Core: Add a possibility to extract active object based on extension

src/Gui/ActiveObjectList.cpp

@@ -197,3 +197,15 @@ void ActiveObjectList::objectDeleted(const ViewProviderDocumentObject &vp)
         }
     }
 }
+
+App::DocumentObject* ActiveObjectList::getObjectWithExtension(const Base::Type extensionTypeId) const
+{
+    for (const auto& pair : _ObjectMap) {
+        App::DocumentObject* obj = getObject(pair.second, true);
+        if (obj && obj->hasExtension(extensionTypeId)) {
+            return obj;
+        }
+    }
+
+    return nullptr;
+}

src/Gui/ActiveObjectList.h

@@ -27,6 +27,7 @@
 
 #include <map>
 #include <string>
+#include <Base/Type.h>
 #include <Gui/TreeItemMode.h>
 #include <FCGlobal.h>
 
@@ -67,6 +68,8 @@ namespace Gui
         void objectDeleted(const ViewProviderDocumentObject& viewProviderIn);
         bool hasObject(App::DocumentObject *obj, const char *, const char *subname=nullptr) const;
 
+        App::DocumentObject* getObjectWithExtension(Base::Type extensionTypeId) const;
+
     private:
         struct ObjectInfo;
         void setHighlight(const ObjectInfo &info, Gui::HighlightMode mode, bool enable);

src/Gui/MDIView.h

@@ -147,6 +147,11 @@ public:
         return ActiveObjects.hasObject(o,n,subname);
     }
 
+    App::DocumentObject* getActiveObjectWithExtension(const Base::Type extensionTypeId) const
+    {
+        return ActiveObjects.getObjectWithExtension(extensionTypeId);
+    }
+
     /*!
      * \brief containsViewProvider
      * Checks if the given view provider is part of this view. The default implementation