App: add signalChanged to Property

For more efficient tracking of single property changes

src/App/Property.cpp

@@ -32,6 +32,7 @@
 #include "ObjectIdentifier.h"
 #include "PropertyContainer.h"
 #include <Base/Exception.h>
+#include <Base/Tools.h>
 #include "Application.h"
 #include "DocumentObject.h"
 
@@ -212,8 +213,13 @@ void Property::setReadOnly(bool readOnly)
 void Property::hasSetValue(void)
 {
     PropertyCleaner guard(this);
-    if (father)
+    if (father) {
         father->onChanged(this);
+        if(!testStatus(Busy)) {
+            Base::BitsetLocker<decltype(StatusBits)> guard(StatusBits,Busy);
+            signalChanged(*this);
+        }
+    }
     StatusBits.set(Touched);
 }
 

src/App/Property.h

@@ -31,6 +31,7 @@
 #include <boost/any.hpp>
 #include <string>
 #include <bitset>
+#include <boost/signals2.hpp>
 
 namespace Py {
 class Object;
@@ -75,6 +76,7 @@ public:
                       // relevant for the container using it
         EvalOnRestore = 14, // In case of expression binding, evaluate the
                             // expression on restore and touch the object on value change.
+        Busy = 15, // internal use to avoid recursive signaling
 
         // The following bits are corresponding to PropertyType set when the
         // property added. These types are meant to be static, and cannot be
@@ -269,6 +271,9 @@ private:
 private:
     PropertyContainer *father;
     const char *myName;
+
+public:
+    boost::signals2::signal<void (const App::Property&)> signalChanged;
 };