#include "pbd/command.h"
#include "pbd/stacktrace.h"
#include "pbd/xml++.h"
+#include "pbd/demangle.h"
#include <sigc++/slot.h>
#include <typeinfo>
+/** A class that can return a Stateful object which is the subject of a MementoCommand.
+ *
+ * The existence of this class means that the undo record can refer to objects which
+ * don't exist in the session file. Currently this is used for
+ *
+ * 1. MIDI automation; when MIDI automation is edited, undo records are
+ * written for the AutomationList being changed. However this AutomationList
+ * is a temporary structure, built by a MidiModel, which doesn't get written
+ * to the session file. Hence we need to be able to go from a MidiSource and
+ * Parameter to an AutomationList. This Binder mechanism allows this through
+ * MidiAutomationListBinder; the undo record stores the source and parameter,
+ * and these are bound to an AutomationList by the Binder.
+ *
+ * 2. Crossfades; unlike regions, these are completely removed from a session
+ * when they are deleted. This means that the undo record can contain
+ * references to non-existant crossfades. To get around this, CrossfadeBinder
+ * can do `just-in-time' binding from the crossfade ID.
+ */
+template <class obj_T>
+class MementoCommandBinder : public PBD::Destructible
+{
+public:
+ /** @return Stateful object to operate on */
+ virtual obj_T* get () const = 0;
+
+ /** @return Name of our type */
+ virtual std::string type_name () const {
+ return PBD::demangled_name (*get ());
+ }
+
+ /** Add our own state to an XMLNode */
+ virtual void add_state (XMLNode *) = 0;
+};
+
+/** A simple MementoCommandBinder which binds directly to an object */
+template <class obj_T>
+class SimpleMementoCommandBinder : public MementoCommandBinder<obj_T>
+{
+public:
+ SimpleMementoCommandBinder (obj_T& o)
+ : _object (o)
+ {
+ _object.Destroyed.connect_same_thread (_object_death_connection, boost::bind (&SimpleMementoCommandBinder::object_died, this));
+ }
+
+ obj_T* get () const {
+ return &_object;
+ }
+
+ void add_state (XMLNode* node) {
+ node->add_property ("obj_id", _object.id().to_s());
+ }
+
+ void object_died () {
+ /* The object we are binding died, so drop references to ourselves */
+ this->drop_references ();
+ }
+
+private:
+ obj_T& _object;
+ PBD::ScopedConnection _object_death_connection;
+};
+
/** This command class is initialized with before and after mementos
* (from Stateful::get_state()), so undo becomes restoring the before
* memento, and redo is restoring the after memento.
class MementoCommand : public Command
{
public:
- MementoCommand(obj_T& a_object, XMLNode* a_before, XMLNode* a_after)
- : obj(a_object), before(a_before), after(a_after)
+ MementoCommand (obj_T& a_object, XMLNode* a_before, XMLNode* a_after)
+ : _binder (new SimpleMementoCommandBinder<obj_T> (a_object)), before (a_before), after (a_after)
{
- /* if the object dies, make sure that we die and that everyone knows about it */
- obj_death_connection = obj.GoingAway.connect (boost::bind (&MementoCommand::object_died, this));
+ /* The binder's object died, so we must die */
+ _binder->DropReferences.connect_same_thread (_binder_death_connection, boost::bind (&MementoCommand::binder_dying, this));
}
+ MementoCommand (MementoCommandBinder<obj_T>* b, XMLNode* a_before, XMLNode* a_after)
+ : _binder (b), before (a_before), after (a_after)
+ {
+ /* The binder's object died, so we must die */
+ _binder->DropReferences.connect_same_thread (_binder_death_connection, boost::bind (&MementoCommand::binder_dying, this));
+ }
+
~MementoCommand () {
drop_references ();
delete before;
delete after;
+ delete _binder;
}
- void object_died () {
+ void binder_dying () {
delete this;
}
void operator() () {
if (after) {
- obj.set_state(*after, Stateful::current_state_version);
+ _binder->get()->set_state(*after, Stateful::current_state_version);
}
}
void undo() {
if (before) {
- obj.set_state(*before, Stateful::current_state_version);
+ _binder->get()->set_state(*before, Stateful::current_state_version);
}
}
}
XMLNode* node = new XMLNode(name);
-
- node->add_property("obj_id", obj.id().to_s());
- node->add_property("type_name", typeid(obj).name());
+ _binder->add_state (node);
+
+ node->add_property ("type_name", _binder->type_name ());
if (before) {
node->add_child_copy(*before);
}
protected:
- obj_T& obj;
+ MementoCommandBinder<obj_T>* _binder;
XMLNode* before;
XMLNode* after;
- boost::signals2::scoped_connection obj_death_connection;
+ PBD::ScopedConnection _binder_death_connection;
};
#endif // __lib_pbd_memento_h__