Revision Map::getImageLayers( ImageLayerVector& out_list ) const { out_list.reserve( _imageLayers.size() ); Threading::ScopedReadLock lock( const_cast<Map*>(this)->_mapDataMutex ); for( ImageLayerVector::const_iterator i = _imageLayers.begin(); i != _imageLayers.end(); ++i ) out_list.push_back( i->get() ); return _dataModelRevision; }