Fixes for the General tab

[themighty1]

Fixes the following things in the General tab:

• prevent the viewport from scrolling after the view was refreshed
• restore the selected row after the view was refreshed
• allow to scroll the viewport using Up,Down keys

This does not fix the currently observed erratic behaviour of the scrollbar when scrolling to the bottom of the view.

[gustavo-iniguez-goya]

ok, this is good. When using the up and down keys works perfect, but when using the mouse to scroll up and down it behaves a little bit weird. It goes back constantly to the last selected row, which is correct, but it's a bit annoying. There should be a way to unselect the row so the original behavior is restored.

Maybe we could add a contextual menu when clicking on a row with the text "monitor" or "follow". Or add a button like wireshark has to "lock" the view or move freely.

All in all I like how the viewport is locked to a list of rows.

Regarding #model.rowCount() returns a maximum of 256, probably a qt bug, using a workaround:, you can check if there're more rows to fetch:

if view.model().canFetchMore():
    view.model().fetchMore()

[themighty1]

Thanks for the input.

while view.model().canFetchMore():
     view.model().fetchMore() 

did the trick. I can fill the whole view with the data, so that when I scrolled to the bottom of the view, there's no more scrollbar jumping.

However ~ every 1 minute we need to make an extra fetchMore() call because the db grows. An extra fetchMore() call takes 0.5 ms. After 24 hours of running we'll have ~1 sec delay in refreshing the view. This is not sustainable.

The problem with QSqlQueryModel is that there is no way to cache the previous query's result and only add new data to the model. Each time there is new data in the db, we have to perform a full-blown query with fetchMore().

Unless there is something that I have overlooked with QSqlQueryModel, I could implement a custom QStandardItemModel which internally uses QSqlQuery to get the most recent 256 entries (no need to fetchMore()) and adds the new entries to the model.

[gustavo-iniguez-goya]

Unless there is something that I have overlooked with QSqlQueryModel, I could implement a custom QStandardItemModel which internally uses QSqlQuery to get the most recent 256 entries (no need to fetchMore()) and adds the new entries to the model.

ok, that's fine for me.

[themighty1]

Closing this in favor of https://github.com/evilsocket/opensnitch/pull/306