changes.

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git-svn-id: svn://localhost/ardour2/branches/3.0@8345 d708f5d6-7413-0410-9779-e7cbd77b26cf
This commit is contained in:
Carl Hetherington
2010-12-28 03:05:09 +00:00
parent fd0c45ec97
commit 390f18c115
2 changed files with 76 additions and 42 deletions
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48
libs/pbd/pbd/properties.h
View File

@@ -33,8 +33,7 @@
namespace PBD {
/** Parent class for classes which represent a single scalar property in a Stateful object
*/
/** Parent class for classes which represent a single scalar property in a Stateful object */
template<class T>
class PropertyTemplate : public PropertyBase
{
@@ -58,6 +57,9 @@ public:
, _current (s._current)
{}
/* OPERATORS / ACCESSORS */
T & operator=(T const& v) {
set (v);
return _current;
@@ -93,16 +95,9 @@ public:
return _current;
}
void clear_changes () {
_have_old = false;
}
void get_changes_as_xml (XMLNode* history_node) const {
XMLNode* node = history_node->add_child (property_name());
node->add_property ("from", to_string (_old));
node->add_property ("to", to_string (_current));
}
/* MANAGEMENT OF Stateful State */
bool set_value (XMLNode const & node) {
XMLProperty const* p = node.property (property_name());
@@ -123,27 +118,46 @@ public:
node.add_property (property_name(), to_string (_current));
}
bool changed () const { return _have_old; }
void apply_changes (PropertyBase const * p) {
T v = dynamic_cast<const PropertyTemplate<T>* > (p)->val ();
if (v != _current) {
set (v);
}
/* MANAGEMENT OF HISTORY */
void clear_changes () {
_have_old = false;
}
bool changed () const { return _have_old; }
void invert () {
T const tmp = _current;
_current = _old;
_old = tmp;
}
/* TRANSFERRING HISTORY TO / FROM A StatefulDiffCommand */
void get_changes_as_xml (XMLNode* history_node) const {
XMLNode* node = history_node->add_child (property_name());
node->add_property ("from", to_string (_old));
node->add_property ("to", to_string (_current));
}
void get_changes_as_properties (PropertyList& changes, Command *) const {
if (this->_have_old) {
changes.add (clone ());
}
}
/* VARIOUS */
void apply_changes (PropertyBase const * p) {
T v = dynamic_cast<const PropertyTemplate<T>* > (p)->val ();
if (v != _current) {
set (v);
}
}
protected:
void set (T const& v) {

70
libs/pbd/pbd/property_basics.h
View File

@@ -38,11 +38,11 @@ typedef GQuark PropertyID;
template<typename T>
struct PropertyDescriptor {
PropertyDescriptor () : property_id (0) {}
PropertyDescriptor (PropertyID pid) : property_id (pid) {}
PropertyID property_id;
typedef T value_type;
PropertyDescriptor () : property_id (0) {}
PropertyDescriptor (PropertyID pid) : property_id (pid) {}
PropertyID property_id;
typedef T value_type;
};
/** A list of IDs of Properties that have changed in some situation or other */
@@ -78,7 +78,11 @@ public:
template<typename T> void add (PropertyDescriptor<T> p);
};
/** Base (non template) part of Property */
/** Base (non template) part of Property
* Properties are used for two main reasons:
* - to handle current state (when serializing Stateful objects)
* - to handle history since some operation was started (when making StatefulDiffCommands for undo)
*/
class PropertyBase
{
public:
@@ -88,18 +92,45 @@ public:
virtual ~PropertyBase () {}
virtual PropertyBase* clone () const = 0;
/* MANAGEMENT OF Stateful STATE */
/** Set the value of this property from a Stateful node.
* @return true if the value was set.
*/
virtual bool set_value (XMLNode const &) = 0;
/** Get this property's value and put it into a Stateful node */
virtual void get_value (XMLNode& node) const = 0;
/* MANAGEMENT OF HISTORY */
/** Forget about any old changes to this property's value */
virtual void clear_changes () = 0;
/** Tell any things we own to forget about their old values */
virtual void clear_owned_changes () {}
/** Get any changes in this property as XML and add them to a node */
/** @return true if this property has changed in value since construction or since
* the last call to clear_changes (), whichever was more recent.
*/
virtual bool changed () const = 0;
/** Invert the changes in this property */
virtual void invert () = 0;
/* TRANSFERRING HISTORY TO / FROM A StatefulDiffCommand */
/** Get any changes in this property as XML and add them to a
* StatefulDiffCommand node.
*/
virtual void get_changes_as_xml (XMLNode *) const = 0;
/** Get any changes in this property as Properties and add them to a list */
/** If this Property has changed, clone it and add it to a given list.
* Used for making StatefulDiffCommands.
*/
virtual void get_changes_as_properties (PropertyList& changes, Command *) const = 0;
/** Collect StatefulDiffCommands for changes to anything that we own */
@@ -110,25 +141,14 @@ public:
*/
virtual PropertyBase* clone_from_xml (const XMLNode &) const { return 0; }
/** Set our value from an XML node.
* @return true if the value was set.
*/
virtual bool set_value (XMLNode const &) = 0;
/** Get our value and put it into an XML node */
virtual void get_value (XMLNode& node) const = 0;
/* VARIOUS */
virtual PropertyBase* clone () const = 0;
/** @return true if this property has changed in value since construction or since
* the last call to clear_changes (), whichever was more recent.
*/
virtual bool changed() const = 0;
/** Apply changes contained in another Property to this one */
/** Set this property's current state from another */
virtual void apply_changes (PropertyBase const *) = 0;
/** Invert the changes in this property */
virtual void invert () = 0;
const gchar* property_name () const { return g_quark_to_string (_property_id); }
PropertyID property_id () const { return _property_id; }