To fix warnings:
/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/bits/shared_ptr_base.h:588:8: warning: delete called on non-final 'NifOsg::ControllerFunction' that has virtual functions but non-virtual destructor
[-Wdelete-non-virtual-dtor]
delete __p;
^
/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/bits/shared_ptr_base.h:595:4: note: in instantiation of function template specialization
'std::__shared_count<__gnu_cxx::_S_atomic>::__shared_count<NifOsg::ControllerFunction *>' requested here
: __shared_count(__p)
^
/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/bits/shared_ptr_base.h:1079:17: note: in instantiation of function template specialization
'std::__shared_count<__gnu_cxx::_S_atomic>::__shared_count<NifOsg::ControllerFunction *>' requested here
: _M_ptr(__p), _M_refcount(__p, typename is_array<_Tp>::type())
^
/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/bits/shared_ptr.h:129:25: note: in instantiation of function template specialization 'std::__shared_ptr<NifOsg::ControllerFunction,
__gnu_cxx::_S_atomic>::__shared_ptr<NifOsg::ControllerFunction, void>' requested here
shared_ptr(_Yp* __p) : __shared_ptr<_Tp>(__p) { }
^
/home/elsid/dev/openmw/components/nifosg/nifloader.cpp:242:39: note: in instantiation of function template specialization 'std::shared_ptr<NifOsg::ControllerFunction>::shared_ptr<NifOsg::ControllerFunction, void>' requested here
callback->setFunction(std::shared_ptr<NifOsg::ControllerFunction>(new NifOsg::ControllerFunction(key)));
^
/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/bits/unique_ptr.h:78:2: warning: delete called on non-final 'MWGui::ResponseCallback' that has virtual functions but non-virtual destructor
[-Wdelete-non-virtual-dtor]
delete __ptr;
^
/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.3.1/../../../../include/c++/7.3.1/bits/unique_ptr.h:268:4: note: in instantiation of member function 'std::default_delete<MWGui::ResponseCallback>::operator()' requested here
get_deleter()(__ptr);
^
/home/elsid/dev/openmw/apps/openmw/mwgui/dialogue.cpp:58:23: note: in instantiation of member function 'std::unique_ptr<MWGui::ResponseCallback, std::default_delete<MWGui::ResponseCallback> >::~unique_ptr' requested here
PersuasionDialog::PersuasionDialog(ResponseCallback* callback)
^
Seems to be closer to how MW is storing it (it has the complete FACT record in the savegame, actually).
This (somewhat) breaks OMW savegame compatibility in that old changes are discarded, but I don't think the faction reactions are quest relevant anywhere.
The progress is not particularly accurate. It simply uses the current / total number of records written/read as indication. Cell records are currently the largest by far, but there is a good chance that could be optimized using a change tracking system.