DocumentObject: Added getOldLabel() method, preparation for renaming of object identifiers.

src/App/DocumentObject.cpp

@@ -182,6 +182,12 @@ void DocumentObject::setDocument(App::Document* doc)
 
 void DocumentObject::onBeforeChange(const Property* prop)
 {
+
+    // Store current name in oldLabel, to be able to easily retrieve old name of document object later
+    // when renaming expressions.
+    if (prop == &Label)
+        oldLabel = static_cast<PropertyString*>(&Label)->getStrValue();
+
     if (_pDoc)
         _pDoc->onBeforeChangeProperty(this,prop);
 }
@@ -191,6 +197,10 @@ void DocumentObject::onChanged(const Property* prop)
 {
     if (_pDoc)
         _pDoc->onChangedProperty(this,prop);
+
+    if (prop == &Label && _pDoc)
+        _pDoc->signalRenamedObject(*this);
+
     if (prop->getType() & Prop_Output)
         return;
     // set object touched

src/App/DocumentObject.h

@@ -160,6 +160,8 @@ public:
 
     virtual void Save (Base::Writer &writer) const;
 
+    const std::string & getOldLabel() const { return oldLabel; }
+
 protected:
     /** get called by the document to recompute this feature
       * Normaly this method get called in the processing of
@@ -205,6 +207,9 @@ protected: // attributes
     /// pointer to the document this object belongs to
     App::Document* _pDoc;
 
+    /// Old label; used for renaming expressions
+    std::string oldLabel;
+
     // pointer to the document name string (for performance)
     const std::string *pcNameInDocument;
 };