Fix BufferView repeating last line for the remainder of the view

src/core/BufferView.cc

@@ -88,7 +88,8 @@ void BufferView::update()
         ld.line = std::make_shared<Buffer::Iterator>(*line_iterator);
         m_lines.push_back(ld);
         row_offset += ld.n_rows;
-        line_iterator->go_next_line();
+        if (!line_iterator->go_next_line())
+            break;
     }
 
     /* Reset some fields if buffer becomes empty. */