A few small cleanups to the property code.

git-svn-id: svn://localhost/ardour2/branches/3.0@6816 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/playlist.cc

@@ -133,7 +133,7 @@ RegionListProperty::copy_for_history () const
 void 
 RegionListProperty::diff (PropertyList& before, PropertyList& after) const
 {
-        if (_have_old) {
+        if (changed()) {
                 RegionListProperty* a = copy_for_history ();
                 RegionListProperty* b = copy_for_history ();
 

libs/pbd/pbd/properties.h

@@ -40,6 +40,7 @@ class PropertyTemplate : public PropertyBase
 public:
 	PropertyTemplate (PropertyDescriptor<T> p, T const& v)
 		: PropertyBase (p.property_id)
+		, _have_old (false)
 		, _current (v)
 	{}
 
@@ -79,6 +80,10 @@ public:
 		return _current;
 	}
 
+	void clear_history () {
+		_have_old = false;
+	}
+
         /** If this property has been changed since the last clear_history() call
             (or its construction), add an (XML) property describing the old value 
             to the XMLNode @param old and another describing the current value to
@@ -112,6 +117,8 @@ public:
                 owner_state.add_property (property_name(), to_string (_current));
 	}
 
+	bool changed () const { return _have_old; }
+
 protected:
         /** Constructs a PropertyTemplate with a default
             value for _old and _current.
@@ -132,6 +139,7 @@ protected:
 	virtual std::string to_string (T const& v) const             = 0;
 	virtual T           from_string (std::string const& s) const = 0;
 
+	bool _have_old;
 	T _current;
 	T _old;
 };

libs/pbd/pbd/property_basics.h

@@ -77,13 +77,10 @@ class PropertyBase
 public:
 	PropertyBase (PropertyID pid)
 		: _property_id (pid)
-		, _have_old (false)
 	{}
 
 	/** Forget about any old value for this state */
-	virtual void clear_history () {
-		_have_old = false;
-	}
+	virtual void clear_history () = 0;
 
 	virtual void add_history_state (XMLNode*)        const = 0;
 	virtual void diff (PropertyList&, PropertyList&) const = 0;
@@ -92,10 +89,10 @@ public:
 
 	virtual bool set_state_from_owner_state (XMLNode const&) = 0;
 	virtual void add_state_to_owner_state (XMLNode&) const   = 0;
+	virtual bool changed() const = 0;
 
 	const gchar*property_name () const { return g_quark_to_string (_property_id); }
 	PropertyID  property_id () const   { return _property_id; }
-        bool changed() const { return _have_old; }
 
 	bool operator==(PropertyID pid) const {
 		return _property_id == pid;
@@ -103,13 +100,6 @@ public:
 
 protected:
 	PropertyID _property_id;
-	bool       _have_old;
-};
-
-class PropertyFactory 
-{
-  public:
-        static PropertyBase* create (const XMLNode&);
 };
 
 }

libs/pbd/pbd/sequence_property.h

@@ -113,9 +113,12 @@ class SequenceProperty : public PropertyBase
                         owner_state_node.add_child_nocopy ((*i)->get_state ());
                 } 
 	}
+
+	bool changed () const {
+		return !_change.added.empty() || !_change.removed.empty();
+	}
 	
 	void clear_history () {
-		PropertyBase::clear_history();
 		_change.added.clear ();
 		_change.removed.clear ();
 	}
@@ -145,21 +148,18 @@ class SequenceProperty : public PropertyBase
 	typename Container::const_reverse_iterator rend() const { return _val.rend(); }
 
 	typename Container::iterator insert (typename Container::iterator i, const typename Container::value_type& v) {
-                _have_old = true;
 		_change.added.insert (v);
 		return _val.insert (i, v);
 	}
 
 	typename Container::iterator erase (typename Container::iterator i) {
 		if (i != _val.end()) {
-                        _have_old = true;
 			_change.removed.insert (*i);
 		}
 		return _val.erase (i);
 	}
 
 	typename Container::iterator erase (typename Container::iterator f, typename Container::iterator l) {
-                _have_old = true;
 		for (typename Container::const_iterator i = f; i != l; ++i) {
 			_change.removed.insert(*i);
 		}
@@ -167,20 +167,17 @@ class SequenceProperty : public PropertyBase
 	}
 
 	void push_back (const typename Container::value_type& v) {
-                _have_old = true;
 		_change.added.insert (v);
 		_val.push_back (v);
 	}
 
 	void push_front (const typename Container::value_type& v) {
-                _have_old = true;
 		_change.added.insert (v);
 		_val.push_front (v);
 	}
 
 	void pop_front () {
                 if (!_val.empty()) {
-                        _have_old = true;
                         _change.removed.insert (front());
                 }
 		_val.pop_front ();
@@ -188,14 +185,12 @@ class SequenceProperty : public PropertyBase
 
 	void pop_back () {
                 if (!_val.empty()) {
-                        _have_old = true;
                         _change.removed.insert (front());
                 }
 		_val.pop_back ();
 	}
 
 	void clear () {
-                _have_old = true;
 		_change.removed.insert (_val.begin(), _val.end());
 		_val.clear ();
 	}
@@ -209,7 +204,6 @@ class SequenceProperty : public PropertyBase
 	}
 
 	Container& operator= (const Container& other) {
-                _have_old = true;
                 _change.removed.insert (_val.begin(), _val.end());
                 _change.added.insert (other.begin(), other.end());
 		return _val = other;